Repository: Iwasawafag/node-potrace
Branch: master
Commit: b86608eaf3b9
Files: 20
Total size: 119.4 KB
Directory structure:
gitextract_jxybqwmb/
├── .editorconfig
├── .gitignore
├── .npmignore
├── .travis.yml
├── LICENSE
├── README.md
├── lib/
│ ├── Posterizer.js
│ ├── Potrace.js
│ ├── index.js
│ ├── types/
│ │ ├── Bitmap.js
│ │ ├── Curve.js
│ │ ├── Histogram.js
│ │ ├── Opti.js
│ │ ├── Path.js
│ │ ├── Point.js
│ │ ├── Quad.js
│ │ └── Sum.js
│ └── utils.js
├── package.json
└── test/
└── test.js
================================================
FILE CONTENTS
================================================
================================================
FILE: .editorconfig
================================================
root = true
[*]
end_of_line = lf
insert_final_newline = false
indent_style = space
indent_size = 2
================================================
FILE: .gitignore
================================================
# Logs
logs
*.log
npm-debug.log*
# Runtime data
pids
*.pid
*.seed
# Directory for instrumented libs generated by jscoverage/JSCover
lib-cov
# Coverage directory used by tools like istanbul
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# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
.grunt
# node-waf configuration
.lock-wscript
# Compiled binary addons (http://nodejs.org/api/addons.html)
build/Release
# Dependency directory
node_modules
# Optional npm cache directory
.npm
# Optional REPL history
.node_repl_history
# JetBrains IDEs
.idea
# Test case output
test/output*.svg
================================================
FILE: .npmignore
================================================
# Logs
logs
*.log
npm-debug.log*
# Runtime data
pids
*.pid
*.seed
# Directory for instrumented libs generated by jscoverage/JSCover
lib-cov
# Coverage directory used by tools like istanbul
coverage
# nyc test coverage
.nyc_output
# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
.grunt
# node-waf configuration
.lock-wscript
# Compiled binary addons (http://nodejs.org/api/addons.html)
build/Release
# IDE files
.project
.idea
*.iml
# Test directory
test/
================================================
FILE: .travis.yml
================================================
language: node_js
node_js:
- "0.12"
- "4"
- "6"
sudo: false
================================================
FILE: LICENSE
================================================
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================================================
FILE: README.md
================================================
# node-potrace
A NodeJS-compatible fork of [Potrace in JavaScript][potrace-by-kilobtye] with some additions, which is in turn a port of [the original Potrace][potrace] — a tool for tracing bitmaps.
## Example and demo
| **Original image** | **Potrace output** | **Posterized output** |
|---------------------------|------------------------------|-----------------------------------------|
|  |  |  |
(Example image inherited from [online demo of the browser version][potrace-js-demo])
## Usage
Install
```sh
npm install potrace
```
Basic usage
```js
var potrace = require('potrace'),
fs = require('fs');
potrace.trace('./path/to/image.png', function(err, svg) {
if (err) throw err;
fs.writeFileSync('./output.svg', svg);
});
```
You can also provide a configuration object as a second argument.
```js
var params = {
background: '#49ffd2',
color: 'blue',
threshold: 120
};
potrace.trace('./path/to/image.png', params, function(err, svg) {
/*...*/
});
```
If you want to run Potrace algorithm multiple times on the same image with different threshold setting and merge results together in a single file - `posterize` method does exactly that.
```js
potrace.posterize('./path/to/image.png', { threshold: 180, steps: 4 }, function(err, svg) {
/*...*/
});
// or if you know exactly where you want to break it on different levels
potrace.posterize('./path/to/image.png', { steps: [40, 85, 135, 180] }, function(err, svg) {
/*...*/
});
```
### Advanced usage and configuration
Both `trace` and `posterize` methods return instances of `Potrace` and `Posterizer` classes respectively to a callback function as third argument.
You can also instantiate these classes directly:
```js
var potrace = require('potrace');
// Tracing
var trace = new potrace.Potrace();
// You can also pass configuration object to the constructor
trace.setParameters({
threshold: 128,
color: '#880000'
});
trace.loadImage('path/to/image.png', function(err) {
if (err) throw err;
trace.getSVG(); // returns SVG document contents
trace.getPathTag(); // will return just <path> tag
trace.getSymbol('traced-image'); // will return <symbol> tag with given ID
});
// Posterization
var posterizer = new potrace.Posterize();
posterizer.loadImage('path/to/image.png', function(err) {
if (err) throw err;
posterizer.setParameter({
color: '#ccc',
background: '#222',
steps: 3,
threshold: 200,
fillStrategy: potrace.Posterize.FILL_MEAN
});
posterizer.getSVG();
// or
posterizer.getSymbol('posterized-image');
});
```
Callback function provided to `loadImage` methods will be executed in context of the `Potrace`/`Posterizer` instance, so if it doesn't go against your code style - you can just do
```js
new potrace.Potrace()
.loadImage('path/to/image.bmp', function() {
if (err) throw err;
this.getSymbol('foo');
});
```
[Jimp module][jimp] is used on the back end, so first argument accepted by `loadImage` method could be anything Jimp can read: a `Buffer`, local path or a url string. Supported formats are: PNG, JPEG or BMP. It also could be a Jimp instance (provided bitmap is not modified)
### Parameters
`Potrace` class expects following parameters:
- **turnPolicy** - how to resolve ambiguities in path decomposition. Possible values are exported as constants: `TURNPOLICY_BLACK`, `TURNPOLICY_WHITE`, `TURNPOLICY_LEFT`, `TURNPOLICY_RIGHT`, `TURNPOLICY_MINORITY`, `TURNPOLICY_MAJORITY`. Refer to [this document][potrace-algorithm] for more information (page 4)
(default: `TURNPOLICY_MINORITY`)
- **turdSize** - suppress speckles of up to this size
(default: 2)
- **alphaMax** - corner threshold parameter
(default: 1)
- **optCurve** - curve optimization
(default: true)
- **optTolerance** - curve optimization tolerance
(default: 0.2)
- **threshold** - threshold below which color is considered black.
Should be a number in range 0..255 or `THRESHOLD_AUTO` in which case threshold will be selected automatically using [Algorithm For Multilevel Thresholding][multilevel-thresholding]
(default: `THRESHOLD_AUTO`)
- **blackOnWhite** - specifies colors by which side from threshold should be turned into vector shape
(default: `true`)
- **color** - Fill color. Will be ignored when exporting as \<symbol\>. (default: `COLOR_AUTO`, which means black or white, depending on `blackOnWhite` property)
- **background** - Background color. Will be ignored when exporting as \<symbol\>. By default is not present (`COLOR_TRANSPARENT`)
---------------
`Posterizer` class has same methods as `Potrace`, in exception of `.getPathTag()`.
Configuration object is extended with following properties:
- **fillStrategy** - determines how fill color for each layer should be selected. Possible values are exported as constants:
- `FILL_DOMINANT` - most frequent color in range (used by default),
- `FILL_MEAN` - arithmetic mean (average),
- `FILL_MEDIAN` - median color,
- `FILL_SPREAD` - ignores color information of the image and just spreads colors equally in range 0..\<threshold\> (or \<threshold\>..255 if `blackOnWhite` is set to `false`),
- **rangeDistribution** - how color stops for each layer should be selected. Ignored if `steps` is an array. Possible values are:
- `RANGES_AUTO` - Performs automatic thresholding (using [Algorithm For Multilevel Thresholding][multilevel-thresholding]). Preferable method for already posterized sources, but takes long time to calculate 5 or more thresholds (exponential time complexity)
*(used by default)*
- `RANGES_EQUAL` - Ignores color information of the image and breaks available color space into equal chunks
- **steps** - Specifies desired number of layers in resulting image. If a number provided - thresholds for each layer will be automatically calculated according to `rangeDistribution` parameter. If an array provided it expected to be an array with precomputed thresholds for each layer (in range 0..255)
(default: `STEPS_AUTO` which will result in `3` or `4`, depending on `threshold` value)
- **threshold** - Breaks image into foreground and background (and only foreground being broken into desired number of layers). Basically when provided it becomes a threshold for last (least opaque) layer and then `steps - 1` intermediate thresholds calculated. If **steps** is an array of thresholds and every value from the array is lower (or larger if **blackOnWhite** parameter set to `false`) than threshold - threshold will be added to the array, otherwise just ignored.
(default: `Potrace.THRESHOLD_AUTO`)
- *all other parameters that Potrace class accepts*
**Notes:**
- When number of `steps` is greater than 10 - an extra layer could be added to ensure presence of darkest/brightest colors if needed to ensure presence of probably-important-at-this-point details like shadows or line art.
- With big number of layers produced image will be looking brighter overall than original due to math error at the rendering phase because of how layers are composited.
- With default configuration `steps`, `threshold` and `rangeDistribution` settings all set to auto, resulting in a 4 thresholds/color stops being calculated with Multilevel Thresholding algorithm mentioned above. Calculation of 4 thresholds takes 3-5 seconds on average laptop. You may want to explicitly limit number of `steps` to 3 to moderately improve processing speed.
## Thanks to
- Peter Selinger for [original Potrace tool and algorithm][potrace]
- @kilobtye for original [javascript port][potrace-by-kilobtye]
## License
The GNU General Public License version 2 (GPLv2). Please see [License File](LICENSE) for more information.
[potrace]: http://potrace.sourceforge.net/
[potrace-algorithm]: http://potrace.sourceforge.net/potrace.pdf
[multilevel-thresholding]: http://www.iis.sinica.edu.tw/page/jise/2001/200109_01.pdf
[potrace-by-kilobtye]: https://github.com/kilobtye/potrace
[potrace-js-demo]: http://kilobtye.github.io/potrace/
[jimp]: https://github.com/oliver-moran/jimp
================================================
FILE: lib/Posterizer.js
================================================
'use strict';
var Potrace = require('./Potrace');
var utils = require('./utils');
/**
* Takes multiple samples using {@link Potrace} with different threshold
* settings and combines output into a single file.
*
* @param {Posterizer~Options} [options]
* @constructor
*/
function Posterizer(options) {
this._potrace = new Potrace();
this._calculatedThreshold = null;
this._params = {
threshold: Potrace.THRESHOLD_AUTO,
blackOnWhite: true,
steps: Posterizer.STEPS_AUTO,
background: Potrace.COLOR_TRANSPARENT,
fillStrategy: Posterizer.FILL_DOMINANT,
rangeDistribution: Posterizer.RANGES_AUTO
};
if (options) {
this.setParameters(options);
}
}
// Inherit constants from Potrace class
for (var key in Potrace) {
if (Object.prototype.hasOwnProperty.call(Potrace, key) && key === key.toUpperCase()) {
Posterizer[key] = Potrace[key];
}
}
Posterizer.STEPS_AUTO = -1;
Posterizer.FILL_SPREAD = 'spread';
Posterizer.FILL_DOMINANT = 'dominant';
Posterizer.FILL_MEDIAN = 'median';
Posterizer.FILL_MEAN = 'mean';
Posterizer.RANGES_AUTO = 'auto';
Posterizer.RANGES_EQUAL = 'equal';
Posterizer.prototype = {
/**
* Fine tuning to color ranges.
*
* If last range (featuring most saturated color) is larger than 10% of color space (25 units)
* then we want to add another color stop, that hopefully will include darkest pixels, improving presence of
* shadows and line art
*
* @param ranges
* @private
*/
_addExtraColorStop: function(ranges) {
var blackOnWhite = this._params.blackOnWhite;
var lastColorStop = ranges[ranges.length - 1];
var lastRangeFrom = blackOnWhite ? 0 : lastColorStop.value;
var lastRangeTo = blackOnWhite ? lastColorStop.value : 255;
if (lastRangeTo - lastRangeFrom > 25 && lastColorStop.colorIntensity !== 1) {
var histogram = this._getImageHistogram();
var levels = histogram.getStats(lastRangeFrom, lastRangeTo).levels;
var newColorStop = levels.mean + levels.stdDev <= 25 ? levels.mean + levels.stdDev
: levels.mean - levels.stdDev <= 25 ? levels.mean - levels.stdDev
: 25;
var newStats = (blackOnWhite ? histogram.getStats(0, newColorStop) : histogram.getStats(newColorStop, 255));
var color = newStats.levels.mean;
ranges.push({
value: Math.abs((blackOnWhite ? 0 : 255) - newColorStop),
colorIntensity: isNaN(color) ? 0 : ((blackOnWhite ? 255 - color : color) / 255)
});
}
return ranges;
},
/**
* Calculates color intensity for each element of numeric array
*
* @param {number[]} colorStops
* @returns {{ levels: number, colorIntensity: number }[]}
* @private
*/
_calcColorIntensity: function(colorStops) {
var blackOnWhite = this._params.blackOnWhite;
var colorSelectionStrat = this._params.fillStrategy;
var histogram = colorSelectionStrat !== Posterizer.FILL_SPREAD ? this._getImageHistogram() : null;
var fullRange = Math.abs(this._paramThreshold() - (blackOnWhite ? 0 : 255));
return colorStops.map(function(threshold, index) {
var nextValue = index + 1 === colorStops.length ? (blackOnWhite ? -1 : 256) : colorStops[index + 1];
var rangeStart = Math.round(blackOnWhite ? nextValue + 1 : threshold);
var rangeEnd = Math.round(blackOnWhite ? threshold : nextValue - 1);
var factor = index / (colorStops.length - 1);
var intervalSize = rangeEnd - rangeStart;
var stats = histogram.getStats(rangeStart, rangeEnd);
var color = -1;
if (stats.pixels === 0) {
return {
value: threshold,
colorIntensity: 0
};
}
switch (colorSelectionStrat) {
case Posterizer.FILL_SPREAD:
// We want it to be 0 (255 when white on black) at the most saturated end, so...
