SWT显示GIF动态图片工具类
整理了一个工具类, 用于在SWT中显示GIF图片
/** * 用于显示GIF图片的util类 * * @author mark.wang */public class ImageViewer extends Canvas {protected Point origin = new Point(0, 0);protected Image image;protected ImageData[] imageDatas;protected Image[] images;protected int current;private int repeatCount;private Runnable animationTimer;private Color bg;private Display display;public ImageViewer(Composite parent) {super(parent, SWT.NO_BACKGROUND | SWT.NO_REDRAW_RESIZE);bg = getBackground();display = getDisplay();addListeners();}/** * @param repeatCount * 0 forever */public void setImages(ImageData[] imageDatas, int repeatCount) {checkWidget();this.image = null;this.imageDatas = imageDatas;this.repeatCount = repeatCount;convertImageDatasToImages();startAnimationTimer();redraw();}@Overridepublic Point computeSize(int wHint, int hHint, boolean changed) {checkWidget();Image image = getCurrentImage();if (image != null) {Rectangle rect = image.getBounds();Rectangle trim = computeTrim(0, 0, rect.width, rect.height);return new Point(trim.width, trim.height);}return new Point(wHint, hHint);}@Overridepublic void dispose() {if (image != null)image.dispose();if (images != null)for (int i = 0; i < images.length; i++)images[i].dispose();super.dispose();}protected void paint(Event e) {Image image = getCurrentImage();if (image == null)return;GC gc = e.gc;gc.drawImage(image, origin.x, origin.y);gc.setBackground(bg);Rectangle rect = image.getBounds();Rectangle client = getClientArea();int marginWidth = client.width - rect.width;if (marginWidth > 0) {gc.fillRectangle(rect.width, 0, marginWidth, client.height);}int marginHeight = client.height - rect.height;if (marginHeight > 0) {gc.fillRectangle(0, rect.height, client.width, marginHeight);}}void addListeners() {addListener(SWT.Paint, new Listener() {public void handleEvent(Event e) {paint(e);}});}void convertImageDatasToImages() {images = new Image[imageDatas.length];// Step 1: Determine the size of the resulting images.int width = imageDatas[0].width;int height = imageDatas[0].height;// Step 2: Construct each image.int transition = SWT.DM_FILL_BACKGROUND;for (int i = 0; i < imageDatas.length; i++) {ImageData id = imageDatas[i];images[i] = new Image(display, width, height);GC gc = new GC(images[i]);// Do the transition from the previous image.switch (transition) {case SWT.DM_FILL_NONE:case SWT.DM_UNSPECIFIED:// Start from last image.gc.drawImage(images[i - 1], 0, 0);break;case SWT.DM_FILL_PREVIOUS:// Start from second last image.gc.drawImage(images[i - 2], 0, 0);break;default:// DM_FILL_BACKGROUND or anything else,// just fill with default background.gc.setBackground(bg);gc.fillRectangle(0, 0, width, height);break;}// Draw the current image and clean up.Image img = new Image(display, id);gc.drawImage(img, 0, 0, id.width, id.height, id.x, id.y, id.width,id.height);img.dispose();gc.dispose();// Compute the next transition.// Special case: Can't do DM_FILL_PREVIOUS on the// second image since there is no "second last"// image to use.transition = id.disposalMethod;if (i == 0 && transition == SWT.DM_FILL_PREVIOUS)transition = SWT.DM_FILL_NONE;}}Image getCurrentImage() {if (image != null)return image;if (images == null)return null;return images[current];}void startAnimationTimer() {if (images == null || images.length < 2)return;final int delay = imageDatas[current].delayTime * 10;display.timerExec(delay, animationTimer = new Runnable() {public void run() {if (isDisposed())return;current = (current + 1) % images.length;redraw();if (current + 1 == images.length && repeatCount != 0&& --repeatCount <= 0)return;display.timerExec(delay, this);}});}void stopAnimationTimer() {if (animationTimer != null)display.timerExec(-1, animationTimer);}public static void main(String[] args) {Display display = new Display();final Shell shell = new Shell(display);CopyOfImageViewer ic = new CopyOfImageViewer(shell);shell.setLayout(new FillLayout());FileDialog dialog = new FileDialog(shell, SWT.OPEN);dialog.setText(" Open an gif image file or cancel, only gif ");String string = dialog.open();ImageLoader loader = new ImageLoader();ImageData[] imageDatas = loader.load(string);ic.setImages(imageDatas, loader.repeatCount);ic.pack();shell.pack();shell.open();while (!shell.isDisposed()) {if (!display.readAndDispatch())display.sleep();}display.dispose();}}