LaTeX to image | Aspose.TeX for Java

How to convert LaTeX to PNG

Let’s take a closer look at the Java code providing the simplest way to convert LaTeX to PNG format.

// Create conversion options for Object LaTeX format upon Object TeX engine extension.
TeXOptions options = TeXOptions.consoleAppOptions(TeXConfig.objectLaTeX());
// Specify a file system working directory for the output.
options.setOutputWorkingDirectory(new OutputFileSystemDirectory(Utils.getOutputDirectory()));
// Initialize the options for saving in PNG format.
options.setSaveOptions(new PngSaveOptions());
// Run LaTeX to PNG conversion.
new TeXJob(Utils.getInputDirectory() + "hello-world.ltx", new ImageDevice(), options).run();

So, the first thing we need to do (sometimes not the very first, as we will find out later) is to create an instance of the TeXOptions class. The only static method that does this is consoleAppOptions(), so let’s not bother with the meaning of its name. The method takes the objectLaTeX() instance of the TeXConfig class, which is exactly suitable for converting a LaTeX file. This configuration instructs the Object TeX engine to load the Object LaTeX format and to be ready to accept the LaTeX file. Object LaTeX format is actually just the LaTeX format, except that it uses Object TeX specific primitives to set up the page metrics.

The first of the required options is OutputWorkingDirectory which defines the space, or area, where the TeX output will be written. Here are the details about the output directory concept in Aspose.TeX for Java. In this example, we use the OutputFileSystemDirectory class, which allows us to write the output to the specified directory, or folder.

The second option is a SaveOptions class instance which will control the transformation of the object model to the target format. Since we are converting LaTeX to PNG, it’s the PngSaveOptions class instance, which allows us to specify the resolution of the output images.

Next, we need to create an instance of the TeXJob class. Wanting to convert a LaTeX file stored in the file system, we use this version of the constructor. We should specify the full path to the file. Otherwise, the engine will look for it in the current directory (which is defined here) and most likely will not find it. Nevertheless, we may omit the extension if our file has the .tex one. The engine will append it automatically. The second argument of the constructor is a Device class instance. Since we are converting LaTeX to PNG, it’s an ImageDevice class (which is common to all supported image formats) instance. As the last argument, we pass the recently prepared conversion options.

All that we have to do now is to run the job.

Regardless of whether the run was successful or not, the first result that we’ll see will be the terminal output. In case of success, it looks something like this:

This is ObjectTeX, Version 3.1415926-1.0 (Aspose.TeX 21.8)
entering extended mode

(<input_directory>\hello-world.ltx
LaTeX2e <2011/06/27>
(article.cls
Document Class: article 2007/10/19 v1.4h Standard LaTeX document class
(size10.clo))
No file hello-world.aux.
[1]
(<output_directory>\hello-world.aux) )
Output written on hello-world.png (1 page).
Transcript written on hello-world.log.

We will find other products of the engine’s run in the folder that we specified as the output directory. Those will be the transcript (.log) file and, Voila!, the main output PNG image file(s).

An alternative way to write the main output PNG file(s)

There is another way to get image data as an array of byte arrays, each array in the second dimension represents image data for a separate page.

// Create conversion options instance.
...
// Initialize the options for saving in PNG format.
PngSaveOptions saveOptions = new PngSaveOptions();
// Set this property to instruct the device not to output images as you will access them alternatively.
saveOptions.deviceWritesImages(false);
options.setSaveOptions(saveOptions);
// Create the image device.
ImageDevice device = new ImageDevice();
// Run LaTeX to PNG conversion.
new TeXJob(Utils.getInputDirectory() + "hello-world.ltx", device, options).run();

// Save pages file by file.
for (int i = 0; i < device.getResult().length; i++)
{
  final OutputStream fs = new FileOutputStream(Utils.getOutputDirectory() + MessageFormat.format("page-{0}.png", (i + 1)));
  try {
    fs.write(device.getResult()[i], 0, device.getResult()[i].length);
  } finally {
    if (fs != null)
      fs.close();
  }
}

The “page-n.png” file(s) will be written to any path we specify. Unlike PDF output, they will duplicate the output PNG files written to the output directory.

About input options

In case our main input file requires dependencies, for example, packages, that are not included in the basic LaTeX system and supported packages, we MUST set the RequiredInputDirectory option the similar way we set the OutputWorkingDirectory option and put the dependencies in that directory. Dependencies may be arbitrarily organized in subdirectories. In case we have our own files to include along the typesetting process, say external graphics files, we MUST also set the InputWorkingDirectory using the path to the location where those files are collected. We may also place the main input file somewhere inside the input directory and specify the relative path in the run() method (or specify no path at all if the main input file is in the root). Here are the details about the input directory concept in Aspose.TeX for Java and provided implementations.

Other TeX job options are discussed here.

You may also check out the free LaTeX-to-PNG conversion web app built based on Aspose.TeX for .NET API. Here is the Java version page.

Below, we discuss the LaTeX conversion to other supported raster image formats. We won’t go into details just because there aren’t actually any details. The only difference is in the type of the SaveOptions property in the conversion options.

How to convert LaTeX to JPG

// Create conversion options instance.
...
// Initialize the options for saving in JPEG format.
options.SaveOptions = new JpegSaveOptions();

You may also check out the free LaTeX-to-JPG conversion web app built based on Aspose.TeX for .NET API. Here is the Java version page.

How to convert LaTeX to TIFF

// Create conversion options instance.
...
// Initialize the options for saving in TIFF format.
options.SaveOptions = new TiffSaveOptions();

You may also check out the free LaTeX-to-TIFF conversion web app built based on Aspose.TeX for .NET API. Here is the Java version page.

How to convert LaTeX to BMP

// Create conversion options instance.
...
// Initialize the options for saving in BMP format.
options.SaveOptions = new BmpSaveOptions();

You may also check out the free LaTeX-to-BMP conversion web app built based on Aspose.TeX for .NET API. Here is the Java version page.

How to convert LaTeX to SVG

And yet another supported target format is SVG. Scalable Vector Graphics (SVG) is an XML-based vector image format for defining two-dimensional graphics, having support for interactivity and animation.

SVG images are defined in a vector graphics format and stored in XML text files. This means that SVG images can be scaled in size without loss of quality, and SVG files can be searched, indexed, scripted, and compressed. The XML text files can be created and edited with text editors or vector graphics editors. Thay are rendered by the most-used web browsers.

Also, there is the Aspose.SVG library that has various features based on the SVG format. These include creating, loading, editing and converting SVG documents.

The conversion to SVG is just as simple as the conversion to raster image formats, except that in addition to the SaveOptions, we have to change the device to an instance of the SvgDevice class.

// Create conversion options for Object LaTeX format upon Object TeX engine extension.
TeXOptions options = TeXOptions.consoleAppOptions(TeXConfig.objectLaTeX());
// Specify a file system working directory for the output.
options.setOutputWorkingDirectory(new OutputFileSystemDirectory(Utils.getOutputDirectory()));
// Initialize the options for saving in SVG format.
options.setSaveOptions(new SvgSaveOptions());
// Run LaTeX to SVG conversion.
new TeXJob(Utils.getInputDirectory() +  "hello-world.ltx", new SvgDevice(), options).run();

You may also check out the free LaTeX-to-SVG conversion web app built based on Aspose.TeX for .NET . Here is the Java version page.