color = (blackOnWhite ? rangeStart : rangeEnd)
+ (blackOnWhite ? 1 : -1) * intervalSize * Math.max(0.5, fullRange / 255) * factor;
break;
case Posterizer.FILL_DOMINANT:
color = histogram.getDominantColor(rangeStart, rangeEnd, utils.clamp(intervalSize, 1, 5));
break;
case Posterizer.FILL_MEAN:
color = stats.levels.mean;
break;
case Posterizer.FILL_MEDIAN:
color = stats.levels.median;
break;
}
// We don't want colors to be too close to each other, so we introduce some spacing in between
if (index !== 0) {
color = blackOnWhite
? utils.clamp(color, rangeStart, rangeEnd - Math.round(intervalSize * 0.1))
: utils.clamp(color, rangeStart + Math.round(intervalSize * 0.1), rangeEnd);
}
return {
value: threshold,
colorIntensity: color === -1 ? 0 : ((blackOnWhite ? 255 - color : color) / 255)
};
});
},
/**
* @returns {Histogram}
* @private
*/
_getImageHistogram: function() {
return this._potrace._luminanceData.histogram();
},
/**
* Processes threshold, steps and rangeDistribution parameters and returns normalized array of color stops
* @returns {*}
* @private
*/
_getRanges: function() {
var steps = this._paramSteps();
if (!Array.isArray(steps)) {
return this._params.rangeDistribution === Posterizer.RANGES_AUTO
? this._getRangesAuto()
: this._getRangesEquallyDistributed();
}
// Steps is array of thresholds and we want to preprocess it
var colorStops = [];
var threshold = this._paramThreshold();
var lookingForDarkPixels = this._params.blackOnWhite;
steps.forEach(function(item) {
if (colorStops.indexOf(item) === -1 && utils.between(item, 0, 255)) {
colorStops.push(item);
}
});
if (!colorStops.length) {
colorStops.push(threshold);
}
colorStops = colorStops.sort(function (a, b) {
return a < b === lookingForDarkPixels ? 1 : -1;
});
if (lookingForDarkPixels && colorStops[0] < threshold) {
colorStops.unshift(threshold);
} else if (!lookingForDarkPixels && colorStops[colorStops.length - 1] < threshold) {
colorStops.push(threshold);
}
return this._calcColorIntensity(colorStops);
},
/**
* Calculates given (or lower) number of thresholds using automatic thresholding algorithm
* @returns {*}
* @private
*/
_getRangesAuto: function() {
var histogram = this._getImageHistogram();
var steps = this._paramSteps(true);
var colorStops;
if (this._params.threshold === Potrace.THRESHOLD_AUTO) {
colorStops = histogram.multilevelThresholding(steps);
} else {
var threshold = this._paramThreshold();
colorStops = this._params.blackOnWhite
? histogram.multilevelThresholding(steps - 1, 0, threshold)
: histogram.multilevelThresholding(steps - 1, threshold, 255);
if (this._params.blackOnWhite) {
colorStops.push(threshold);
} else {
colorStops.unshift(threshold);
}
}
if (this._params.blackOnWhite) {
colorStops = colorStops.reverse();
}
return this._calcColorIntensity(colorStops);
},
/**
* Calculates color stops and color representing each segment, returning them
* from least to most intense color (black or white, depending on blackOnWhite parameter)
*
* @private
*/
_getRangesEquallyDistributed: function() {
var blackOnWhite = this._params.blackOnWhite;
var colorsToThreshold = blackOnWhite ? this._paramThreshold() : 255 - this._paramThreshold();
var steps = this._paramSteps();
var stepSize = colorsToThreshold / steps;
var colorStops = [];
var i = steps - 1,
factor,
threshold;
while (i >= 0) {
factor = i / (steps - 1);
threshold = Math.min(colorsToThreshold, (i + 1) * stepSize);
threshold = blackOnWhite ? threshold : 255 - threshold;
i--;
colorStops.push(threshold);
}
return this._calcColorIntensity(colorStops);
},
/**
* Returns valid steps value
* @param {Boolean} [count=false]
* @returns {number|number[]}
* @private
*/
_paramSteps: function(count) {
var steps = this._params.steps;
if (Array.isArray(steps)) {
return count ? steps.length : steps;
}
if (steps === Posterizer.STEPS_AUTO && this._params.threshold === Potrace.THRESHOLD_AUTO) {
return 4;
}
var blackOnWhite = this._params.blackOnWhite;
var colorsCount = blackOnWhite ? this._paramThreshold() : 255 - this._paramThreshold();
return steps === Posterizer.STEPS_AUTO
? (colorsCount > 200 ? 4 : 3)
: Math.min(colorsCount, Math.max(2, steps));
},
/**
* Returns valid threshold value
* @returns {number}
* @private
*/
_paramThreshold: function() {
if (this._calculatedThreshold !== null) {
return this._calculatedThreshold;
}
if (this._params.threshold !== Potrace.THRESHOLD_AUTO) {
this._calculatedThreshold = this._params.threshold;
return this._calculatedThreshold;
}
var twoThresholds = this._getImageHistogram().multilevelThresholding(2);
this._calculatedThreshold = this._params.blackOnWhite ? twoThresholds[1] : twoThresholds[0];
this._calculatedThreshold = this._calculatedThreshold || 128;
return this._calculatedThreshold;
},
/**
* Running potrace on the image multiple times with different thresholds and returns an array
* of path tags
*
* @param {Boolean} [noFillColor]
* @returns {string[]}
* @private
*/
_pathTags: function(noFillColor) {
var ranges = this._getRanges();
var potrace = this._potrace;
var blackOnWhite = this._params.blackOnWhite;
if (ranges.length >= 10) {
ranges = this._addExtraColorStop(ranges);
}
potrace.setParameters({ blackOnWhite: blackOnWhite });
var actualPrevLayersOpacity = 0;
return ranges.map(function(colorStop) {
var thisLayerOpacity = colorStop.colorIntensity;
if (thisLayerOpacity === 0) {
return '';
}
// NOTE: With big number of layers (something like 70) there will be noticeable math error on rendering side.
// In Chromium at least image will end up looking brighter overall compared to the same layers painted in solid colors.
// However it works fine with sane number of layers, and it's not like we can do much about it.
var calculatedOpacity = (!actualPrevLayersOpacity || thisLayerOpacity === 1)
? thisLayerOpacity
: ((actualPrevLayersOpacity - thisLayerOpacity) / (actualPrevLayersOpacity - 1));
calculatedOpacity = utils.clamp(parseFloat(calculatedOpacity.toFixed(3)), 0, 1);
actualPrevLayersOpacity = actualPrevLayersOpacity + (1 - actualPrevLayersOpacity) * calculatedOpacity;
potrace.setParameters({ threshold: colorStop.value });
var element = noFillColor ? potrace.getPathTag('') : potrace.getPathTag();
element = utils.setHtmlAttr(element, 'fill-opacity', calculatedOpacity.toFixed(3));
var canBeIgnored = calculatedOpacity === 0 || element.indexOf(' d=""') !== -1;
// var c = Math.round(Math.abs((blackOnWhite ? 255 : 0) - 255 * thisLayerOpacity));
// element = utils.setHtmlAttr(element, 'fill', 'rgb('+c+', '+c+', '+c+')');
// element = utils.setHtmlAttr(element, 'fill-opacity', '');
return canBeIgnored ? '' : element;
});
},
/**
* Loads image.
*
* @param {string|Buffer|Jimp} target Image source. Could be anything that {@link Jimp} can read (buffer, local path or url). Supported formats are: PNG, JPEG or BMP
* @param {Function} callback
*/
loadImage: function(target, callback) {
var self = this;
this._potrace.loadImage(target, function(err) {
self._calculatedThreshold = null;
callback.call(self, err);
});
},
/**
* Sets parameters. Accepts same object as {Potrace}
*
* @param {Posterizer~Options} params
*/
setParameters: function(params) {
if (!params) {
return;
}
this._potrace.setParameters(params);
if (params.steps && !Array.isArray(params.steps) && (!utils.isNumber(params.steps) || !utils.between(params.steps, 1, 255))) {
throw new Error('Bad \'steps\' value');
}
for (var key in this._params) {
if (this._params.hasOwnProperty(key) && params.hasOwnProperty(key)) {
this._params[key] = params[key];
}
}
this._calculatedThreshold = null;
},
/**
* Returns image as <symbol> tag. Always has viewBox specified
*
* @param {string} id
*/
getSymbol: function(id) {
var width = this._potrace._luminanceData.width;
var height = this._potrace._luminanceData.height;
var paths = this._pathTags(true);
return '<symbol viewBox="0 0 ' + width + ' ' + height + '" id="' + id + '">' +
paths.join('') +
'</symbol>';
},
/**
* Generates SVG image
* @returns {String}
*/
getSVG: function() {
var width = this._potrace._luminanceData.width,
height = this._potrace._luminanceData.height;
var tags = this._pathTags(false);
var svg = '<svg xmlns="http://www.w3.org/2000/svg" ' +
'width="' + width + '" ' +
'height="' + height + '" ' +
'viewBox="0 0 ' + width + ' ' + height + '" ' +
'version="1.1">\n\t' +
(this._params.background !== Potrace.COLOR_TRANSPARENT
? '<rect x="0" y="0" width="100%" height="100%" fill="' + this._params.background + '" />\n\t'
: '') +
tags.join('\n\t') +
'\n</svg>';
return svg.replace(/\n(?:\t*\n)+(\t*)/g, '\n$1');
}
};
module.exports = Posterizer;
/**
* Posterizer options
*
* @typedef {Potrace~Options} Posterizer~Options
* @property {Number} [steps] - Number of samples that needs to be taken (and number of layers in SVG). (default: Posterizer.STEPS_AUTO, which most likely will result in 3, sometimes 4)
* @property {*} [fillStrategy] - How to select fill color for color ranges - equally spread or dominant. (default: Posterizer.FILL_DOMINANT)
* @property {*} [rangeDistribution] - How to choose thresholds in-between - after equal intervals or automatically balanced. (default: Posterizer.RANGES_AUTO)
*/
================================================
FILE: lib/Potrace.js
================================================
'use strict';
var Jimp = require('jimp');
var Bitmap = require('./types/Bitmap');
var Curve = require('./types/Curve');
var Point = require('./types/Point');
var Path = require('./types/Path');
var Quad = require('./types/Quad');
var Sum = require('./types/Sum');
var Opti = require('./types/Opti');
var utils = require('./utils');
/**
* Potrace class
*
* @param {Potrace~Options} [options]
* @constructor
*/
function Potrace (options) {
this._luminanceData = null;
this._pathlist = [];
this._imageLoadingIdentifier = null;
this._imageLoaded = false;
this._processed = false;
this._params = {
turnPolicy: Potrace.TURNPOLICY_MINORITY,
turdSize: 2,
alphaMax: 1,
optCurve: true,
optTolerance: 0.2,
threshold: Potrace.THRESHOLD_AUTO,
blackOnWhite: true,
color: Potrace.COLOR_AUTO,
background: Potrace.COLOR_TRANSPARENT
};
if (options) {
this.setParameters(options);
}
}
Potrace.COLOR_AUTO = 'auto';
Potrace.COLOR_TRANSPARENT = 'transparent';
Potrace.THRESHOLD_AUTO = -1;
Potrace.TURNPOLICY_BLACK = 'black';
Potrace.TURNPOLICY_WHITE = 'white';
Potrace.TURNPOLICY_LEFT = 'left';
Potrace.TURNPOLICY_RIGHT = 'right';
Potrace.TURNPOLICY_MINORITY = 'minority';
Potrace.TURNPOLICY_MAJORITY = 'majority';
var SUPPORTED_TURNPOLICY_VALUES = [
Potrace.TURNPOLICY_BLACK, Potrace.TURNPOLICY_WHITE,
Potrace.TURNPOLICY_LEFT, Potrace.TURNPOLICY_RIGHT,
Potrace.TURNPOLICY_MINORITY, Potrace.TURNPOLICY_MAJORITY
];
Potrace.prototype = {
/**
* Creating a new {@link Path} for every group of black pixels.
