基于java实现图像裁剪以及生成缩略图功能
本文主要介绍基于java实现图像裁剪以及生成缩略图的方法。结果表明，JDK原生图像处理工具包（imageIO）对gif格式处理先天不足，详细探索代码如下：
import java.awt.Color; import java.awt.Graphics; import java.awt.Image; import java.awt.image.BufferedImage; import java.io.File; import java.io.IOException; import java.util.Arrays; import java.util.Iterator; import javax.imageio.IIOImage; import javax.imageio.ImageIO; import javax.imageio.ImageReader; import javax.imageio.ImageWriter; import javax.imageio.stream.ImageInputStream; import javax.imageio.stream.ImageOutputStream; /** * 图像裁剪以及压缩处理工具类 * * 主要针对动态的GIF格式图片裁剪之后，只出现一帧动态效果的现象提供解决方案 * * 提供依赖三方包解决方案（针对GIF格式数据特征一一解析，进行编码解码操作） * 提供基于JDK Image I/O 的解决方案(JDK探索失败) * * * @author Andy * @see GifDecoder.class * @see AnimatedGifEncoder.class * @see BufferedImage.class * @see ImageIO.class * @see ImageReader.class * @since 1.0 2011.12.21 */ public class ImageCutterUtil { public enum IMAGE_FORMAT{ BMP("bmp"), JPG("jpg"), WBMP("wbmp"), JPEG("jpeg"), PNG("png"), GIF("gif"); private String value; IMAGE_FORMAT(String value){ this.value = value; } public String getValue() { return value; } public void setValue(String value) { this.value = value; } } /** * 获取图片格式 * @param file 图片文件 * @return 图片格式 */ public static String getImageFormatName(File file)throws IOException{ String formatName = null; ImageInputStream iis = ImageIO.createImageInputStream(file); Iterator<ImageReader> imageReader = ImageIO.getImageReaders(iis); if(imageReader.hasNext()){ ImageReader reader = imageReader.next(); formatName = reader.getFormatName(); } return formatName; } /************************* 基于三方包解决方案 *****************************/ /** * 剪切图片 * * @param source 待剪切图片路径 * @param targetPath 裁剪后保存路径（默认为源路径） * @param x 起始横坐标 * @param y 起始纵坐标 * @param width 剪切宽度 * @param height 剪切高度 * * @returns 裁剪后保存路径（图片后缀根据图片本身类型生成） * @throws IOException */ public static String cutImage(String sourcePath , String targetPath , int x , int y , int width , int height) throws IOException{ File file = new File(sourcePath); if(!file.exists()) { throw new IOException("not found the image：" + sourcePath); } if(null == targetPath || targetPath.isEmpty()) targetPath = sourcePath; String formatName = getImageFormatName(file); if(null == formatName) return targetPath; formatName = formatName.toLowerCase(); // 防止图片后缀与图片本身类型不一致的情况 String pathPrefix = getPathWithoutSuffix(targetPath); targetPath = pathPrefix + formatName; // GIF需要特殊处理 if(IMAGE_FORMAT.GIF.getValue() == formatName){ GifDecoder decoder = new GifDecoder(); int status = decoder.read(sourcePath); if (status != GifDecoder.STATUS_OK) { throw new IOException("read image " + sourcePath + " error!"); } AnimatedGifEncoder encoder = new AnimatedGifEncoder(); encoder.start(targetPath); encoder.setRepeat(decoder.getLoopCount()); for (int i = 0; i < decoder.getFrameCount(); i ++) { encoder.setDelay(decoder.getDelay(i)); BufferedImage childImage = decoder.getFrame(i); BufferedImage image = childImage.getSubimage(x, y, width, height); encoder.addFrame(image); } encoder.finish(); }else{ BufferedImage image = ImageIO.read(file); image = image.getSubimage(x, y, width, height); ImageIO.write(image, formatName, new File(targetPath)); } return targetPath; } /** * 压缩图片 * @param sourcePath 待压缩的图片路径 * @param targetPath 压缩后图片路径（默认为初始路径） * @param width 压缩宽度 * @param height 压缩高度 * * @returns 裁剪后保存路径（图片后缀根据图片本身类型生成） * @throws IOException */ public static String zoom(String sourcePath , String targetPath, int width , int height) throws IOException{ File file = new File(sourcePath); if(!file.exists()) { throw new IOException("not found the image ：" + sourcePath); } if(null == targetPath || targetPath.isEmpty()) targetPath = sourcePath; String formatName = getImageFormatName(file); if(null == formatName) return targetPath; formatName = formatName.toLowerCase(); // 防止图片后缀与图片本身类型不一致的情况 String pathPrefix = getPathWithoutSuffix(targetPath); targetPath = pathPrefix + formatName; // GIF需要特殊处理 if(IMAGE_FORMAT.GIF.getValue() == formatName){ GifDecoder decoder = new GifDecoder(); int status = decoder.read(sourcePath); if (status != GifDecoder.STATUS_OK) { throw new IOException("read image " + sourcePath + " error!"); } AnimatedGifEncoder encoder = new