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What is Batik?

Batik use cases Batik is a Java(tm) technology based toolkit for applications that want to use images in the Scalable Vector Graphics (SVG) format for various purposes, such as viewing, generation or manipulation.

The project's ambition is to give developers a set of core modules which can be used together or individually to support specific SVG solutions. Examples of modules are an SVG parser, an SVG generator and an SVG DOM implementations. Another ambition of the Batik project is to make it highly extensible (for example, Batik allows the developer to handle custom SVG tags). Even though the goal of the project is to provide a set of core modules, one of the deliveries is a full fledged SVG Browser implementation which validates the various modules and their inter-operability.

In a nutshell, Batik provides building blocks that developers can assemble in various ways in their Java technology applications to generate, parse, view or convert SVG contents. For example, Batik contains a Swing component that can add SVG viewing capability to all Java technology applications. Batik can also be used to generate SVG on a client or on a server, and Batik can convert SVG content into other formats such as JPEG or PNG. Batik's goal is to make it easy for application developers to handle SVG content for various purposes, client-side or server-side, as illustrated in the above diagram.


What is SVG?

SVG (Scalable Vector Graphics) is an open-standard language for describing two-dimensional (2D) graphics in XML. It is a Candidate Recommendation from the W3C. SVG lets you describe rich images with features such as gradients, transparency, filter effects and animation.

SVG allows for three types of graphic objects: shapes (e.g., paths consisting of straight lines and curves), images and text. Graphical objects can be grouped, styled, transformed and composited (e.g., drawn with transparency). SVG has a large set of static features that includes nested transformations, clipping paths, masking and filter effects.

In addition, SVG images can be dynamic and interactive. A rich set of event handlers such as onmouseover and onclick can be assigned to any SVG graphical object. These handlers can invoke scripts, which, in response to an event, can dynamically modify the SVG graphic through the SVG Document Object Model (DOM) API, allowing, for example scripts to change the color or location of graphical elements in reaction to events.

SVG graphical elements can also be animated through scripting. Alternatively, animation sequences can be expressed directly in XML because SVG leverages the SMIL specification for multimedia, another W3C specification.


What can I do with Batik?

Batik contains several core modules that can be used independently or jointly to generate SVG content (see the SVG Generator, an SVG DOM implementation documentation) view SVG content (see the JSVGCanvas) or convert to and from the SVG format (see the SVG Transcoders tutorial).

In addition, Batik contains low level modules such as an object oriented Graphic Vector Toolkit (GVT), a set of low level parsers specific to the SVG syntax and a set of extensions to the Java 2D API (such as sophisticated fill types and filter effects).

Finally, Batik comes with packaged applications to help developers get familiar with the code and be quickly able to use the various modules: an SVG browser (in the org.apache.batik.apps.svgbrowser package) an SVG rasterizer (in the org.apache.batik.apps.rasterizer package), a Font converter (in the org.apache.batik.apps.ttf2svg package) and an SVG pretty printer (in the org.apache.batik.apps.svgpp package).

The SVG browser can display SVG documents and lets the user zoom, pan and rotate any SVG document, view the SVG source, link between SVG documents, view a tree representation of the SVG DOM and more. One important component of the SVG viewer is the org.apache.batik.swing.JSVGCanvas component that can be plugged in any Java application to provide SVG viewing capability.

The SVG rasterizer lets the user convert SVG files to raster formats such as JPEG and PNG. It contains an extensible mechanism so that arbitrary raster formats can be added. For example, the rasterizer lets you create one SVG file with a special effect (e.g., shadows, gradients, etc...), turn it into an PNG image, then modify the SVG source (e.g., modify a piece of text or a color), and generate another PNG image from it. This way, you can easily generate a series of images sharing a common theme or look and feel to post on a web site (note that the rasterizer can also be used on a web server to do this conversion automatically).

The SVG Font Converter lets the user easily create an SVG Font for a set of characters from a True Type Font file. That SVG Font definition can be embedded in a document using the characters. This allows users to create SVG documents that are self contained and do not rely on system fonts, and guarantees that the SVG file will be displayed exactly as it was authored on all platforms.

The SVG Pretty Printer is a convenience tool to pretty print an SVG document, which means that you can reformat any existing SVG document to produce a properly formatted and highly legible version.

These applications show that Batik can be used client side (the browser can be used on any client machine) and server side (the rasterizer can be used to serve SVG images to client machines that do not have SVG support).

The SVG viewer and the rasterizer are only examples of the type of applications Batik allows. Its architecture allows the different modules to be used in different ways and other applications are possible, such as transcoders (to other vector formats, such as PDF, for example). Furthermore, the Graphic Vector Toolkit could be used to render other graphic formats such as XHTML.


How can I see a demo?

You can either download Batik or see screenshots of the Batik SVG viewer, images created from the rasterizer and an example of how to use the SVG Graphics2D generator.


Why do we have such a project at Apache?

Apache's mission is to allow the web to be an open environment and to remain an open environment. Batik is an open source implementation of a key format for today and tomorrow's web and fits well in Apache's mission.


How does Batik relate to other Apache projects?

Batik is used in Cocoon for server side rasterization of SVG images. In addition, the Batik and the FOP teams have started to work together to define how the projects can leverage each other's work for SVG to PDF conversion.


How did it start?

Batik started out because several teams doing SVG related projects decided to join efforts with the idea that the whole will be greater than the sum of the parts. The following companies or institutions are part of the team that contributed and/or created the initial Batik project:

In addition, the Batik project is supported by IBM.