* @private
*/
_bmToPathlist: function() {
var self = this,
threshold = this._params.threshold,
blackOnWhite = this._params.blackOnWhite,
blackMap,
currentPoint = new Point(0, 0),
path;
if (threshold === Potrace.THRESHOLD_AUTO) {
threshold = this._luminanceData.histogram().autoThreshold() || 128;
}
blackMap = this._luminanceData.copy(function(lum) {
var pastTheThreshold = blackOnWhite
? lum > threshold
: lum < threshold;
return pastTheThreshold ? 0 : 1;
});
/**
* finds next black pixel of the image
*
* @param {Point} point
* @returns {boolean}
* @private
*/
function findNext(point) {
var i = blackMap.pointToIndex(point);
while (i < blackMap.size && blackMap.data[i] !== 1) {
i++;
}
return i < blackMap.size && blackMap.indexToPoint(i);
}
function majority(x, y) {
var i, a, ct;
for (i = 2; i < 5; i++) {
ct = 0;
for (a = -i + 1; a <= i - 1; a++) {
ct += blackMap.getValueAt(x + a, y + i - 1) ? 1 : -1;
ct += blackMap.getValueAt(x + i - 1, y + a - 1) ? 1 : -1;
ct += blackMap.getValueAt(x + a - 1, y - i) ? 1 : -1;
ct += blackMap.getValueAt(x - i, y + a) ? 1 : -1;
}
if (ct > 0) {
return 1;
} else if (ct < 0) {
return 0;
}
}
return 0;
}
function findPath(point) {
var path = new Path(),
x = point.x,
y = point.y,
dirx = 0,
diry = 1,
tmp;
path.sign = blackMap.getValueAt(point.x, point.y) ? "+" : "-";
while (1) {
path.pt.push(new Point(x, y));
if (x > path.maxX)
path.maxX = x;
if (x < path.minX)
path.minX = x;
if (y > path.maxY)
path.maxY = y;
if (y < path.minY)
path.minY = y;
path.len++;
x += dirx;
y += diry;
path.area -= x * diry;
if (x === point.x && y === point.y)
break;
var l = blackMap.getValueAt(x + (dirx + diry - 1 ) / 2, y + (diry - dirx - 1) / 2);
var r = blackMap.getValueAt(x + (dirx - diry - 1) / 2, y + (diry + dirx - 1) / 2);
if (r && !l) {
if (self._params.turnPolicy === "right" ||
(self._params.turnPolicy === "black" && path.sign === '+') ||
(self._params.turnPolicy === "white" && path.sign === '-') ||
(self._params.turnPolicy === "majority" && majority(x, y)) ||
(self._params.turnPolicy === "minority" && !majority(x, y))) {
tmp = dirx;
dirx = -diry;
diry = tmp;
} else {
tmp = dirx;
dirx = diry;
diry = -tmp;
}
} else if (r) {
tmp = dirx;
dirx = -diry;
diry = tmp;
} else if (!l) {
tmp = dirx;
dirx = diry;
diry = -tmp;
}
}
return path;
}
function xorPath(path){
var y1 = path.pt[0].y,
len = path.len,
x, y, maxX, minY, i, j,
indx;
for (i = 1; i < len; i++) {
x = path.pt[i].x;
y = path.pt[i].y;
if (y !== y1) {
minY = y1 < y ? y1 : y;
maxX = path.maxX;
for (j = x; j < maxX; j++) {
indx = blackMap.pointToIndex(j, minY);
blackMap.data[indx] = blackMap.data[indx] ? 0 : 1;
}
y1 = y;
}
}
}
// Clear path list
this._pathlist = [];
while (currentPoint = findNext(currentPoint)) {
path = findPath(currentPoint);
xorPath(path);
if (path.area > self._params.turdSize) {
this._pathlist.push(path);
}
}
},
/**
* Processes path list created by _bmToPathlist method creating and optimizing {@link Curve}'s
* @private
*/
_processPath: function() {
var self = this;
function calcSums(path) {
var i, x, y;
path.x0 = path.pt[0].x;
path.y0 = path.pt[0].y;
path.sums = [];
var s = path.sums;
s.push(new Sum(0, 0, 0, 0, 0));
for(i = 0; i < path.len; i++){
x = path.pt[i].x - path.x0;
y = path.pt[i].y - path.y0;
s.push(new Sum(s[i].x + x, s[i].y + y, s[i].xy + x * y,
s[i].x2 + x * x, s[i].y2 + y * y));
}
}
function calcLon(path) {
var n = path.len,
pt = path.pt,
dir,
pivk = new Array(n),
nc = new Array(n),
ct = new Array(4);
path.lon = new Array(n);
var constraint = [new Point(), new Point()],
cur = new Point(),
off = new Point(),
dk = new Point(),
foundk;
var i, j, k1, a, b, c, d, k = 0;
for(i = n - 1; i >= 0; i--){
if (pt[i].x != pt[k].x && pt[i].y != pt[k].y) {
k = i + 1;
}
nc[i] = k;
}
for (i = n - 1; i >= 0; i--) {
ct[0] = ct[1] = ct[2] = ct[3] = 0;
dir = (3 + 3 * (pt[utils.mod(i + 1, n)].x - pt[i].x) +
(pt[utils.mod(i + 1, n)].y - pt[i].y)) / 2;
ct[dir]++;
constraint[0].x = 0;
constraint[0].y = 0;
constraint[1].x = 0;
constraint[1].y = 0;
k = nc[i];
k1 = i;
while (1) {
foundk = 0;
dir = (3 + 3 * utils.sign(pt[k].x - pt[k1].x) +
utils.sign(pt[k].y - pt[k1].y)) / 2;
ct[dir]++;
if (ct[0] && ct[1] && ct[2] && ct[3]) {
pivk[i] = k1;
foundk = 1;
break;
}
cur.x = pt[k].x - pt[i].x;
cur.y = pt[k].y - pt[i].y;
if (utils.xprod(constraint[0], cur) < 0 || utils.xprod(constraint[1], cur) > 0) {
break;
}
if (Math.abs(cur.x) <= 1 && Math.abs(cur.y) <= 1) {
} else {
off.x = cur.x + ((cur.y >= 0 && (cur.y > 0 || cur.x < 0)) ? 1 : -1);
off.y = cur.y + ((cur.x <= 0 && (cur.x < 0 || cur.y < 0)) ? 1 : -1);
if (utils.xprod(constraint[0], off) >= 0) {
constraint[0].x = off.x;
constraint[0].y = off.y;
}
off.x = cur.x + ((cur.y <= 0 && (cur.y < 0 || cur.x < 0)) ? 1 : -1);
off.y = cur.y + ((cur.x >= 0 && (cur.x > 0 || cur.y < 0)) ? 1 : -1);
if (utils.xprod(constraint[1], off) <= 0) {
constraint[1].x = off.x;
constraint[1].y = off.y;
}
}
k1 = k;
k = nc[k1];
if (!utils.cyclic(k, i, k1)) {
break;
}
}
if (foundk === 0) {
dk.x = utils.sign(pt[k].x-pt[k1].x);
dk.y = utils.sign(pt[k].y-pt[k1].y);
cur.x = pt[k1].x - pt[i].x;
cur.y = pt[k1].y - pt[i].y;
a = utils.xprod(constraint[0], cur);
b = utils.xprod(constraint[0], dk);
c = utils.xprod(constraint[1], cur);
d = utils.xprod(constraint[1], dk);
j = 10000000;
if (b < 0) {
j = Math.floor(a / -b);
}
if (d > 0) {
j = Math.min(j, Math.floor(-c / d));
}
pivk[i] = utils.mod(k1+j,n);
}
}
j=pivk[n-1];
path.lon[n-1]=j;
for (i=n-2; i>=0; i--) {
if (utils.cyclic(i+1,pivk[i],j)) {
j=pivk[i];
}
path.lon[i]=j;
}
for (i=n-1; utils.cyclic(utils.mod(i+1,n),j,path.lon[i]); i--) {
path.lon[i] = j;
}
}
function bestPolygon(path) {
function penalty3(path, i, j) {
var n = path.len, pt = path.pt, sums = path.sums;
var x, y, xy, x2, y2,
k, a, b, c, s,
px, py, ex, ey,
r = 0;
if (j>=n) {
j -= n;
r = 1;
}
if (r === 0) {
x = sums[j+1].x - sums[i].x;
y = sums[j+1].y - sums[i].y;
x2 = sums[j+1].x2 - sums[i].x2;
xy = sums[j+1].xy - sums[i].xy;
y2 = sums[j+1].y2 - sums[i].y2;
k = j+1 - i;
} else {
x = sums[j+1].x - sums[i].x + sums[n].x;
y = sums[j+1].y - sums[i].y + sums[n].y;
x2 = sums[j+1].x2 - sums[i].x2 + sums[n].x2;
xy = sums[j+1].xy - sums[i].xy + sums[n].xy;
y2 = sums[j+1].y2 - sums[i].y2 + sums[n].y2;
k = j+1 - i + n;
}
px = (pt[i].x + pt[j].x) / 2.0 - pt[0].x;
py = (pt[i].y + pt[j].y) / 2.0 - pt[0].y;
ey = (pt[j].x - pt[i].x);
ex = -(pt[j].y - pt[i].y);
a = ((x2 - 2*x*px) / k + px*px);
b = ((xy - x*py - y*px) / k + px*py);
c = ((y2 - 2*y*py) / k + py*py);
s = ex*ex*a + 2*ex*ey*b + ey*ey*c;
return Math.sqrt(s);
}
var i, j, m, k,
n = path.len,
pen = new Array(n + 1),
prev = new Array(n + 1),
clip0 = new Array(n),
clip1 = new Array(n + 1),
seg0 = new Array (n + 1),
seg1 = new Array(n + 1),
thispen, best, c;
for (i=0; i<n; i++) {
c = utils.mod(path.lon[utils.mod(i-1,n)]-1,n);
if (c == i) {
c = utils.mod(i+1,n);
}
if (c < i) {
clip0[i] = n;
} else {
clip0[i] = c;
}
}
j = 1;
for (i=0; i<n; i++) {
while (j <= clip0[i]) {
clip1[j] = i;
j++;
}
}
i = 0;
for (j=0; i<n; j++) {
seg0[j] = i;
i = clip0[i];
}
seg0[j] = n;
m = j;
i = n;
for (j=m; j>0; j--) {
seg1[j] = i;
i = clip1[i];
}
seg1[0] = 0;
pen[0]=0;
for (j=1; j<=m; j++) {
for (i=seg1[j]; i<=seg0[j]; i++) {
best = -1;
for (k=seg0[j-1]; k>=clip1[i]; k--) {
thispen = penalty3(path, k, i) + pen[k];
if (best < 0 || thispen < best) {
prev[i] = k;
best = thispen;
}
}
pen[i] = best;
}
}
path.m = m;
path.po = new Array(m);
for (i=n, j=m-1; i>0; j--) {
i = prev[i];
path.po[j] = i;
}
}
function adjustVertices(path) {
function pointslope(path, i, j, ctr, dir) {
var n = path.len, sums = path.sums,
x, y, x2, xy, y2,
k, a, b, c, lambda2, l, r=0;
while (j>=n) {
j-=n;
r+=1;
}
while (i>=n) {
i-=n;
r-=1;
}
while (j<0) {
j+=n;
r-=1;
}
while (i<0) {
i+=n;
r+=1;
}
x = sums[j+1].x-sums[i].x+r*sums[n].x;
y = sums[j+1].y-sums[i].y+r*sums[n].y;
x2 = sums[j+1].x2-sums[i].x2+r*sums[n].x2;
xy = sums[j+1].xy-sums[i].xy+r*sums[n].xy;
y2 = sums[j+1].y2-sums[i].y2+r*sums[n].y2;
k = j+1-i+r*n;
ctr.x = x/k;
ctr.y = y/k;
a = (x2-x*x/k)/k;
b = (xy-x*y/k)/k;
c = (y2-y*y/k)/k;
lambda2 = (a+c+Math.sqrt((a-c)*(a-c)+4*b*b))/2;
a -= lambda2;
c -= lambda2;
if (Math.abs(a) >= Math.abs(c)) {
l = Math.sqrt(a*a+b*b);
if (l!==0) {
dir.x = -b/l;
dir.y = a/l;
}
} else {
l = Math.sqrt(c*c+b*b);
if (l!==0) {
dir.x = -c/l;
dir.y = b/l;
}
}
if (l===0) {
dir.x = dir.y = 0;
}
}
var m = path.m, po = path.po, n = path.len, pt = path.pt,
x0 = path.x0, y0 = path.y0,
ctr = new Array(m), dir = new Array(m),
q = new Array(m),
v = new Array(3), d, i, j, k, l,
s = new Point();
path.curve = new Curve(m);
for (i=0; i<m; i++) {
j = po[utils.mod(i+1,m)];
j = utils.mod(j-po[i],n)+po[i];
ctr[i] = new Point();
dir[i] = new Point();
pointslope(path, po[i], j, ctr[i], dir[i]);
}
for (i=0; i<m; i++) {
q[i] = new Quad();
d = dir[i].x * dir[i].x + dir[i].y * dir[i].y;
if (d === 0.0) {
for (j=0; j<3; j++) {
for (k=0; k<3; k++) {
q[i].data[j * 3 + k] = 0;
}
}
} else {
v[0] = dir[i].y;
v[1] = -dir[i].x;
v[2] = - v[1] * ctr[i].y - v[0] * ctr[i].x;
for (l=0; l<3; l++) {
for (k=0; k<3; k++) {
q[i].data[l * 3 + k] = v[l] * v[k] / d;
}
}
}
}
var Q, w, dx, dy, det, min, cand, xmin, ymin, z;
for (i=0; i<m; i++) {
Q = new Quad();
w = new Point();
s.x = pt[po[i]].x-x0;
s.y = pt[po[i]].y-y0;
j = utils.mod(i-1,m);
for (l=0; l<3; l++) {
for (k=0; k<3; k++) {
Q.data[l * 3 + k] = q[j].at(l, k) + q[i].at(l, k);
}
}
while(1) {
det = Q.at(0, 0)*Q.at(1, 1) - Q.at(0, 1)*Q.at(1, 0);
if (det !== 0.0) {
w.x = (-Q.at(0, 2)*Q.at(1, 1) + Q.at(1, 2)*Q.at(0, 1)) / det;
w.y = ( Q.at(0, 2)*Q.at(1, 0) - Q.at(1, 2)*Q.at(0, 0)) / det;
break;
}
if (Q.at(0, 0)>Q.at(1, 1)) {
v[0] = -Q.at(0, 1);
v[1] = Q.at(0, 0);
} else if (Q.at(1, 1)) {
v[0] = -Q.at(1, 1);
v[1] = Q.at(1, 0);
} else {
v[0] = 1;
v[1] = 0;
}
d = v[0] * v[0] + v[1] * v[1];
v[2] = - v[1] * s.y - v[0] * s.x;
for (l=0; l<3; l++) {
for (k=0; k<3; k++) {
Q.data[l * 3 + k] += v[l] * v[k] / d;
}
}
}
dx = Math.abs(w.x-s.x);
dy = Math.abs(w.y-s.y);
if (dx <= 0.5 && dy <= 0.5) {
path.curve.vertex[i] = new Point(w.x+x0, w.y+y0);
continue;
}
min = utils.quadform(Q, s);
xmin = s.x;
ymin = s.y;
if (Q.at(0, 0) !== 0.0) {
for (z=0; z<2; z++) {
w.y = s.y-0.5+z;
w.x = - (Q.at(0, 1) * w.y + Q.at(0, 2)) / Q.at(0, 0);
dx = Math.abs(w.x-s.x);
cand = utils.quadform(Q, w);
if (dx <= 0.5 && cand < min) {
min = cand;
xmin = w.x;
ymin = w.y;
}
}
}
if (Q.at(1, 1) !== 0.0) {
for (z=0; z<2; z++) {
w.x = s.x-0.5+z;
w.y = - (Q.at(1, 0) * w.x + Q.at(1, 2)) / Q.at(1, 1);
dy = Math.abs(w.y-s.y);
cand = utils.quadform(Q, w);
if (dy <= 0.5 && cand < min) {
min = cand;
xmin = w.x;
ymin = w.y;
}
}
}
for (l=0; l<2; l++) {
for (k=0; k<2; k++) {
w.x = s.x-0.5+l;
w.y = s.y-0.5+k;
cand = utils.quadform(Q, w);
if (cand < min) {
min = cand;
xmin = w.x;
ymin = w.y;
}
}
}
path.curve.vertex[i] = new Point(xmin + x0, ymin + y0);
}
}
function reverse(path) {
var curve = path.curve, m = curve.n, v = curve.vertex, i, j, tmp;
for (i=0, j=m-1; i<j; i++, j--) {
tmp = v[i];
v[i] = v[j];
v[j] = tmp;
}
}
function smooth(path) {
var m = path.curve.n, curve = path.curve;
var i, j, k, dd, denom, alpha,
p2, p3, p4;
for (i=0; i<m; i++) {
j = utils.mod(i+1, m);
k = utils.mod(i+2, m);
p4 = utils.interval(1/2.0, curve.vertex[k], curve.vertex[j]);
denom = utils.ddenom(curve.vertex[i], curve.vertex[k]);
if (denom !== 0.0) {
dd = utils.dpara(curve.vertex[i], curve.vertex[j], curve.vertex[k]) / denom;
dd = Math.abs(dd);
alpha = dd>1 ? (1 - 1.0/dd) : 0;
alpha = alpha / 0.75;
} else {
alpha = 4/3.0;
}
curve.alpha0[j] = alpha;
if (alpha >= self._params.alphaMax) {
curve.tag[j] = "CORNER";
curve.c[3 * j + 1] = curve.vertex[j];
curve.c[3 * j + 2] = p4;
} else {
if (alpha < 0.55) {
alpha = 0.55;
} else if (alpha > 1) {
alpha = 1;
}
p2 = utils.interval(0.5+0.5*alpha, curve.vertex[i], curve.vertex[j]);
p3 = utils.interval(0.5+0.5*alpha, curve.vertex[k], curve.vertex[j]);
curve.tag[j] = "CURVE";
curve.c[3 * j + 0] = p2;
curve.c[3 * j + 1] = p3;
curve.c[3 * j + 2] = p4;
}
curve.alpha[j] = alpha;
curve.beta[j] = 0.5;
}
curve.alphaCurve = 1;
}
function optiCurve(path) {
function opti_penalty(path, i, j, res, opttolerance, convc, areac) {
var m = path.curve.n, curve = path.curve, vertex = curve.vertex,
k, k1, k2, conv, i1,
area, alpha, d, d1, d2,
p0, p1, p2, p3, pt,
A, R, A1, A2, A3, A4,
s, t;
if (i==j) {
return 1;
}
k = i;
i1 = utils.mod(i+1, m);
k1 = utils.mod(k+1, m);
conv = convc[k1];
if (conv === 0) {
return 1;
}
d = utils.ddist(vertex[i], vertex[i1]);
