MultiTouch Gestures for Java

This project aims to provide an easy way to enable MultiTouch touchpad gestures for Java in Swing. This project was originally started as an alternative for the AppleJavaExtensions com.apple.eawt package.

Read this is you came here because com.apple.eawt is not working

You landed on this page, probably because you are unable to make com.apple.eawt compile on newer versions of Java (JDK 7 and higher). However after creating this project, I found that there is a workaround. You should have a look at this question on StackOverflow: Using internal sun classes with javac. All the classes in the com.apple.eawt package are not included in the $JAVA_HOME/lib/ct.sym file, which makes the compilation fail with an error like:

com.apple.eawt can not find package
package com.apple.eawt does not exist

Adding -XDignore.symbol.file to your compiler flags solves it.

However, this project still has a purpose, I believe, since you can have smooth two finger scrolling. The Apple gesture features don't report scroll events, which are way smoother than the ones you get using a classic MouseWheelListener.

Supported Platforms

Since my personal need for now is only OS X, this is supported. However, if anyone needs support for other platforms as well, feel free to fork and create a corresponding native source file for your platform.

Building

Building the native library will automatically place the resuting binary in the resources folder of the Java project. The Java library will automatically extract the required native binary to a temporary file (that will be deleted after the application quits) and link against it. So, the only thing you will have to do to be able to use this is to build the native library and include the Java project as a dependency in Maven or add it manually to the classpath.

Java

This project is a Maven project made in NetBeans on the Java side of it. So just open this in NetBeans and you are basically good to go. You can compile this manually as well.

Native Mac OS X

This is an Xcode project that resides in the mac/ directory. Just open the project in Xcode and hit "Run". This will produce the native library file (ending in .dylib) on the right location.

Testing

There is a test file provided in:

src/main/java/com/martijncourteaux/multitouchgestures/demo/DemoSimpleGestures.java

You can have a look at that file for a sample.

You can see how this compares to the Apple Gesture support using this demo file:

src/main/java/com/martijncourteaux/multitouchgestures/demo/DemoCompareGestures.java

Usage

The usage is pretty similar to Apple's AppleJavaExtensions package from Java 6. You build your Swing frame, just as regular. Then you can do this:

MultiTouchGestureUtilities.addGestureListener(comp, listener);

Where listener is a MultiTouchGestureListener and comp is the JComponent you want to add the listener to. When you dispose/remove a JFrame or component with a listener, you MUST remove the MultiTouchGestureListener using one of following techniques:

MultiTouchGestureUtilities.removeGestureListener(comp, listener);
MultiTouchGestureUtilities.removeAllGestureListeners(comp);

The MultiTouchGestureListener interface has these methods:

public void magnify(MagnifyGestureEvent e);
public void rotate(RotateGestureEvent e);
public void scroll(ScrollGestureEvent e);

Where each event type has these parameters:

• mouseX: x-coordinate of the mouse in the component space.
• mouseX: y-coordinate of the mouse in the component space.
• absMouseX: x-coordinate of the mouse on the screen
• absMouseY: y-coordinate of the mouse on the screen
• phase: a GesturePhase enum indicating what phase the gesture is in.

A GesturePhase is an enum containing these values:

• MOMENTUM: Indicates this event is caused by momentum (like OS X).
• BEGIN: The gesture just began.
• CHANGED: The gesture updated (e.g.: rotating, zooming)
• END: The gesture ended.
• CANCELLED: The gesture was cancelled due to some popup or other thing.
• OTHER: Any other reason for an event. Most of the time this will be errornous.

Remark: On OS X, the MOMENTUM events come after the END event.

Remark for OS X

The built-in Java scrolling listeners are not as smooth as the one provided in this project. So I highly recommend checking it out. This gives you the native OS X scrolling experience.