imagetracerjava

Simple raster image tracer and vectorizer written in Java for desktop. See https://github.com/jankovicsandras/imagetracerandroid for the Android version.

by András Jankovics

This is a port of imagetracer.js: https://github.com/jankovicsandras/imagetracerjs

1.1.5

• Updated to Java 17 (reformats all code)
• Added module-info.java
• removed use of deprecated new Integer(x) constuctor

1.1.4

• No changes in algorithm
• Ported the project setup to maven

1.1.3

• Imported Quantize.java by Adam Doppelt to replace the old quantization algorithm, which, because it was based on K-means, it averaged the colors, resulting in a non-intuitive final result, where the palette was less saturated than the original.
• Refactored the code so that it is distributed along smaller files.

1.1.2

• minor bugfixes
• lookup based pathscan()

1.1.1

• Bugfix: CSS3 RGBA output in SVG was technically incorrect (however supported by major browsers), so this is changed. More info
• transparency support: alpha is not discarded now, it is given more weight in color quantization
• new options.roundcoords : rounding coordinates to a given decimal place. This can reduce SVG length significantly (>20%) with minor loss of precision.
• new options.desc : setting this to false will turn off path descriptions, reducing SVG length.
• new options.viewbox : setting this to true will use viewBox instead of exact width and height
• new options.colorsampling : color quantization will sample the colors now by default, can be turned off.
• new options.blurradius : setting this to 1..5 will preprocess the image with a selective Gaussian blur with options.blurdelta treshold. This can filter noise and improve quality.
• IndexedImage has width and height
• getsvgstring() needs now only IndexedImage (tracedata) and options as parameters
• colorquantization() needs now only imgd, palette and options as parameters
• background field is removed from the results of color quantization

Running as a standalone program

Warning: if the outfilename parameter is not specified, then this will overwrite .svg .

Basic usage:

mvn package
java -jar target/ImageTracer-1.1.5.jar smiley.png

With options:

java -jar ImageTracer.jar smiley.png outfilename output.svg ltres 1 qtres 1 pathomit 8 colorsampling 1 numberofcolors 16 mincolorratio 0.02 colorquantcycles 3 scale 1 simplifytolerance 0 roundcoords 1 lcpr 0 qcpr 0 desc 1 viewbox 0 blurradius 0 blurdelta 20

Including in Java projects

No Project Management tool:

1. Build library
2. Copy ImageTracer-1.1.5.jar from the output directory to your project's library folder
3. Add it to your build path.

Maven:

Jitpack (downloads straight from Github):

1. Add the "jitpack" site as a repository to your repositories, like so:

   <repositories>
   	<repository>
   		<snapshots>
   			<enabled>false</enabled>
   		</snapshots>
   		<id>central</id>
   		<name>Central Repository</name>
   		<url>https://repo.maven.apache.org/maven2</url>
   	</repository>
   	<repository>
   		<id>jitpack.io</id>
   		<url>https://jitpack.io</url>
   	</repository>
   </repositories>

2. Add the github-address of this library with the latest commit hash as version to your dependencies:

   <dependencies>
   	<dependency>
   		<groupId>com.github.brixomatic</groupId>
   		<artifactId>imagetracerjava</artifactId>
   		<version>1.1.5</version> <!-- version 1.1.5 -->
   	</dependency>
   </dependencies>

See also: https://jitpack.io

Local lib-folder:

1. Add the "lib" folder as a repository

2. Build the imagetracer maven-project

3. from the .m2 directory (in the users home dir), copy this libraries file structor to the "lib" folder in your project:

   +MyProject
    *src
    +lib
     +jankovicsandras.imagetracer
       +imagetracer
        +ImageTracer
   	     +1.1.5
   	      _remote.repositories
   	      ImageTracer-1.1.4.jar
   	      ImageTracer-1.1.4.pom
   	     maven-metadata-local.xml     
   

4. Add the lib-folder as repository to your pom-file:

   <repositories>
   	<repository>
   		<snapshots>
   			<enabled>false</enabled>
   		</snapshots>
   		<id>central</id>
   		<name>Central Repository</name>
   		<url>https://repo.maven.apache.org/maven2</url>
   	</repository>
   	<repository>
   		<id>lib_folder</id>
   		<url>file://${basedir}/lib/</url>
   	</repository>
   </repositories>

5. Now include the dependency to the library:

   <dependencies>
   	<dependency>
   		<groupId>jankovicsandras.imagetracer</groupId>
   		<artifactId>ImageTracer</artifactId>
   		<version>1.1.5</version>
   	</dependency>
   </dependencies>

Using the library

Import and use the static methods:

import jankovicsandras.imagetracer.ImageTracer;

...