for (k=k1; k!=j; k=k1) {
k1 = utils.mod(k+1, m);
k2 = utils.mod(k+2, m);
if (convc[k1] != conv) {
return 1;
}
if (utils.sign(utils.cprod(vertex[i], vertex[i1], vertex[k1], vertex[k2])) !=
conv) {
return 1;
}
if (utils.iprod1(vertex[i], vertex[i1], vertex[k1], vertex[k2]) <
d * utils.ddist(vertex[k1], vertex[k2]) * -0.999847695156) {
return 1;
}
}
p0 = curve.c[utils.mod(i,m) * 3 + 2].copy();
p1 = vertex[utils.mod(i+1,m)].copy();
p2 = vertex[utils.mod(j,m)].copy();
p3 = curve.c[utils.mod(j,m) * 3 + 2].copy();
area = areac[j] - areac[i];
area -= utils.dpara(vertex[0], curve.c[i * 3 + 2], curve.c[j * 3 + 2])/2;
if (i>=j) {
area += areac[m];
}
A1 = utils.dpara(p0, p1, p2);
A2 = utils.dpara(p0, p1, p3);
A3 = utils.dpara(p0, p2, p3);
A4 = A1+A3-A2;
if (A2 == A1) {
return 1;
}
t = A3/(A3-A4);
s = A2/(A2-A1);
A = A2 * t / 2.0;
if (A === 0.0) {
return 1;
}
R = area / A;
alpha = 2 - Math.sqrt(4 - R / 0.3);
res.c[0] = utils.interval(t * alpha, p0, p1);
res.c[1] = utils.interval(s * alpha, p3, p2);
res.alpha = alpha;
res.t = t;
res.s = s;
p1 = res.c[0].copy();
p2 = res.c[1].copy();
res.pen = 0;
for (k=utils.mod(i+1,m); k!=j; k=k1) {
k1 = utils.mod(k+1,m);
t = utils.tangent(p0, p1, p2, p3, vertex[k], vertex[k1]);
if (t<-0.5) {
return 1;
}
pt = utils.bezier(t, p0, p1, p2, p3);
d = utils.ddist(vertex[k], vertex[k1]);
if (d === 0.0) {
return 1;
}
d1 = utils.dpara(vertex[k], vertex[k1], pt) / d;
if (Math.abs(d1) > opttolerance) {
return 1;
}
if (utils.iprod(vertex[k], vertex[k1], pt) < 0 ||
utils.iprod(vertex[k1], vertex[k], pt) < 0) {
return 1;
}
res.pen += d1 * d1;
}
for (k=i; k!=j; k=k1) {
k1 = utils.mod(k+1,m);
t = utils.tangent(p0, p1, p2, p3, curve.c[k * 3 + 2], curve.c[k1 * 3 + 2]);
if (t<-0.5) {
return 1;
}
pt = utils.bezier(t, p0, p1, p2, p3);
d = utils.ddist(curve.c[k * 3 + 2], curve.c[k1 * 3 + 2]);
if (d === 0.0) {
return 1;
}
d1 = utils.dpara(curve.c[k * 3 + 2], curve.c[k1 * 3 + 2], pt) / d;
d2 = utils.dpara(curve.c[k * 3 + 2], curve.c[k1 * 3 + 2], vertex[k1]) / d;
d2 *= 0.75 * curve.alpha[k1];
if (d2 < 0) {
d1 = -d1;
d2 = -d2;
}
if (d1 < d2 - opttolerance) {
return 1;
}
if (d1 < d2) {
res.pen += (d1 - d2) * (d1 - d2);
}
}
return 0;
}
var curve = path.curve, m = curve.n, vert = curve.vertex,
pt = new Array(m + 1),
pen = new Array(m + 1),
len = new Array(m + 1),
opt = new Array(m + 1),
om, i,j,r,
o = new Opti(), p0,
i1, area, alpha, ocurve,
s, t;
var convc = new Array(m), areac = new Array(m + 1);
for (i=0; i<m; i++) {
if (curve.tag[i] == "CURVE") {
convc[i] = utils.sign(utils.dpara(vert[utils.mod(i-1,m)], vert[i], vert[utils.mod(i+1,m)]));
} else {
convc[i] = 0;
}
}
area = 0.0;
areac[0] = 0.0;
p0 = curve.vertex[0];
for (i=0; i<m; i++) {
i1 = utils.mod(i+1, m);
if (curve.tag[i1] == "CURVE") {
alpha = curve.alpha[i1];
area += 0.3 * alpha * (4-alpha) *
utils.dpara(curve.c[i * 3 + 2], vert[i1], curve.c[i1 * 3 + 2])/2;
area += utils.dpara(p0, curve.c[i * 3 + 2], curve.c[i1 * 3 + 2])/2;
}
areac[i+1] = area;
}
pt[0] = -1;
pen[0] = 0;
len[0] = 0;
for (j=1; j<=m; j++) {
pt[j] = j-1;
pen[j] = pen[j-1];
len[j] = len[j-1]+1;
for (i=j-2; i>=0; i--) {
r = opti_penalty(path, i, utils.mod(j,m), o, self._params.optTolerance, convc,
areac);
if (r) {
break;
}
if (len[j] > len[i]+1 ||
(len[j] == len[i]+1 && pen[j] > pen[i] + o.pen)) {
pt[j] = i;
pen[j] = pen[i] + o.pen;
len[j] = len[i] + 1;
opt[j] = o;
o = new Opti();
}
}
}
om = len[m];
ocurve = new Curve(om);
s = new Array(om);
t = new Array(om);
j = m;
for (i=om-1; i>=0; i--) {
if (pt[j]==j-1) {
ocurve.tag[i] = curve.tag[utils.mod(j,m)];
ocurve.c[i * 3 + 0] = curve.c[utils.mod(j,m) * 3 + 0];
ocurve.c[i * 3 + 1] = curve.c[utils.mod(j,m) * 3 + 1];
ocurve.c[i * 3 + 2] = curve.c[utils.mod(j,m) * 3 + 2];
ocurve.vertex[i] = curve.vertex[utils.mod(j,m)];
ocurve.alpha[i] = curve.alpha[utils.mod(j,m)];
ocurve.alpha0[i] = curve.alpha0[utils.mod(j,m)];
ocurve.beta[i] = curve.beta[utils.mod(j,m)];
s[i] = t[i] = 1.0;
} else {
ocurve.tag[i] = "CURVE";
ocurve.c[i * 3 + 0] = opt[j].c[0];
ocurve.c[i * 3 + 1] = opt[j].c[1];
ocurve.c[i * 3 + 2] = curve.c[utils.mod(j,m) * 3 + 2];
ocurve.vertex[i] = utils.interval(opt[j].s, curve.c[utils.mod(j,m) * 3 + 2],
vert[utils.mod(j,m)]);
ocurve.alpha[i] = opt[j].alpha;
ocurve.alpha0[i] = opt[j].alpha;
s[i] = opt[j].s;
t[i] = opt[j].t;
}
j = pt[j];
}
for (i=0; i<om; i++) {
i1 = utils.mod(i+1,om);
ocurve.beta[i] = s[i] / (s[i] + t[i1]);
}
ocurve.alphaCurve = 1;
path.curve = ocurve;
}
for (var i = 0; i < this._pathlist.length; i++) {
var path = this._pathlist[i];
calcSums(path);
calcLon(path);
bestPolygon(path);
adjustVertices(path);
if (path.sign === "-") {
reverse(path);
}
smooth(path);
if (self._params.optCurve) {
optiCurve(path);
}
}
},
/**
* Validates some of parameters
* @param params
* @private
*/
_validateParameters: function(params) {
if (params && params.turnPolicy && SUPPORTED_TURNPOLICY_VALUES.indexOf(params.turnPolicy) === -1) {
var goodVals = '\'' + SUPPORTED_TURNPOLICY_VALUES.join('\', \'') + '\'';
throw new Error('Bad turnPolicy value. Allowed values are: ' + goodVals);
}
if (params && params.threshold != null && params.threshold !== Potrace.THRESHOLD_AUTO) {
if (typeof params.threshold !== 'number' || !utils.between(params.threshold, 0, 255)) {
throw new Error('Bad threshold value. Expected to be an integer in range 0..255');
}
}
if (params && params.optCurve != null && typeof params.optCurve !== 'boolean') {
throw new Error('\'optCurve\' must be Boolean');
}
},
_processLoadedImage: function(image) {
var bitmap = new Bitmap(image.bitmap.width, image.bitmap.height);
var pixels = image.bitmap.data;
image.scan(0, 0, image.bitmap.width, image.bitmap.height, function(x, y, idx) {
// We want background underneath non-opaque regions to be white
var opacity = pixels[idx + 3] / 255,
r = 255 + (pixels[idx + 0] - 255) * opacity,
g = 255 + (pixels[idx + 1] - 255) * opacity,
b = 255 + (pixels[idx + 2] - 255) * opacity;
bitmap.data[idx/4] = utils.luminance(r, g, b);
});
this._luminanceData = bitmap;
this._imageLoaded = true;
},
/**
* Reads given image. Uses {@link Jimp} under the hood, so target can be whatever Jimp can take
*
* @param {string|Buffer|Jimp} target Image source. Could be anything that {@link Jimp} can read (buffer, local path or url). Supported formats are: PNG, JPEG or BMP
* @param {Function} callback
*/
loadImage: function(target, callback) {
var self = this;
var jobId = {};
this._imageLoadingIdentifier = jobId;
this._imageLoaded = false;
if (target instanceof Jimp) {
this._imageLoadingIdentifier = null;
this._imageLoaded = true;
self._processLoadedImage(target);
callback.call(self, null);
} else {
Jimp.read(target, function(err, img) {
var sourceChanged = self._imageLoadingIdentifier !== jobId;
if (sourceChanged) {
var error = err ? err : new Error('Another image was loaded instead');
return callback.call(self, error);
}
self._imageLoadingIdentifier = null;
self._processLoadedImage(img);
callback.call(self, null);
});
}
},
/**
* Sets algorithm parameters
* @param {Potrace~Options} newParams
*/
setParameters: function(newParams) {
var key, tmpOldVal;
this._validateParameters(newParams);
for (key in this._params) {
if (this._params.hasOwnProperty(key) && newParams.hasOwnProperty(key)) {
tmpOldVal = this._params[key];
this._params[key] = newParams[key];
if (tmpOldVal !== this._params[key] && ['color', 'background'].indexOf(key) === -1) {
this._processed = false;
}
}
}
},
/**
* Generates just <path> tag without rest of the SVG file
*
* @param {String} [fillColor] - overrides color from parameters
* @returns {String}
*/
getPathTag: function(fillColor) {
fillColor = arguments.length === 0 ? this._params.color : fillColor;
if (fillColor === Potrace.COLOR_AUTO) {
fillColor = this._params.blackOnWhite ? 'black' : 'white';
}
if (!this._imageLoaded) {
throw new Error('Image should be loaded first');
}
if (!this._processed) {
this._bmToPathlist();
this._processPath();
this._processed = true;
}
var tag = '<path d="';
this._pathlist.forEach(function(path) {
tag += utils.renderCurve(path.curve, 1);
});
tag += '" stroke="none" fill="' + fillColor + '" fill-rule="evenodd"/>';
return tag;
},
/**
* Returns <symbol> tag. Always has viewBox specified and comes with no fill color,
* so it could be changed with <use> tag
*
* @param id
* @returns {string}
*/
getSymbol: function(id) {
return '<symbol ' +
'viewBox="0 0 ' + this._luminanceData.width + ' ' + this._luminanceData.height + '" ' +
'id="' + id + '">' +
this.getPathTag('') +
'</symbol>';
},
/**
* Generates SVG image
* @returns {String}
*/
getSVG: function() {
var width = this._luminanceData.width;
var height = this._luminanceData.height;
return '<svg xmlns="http://www.w3.org/2000/svg" ' +
'width="' + width + '" ' +
'height="' + height + '" ' +
'viewBox="0 0 ' + width + ' ' + height + '" ' +
'version="1.1">\n'+
(this._params.background !== Potrace.COLOR_TRANSPARENT
? '\t<rect x="0" y="0" width="100%" height="100%" fill="' + this._params.background + '" />\n'
: '') +
'\t' + this.getPathTag(this._params.color) + '\n' +
'</svg>';
}
};
module.exports = Potrace;
/**
* Potrace options
*
* @typedef {Object} Potrace~Options
* @property {*} [turnPolicy] - how to resolve ambiguities in path decomposition (default Potrace.TURNPOLICY_MINORITY)
* @property {Number} [turdSize] - suppress speckles of up to this size (default 2)
* @property {Number} [alphaMax] - corner threshold parameter (default 1)
* @property {Boolean} [optCurve] - curve optimization (default true)
* @property {Number} [optTolerance] - curve optimization tolerance (default 0.2)
* @property {Number} [threshold] - threshold below which color is considered black (0..255, default Potrace.THRESHOLD_AUTO)
* @property {Boolean} [blackOnWhite] - specifies colors by which side from threshold should be traced (default true)
* @property {string} [color] - foreground color (default: 'auto' (black or white)) Will be ignored when exporting as <symbol>
* @property {string} [background] - background color (default: 'transparent') Will be ignored when exporting as <symbol>
*/
/**
* Jimp module
* @external Jimp
* @see https://www.npmjs.com/package/jimp
*/
================================================
FILE: lib/index.js
================================================
'use strict';
var Potrace = require('./Potrace');
var Posterizer = require('./Posterizer');
/**
* Wrapper for Potrace that simplifies use down to one function call
*
* @param {string|Buffer|Jimp} file Source image, file path or {@link Jimp} instance
* @param {Potrace~Options} [options]
* @param {traceCallback} cb Callback function. Accepts 3 arguments: error, svg content and instance of {@link Potrace} (so it could be reused with different set of parameters)
*/
function trace(file, options, cb) {
if (arguments.length === 2) {
cb = options;
options = {};
}
var potrace = new Potrace(options);
potrace.loadImage(file, function(err) {
if (err) { return cb(err); }
cb(null, potrace.getSVG(), potrace);
});
}
/**
* Wrapper for Potrace that simplifies use down to one function call
*
* @param {string|Buffer|Jimp} file Source image, file path or {@link Jimp} instance
* @param {Posterizer~Options} [options]
* @param {posterizeCallback} cb Callback function. Accepts 3 arguments: error, svg content and instance of {@link Potrace} (so it could be reused with different set of parameters)
*/
function posterize(file, options, cb) {
if (arguments.length === 2) {
cb = options;
options = {};
}
var posterizer = new Posterizer(options);
posterizer.loadImage(file, function(err) {
if (err) { return cb(err); }
cb(null, posterizer.getSVG(), posterizer);
});
}
module.exports = {
trace: trace,
posterize: posterize,
Potrace: Potrace,
Posterizer: Posterizer
};
/**
* Callback for trace method
* @callback traceCallback
* @param {Error|null} err
* @param {string} svg SVG document contents
* @param {Potrace} [instance] Potrace class instance
*/
/**
* Callback for posterize method
* @callback posterizeCallback
* @param {Error|null} err
* @param {string} svg SVG document contents
* @param {Posterizer} [instance] Posterizer class instance
*/
================================================
FILE: lib/types/Bitmap.js
================================================
'use strict';
var Point = require('./Point');
var utils = require('../utils');
var Histogram;
/**
* Represents a bitmap where each pixel can be a number in range of 0..255
* Used internally to store luminance data.