AnimatedGifEncoder(); encoder.start(targetPath); encoder.setRepeat(decoder.getLoopCount()); for (int i = 0; i < decoder.getFrameCount(); i ++) { encoder.setDelay(decoder.getDelay(i)); BufferedImage image = zoom(decoder.getFrame(i), width , height); encoder.addFrame(image); } encoder.finish(); }else{ BufferedImage image = ImageIO.read(file); BufferedImage zoomImage = zoom(image , width , height); ImageIO.write(zoomImage, formatName, new File(targetPath)); } return targetPath; } /*********************** 基于JDK 解决方案 ********************************/ /** * 读取图片 * @param file 图片文件 * @return 图片数据 * @throws IOException */ public static BufferedImage[] readerImage(File file) throws IOException{ BufferedImage sourceImage = ImageIO.read(file); BufferedImage[] images = null; ImageInputStream iis = ImageIO.createImageInputStream(file); Iterator<ImageReader> imageReaders = ImageIO.getImageReaders(iis); if(imageReaders.hasNext()){ ImageReader reader = imageReaders.next(); reader.setInput(iis); int imageNumber = reader.getNumImages(true); images = new BufferedImage[imageNumber]; for (int i = 0; i < imageNumber; i++) { BufferedImage image = reader.read(i); if(sourceImage.getWidth() > image.getWidth() || sourceImage.getHeight() > image.getHeight()){ image = zoom(image, sourceImage.getWidth(), sourceImage.getHeight()); } images[i] = image; } reader.dispose(); iis.close(); } return images; } /** * 根据要求处理图片 * * @param images 图片数组 * @param x 横向起始位置 * @param y 纵向起始位置 * @param width 宽度 * @param height 宽度 * @return 处理后的图片数组 * @throws Exception */ public static BufferedImage[] processImage(BufferedImage[] images , int x , int y , int width , int height) throws Exception{ if(null == images){ return images; } BufferedImage[] oldImages = images; images = new BufferedImage[images.length]; for (int i = 0; i < oldImages.length; i++) { BufferedImage image = oldImages[i]; images[i] = image.getSubimage(x, y, width, height); } return images; } /** * 写入处理后的图片到file * * 图片后缀根据图片格式生成 * * @param images 处理后的图片数据 * @param formatName 图片格式 * @param file 写入文件对象 * @throws Exception */ public static void writerImage(BufferedImage[] images , String formatName , File file) throws Exception{ Iterator<ImageWriter> imageWriters = ImageIO.getImageWritersByFormatName(formatName); if(imageWriters.hasNext()){ ImageWriter writer = imageWriters.next(); String fileName = file.getName(); int index = fileName.lastIndexOf("."); if(index > 0){ fileName = fileName.substring(0, index + 1) + formatName; } String pathPrefix = getFilePrefixPath(file.getPath()); File outFile = new File(pathPrefix + fileName); ImageOutputStream ios = ImageIO.createImageOutputStream(outFile); writer.setOutput(ios); if(writer.canWriteSequence()){ writer.prepareWriteSequence(null); for (int i = 0; i < images.length; i++) { BufferedImage childImage = images[i]; IIOImage image = new IIOImage(childImage, null , null); writer.writeToSequence(image, null); } writer.endWriteSequence(); }else{ for (int i = 0; i < images.length; i++) { writer.write(images[i]); } } writer.dispose(); ios.close(); } } /** * 剪切格式图片 * * 基于JDK Image I/O解决方案 * * @param sourceFile 待剪切图片文件对象 * @param destFile 裁剪后保存文件对象 * @param x 剪切横向起始位置 * @param y 剪切纵向起始位置 * @param width 剪切宽度 * @param height 剪切宽度 * @throws Exception */ public static void cutImage(File sourceFile , File destFile, int x , int y , int width , int height) throws Exception{ // 读取图片信息 BufferedImage[] images = readerImage(sourceFile); // 处理图片 images = processImage(images, x, y, width, height); // 获取文件后缀 String formatName = getImageFormatName(sourceFile); destFile = new File(getPathWithoutSuffix(destFile.getPath()) + formatName); // 写入处理后的图片到文件 writerImage(images, formatName , destFile); } /** * 获取系统支持的图片格式 */ public static void getOSSupportsStandardImageFormat(){ String[] readerFormatName = ImageIO.getReaderFormatNames(); String[] readerSuffixName = ImageIO.getReaderFileSuffixes(); String[] readerMIMEType = ImageIO.getReaderMIMETypes(); System.out.println("========================= OS supports reader ========================"); System.out.println("OS supports reader format name : " + Arrays.asList(readerFormatName)); System.out.println("OS supports reader suffix name : " + Arrays.asList(readerSuffixName)); System.out.println("OS supports reader MIME type : " + Arrays.asList(readerMIMEType)); String[] writerFormatName = ImageIO.getWriterFormatNames(); String[] writerSuffixName = ImageIO.getWriterFileSuffixes(); String[] writerMIMEType = ImageIO.getWriterMIMETypes(); System.out.println("========================= OS supports writer ========================"); System.out.println("OS supports writer format name : " + Arrays.asList(writerFormatName)); System.out.println("OS supports writer suffix name : " + Arrays.asList(writerSuffixName)); System.out.println("OS supports writer MIME type : " + Arrays.asList(writerMIMEType)); } /** * 压缩图片 * @param sourceImage 待压缩图片 * @param width 压缩图片高度 * @param heigt 压缩图片宽度 */ private static BufferedImage zoom(BufferedImage sourceImage , int width , int height){ BufferedImage zoomImage = new BufferedImage(width, height, sourceImage.getType()); Image image = sourceImage.getScaledInstance(width, height, Image.SCALE_SMOOTH); Graphics gc = zoomImage.getGraphics(); gc.setColor(Color.WHITE); gc.drawImage( image , 0, 0, null); return zoomImage; } /** * 获取某个文件的前缀路径 * * 不包含文件名的路径 * * @param file 当前文件对象 * @return * @throws IOException */ public static String getFilePrefixPath(File file) throws IOException{ String path = null; if(!file.exists()) { throw new IOException("not found the file !" ); } String fileName = file.getName(); path = file.getPath().replace(fileName, ""); return path; } /** * 获取某个文件的前缀路径 * * 不包含文件名的路径 * * @param path 当前文件路径 * @return 不包含文件名的路径 * @throws Exception */ public static String getFilePrefixPath(String path) throws Exception{ if(null == path || path.isEmpty()) throw new Exception("文件路径为空！"); int index = path.lastIndexOf(File.separator); if(index > 0){ path = path.substring(0, index + 1); } return path; } /** * 获取不包含后缀的文件路径 * * @param src * @return */ public static String getPathWithoutSuffix(String src){ String path = src; int index = path.lastIndexOf("."); if(index > 0){ path = path.substring(0, index + 1); } return path; } /** * 获取文件名 * @param filePath 文件路径 * @return 文件名 * @throws IOException */ public static String getFileName(String filePath) throws IOException{ File file = new File(filePath); if(!file.exists()) { throw new IOException("not found the file !" ); } return file.getName(); } /** * @param args * @throws Exception */ public static void main(String[] args) throws Exception { // 获取系统支持的图片格式 //ImageCutterUtil.getOSSupportsStandardImageFormat(); try { // 起始坐标，剪切大小 int x = 100; int y = 75; int width = 100; int height = 100; // 参考图像大小 int clientWidth = 300; int clientHeight = 250; File file = new File("D:\\PCM Project\\upload\\tmp\\1.gif"); BufferedImage image = ImageIO.read(file); double destWidth = image.getWidth(); double destHeight = image.getHeight(); if(destWidth < width || destHeight < height) throw new Exception("源图大小小于截取图片大小!"); double widthRatio = destWidth / clientWidth; double heightRatio = destHeight / clientHeight; x = Double.valueOf(x * widthRatio).intValue(); y = Double.valueOf(y * heightRatio).intValue(); width = Double.valueOf(width * widthRatio).intValue(); height = Double.valueOf(height * heightRatio).intValue(); System.out.println("裁剪大小 x:" + x + ",y:" + y + ",width:" + width + ",height:" + height); /************************ 基于三方包解决方案 *************************/ String formatName = getImageFormatName(file); String pathSuffix = "." + formatName; String pathPrefix = getFilePrefixPath(file); String targetPath = pathPrefix + System.currentTimeMillis() + pathSuffix; targetPath = ImageCutterUtil.cutImage(file.getPath(), targetPath, x , y , width, height); String bigTargetPath = pathPrefix + System.currentTimeMillis() + pathSuffix; ImageCutterUtil.zoom(targetPath, bigTargetPath, 100, 100); String smallTargetPath = pathPrefix + System.currentTimeMillis() + pathSuffix; ImageCutterUtil.zoom(targetPath, smallTargetPath, 50, 50); /************************ 基于JDK Image I/O 解决方案(JDK探索失败) *************************/ // File destFile = new File(targetPath); // ImageCutterUtil.cutImage(file, destFile, x, y, width, height); } catch (IOException e) { e.printStackTrace(); } } }
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