ImageTracer.saveString(
				"output.svg" ,
				ImageTracer.imageToSVG("input.jpg",null,null)
);

With options and palette

// Options
HashMap<String,Float> options = new HashMap<String,Float>();

// Tracing
options.put("ltres",1f);
options.put("qtres",1f);
options.put("pathomit",8f);

// Color quantization
options.put("colorsampling",1f); // 1f means true ; 0f means false: starting with generated palette
options.put("numberofcolors",16f);
options.put("mincolorratio",0.02f);
options.put("colorquantcycles",3f);

// SVG rendering
options.put("scale",1f);
options.put("roundcoords",1f); // 1f means rounded to 1 decimal places, like 7.3 ; 3f means rounded to 3 places, like 7.356 ; etc.
options.put("lcpr",0f);
options.put("qcpr",0f);
options.put("desc",1f); // 1f means true ; 0f means false: SVG descriptions deactivated
options.put("viewbox",0f); // 1f means true ; 0f means false: fixed width and height

// Selective Gauss Blur
options.put("blurradius",0f); // 0f means deactivated; 1f .. 5f : blur with this radius
options.put("blurdelta",20f); // smaller than this RGB difference will be blurred

// Palette
// This is an example of a grayscale palette
// please note that signed byte values [ -128 .. 127 ] will be converted to [ 0 .. 255 ] in the getsvgstring function
byte[][] palette = new byte[8][4];
for(int colorcnt=0; colorcnt < 8; colorcnt++){
	palette[colorcnt][0] = (byte)( -128 + colorcnt * 32); // R
	palette[colorcnt][1] = (byte)( -128 + colorcnt * 32); // G
	palette[colorcnt][2] = (byte)( -128 + colorcnt * 32); // B
	palette[colorcnt][3] = (byte)127; 		      // A
}

ImageTracer.saveString(
				"output.svg" ,
				ImageTracer.imageToSVG("input.jpg",options,palette)
);

Deterministic output

See options for deterministic tracing

Main Functions

Function name	Arguments	Returns
imageToSVG	String filename, HashMap<String,Float> options /*can be null*/, byte [][] palette /*can be null*/	String /*SVG content*/
imageToSVG	BufferedImage image, HashMap<String,Float> options /*can be null*/, byte [][] palette /*can be null*/	String /*SVG content*/
imagedataToSVG	ImageData imgd, HashMap<String,Float> options /*can be null*/, byte [][] palette /*can be null*/	String /*SVG content*/
imageToTracedata	String filename, HashMap<String,Float> options /*can be null*/, byte [][] palette /*can be null*/	IndexedImage /*read the source for details*/
imageToTracedata	BufferedImage image, HashMap<String,Float> options /*can be null*/, byte [][] palette /*can be null*/	IndexedImage /*read the source for details*/
imagedataToTracedata	ImageData imgd, HashMap<String,Float> options /*can be null*/, byte [][] palette /*can be null*/	IndexedImage /*read the source for details*/

Helper Functions

Function name	Arguments	Returns
saveString	String filename, String str	void
loadImageData	String filename	ImageData /*read the source for details*/
loadImageData	BufferedImage image	ImageData /*read the source for details*/

ImageData is similar to ImageData here.

There are more functions for advanced users, read the source if you are interested. :)

Options

Option name	Default value	Meaning
ltres	1f	Error treshold for straight lines.
qtres	1f	Error treshold for quadratic splines.
pathomit	8f	Edge node paths shorter than this will be discarded for noise reduction.
colorsampling	1f	Enable or disable color sampling. 1f is on, 0f is off.
numberofcolors	16f	Number of colors to use on palette if pal object is not defined.
mincolorratio	0.02f	Color quantization will randomize a color if fewer pixels than (total pixels*mincolorratio) has it.
colorquantcycles	3f	Color quantization will be repeated this many times.
blurradius	0f	Set this to 1f..5f for selective Gaussian blur preprocessing.
blurdelta	20f	RGBA delta treshold for selective Gaussian blur preprocessing.
scale	1f	Every coordinate will be multiplied with this, to scale the SVG.
roundcoords	1f	rounding coordinates to a given decimal place. 1f means rounded to 1 decimal place like 7.3 ; 3f means rounded to 3 places, like 7.356
viewbox	0f	Enable or disable SVG viewBox. 1f is on, 0f is off.
desc	1f	Enable or disable SVG descriptions. 1f is on, 0f is off.
lcpr	0f	Straight line control point radius, if this is greater than zero, small circles will be drawn in the SVG. Do not use this for big/complex images.
qcpr	0f	Quadratic spline control point radius, if this is greater than zero, small circles and lines will be drawn in the SVG. Do not use this for big/complex images.

Process overview

See Process overview and Ideas for improvement

License

The Unlicense / PUBLIC DOMAIN

This is free and unencumbered software released into the public domain.

Anyone is free to copy, modify, publish, use, compile, sell, or distribute this software, either in source code form or as a compiled binary, for any purpose, commercial or non-commercial, and by any means.

In jurisdictions that recognize copyright laws, the author or authors of this software dedicate any and all copyright interest in the software to the public domain. We make this dedication for the benefit of the public at large and to the detriment of our heirs and successors. We intend this dedication to be an overt act of relinquishment in perpetuity of all present and future rights to this software under copyright law.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

For more information, please refer to http://unlicense.org