*
* @param {Number} w
* @param {Number} h
* @constructor
*/
function Bitmap(w, h) {
this._histogram = null;
this.width = w;
this.height = h;
this.size = w * h;
this.arrayBuffer = new ArrayBuffer(this.size);
this.data = new Uint8Array(this.arrayBuffer);
}
module.exports = Bitmap;
Histogram = require('./Histogram');
Bitmap.prototype = {
/**
* Returns pixel value
*
* @param {Number|Point} x - index, point or x
* @param {Number} [y]
*/
getValueAt: function(x, y) {
var index = (typeof x === 'number' && typeof y !== 'number') ? x : this.pointToIndex(x, y);
return this.data[index];
},
/**
* Converts {@link Point} to index value
*
* @param {Number} index
* @returns {Point}
*/
indexToPoint: function(index) {
var point = new Point();
if (utils.between(index, 0, this.size)) {
point.y = Math.floor(index / this.width);
point.x = index - point.y * this.width;
} else {
point.x = -1;
point.y = -1;
}
return point;
},
/**
* Calculates index for point or coordinate pair
*
* @param {Number|Point} pointOrX
* @param {Number} [y]
* @returns {Number}
*/
pointToIndex: function(pointOrX, y) {
var _x = pointOrX,
_y = y;
if (pointOrX instanceof Point) {
_x = pointOrX.x;
_y = pointOrX.y;
}
if (!utils.between(_x, 0, this.width) || !utils.between(_y, 0, this.height)) {
return -1;
}
return this.width * _y + _x;
},
/**
* Makes a copy of current bitmap
*
* @param {Function} [iterator] optional callback, used for processing pixel value. Accepted arguments: value, index
* @returns {Bitmap}
*/
copy: function(iterator) {
var bm = new Bitmap(this.width, this.height),
iteratorPresent = typeof iterator === 'function',
i;
for (i = 0; i < this.size; i++) {
bm.data[i] = iteratorPresent ? iterator(this.data[i], i) : this.data[i];
}
return bm;
},
histogram: function() {
var Histogram = require('./Histogram');
if (this._histogram) {
return this._histogram;
}
this._histogram = new Histogram(this);
return this._histogram;
}
};
================================================
FILE: lib/types/Curve.js
================================================
'use strict';
/**
* Curve type
*
* @param n
* @constructor
* @protected
*/
function Curve(n) {
this.n = n;
this.tag = new Array(n);
this.c = new Array(n * 3);
this.alphaCurve = 0;
this.vertex = new Array(n);
this.alpha = new Array(n);
this.alpha0 = new Array(n);
this.beta = new Array(n);
}
module.exports = Curve;
================================================
FILE: lib/types/Histogram.js
================================================
"use strict";
// Histogram
var utils = require('../utils');
var Jimp = null; try { Jimp = require('jimp'); } catch(e) {}
var Bitmap = require('./Bitmap');
var COLOR_DEPTH = 256;
var COLOR_RANGE_END = COLOR_DEPTH - 1;
/**
* Calculates array index for pair of indexes. We multiple column (x) by 256 and then add row to it,
* this way `(index(i, j) + 1) === index(i, j + i)` thus we can reuse `index(i, j)` we once calculated
*
* Note: this is different from how indexes calculated in {@link Bitmap} class, keep it in mind.
*
* @param x
* @param y
* @returns {*}
* @private
*/
function index(x, y) {
return COLOR_DEPTH * x + y;
}
function normalizeMinMax(levelMin, levelMax) {
/**
* Shared parameter normalization for methods 'multilevelThresholding', 'autoThreshold', 'getDominantColor' and 'getStats'
*
* @param levelMin
* @param levelMax
* @returns {number[]}
* @private
*/
levelMin = typeof levelMin === 'number' ? utils.clamp(Math.round(levelMin), 0, COLOR_RANGE_END) : 0;
levelMax = typeof levelMax === 'number' ? utils.clamp(Math.round(levelMax), 0, COLOR_RANGE_END) : COLOR_RANGE_END;
if (levelMin > levelMax) {
throw new Error('Invalid range "'+ levelMin + '...' + levelMax + '"');
}
return [levelMin, levelMax];
}
/**
* 1D Histogram
*
* @param {Number|Bitmap|Jimp} imageSource - Image to collect pixel data from. Or integer to create empty histogram for image of specific size
* @param [mode] Used only for Jimp images. {@link Bitmap} currently can only store 256 values per pixel, so it's assumed that it contains values we are looking for
* @constructor
* @protected
*/
function Histogram(imageSource, mode) {
this.data = null;
this.pixels = 0;
this._sortedIndexes = null;
this._cachedStats = {};
this._lookupTableH = null;
if (typeof imageSource === 'number') {
this._createArray(imageSource);
} else if (imageSource instanceof Bitmap) {
this._collectValuesBitmap(imageSource);
} else if (Jimp && imageSource instanceof Jimp) {
this._collectValuesJimp(imageSource, mode);
} else {
throw new Error('Unsupported image source');
}
}
Histogram.MODE_LUMINANCE = 'luminance';
Histogram.MODE_R = 'r';
Histogram.MODE_G = 'g';
Histogram.MODE_B = 'b';
Histogram.prototype = {
/**
* Initializes data array for an image of given pixel size
* @param imageSize
* @returns {Uint8Array|Uint16Array|Uint32Array}
* @private
*/
_createArray: function(imageSize) {
var ArrayType = imageSize <= Math.pow(2, 8) ? Uint8Array
: imageSize <= Math.pow(2, 16) ? Uint16Array : Uint32Array;
this.pixels = imageSize;
return this.data = new ArrayType(COLOR_DEPTH);
},
/**
* Aggregates color data from {@link Jimp} instance
* @param {Jimp} source
* @param mode
* @private
*/
_collectValuesJimp: function(source, mode) {
var pixelData = source.bitmap.data;
var data = this._createArray(source.bitmap.width * source.bitmap.height);
source.scan(0, 0, source.bitmap.width, source.bitmap.height, function(x, y, idx) {
var val = mode === Histogram.MODE_R ? pixelData[idx]
: mode === Histogram.MODE_G ? pixelData[idx + 1]
: mode === Histogram.MODE_B ? pixelData[idx + 2]
: utils.luminance(pixelData[idx], pixelData[idx + 1], pixelData[idx + 2]);
data[val]++;
});
},
/**
* Aggregates color data from {@link Bitmap} instance
* @param {Bitmap} source
* @private
*/
_collectValuesBitmap: function(source) {
var data = this._createArray(source.size);
var len = source.data.length;
var color;
for (var i = 0; i < len; i++) {
color = source.data[i];
data[color]++
}
},
/**
* Returns array of color indexes in ascending order
* @param refresh
* @returns {*}
* @private
*/
_getSortedIndexes: function(refresh) {
if (!refresh && this._sortedIndexes) {
return this._sortedIndexes;
}
var data = this.data;
var indexes = new Array(COLOR_DEPTH);
var i = 0;
for (i; i < COLOR_DEPTH; i++) {
indexes[i] = i;
}
indexes.sort(function(a, b) {
return data[a] > data[b] ? 1 : data[a] < data[b] ? -1 : 0;
});
this._sortedIndexes = indexes;
return indexes;
},
/**
* Builds lookup table H from lookup tables P and S.
* see {@link http://www.iis.sinica.edu.tw/page/jise/2001/200109_01.pdf|this paper} for more details
*
* @returns {Float64Array}
* @private
*/
_thresholdingBuildLookupTable: function() {
var P = new Float64Array(COLOR_DEPTH * COLOR_DEPTH);
var S = new Float64Array(COLOR_DEPTH * COLOR_DEPTH);
var H = new Float64Array(COLOR_DEPTH * COLOR_DEPTH);
var pixelsTotal = this.pixels;
var i, j, idx, tmp;
// diagonal
for (i = 1; i < COLOR_DEPTH; ++i) {
idx = index(i, i);
tmp = this.data[i] / pixelsTotal;
P[idx] = tmp;
S[idx] = i * tmp;
}
// calculate first row (row 0 is all zero)
for (i = 1; i < COLOR_DEPTH - 1; ++i) {
tmp = this.data[i + 1] / pixelsTotal;
idx = index(1, i);
P[idx+1] = P[idx] + tmp;
S[idx+1] = S[idx] + (i + 1) * tmp;
}
// using row 1 to calculate others
for (i = 2; i < COLOR_DEPTH; i++) {
for (j=i+1; j < COLOR_DEPTH; j++) {
P[index(i, j)] = P[index(1, j)] - P[index(1, i-1)];
S[index(i, j)] = S[index(1, j)] - S[index(1, i-1)];
}
}
// now calculate H[i][j]
for (i = 1; i < COLOR_DEPTH; ++i) {
for (j = i + 1; j < COLOR_DEPTH; j++) {
idx = index(i, j);
H[idx] = P[idx] !== 0 ? S[idx] * S[idx] / P[idx] : 0;
}
}
return this._lookupTableH = H;
},
/**
* Implements Algorithm For Multilevel Thresholding
* Receives desired number of color stops, returns array of said size. Could be limited to a range levelMin..levelMax
*
* Regardless of levelMin and levelMax values it still relies on between class variances for the entire histogram
*
* @param amount - how many thresholds should be calculated
* @param [levelMin=0] - histogram segment start
* @param [levelMax=255] - histogram segment end
* @returns {number[]}
*/
multilevelThresholding: function (amount, levelMin, levelMax) {
levelMin = normalizeMinMax(levelMin, levelMax);
levelMax = levelMin[1];
levelMin = levelMin[0];
amount = Math.min(levelMax - levelMin - 2, ~~amount);
if (amount < 1) {
return [];
}
if (!this._lookupTableH) {
this._thresholdingBuildLookupTable();
}
var H = this._lookupTableH;
var colorStops = null;
var maxSig = 0;
if (amount > 4) {
console.log('[Warning]: Threshold computation for more than 5 levels may take a long time');
}
function iterateRecursive (startingPoint, prevVariance, indexes, previousDepth) {
startingPoint = (startingPoint || 0) + 1;
prevVariance = prevVariance || 0;
indexes = indexes || (new Array(amount));
previousDepth = previousDepth || 0;
var depth = previousDepth + 1; // t
var variance;
for (var i = startingPoint; i < levelMax - amount + previousDepth; i++) {
variance = prevVariance + H[index(startingPoint, i)];
indexes[depth - 1] = i;
if (depth + 1 < amount + 1) {
// we need to go deeper
iterateRecursive(i, variance, indexes, depth);
} else {
// enough, we can compare values now
variance += H[index(i + 1, levelMax)];
if (maxSig < variance) {
maxSig = variance;
colorStops = indexes.slice();
}
}
}
}
iterateRecursive(levelMin || 0);
return colorStops ? colorStops : [];
},
/**
* Automatically finds threshold value using Algorithm For Multilevel Thresholding
*
* @param {number} [levelMin]
* @param {number} [levelMax]
* @returns {null|number}
*/
autoThreshold: function(levelMin, levelMax) {
var value = this.multilevelThresholding(1, levelMin, levelMax);
return value.length ? value[0] : null;
},
/**
* Returns dominant color in given range. Returns -1 if not a single color from the range present on the image
*
* @param [levelMin=0]
* @param [levelMax=255]
* @param [tolerance=1]
* @returns {number}
*/
getDominantColor: function(levelMin, levelMax, tolerance) {
levelMin = normalizeMinMax(levelMin, levelMax);
levelMax = levelMin[1];
levelMin = levelMin[0];
tolerance = tolerance || 1;
var colors = this.data,
dominantIndex = -1,
dominantValue = -1,
i, j, tmp;
if (levelMin === levelMax) {
return colors[levelMin] ? levelMin : -1;
}
for (i=levelMin; i <= levelMax; i++) {
tmp = 0;
for (j = ~~(tolerance / -2); j < tolerance; j++) {
tmp += utils.between(i + j, 0, COLOR_RANGE_END) ? colors[i + j] : 0;
}
var summIsBigger = tmp > dominantValue;
var summEqualButMainColorIsBigger = dominantValue === tmp && (dominantIndex < 0 || colors[i] > colors[dominantIndex]);
if (summIsBigger || summEqualButMainColorIsBigger) {
dominantIndex = i;
dominantValue = tmp;
}
}
return dominantValue <= 0 ? -1 : dominantIndex;
},
/**
* Returns stats for histogram or its segment.
