public static void main(String[] args) {
final Display display = new Display();
final Image image = display.getSystemImage(SWT.ICON_INFORMATION);
final Shell shell = new Shell(display, SWT.NO_TRIM);
Region region = new Region();
final ImageData imageData = image.getImageData();
if (imageData.alphaData != null) {
Rectangle pixel = new Rectangle(0, 0, 1, 1);
for (int y = 0; y < imageData.height; y++) {
for (int x = 0; x < imageData.width; x++) {
if (imageData.getAlpha(x, y) == 255) {
pixel.x = imageData.x + x;
pixel.y = imageData.y + y;
region.add(pixel);
}
}
}
} else {
ImageData mask = imageData.getTransparencyMask();
Rectangle pixel = new Rectangle(0, 0, 1, 1);
for (int y = 0; y < mask.height; y++) {
for (int x = 0; x < mask.width; x++) {
if (mask.getPixel(x, y) != 0) {
pixel.x = imageData.x + x;
pixel.y = imageData.y + y;
region.add(pixel);
}
}
}
}
shell.setRegion(region);
Listener l =
new Listener() {
/** The x/y of the MouseDown, relative to top-left of the shell. */
int startX, startY;
@Override
public void handleEvent(Event e) {
if (e.type == SWT.KeyDown && e.character == SWT.ESC) {
shell.dispose();
}
if (e.type == SWT.MouseDown && e.button == 1) {
Point p = shell.toDisplay(e.x, e.y);
Point loc = shell.getLocation();
startX = p.x - loc.x;
startY = p.y - loc.y;
}
if (e.type == SWT.MouseMove && (e.stateMask & SWT.BUTTON1) != 0) {
Point p = shell.toDisplay(e.x, e.y);
p.x -= startX;
p.y -= startY;
shell.setLocation(p);
}
if (e.type == SWT.Paint) {
e.gc.drawImage(image, imageData.x, imageData.y);
}
}
};
shell.addListener(SWT.KeyDown, l);
shell.addListener(SWT.MouseDown, l);
shell.addListener(SWT.MouseMove, l);
shell.addListener(SWT.Paint, l);
shell.open();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) display.sleep();
}
region.dispose();
image.dispose();
display.dispose();
}