Archived

Superseded by KeenType, which builds upon NTS to provide far greater functionality.

KeenTeX

Java library for displaying mathematical formulas using TeX notation.

This is a fork of JMathTex. The intention of the fork is to render simple math-oriented formulas in real-time. Besides performance, the fork fixes rendering issues with the original. This is not a LaTeX engine, nor a full implementation of TeX. Rather, it is a subset of TeX that can be used to generate simple mathematical expressions.

The library can parse and generate 1,000 simple formulas into SVG format in about 500 milliseconds on modern hardware.

Building

Ensure the JAVA_HOME environment variable is set to the JDK installation directory root (e.g., /opt/jdk).

Build the library as follows:

gradle clean build

Build an optimized version as follows:

gradle clean build; ./squish.sh

This runs a bytecode optimizer to produce a smallar JAR file.

Test the minified library as follows:

gradle clean build
./squish.sh
java \
  -cp ./build/libs/keentex-min.jar:./build/classes/java/test \
  com.whitemagicsoftware.tex.FormulaTest

This runs the unit tests, rendering SVG files into /tmp on Linux.

Getting Started

Use the library as follows:

Initialize the TeX fonts and graphics engine.
Parse the TeX formula into a root-level box.
Resize the graphics engine to fit the box contents.
Display (or export) the vector graphics as needed.

Let's see an example.

Initialization

Generating a formula requires a font, a font size, and a graphics engine. The graphics engine must be scaled to the font size for its internal matrix transformations. Accomplish these steps as follows:

final var size = 20f;
final var texFont = new DefaultTeXFont( size );
final var env = new TeXEnvironment( texFont );
final var g = new SvgGraphics2D();
g.scale( size, size );

The font, environment, and graphics objects are reusable, but not thread-safe. The SvgGraphics2D is a high-performance, bare-bones drop-in replacement for Java's Graphics2D class. It is faster than the equivalent functionality from either Batik or JFreeSVG because it optimizes for transcoding glyph path coordinates into SVG paths.

Much of the code that configures the system takes place in static blocks that run only once, prior to instantiating classes.

Parse TeX

Given an equation, parse it into a layout suitable for rendering as follows:

final var equation = "\\sigma=\\sqrt{\\sum_{i=1}^{k} p_i(x_i-\\mu)^2}";
final var formula = new TeXFormula( equation );
final var box = formula.createBox( env );
final var layout = new TeXLayout( box, size );

The layout object contains the final bounding rectangle that fully encapsulates the equation.

Resize Graphics

Having a reusable SvgGraphics2D object requires resetting its state each time a new formula is to be drawn. This is accomplished by calling initialize using the dimensions from the TeXLayout object:

g.initialize( layout.getWidth(), layout.getHeight() );
box.draw( g, layout.getX(), layout.getY() );

Calls to box.draw can take any valid Graphics2D class or subclass. The SvgGraphics2D class implements the minimum drawing primitives used to draw the glyph boxes.

Generate Scalable Vector Graphics

At this point, the internal buffer for SvgGraphics2D contains a nearly complete document. Finalize and extract the document by calling toString():