*
* Returned object contains median, mean and standard deviation for pixel values;
* peak, mean and median number of pixels per level and few other values
*
* If no pixels colors from specified range present on the image - most values will be NaN
*
* @param {Number} [levelMin=0] - histogram segment start
* @param {Number} [levelMax=255] - histogram segment end
* @param {Boolean} [refresh=false] - if cached result can be returned
* @returns {{levels: {mean: (number|*), median: *, stdDev: number, unique: number}, pixelsPerLevel: {mean: (number|*), median: (number|*), peak: number}, pixels: number}}
*/
getStats: function(levelMin, levelMax, refresh) {
levelMin = normalizeMinMax(levelMin, levelMax);
levelMax = levelMin[1];
levelMin = levelMin[0];
if (!refresh && this._cachedStats[levelMin + '-' + levelMax]) {
return this._cachedStats[levelMin + '-' + levelMax];
}
var data = this.data;
var sortedIndexes = this._getSortedIndexes();
var pixelsTotal = 0;
var medianValue = null;
var meanValue;
var medianPixelIndex;
var pixelsPerLevelMean;
var pixelsPerLevelMedian;
var tmpSumOfDeviations = 0;
var tmpPixelsIterated = 0;
var allPixelValuesCombined = 0;
var i, tmpPixels, tmpPixelValue;
var uniqueValues = 0; // counter for levels that's represented by at least one pixel
var mostPixelsPerLevel = 0;
// Finding number of pixels and mean
for (i = levelMin; i <= levelMax; i++) {
pixelsTotal += data[i];
allPixelValuesCombined += data[i] * i;
uniqueValues += data[i] === 0 ? 0 : 1;
if (mostPixelsPerLevel < data[i]) {
mostPixelsPerLevel = data[i];
}
}
meanValue = allPixelValuesCombined / pixelsTotal;
pixelsPerLevelMean = pixelsTotal / (levelMax - levelMin);
pixelsPerLevelMedian = pixelsTotal / uniqueValues;
medianPixelIndex = Math.floor(pixelsTotal / 2);
// Finding median and standard deviation
for (i = 0; i < COLOR_DEPTH; i++) {
tmpPixelValue = sortedIndexes[i];
tmpPixels = data[tmpPixelValue];
if (tmpPixelValue < levelMin || tmpPixelValue > levelMax) {
continue;
}
tmpPixelsIterated += tmpPixels;
tmpSumOfDeviations += Math.pow(tmpPixelValue - meanValue, 2) * tmpPixels;
if (medianValue === null && tmpPixelsIterated >= medianPixelIndex) {
medianValue = tmpPixelValue;
}
}
return this._cachedStats[levelMin + '-' + levelMax] = {
// various pixel counts for levels (0..255)
levels: {
mean: meanValue,
median: medianValue,
stdDev: Math.sqrt(tmpSumOfDeviations / pixelsTotal),
unique: uniqueValues
},
// what's visually represented as bars
pixelsPerLevel: {
mean: pixelsPerLevelMean,
median: pixelsPerLevelMedian,
peak: mostPixelsPerLevel
},
pixels: pixelsTotal
};
}
};
module.exports = Histogram;
================================================
FILE: lib/types/Opti.js
================================================
'use strict';
var Point = require('./Point');
function Opti() {
this.pen = 0;
this.c = [new Point(), new Point()];
this.t = 0;
this.s = 0;
this.alpha = 0;
}
module.exports = Opti;
================================================
FILE: lib/types/Path.js
================================================
'use strict';
function Path() {
this.area = 0;
this.len = 0;
this.curve = {};
this.pt = [];
this.minX = 100000;
this.minY = 100000;
this.maxX = -1;
this.maxY = -1;
}
module.exports = Path;
================================================
FILE: lib/types/Point.js
================================================
'use strict';
function Point(x, y) {
this.x = x || 0;
this.y = y || 0;
}
Point.prototype = {
copy: function() {
return new Point(this.x, this.y);
}
};
module.exports = Point;
================================================
FILE: lib/types/Quad.js
================================================
'use strict';
function Quad() {
this.data = [0,0,0,0,0,0,0,0,0];
}
Quad.prototype.at = function(x, y) {
return this.data[x * 3 + y];
};
module.exports = Quad;
================================================
FILE: lib/types/Sum.js
================================================
'use strict';
function Sum(x, y, xy, x2, y2) {
this.x = x;
this.y = y;
this.xy = xy;
this.x2 = x2;
this.y2 = y2;
}
module.exports = Sum;
================================================
FILE: lib/utils.js
================================================
'use strict';
var Point = require('./types/Point');
var attrRegexps = {};
function getAttrRegexp(attrName) {
if (attrRegexps[attrName]) {
return attrRegexps[attrName];
}
attrRegexps[attrName] = new RegExp(' ' + attrName + '="((?:\\\\(?=")"|[^"])+)"', 'i');
return attrRegexps[attrName];
}
function setHtmlAttribute(html, attrName, value) {
var attr = ' ' + attrName + '="' + value + '"';
if (html.indexOf(' ' + attrName + '="') === -1) {
html = html.replace(/<[a-z]+/i, function(beginning) { return beginning + attr; });
} else {
html = html.replace(getAttrRegexp(attrName), attr);
}
return html;
}
function fixed(number) {
return number.toFixed(3).replace('.000', '');
}
function mod(a, n) {
return a >= n ? a % n : a>=0 ? a : n-1-(-1-a) % n;
}
function xprod(p1, p2) {
return p1.x * p2.y - p1.y * p2.x;
}
function cyclic(a, b, c) {
if (a <= c) {
return (a <= b && b < c);
} else {
return (a <= b || b < c);
}
}
function sign(i) {
return i > 0 ? 1 : i < 0 ? -1 : 0;
}
function quadform(Q, w) {
var v = new Array(3), i, j, sum;
v[0] = w.x;
v[1] = w.y;
v[2] = 1;
sum = 0.0;
for (i=0; i<3; i++) {
for (j=0; j<3; j++) {
sum += v[i] * Q.at(i, j) * v[j];
}
}
return sum;
}
function interval(lambda, a, b) {
var res = new Point();
res.x = a.x + lambda * (b.x - a.x);
res.y = a.y + lambda * (b.y - a.y);
return res;
}
function dorth_infty(p0, p2) {
var r = new Point();
r.y = sign(p2.x - p0.x);
r.x = -sign(p2.y - p0.y);
return r;
}
function ddenom(p0, p2) {
var r = dorth_infty(p0, p2);
return r.y * (p2.x - p0.x) - r.x * (p2.y - p0.y);
}
function dpara(p0, p1, p2) {
var x1, y1, x2, y2;
x1 = p1.x - p0.x;
y1 = p1.y - p0.y;
x2 = p2.x - p0.x;
y2 = p2.y - p0.y;
return x1 * y2 - x2 * y1;
}
function cprod(p0, p1, p2, p3) {
var x1, y1, x2, y2;
x1 = p1.x - p0.x;
y1 = p1.y - p0.y;
x2 = p3.x - p2.x;
y2 = p3.y - p2.y;
return x1 * y2 - x2 * y1;
}
function iprod(p0, p1, p2) {
var x1, y1, x2, y2;
x1 = p1.x - p0.x;
y1 = p1.y - p0.y;
x2 = p2.x - p0.x;
y2 = p2.y - p0.y;
return x1*x2 + y1*y2;
}
function iprod1(p0, p1, p2, p3) {
var x1, y1, x2, y2;
x1 = p1.x - p0.x;
y1 = p1.y - p0.y;
x2 = p3.x - p2.x;
y2 = p3.y - p2.y;
return x1 * x2 + y1 * y2;
}
function ddist(p, q) {
return Math.sqrt((p.x - q.x) * (p.x - q.x) + (p.y - q.y) * (p.y - q.y));
}
module.exports = {
luminance: function (r, g, b) {
return Math.round(0.2126 * r + 0.7153 * g + 0.0721 * b);
},
between: function(val, min, max) {
return val >= min && val <= max;
},
clamp: function(val, min, max) {
return Math.min(max, Math.max(min, val));
},
isNumber: function(val) {
return typeof val === 'number';
},
setHtmlAttr: setHtmlAttribute,
/**
* Generates path instructions for given curve
*
* @param {Curve} curve
* @param {Number} [scale]
* @returns {string}
*/
renderCurve: function(curve, scale) {
scale = scale || 1;
var startingPoint = curve.c[(curve.n - 1) * 3 + 2];
var path = 'M '
+ fixed(startingPoint.x * scale) + ' '
+ fixed(startingPoint.y * scale) + ' ';
curve.tag.forEach(function(tag, i) {
var i3 = i * 3;
var p0 = curve.c[i3];
var p1 = curve.c[i3 + 1];
var p2 = curve.c[i3 + 2];
if (tag === "CURVE") {
path += 'C ';
path += fixed(p0.x * scale) + ' ' + fixed(p0.y * scale) + ', ';
path += fixed(p1.x * scale) + ' ' + fixed(p1.y * scale) + ', ';
path += fixed(p2.x * scale) + ' ' + fixed(p2.y * scale) + ' ';
} else if (tag === "CORNER") {
path += 'L ';
path += fixed(p1.x * scale) + ' ' + fixed(p1.y * scale) + ' ';
path += fixed(p2.x * scale) + ' ' + fixed(p2.y * scale) + ' ';
}
});
return path;
},
bezier: function bezier(t, p0, p1, p2, p3) {
var s = 1 - t, res = new Point();
res.x = s*s*s*p0.x + 3*(s*s*t)*p1.x + 3*(t*t*s)*p2.x + t*t*t*p3.x;
res.y = s*s*s*p0.y + 3*(s*s*t)*p1.y + 3*(t*t*s)*p2.y + t*t*t*p3.y;
return res;
},
tangent: function tangent(p0, p1, p2, p3, q0, q1) {
var A, B, C, a, b, c, d, s, r1, r2;
A = cprod(p0, p1, q0, q1);
B = cprod(p1, p2, q0, q1);
C = cprod(p2, p3, q0, q1);
a = A - 2 * B + C;
b = -2 * A + 2 * B;
c = A;
d = b * b - 4 * a * c;
if (a===0 || d<0) {
return -1.0;
}
s = Math.sqrt(d);
r1 = (-b + s) / (2 * a);
r2 = (-b - s) / (2 * a);
if (r1 >= 0 && r1 <= 1) {
return r1;
} else if (r2 >= 0 && r2 <= 1) {
return r2;
} else {
return -1.0;
}
},
mod: mod,
xprod: xprod,
cyclic: cyclic,
sign: sign,
quadform: quadform,
interval: interval,
dorth_infty: dorth_infty,
ddenom: ddenom,
dpara: dpara,
cprod: cprod,
iprod: iprod,
iprod1: iprod1,
ddist: ddist
};
================================================
FILE: package.json
================================================
{
"name": "potrace",
"version": "2.1.2",
"description": "Potrace in Javascript, for NodeJS",
"main": "lib/index.js",
"scripts": {
"test": "cd test && mocha test.js --reporter spec"
},
"repository": {
"type": "git",
"url": "git+https://github.com/tooolbox/node-potrace.git"
},
"keywords": [
"potrace",
"trace",
"tracing",
"svg",
"bitmap",
"posterization"
],
"author": "mattmc",
"license": "GPL-2.0",
"bugs": {
"url": "https://github.com/tooolbox/node-potrace/issues"
},
"homepage": "https://github.com/tooolbox/node-potrace#readme",
"dependencies": {
"jimp": "^0.6.4"
},
"devDependencies": {
"lodash": "^4.15.0",
"mocha": "^3.0.2",
"should": "^11.1.0",
"should-sinon": "0.0.5",
"sinon": "^1.17.5"
}
}
================================================
FILE: test/test.js
================================================
'use strict';
var _ = require('lodash'),
assert = require('assert'),
should = require('should'),
sinon = require('sinon');
require('should-sinon');
var fs = require('fs'),
Jimp = require('jimp'),
Potrace = require('../lib/Potrace'),
Posterizer = require('../lib/Posterizer'),
Histogram = require('../lib/types/Histogram'),
lib = require('../lib/index');
var PATH_TO_YAO = './sources/yao.jpg';
var PATH_TO_LENNA = './sources/Lenna.png';
var PATH_TO_BLACK_AND_WHITE_IMAGE = './sources/clouds.jpg';
var blackImage = new Jimp(100, 100, 0x000000FF);
var whiteImage = new Jimp(100, 100, 0xFFFFFFFF);
describe('Histogram class (private, responsible for auto thresholding)', function() {
var histogram = null;
var blackHistogram = new Histogram(blackImage, Histogram.MODE_LUMINANCE);
var whiteHistogram = new Histogram(whiteImage, Histogram.MODE_LUMINANCE);
before(function(done) {
this.timeout(10000);
Jimp.read(PATH_TO_LENNA, function(err, img) {
if (err) throw err;
histogram = new Histogram(img, Histogram.MODE_LUMINANCE);
done();
});
});
describe('#getDominantColor', function() {
it('gives different results with different tolerance values', function() {
assert.equal(histogram.getDominantColor(0, 255), 149);
assert.equal(histogram.getDominantColor(0, 255, 10), 143);
});
it('has default argument values of 0, 255 and 1', function() {
assert.equal(histogram.getDominantColor(), histogram.getDominantColor(0, 255, 1));
});
it('works for a segment of histogram', function() {
assert.equal(41, histogram.getDominantColor(20, 80));
});
it('does not fail when min and max values are the same', function() {
assert.equal(histogram.getDominantColor(42, 42), 42);
});
it('returns -1 if colors from the range are not present on image', function() {
assert.equal(histogram.getDominantColor(0, 15), -1);
assert.equal(histogram.getDominantColor(7, 7, 1), -1);
});
it('throws error if range start is larger than range end', function() {
(function() {
histogram.getDominantColor(80, 20);
}).should.throw();
});
it('behaves predictably in edge cases', function() {
blackHistogram.getDominantColor(0, 255).should.be.equal(0);
whiteHistogram.getDominantColor(0, 255).should.be.equal(255);
whiteHistogram.getDominantColor(25, 235).should.be.equal(-1);
// Tolerance should not affect returned value
blackHistogram.getDominantColor(0, 255, 15).should.be.equal(0);
whiteHistogram.getDominantColor(0, 255, 15).should.be.equal(255);
})
});
describe('#getStats', function() {
function toFixedDeep(stats, fractionalDigits) {
return _.cloneDeepWith(stats, function(val) {
if (_.isNumber(val) && !_.isInteger(val)) {
return parseFloat(val.toFixed(fractionalDigits));
}
});
}
it('produces expected stats object for entire histogram', function() {
var expectedValue = {
levels: {
mean: 116.7673568725586,
median: 95,
stdDev: 49.42205692905339,
unique: 222
},
pixelsPerLevel: {
mean: 1028.0156862745098,
median: 1180.8288288288288,
peak: 2495
},
pixels: 262144
};
assert.deepEqual(
toFixedDeep(histogram.getStats(), 4),
toFixedDeep(expectedValue, 4)
);
});
it('produces expected stats object for histogram segment', function() {
var expectedValue = {
levels: {
mean: 121.89677761754915,
median: 93,
stdDev: 30.2466970087377,
unique: 121
},
pixelsPerLevel: {
mean: 1554.4916666666666,
median: 1541.6446280991736,
peak: 2495
},
pixels: 186539
};
assert.deepEqual(
toFixedDeep(histogram.getStats(60, 180), 4),
toFixedDeep(expectedValue, 4)
);
});
it('throws error if range start is larger than range end', function() {
(function() {
histogram.getStats(255, 123);
}).should.throw();
});
it('behaves predictably in edge cases', function() {
var blackImageStats = blackHistogram.getStats();
var whiteImageStats = blackHistogram.getStats();
blackImageStats.levels.mean.should.be.equal(blackImageStats.levels.median);
whiteImageStats.levels.mean.should.be.equal(whiteImageStats.levels.median);
blackHistogram.getStats(25, 235).should.be.deepEqual(whiteHistogram.getStats(25, 235));
