/** * 缩放 * * @param source 目标图片路径 * @param targetW 宽度 * @param targetH 高度 */ public static BufferedImage resize(BufferedImage source, int targetW, int targetH) { // targetW,targetH分别表示目标长和宽 int type = source.getType(); BufferedImage target = null; double sx = (double) targetW / source.getWidth(); double sy = (double) targetH / source.getHeight(); //这里想实现在targetW,targetH范围内实现等比缩放。如果不需要等比缩放 //则将下面的if else语句注释即可 if(sx>sy) { sx = sy; targetW = (int)(sx * source.getWidth()); }else{ sy = sx; targetH = (int)(sy * source.getHeight()); } if (type == BufferedImage.TYPE_CUSTOM) { //handmade ColorModel cm = source.getColorModel(); WritableRaster raster = cm.createCompatibleWritableRaster(targetW, targetH); boolean alphaPremultiplied = cm.isAlphaPremultiplied(); target = new BufferedImage(cm, raster, alphaPremultiplied, null); } else target = new BufferedImage(targetW, targetH, type); Graphics2D g = target.createGraphics(); //smoother than exlax: g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY ); g.drawRenderedImage(source, AffineTransform.getScaleInstance(sx, sy)); g.dispose(); return target; } /** * 缩放 * * @param fromFileStr 源图片路径 * @param saveToFileStr 目标图片路径 * @param height 高度 * @param width 宽度 */ public static void resizeImage(String fromFileStr,String saveToFileStr,int width,int hight) throws Exception { BufferedImage srcImage; String imgType = "JPEG"; if (fromFileStr.toLowerCase().endsWith(".png")) { imgType = "PNG"; } File saveFile=new File(saveToFileStr); File fromFile=new File(fromFileStr); srcImage = ImageIO.read(fromFile); if(width > 0 || hight > 0){ srcImage = resize(srcImage, width, hight); } ImageIO.write(srcImage, imgType, saveFile); }
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