20個非常有用的JAVA程式片段
阿新 • • 發佈：2018-12-16
- private void createThumbnail(String filename, int thumbWidth, int thumbHeight, int quality, String outFilename)
- throws InterruptedException, FileNotFoundException, IOException
- {
- // load image from filename
- Image image = Toolkit.getDefaultToolkit().getImage(filename);
- MediaTracker mediaTracker = new MediaTracker(new Container());
- mediaTracker.addImage(image, 0);
- mediaTracker.waitForID(0);
- // use this to test for errors at this point: System.out.println(mediaTracker.isErrorAny());
- // determine thumbnail size from WIDTH and HEIGHT
- double thumbRatio = (double)thumbWidth / (double)thumbHeight;
- int imageWidth = image.getWidth(null);
- int imageHeight = image.getHeight(null);
- double imageRatio = (double)imageWidth / (double)imageHeight;
- if (thumbRatio < imageRatio) {
- thumbHeight = (int)(thumbWidth / imageRatio);
- } else {
- thumbWidth = (int)(thumbHeight * imageRatio);
- }
- // draw original image to thumbnail image object and
- // scale it to the new size on-the-fly
- BufferedImage thumbImage = new BufferedImage(thumbWidth, thumbHeight, BufferedImage.TYPE_INT_RGB);
- Graphics2D graphics2D = thumbImage.createGraphics();
- graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
- graphics2D.drawImage(image, 0, 0, thumbWidth, thumbHeight, null);
- // save thumbnail image to outFilename
- BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(outFilename));
- JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
- JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(thumbImage);
- quality = Math.max(0, Math.min(quality, 100));
- param.setQuality((float)quality / 100.0f, false);
- encoder.setJPEGEncodeParam(param);
- encoder.encode(thumbImage);
- out.close();
- }