});
});
describe('#multilevelThresholding', function() {
it('calculates correct thresholds', function() {
assert.deepEqual(histogram.multilevelThresholding(1), [111]);
assert.deepEqual(histogram.multilevelThresholding(2), [ 92, 154 ]);
assert.deepEqual(histogram.multilevelThresholding(3), [ 73, 121, 168 ]);
});
it('works for histogram segment', function() {
assert.deepEqual(histogram.multilevelThresholding(2, 60, 180), [ 103, 138 ]);
});
it('calculates as many thresholds as can be fit in given range', function() {
assert.deepEqual(histogram.multilevelThresholding(2, 102, 106), [ 103, 104 ]);
assert.deepEqual(histogram.multilevelThresholding(2, 103, 106), [ 104 ]);
});
it('returns empty array if no colors from histogram segment is present on the image', function() {
assert.deepEqual(histogram.multilevelThresholding(3, 2, 14), []);
});
it('throws error if range start is larger than range end', function() {
(function() {
histogram.multilevelThresholding(2, 180, 60);
}).should.throw();
});
});
});
describe('Potrace class', function() {
var jimpInstance = null;
this.timeout(10000);
before(function(done) {
Jimp.read(PATH_TO_YAO, function(err, img) {
if (err) {
return done(err);
}
jimpInstance = img;
done();
});
});
describe('#loadImage', function() {
it('instance is being passed to callback function as context', function(done) {
var instance = new Potrace();
instance.loadImage(PATH_TO_YAO, function(err) {
this.should.be.an.instanceOf(Potrace).and.be.equal(instance);
done(err);
});
});
it('supports Jimp instances provided as source image', function(done) {
var instance = new Potrace();
instance.loadImage(jimpInstance, done);
});
it('should throw error if called before previous image was loaded', function(done) {
function onImageLoad() {
if (firstFinished && secondFinished) {
done();
}
}
var potraceInstance = new Potrace();
var firstFinished = false;
var secondFinished = false;
potraceInstance.loadImage(PATH_TO_LENNA, function(err) {
firstFinished = true;
should(function() { should.ifError(err); }).throw(/another.*instead/i);
onImageLoad();
});
potraceInstance.loadImage(PATH_TO_YAO, function(err) {
secondFinished = true;
should(function() { should.ifError(err); }).not.throw();
onImageLoad();
});
});
});
describe('#_processPath', function() {
var instance = new Potrace();
var processingSpy = null;
before(function() {
processingSpy = instance._processPath = sinon.spy(Potrace.prototype._processPath);
});
it('should not execute until path is requested for the first time', function(done) {
instance.loadImage(jimpInstance, function() {
processingSpy.should.have.callCount(0);
this.getSVG();
processingSpy.should.have.callCount(1);
done();
});
});
it('should not execute on repetitive SVG/Symbol export', function() {
instance.loadImage(jimpInstance, function() {
var initialCallCount = processingSpy.callCount;
this.getSVG();
this.getSVG();
this.getPathTag();
this.getPathTag('red');
this.getSymbol('symbol-id');
processingSpy.should.have.callCount(initialCallCount);
});
});
it('should not execute after change of foreground/background colors', function() {
instance.loadImage(jimpInstance, function() {
var initialCallCount = processingSpy.callCount;
this.setParameters({ color: 'red' });
this.getSVG();
this.setParameters({ background: 'crimson' });
this.getSVG();
processingSpy.should.have.callCount(initialCallCount);
});
});
});
describe('#getSVG', function() {
var instanceYao = new Potrace();
before(function(done) {
instanceYao.loadImage(jimpInstance, done);
});
it('produces expected results with different thresholds', function() {
var expected;
expected = fs.readFileSync('./reference-copies/potrace-bw-threshold-128.svg', { encoding: 'utf8' });
instanceYao.setParameters({ threshold: 128 });
assert.equal(instanceYao.getSVG(), expected, 'Image with threshold 128 does not match with reference copy');
expected = fs.readFileSync('./reference-copies/potrace-bw-threshold-65.svg', { encoding: 'utf8' });
instanceYao.setParameters({ threshold: 65 });
assert.equal(instanceYao.getSVG(), expected, 'Image with threshold 65 does not match with reference copy');
expected = fs.readFileSync('./reference-copies/potrace-bw-threshold-170.svg', { encoding: 'utf8' });
instanceYao.setParameters({ threshold: 170 });
assert.equal(instanceYao.getSVG(), expected, 'Image with threshold 170 does not match with reference copy');
});
it('produces expected white on black image with threshold 170', function(done) {
var instance = new Potrace({
threshold: 128,
blackOnWhite: false,
color: 'cyan',
background: 'darkred'
});
instance.loadImage(PATH_TO_BLACK_AND_WHITE_IMAGE, function(err) {
if (err) return done(err);
var expected = fs.readFileSync('./reference-copies/potrace-wb-threshold-128.svg', { encoding: 'utf8' });
var actual = instance.getSVG();
assert.equal(actual, expected);
done();
});
});
});
describe('#getSymbol', function() {
var instanceYao = new Potrace();
before(function(done) {
instanceYao.loadImage(jimpInstance, done);
});
it('should not have fill color or background', function() {
instanceYao.setParameters({
color: 'red',
background: 'cyan'
});
var symbol = instanceYao.getSymbol('whatever');
symbol.should.not.match(/<rect/i);
symbol.should.match(/<path[^>]+(?:fill="\s*"|fill='\s*'|)[^>]*>/i);
});
});
describe('behaves predictably in edge cases', function() {
var instance = new Potrace();
var bwBlackThreshold0;
var bwBlackThreshold255;
var bwWhiteThreshold0;
var bwWhiteThreshold255;
var wbWhiteThreshold0;
var wbWhiteThreshold255;
var wbBlackThreshold0;
var wbBlackThreshold255;
before(function() {
bwBlackThreshold0 = fs.readFileSync('./reference-copies/potrace-bw-black-threshold-0.svg', { encoding: 'utf8' });
bwBlackThreshold255 = fs.readFileSync('./reference-copies/potrace-bw-black-threshold-255.svg', { encoding: 'utf8' });
bwWhiteThreshold0 = fs.readFileSync('./reference-copies/potrace-bw-white-threshold-0.svg', { encoding: 'utf8' });
bwWhiteThreshold255 = fs.readFileSync('./reference-copies/potrace-bw-white-threshold-255.svg', { encoding: 'utf8' });
wbWhiteThreshold0 = fs.readFileSync('./reference-copies/potrace-wb-white-threshold-0.svg', { encoding: 'utf8' });
wbWhiteThreshold255 = fs.readFileSync('./reference-copies/potrace-wb-white-threshold-255.svg', { encoding: 'utf8' });
wbBlackThreshold0 = fs.readFileSync('./reference-copies/potrace-wb-black-threshold-0.svg', { encoding: 'utf8' });
wbBlackThreshold255 = fs.readFileSync('./reference-copies/potrace-wb-black-threshold-255.svg', { encoding: 'utf8' });
});
it('compares colors against threshold in the same way as original tool', function(done) {
instance.loadImage(blackImage, function(err) {
if (err) { return done(err); }
instance.setParameters({ blackOnWhite: true, threshold: 0 });
instance.getSVG().should.be.equal(bwBlackThreshold0);
instance.setParameters({ blackOnWhite: true, threshold: 255 });
instance.getSVG().should.be.equal(bwBlackThreshold255);
instance.loadImage(whiteImage, function() {
if (err) { return done(err); }
instance.setParameters({ blackOnWhite: true, threshold: 0 });
instance.getSVG().should.be.equal(bwWhiteThreshold0);
instance.setParameters({ blackOnWhite: true, threshold: 255 });
instance.getSVG().should.be.equal(bwWhiteThreshold255);
done();
});
});
});
it('acts in the same way when colors are inverted', function(done) {
instance.loadImage(whiteImage, function(err) {
if (err) { return done(err); }
instance.setParameters({ blackOnWhite: false, threshold: 255 });
instance.getSVG().should.be.equal(wbWhiteThreshold255);
instance.setParameters({ blackOnWhite: false, threshold: 0 });
instance.getSVG().should.be.equal(wbWhiteThreshold0);
instance.loadImage(blackImage, function() {
if (err) { return done(err); }
instance.setParameters({ blackOnWhite: false, threshold: 255 });
instance.getSVG().should.be.equal(wbBlackThreshold255);
instance.setParameters({ blackOnWhite: false, threshold: 0 });
instance.getSVG().should.be.equal(wbBlackThreshold0);
done();
});
});
});
});
});
describe('Posterizer class', function() {
var jimpInstance = null;
var sharedPosterizerInstance = new Posterizer();
this.timeout(10000);
before(function(done) {
Jimp.read(PATH_TO_YAO, function(err, img) {
if (err) {
return done(err);
}
jimpInstance = img;
done();
});
});
describe('#_getRanges', function() {
var posterizer = new Posterizer();
function getColorStops() {
return posterizer._getRanges().map(function(item) {
return item.value;
});
}
before(function(done) {
posterizer.loadImage(PATH_TO_YAO, done);
});
it('returns correctly calculated color stops with "equally spread" distribution', function() {
posterizer.setParameters({
rangeDistribution: Posterizer.RANGES_EQUAL,
threshold: 200,
steps: 4,
blackOnWhite: true
});
getColorStops().should.be.deepEqual([200, 150, 100, 50]);
posterizer.setParameters({
rangeDistribution: Posterizer.RANGES_EQUAL,
threshold: 155,
steps: 4,
blackOnWhite: false
});
getColorStops().should.be.deepEqual([155, 180, 205, 230]);
posterizer.setParameters({
rangeDistribution: Posterizer.RANGES_EQUAL,
threshold: Potrace.THRESHOLD_AUTO,
steps: 4,
blackOnWhite: true
});
getColorStops().should.be.deepEqual([206, 154.5, 103, 51.5]);
});
it('returns correctly calculated color stops with "auto" distribution', function() {
posterizer.setParameters({
rangeDistribution: Posterizer.RANGES_AUTO,
threshold: Potrace.THRESHOLD_AUTO,
steps: 3,
blackOnWhite: true
});
getColorStops().should.be.deepEqual([219, 156, 71]);
posterizer.setParameters({
rangeDistribution: Posterizer.RANGES_AUTO,
threshold: Potrace.THRESHOLD_AUTO,
steps: 3,
blackOnWhite: false
});
getColorStops().should.be.deepEqual([71, 156, 219]);
// Now with predefined threshold
posterizer.setParameters({
rangeDistribution: Posterizer.RANGES_AUTO,
threshold: 128,
steps: 4,
blackOnWhite: true
});
getColorStops().should.be.deepEqual([128, 97, 62, 24]);
posterizer.setParameters({
rangeDistribution: Posterizer.RANGES_AUTO,
threshold: 128,
steps: 4,
blackOnWhite: false
});
getColorStops().should.be.deepEqual([128, 166, 203, 237]);
});
it('correctly handles predefined array of color stops', function() {
posterizer.setParameters({
steps: [20, 60, 80, 160],
threshold: 120,
blackOnWhite: true
});
getColorStops().should.be.deepEqual([160, 80, 60, 20]);
posterizer.setParameters({
steps: [20, 60, 80, 160],
threshold: 180,
blackOnWhite: true
});
getColorStops().should.be.deepEqual([180, 160, 80, 60, 20]);
posterizer.setParameters({
steps: [20, 60, 80, 160],
threshold: 180,
blackOnWhite: false
});
getColorStops().should.be.deepEqual([20, 60, 80, 160, 180]);
posterizer.setParameters({
steps: [212, 16, 26, 50, 212, 128, 211],
threshold: 180,
blackOnWhite: false
});
getColorStops().should.be.deepEqual([16, 26, 50, 128, 211, 212], 'Duplicated items should be present only once');
posterizer.setParameters({
steps: [15, 42, 200, 460, 0, -10],
threshold: 180,
blackOnWhite: false
});
getColorStops().should.be.deepEqual([0, 15, 42, 200], 'Values out of range should be ignored');
});
});
describe('#loadImage', function() {
it('instance is being passed to callback function as context', function(done) {
sharedPosterizerInstance.loadImage(PATH_TO_YAO, function(err) {
this.should.be.an.instanceOf(Posterizer).and.be.equal(sharedPosterizerInstance);
done(err);
});
});
});
describe('#getSVG', function() {
var instanceYao = sharedPosterizerInstance;
it('produces expected results with different thresholds', function() {
var expected;
instanceYao.setParameters({ threshold: 128 });
expected = fs.readFileSync('./reference-copies/posterized-yao-black-threshold-128.svg', { encoding: 'utf8' });
assert.equal(instanceYao.getSVG(), expected, 'Image with threshold 128 does not match with reference copy');
instanceYao.setParameters({ threshold: 65 });
expected = fs.readFileSync('./reference-copies/posterized-yao-black-threshold-65.svg', { encoding: 'utf8' });
assert.equal(instanceYao.getSVG(), expected, 'Image with threshold 65 does not match with reference copy');
instanceYao.setParameters({ threshold: 170 });
expected = fs.readFileSync('./reference-copies/posterized-yao-black-threshold-170.svg', { encoding: 'utf8' });
assert.equal(instanceYao.getSVG(), expected, 'Image with threshold 170 does not match with reference copy');
});
it('produces expected white on black image with threshold 170', function(done) {
var instance = new Posterizer({
threshold: 40,
blackOnWhite: false,
steps: 3,
color: 'beige',
background: '#222'
});
instance.loadImage('sources/clouds.jpg', function(err) {
if (err) return done(err);
var expected = fs.readFileSync('./reference-copies/posterized-clouds-white-40.svg', { encoding: 'utf8' });
var actual = instance.getSVG();
assert.equal(actual, expected);
done();
});
});
});
describe('#getSymbol', function() {
var instanceYao = new Posterizer();
before(function(done) {
instanceYao.loadImage(jimpInstance, done);
});
it('should not have fill color or background', function() {
instanceYao.setParameters({
color: 'red',
background: 'cyan',
steps: 3
});
var symbol = instanceYao.getSymbol('whatever');
symbol.should.not.match(/<rect/i);
symbol.should.match(/<path[^>]+(?:fill="\s*"|fill='\s*'|)[^>]*>/i);
});
});
describe('edge cases', function() {
var instance = new Posterizer();
it('does not break on images filled with one color', function(done) {
instance.loadImage(blackImage, function(err) {
if (err) { return done(err); }
// black image should give us one black layer...