We encourage anyone to participate. As with all ASF project, all efforts are volunteer-based. We are looking for individuals to work with us on fulfilling our goals for Batik in the spirit of collaborative open-source software development.


How can I contribute?

The Batik Project is an open volunteer project based on the spirit of the Apache Software Foundation (ASF). This means that there are lots of ways to contribute to the project, either with direct participation (coding, documenting, answering questions, proposing ideas, reporting bugs, suggesting bug-fixes, etc..) or by resource donation (publicity, hardware, software, conference presentations, speeches, etc...). Applications that use the Batik modules, such as tools or extensions, are of special interest to the project.

The process for contributing to Batik is the same as for other Java projects at Apache. A formal description of that process can be found on the Jakarta web site.

For direct participation, we suggest you to subscribe to the Batik mailing list (follow the link for information on how to subscribe and to access the mail list archives), and to checkout the latest code.


Where is Batik going? What is next?

The SVG implementation is not complete, and there is more work to do to achieve a fully functional viewer, especially in dynamic behavior (the scripting support is not fully implemented yet and there is no SMIL animation support yet).

The type of applications (e.g., transcoding applications) that can or will be added to Batik depends on contributions and feedback.


How can I create and author SVG content?

Well, you can always use a plain text editor such as vi or xemacs, but there are many graphic authoring packages that can export SVG documents and that will let you author SVG content visually.

You can get a list of tools that can export SVG from the implementation section of the SVG Home page on the W3C web site. You can also imagine building a tool on top of Batik: feel free to contribute!

Authoring is one way of creating SVG content, and graphic authoring packages are useful for that purpose. However, there are many types of graphics which can be generated, such as stock quotes, statistical data, etc. For these types of graphics, there are many ways to generate SVG content. For example, if your data (say stock information) is contained in an XML document, you could use XSLT to transform your XML data into SVG. If your data comes from a database and you retrieve that data in a servlet on a Web server (e.g., using JDBC), you could use the Java binding for the DOM API to generate an SVG document from the data base data. You could also use Batik's SVG generator and use the Java 2D API to generate that graphic.

The following URLs will be useful to learn more about each of these solutions:


What other SVG products are out there?

There are many companies supporting SVG and you will find a list of available implementations on the W3C's SVG implementation page


Where can I find the SVG specification?

The SVG specification is available from the W3C Web site


How much of SVG does Batik implement?

The following status page shows how much of the SVG specification Batik implements by showing which of the tests in the SVG Basic Effectivity test suite Batik successfully passes.


What are the benefits of SVG being an XML grammar?

Being an XML grammar means SVG can leverage work done around XML, and SVG actually leverages other grammars such as XLink for linking and SMIL for the animation.

Beyond the use and mix with other XML syntaxes, being an XML grammar lets SVG benefit from the pletora of XML tools that make it so easy to manipulate, generate, search and edit SVG files.


Where does the name come from?

Batik is a highly evolved art tradition that developed in Java (one of the islands comprising what is now called Indonesia). Batik is generally thought of as the quintessentially Indonesian textile. Motifs of flowers, twining plants, leaves, buds, birds, butterflies, fish, insects and geometric forms are rich in symbolic association and variety; there are about three thousand recorded batik patterns.

We think that Batik gracefully evokes Java, graphics and high-quality, terms that constitute the core of the toolkit.

The following page shows examples of what Batik textures look like.


What are the System Requirements to run Batik?

Batik is written in the Java language and requires a version 1.3 implementation at this time. Note that the Batik team is working on removing the few dependancies that Batik has on 1.3-specific APIs so that users may choose to run Batik on JDK 1.2.2. Note, however, that performances on version 1.3 are much better.


How do I install Batik?

You will need the JDK 1.3 to run Batik.

To install Batik you need to download the binary or source distribution and unzip it on your computer.

You can have a look at the installation instructions for more information.


How do I submit patches or bug fixes?

You can submit bug fixes and patches to the Batik developers mailing list and you can enter bugs in Bugzilla.


What scripting languages can I use in my SVG files?

A limited support of scripting in SVG files is provided with the current version of Batik (script are executed but dynamic update is not supported).

Batik can recognized the following scripting languages:

  • ECMAScript thanks to the Mozilla Rhino JavaScript engine included in the distribution.
  • Python for which you need to download the JPython engine.
  • Tcl for which you need to download the Jacl engine.

To get more information on how to install optional scripting languages you can have a look at the installation instructions.


When I try to run Batik it results in a NoSuchMethodException. What is the problem?

There is certainly something wrong with your classpath. Clear your CLASSPATH environment variable and be sure to remove all the libraries which use the W3C's DOM bindings from jre/lib/ext before running any of the Batik's applications.


I can use the Batik extension tags with the source distribution but not with the binary distribution. What am I missing?

When running from the source distribution you automatically get the service provider entries for the Batik extension tags (regularPolygon, and star for example). We choose not to include these by default in the binary distribution for the Batik applications.

You can make the Batik extension tags available by putting the 'lib/batik-extensions.jar' file on the java class path.


Why do I get red circles when I view the samples/extensions files?

You are using the binary distribution. This distribution does not include support for our example extensions (they are just examples so other people can do much more interesting things).

If you really want to view these examples (they aren't that interesting) you should arrange for lib/batik-extensions.jar to be on your class path.




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