JAVA功能代碼《8》—-Java建立圖片的縮圖

8.Java建立圖片的縮圖

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