图片缩放与转换

通过对图片重绘，达到图片缩放、压缩编码转换功能。

import java.awt.Image;import java.awt.image.BufferedImage;import java.awt.image.RenderedImage;import java.io.File;import java.io.InputStream;import java.io.OutputStream;import javax.imageio.ImageIO;/** *  * @author 梁栋 * @version 1.0 * @since 1.0 */public abstract class ImageUtils {/** * 缩放图片 *  * @param width *            输出宽度 * @param height *            输出高度 * @param input *            输入流 * @param output *            输出流 * @param format *            输出格式 * @return * @throws Exception */public static boolean convert(int width, int height, InputStream input,OutputStream output, String format) throws Exception {// 输入BufferedImage inputImage = ImageIO.read(input);// 转换RenderedImage im = (RenderedImage) convert(height, height, inputImage);// 输出return ImageIO.write(im, format, output);}/** * 转换压缩算法 *  * @param input *            输入文件 * @param output *            输出文件 * @return * @throws Exception */public static boolean convert(File input, File output) throws Exception {// 输入BufferedImage inputImage = ImageIO.read(input);// 转换int width = inputImage.getWidth();int height = inputImage.getHeight();RenderedImage im = (RenderedImage) convert(width, height, inputImage);String outputFilename = output.getName();String format = outputFilename.substring(outputFilename.lastIndexOf('.') + 1);// 输出return ImageIO.write(im, format, output);}/** * 缩放图片 *  * @param width *            输出宽度 * @param height *            输出高度 * @param input *            输入文件 * @param output *            输出文件 * @return * @throws Exception */public static boolean convert(int width, int height, File input, File output)throws Exception {// 输入BufferedImage inputImage = ImageIO.read(input);// 转换RenderedImage im = (RenderedImage) convert(width, height, inputImage);String outputFilename = output.getName();String format = outputFilename.substring(outputFilename.lastIndexOf('.') + 1);// 输出return ImageIO.write(im, format, output);}/** * 缩放图片 *  * @param width *            输出宽度 * @param height *            输出高度 * @param input *            输入路径 * @param output *            输出路径 * @return * @throws Exception */public static boolean convert(int width, int height, String inputPath,String outputPath) throws Exception {return convert(width, height, new File(inputPath), new File(outputPath));}/** * 转换 *  * @param width *            输出宽度 * @param height *            输出高度 * @param input *            BufferedImage * @return BufferedImage * @throws Exception */private static BufferedImage convert(int width, int height,BufferedImage input) throws Exception {// 初始化输出图片BufferedImage output = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);// 重新绘图Image image = input.getScaledInstance(output.getWidth(), output.getHeight(), output.getType());output.createGraphics().drawImage(image, null, null);return output;}/** * 等比缩放图片 *  * @param width *            输出宽度 * @param height *            输出高度 * @param input *            输入流 * @param output *            输出流 * @return * @throws Exception */public static boolean equimultipleConvert(int width, int height,String input, String output) throws Exception {return equimultipleConvert(width, height, new File(input), new File(output));}/** * 等比缩放图片 *  * @param width *            输出宽度 * @param height *            输出高度 * @param input *            输入流 * @param output *            输出流 * @return *  * @throws Exception */public static boolean equimultipleConvert(int width, int height,File input, File output) throws Exception {// 输入BufferedImage image = ImageIO.read(input);// 重新核算尺寸if (image.getWidth() > 0 && image.getHeight() > 0) {if ((image.getWidth() / image.getHeight()) >= (width / height)) {if (image.getWidth() > width) {height = (image.getHeight() * width) / image.getWidth();} else {width = image.getWidth();height = image.getHeight();}} else {if (image.getHeight() > height) {width = (image.getWidth() * height) / image.getHeight();} else {width = image.getWidth();height = image.getHeight();}}}// 转换 输出return convert(width, height, input, output);}}

给出一个简单的测试类：

import org.junit.Test;/** *  * @author 梁栋 * @version 1.0 * @since 1.0 */public class ImageUtilsTest {/** * Test method for * {@link org.zlex.common.image.ImageUtils#main(java.lang.String[])}. */@Testpublic void test() throws Exception {System.out.println(ImageUtils.convert(1650, 1024, "c://1.png","c://1.png.jpg"));System.out.println(ImageUtils.convert(400, 300, "c://1.jpg","c://1.jpg.jpg"));System.out.println(ImageUtils.convert(400, 300, "c://1.jpg","c://1.jpg.png"));System.out.println(ImageUtils.convert(50, 50, "c://1.jpg","c://1.jpg.gif"));System.out.println(ImageUtils.convert(40, 30, "c://1.bmp","c://1.bmp.gif"));System.out.println(ImageUtils.convert(40, 30, "c://1.bmp", "c://1.jpeg"));System.out.println(ImageUtils.equimultipleConvert(1600, 1400, new File("c://1.bmp"), new File("c://1Equimultiple.jpeg")));}}