instance.setParameters({ blackOnWhite: true, threshold: 128 });
instance.getSVG().should.match(/<path fill-opacity="1\.000"/);
instance.setParameters({ blackOnWhite: false });
instance.getSVG().should.not.match(/<path/);
instance.loadImage(whiteImage, function() {
if (err) { return done(err); }
instance.setParameters({ blackOnWhite: true });
instance.getSVG().should.not.match(/<path/);
// white image should give us one layer...
instance.setParameters({ blackOnWhite: false });
instance.getSVG().should.match(/<path fill-opacity="1\.000"/);
done();
});
});
});
it('does not break when no thresholds can be found', function(done) {
instance.loadImage(whiteImage, function(err) {
if (err) { return done(err); }
var svg1, svg2, svg3, svg4;
instance.setParameters({ blackOnWhite: true });
svg1 = instance.getSVG();
instance.setParameters({ blackOnWhite: true, steps: 3, threshold: 128 });
svg2 = instance.getSVG();
instance.setParameters({ blackOnWhite: true, steps: [], threshold: 128 });
svg3 = instance.getSVG();
instance.setParameters({ blackOnWhite: true, steps: [0, 55, 128, 169, 210], threshold: 250 });
svg4 = instance.getSVG();
svg1.should.be.equal(svg2).and.equal(svg3).and.equal(svg4).and.not.match(/<path/);
instance.loadImage(blackImage, function() {
if (err) { return done(err); }
instance.setParameters({ blackOnWhite: false, threshold: 255 });
svg1 = instance.getSVG();
instance.setParameters({ blackOnWhite: false, threshold: 0 });
svg2 = instance.getSVG();
svg1.should.equal(svg2).and.not.match(/<path/);
done();
});
});
});
});
});
describe('Shorthand methods', function() {
var jimpInstance = null;
this.timeout(10000);
before(function(done) {
Jimp.read(PATH_TO_YAO, function(err, img) {
if (err) {
return done(err);
}
jimpInstance = img;
done();
});
});
describe('#trace', function() {
var instance = null;
it('works with two arguments', function(done) {
lib.trace(jimpInstance, function(err, svgContents, inst) {
if (err) {
throw err;
}
var expected = fs.readFileSync('./reference-copies/output.svg', { encoding: 'utf8' });
instance = inst;
assert.equal(svgContents, expected);
done();
});
});
it('works with three arguments', function(done) {
lib.trace(jimpInstance, { threshold: 170 }, function(err, svgContents) {
if (err) {
throw err;
}
var expected = fs.readFileSync('./reference-copies/potrace-bw-threshold-170.svg', { encoding: 'utf8' });
assert.equal(svgContents, expected);
done();
});
});
it('returns Potrace instance as third argument', function() {
instance.should.be.instanceOf(Potrace);
});
});
describe('#posterize', function() {
var instance = null;
it('works with two arguments', function(done) {
lib.posterize(jimpInstance, function(err, svgContents, inst) {
if (err) {
throw err;
}
var expected = fs.readFileSync('./reference-copies/output-posterized.svg', { encoding: 'utf8' });
instance = inst;
assert.equal(svgContents, expected);
done();
});
});
it('works with three arguments', function(done) {
lib.posterize(jimpInstance, { threshold: 170 }, function(err, svgContents) {
if (err) {
throw err;
}
var expected = fs.readFileSync('./reference-copies/posterized-bw-threshold-170.svg', { encoding: 'utf8' });
assert.equal(svgContents, expected);
done();
});
});
it('returns Posterizer instance as third argument', function() {
instance.should.be.instanceOf(Posterizer);
});
});
});
// lib.trace('./yao.jpg', function(err, svg) {
// if (err) { throw err; }
// fs.writeFileSync('./output.svg', svg);
// });
//
// lib.posterize('./yao.jpg', function(err, svg) {
// if (err) { throw err; }
// fs.writeFileSync('./output-posterized.svg', svg);
// });
//
// // Generating example for readme with hand-picked thresholds
//
// lib.trace('./yao.jpg', { threshold: 128 }, function(err, svg) {
// if (err) { throw err; }
// fs.writeFileSync('./example-output.svg', svg);
// });
//
// lib.posterize('./yao.jpg', { steps: [50, 85, 120, 165, 220] }, function(err, svg) {
// if (err) { throw err; }
// fs.writeFileSync('./example-output-posterized.svg', svg);
// });
gitextract_jxybqwmb/
├── .editorconfig
├── .gitignore
├── .npmignore
├── .travis.yml
├── LICENSE
├── README.md
├── lib/
│ ├── Posterizer.js
│ ├── Potrace.js
│ ├── index.js
│ ├── types/
│ │ ├── Bitmap.js
│ │ ├── Curve.js
│ │ ├── Histogram.js
│ │ ├── Opti.js
│ │ ├── Path.js
│ │ ├── Point.js
│ │ ├── Quad.js
│ │ └── Sum.js
│ └── utils.js
├── package.json
└── test/
└── test.js
SYMBOL INDEX (45 symbols across 13 files)
FILE: lib/Posterizer.js
function Posterizer (line 13) | function Posterizer(options) {
FILE: lib/Potrace.js
function Potrace (line 20) | function Potrace (options) {
function findNext (line 93) | function findNext(point) {
function majority (line 103) | function majority(x, y) {
function findPath (line 124) | function findPath(point) {
function xorPath (line 183) | function xorPath(path){
function calcSums (line 225) | function calcSums(path) {
function calcLon (line 241) | function calcLon(path) {
function bestPolygon (line 358) | function bestPolygon(path) {
function adjustVertices (line 470) | function adjustVertices(path) {
function reverse (line 669) | function reverse(path) {
function smooth (line 679) | function smooth(path) {
function optiCurve (line 724) | function optiCurve(path) {
FILE: lib/index.js
function trace (line 13) | function trace(file, options, cb) {
function posterize (line 34) | function posterize(file, options, cb) {
FILE: lib/types/Bitmap.js
function Bitmap (line 15) | function Bitmap(w, h) {
FILE: lib/types/Curve.js
function Curve (line 10) | function Curve(n) {
FILE: lib/types/Histogram.js
function index (line 23) | function index(x, y) {
function normalizeMinMax (line 27) | function normalizeMinMax(levelMin, levelMax) {
function Histogram (line 54) | function Histogram(imageSource, mode) {
function iterateRecursive (line 241) | function iterateRecursive (startingPoint, prevVariance, indexes, previou...
FILE: lib/types/Opti.js
function Opti (line 5) | function Opti() {
FILE: lib/types/Path.js
function Path (line 3) | function Path() {
FILE: lib/types/Point.js
function Point (line 3) | function Point(x, y) {
FILE: lib/types/Quad.js
function Quad (line 3) | function Quad() {
FILE: lib/types/Sum.js
function Sum (line 3) | function Sum(x, y, xy, x2, y2) {
FILE: lib/utils.js
function getAttrRegexp (line 6) | function getAttrRegexp(attrName) {
function setHtmlAttribute (line 15) | function setHtmlAttribute(html, attrName, value) {
function fixed (line 27) | function fixed(number) {
function mod (line 31) | function mod(a, n) {
function xprod (line 35) | function xprod(p1, p2) {
function cyclic (line 39) | function cyclic(a, b, c) {
function sign (line 47) | function sign(i) {
function quadform (line 51) | function quadform(Q, w) {
function interval (line 67) | function interval(lambda, a, b) {
function dorth_infty (line 75) | function dorth_infty(p0, p2) {
function ddenom (line 84) | function ddenom(p0, p2) {
function dpara (line 90) | function dpara(p0, p1, p2) {
function cprod (line 101) | function cprod(p0, p1, p2, p3) {
function iprod (line 112) | function iprod(p0, p1, p2) {
function iprod1 (line 123) | function iprod1(p0, p1, p2, p3) {
function ddist (line 134) | function ddist(p, q) {
FILE: test/test.js
function toFixedDeep (line 82) | function toFixedDeep(stats, fractionalDigits) {
function onImageLoad (line 213) | function onImageLoad() {
function getColorStops (line 438) | function getColorStops() {
Condensed preview — 20 files, each showing path, character count, and a content snippet. Download the .json file or copy for the full structured content (127K chars).
[
{
"path": ".editorconfig",
"chars": 100,
"preview": "root = true\n\n[*]\nend_of_line = lf\ninsert_final_newline = false\nindent_style = space\nindent_size = 2\n"
},
{
"path": ".gitignore",
"chars": 589,
"preview": "# Logs\nlogs\n*.log\nnpm-debug.log*\n\n# Runtime data\npids\n*.pid\n*.seed\n\n# Directory for instrumented libs generated by jscov"
},
{
"path": ".npmignore",
"chars": 502,
"preview": "# Logs\nlogs\n*.log\nnpm-debug.log*\n\n# Runtime data\npids\n*.pid\n*.seed\n\n# Directory for instrumented libs generated by jscov"
},
{
"path": ".travis.yml",
"chars": 65,
"preview": "language: node_js\nnode_js:\n - \"0.12\"\n - \"4\"\n - \"6\"\nsudo: false"
},
{
"path": "LICENSE",
"chars": 18046,
"preview": " GNU GENERAL PUBLIC LICENSE\n Version 2, June 1991\n\n Copyright (C) 1989, 1991 Fr"
},
{
"path": "README.md",
"chars": 8296,
"preview": "# node-potrace\nA NodeJS-compatible fork of [Potrace in JavaScript][potrace-by-kilobtye] with some additions, which is in"
},
{
"path": "lib/Posterizer.js",
"chars": 14191,
"preview": "'use strict';\n\nvar Potrace = require('./Potrace');\nvar utils = require('./utils');\n\n/**\n * Takes multiple samples using "
},
{
"path": "lib/Potrace.js",
"chars": 31749,
"preview": "'use strict';\n\nvar Jimp = require('jimp');\nvar Bitmap = require('./types/Bitmap');\nvar Curve = require('./types/Curve');"
},
{
"path": "lib/index.js",
"chars": 1928,
"preview": "'use strict';\n\nvar Potrace = require('./Potrace');\nvar Posterizer = require('./Posterizer');\n\n/**\n * Wrapper for Potrace"
},
{
"path": "lib/types/Bitmap.js",
"chars": 2419,
"preview": "'use strict';\n\nvar Point = require('./Point');\nvar utils = require('../utils');\nvar Histogram;\n\n/**\n * Represents a bitm"
},
{
"path": "lib/types/Curve.js",
"chars": 338,
"preview": "'use strict';\n\n/**\n * Curve type\n *\n * @param n\n * @constructor\n * @protected\n */\nfunction Curve(n) {\n this.n = n;\n th"
},
{
"path": "lib/types/Histogram.js",
"chars": 12343,
"preview": "\"use strict\";\n\n// Histogram\n\nvar utils = require('../utils');\nvar Jimp = null; try { Jimp = require('jimp'); } catch(e) "
},
{
"path": "lib/types/Opti.js",
"chars": 192,
"preview": "'use strict';\n\nvar Point = require('./Point');\n\nfunction Opti() {\n this.pen = 0;\n this.c = [new Point(), new Point()];"
},
{
"path": "lib/types/Path.js",
"chars": 206,
"preview": "'use strict';\n\nfunction Path() {\n this.area = 0;\n this.len = 0;\n this.curve = {};\n this.pt = [];\n this.minX = 10000"
},
{
"path": "lib/types/Point.js",
"chars": 189,
"preview": "'use strict';\n\nfunction Point(x, y) {\n this.x = x || 0;\n this.y = y || 0;\n}\n\nPoint.prototype = {\n copy: function() {\n"
},
{
"path": "lib/types/Quad.js",
"chars": 165,
"preview": "'use strict';\n\nfunction Quad() {\n this.data = [0,0,0,0,0,0,0,0,0];\n}\n\nQuad.prototype.at = function(x, y) {\n return thi"
},
{
"path": "lib/types/Sum.js",
"chars": 148,
"preview": "'use strict';\n\nfunction Sum(x, y, xy, x2, y2) {\n this.x = x;\n this.y = y;\n this.xy = xy;\n this.x2 = x2;\n this.y2 = "
},
{
"path": "lib/utils.js",
"chars": 4892,
"preview": "'use strict';\n\nvar Point = require('./types/Point');\nvar attrRegexps = {};\n\nfunction getAttrRegexp(attrName) {\n if (att"
},
{
"path": "package.json",
"chars": 802,
"preview": "{\n \"name\": \"potrace\",\n \"version\": \"2.1.2\",\n \"description\": \"Potrace in Javascript, for NodeJS\",\n \"main\": \"lib/index."
},
{
"path": "test/test.js",
"chars": 25115,
"preview": "'use strict';\n\nvar _ = require('lodash'),\n assert = require('assert'),\n should = require('should'),\n sinon = re"
}
]
About this extraction
This page contains the full source code of the Iwasawafag/node-potrace GitHub repository, extracted and formatted as plain text for AI agents and large language models (LLMs). The extraction includes 20 files (119.4 KB), approximately 33.9k tokens, and a symbol index with 45 extracted functions, classes, methods, constants, and types. Use this with OpenClaw, Claude, ChatGPT, Cursor, Windsurf, or any other AI tool that accepts text input. You can copy the full output to your clipboard or download it as a .txt file.
Extracted by GitExtract — free GitHub repo to text converter for AI. Built by Nikandr Surkov.