java IMAGEIO
javax.imageio使用 ImageIO 类的静态方法可以执行许多常见的图像 I/O 操作。
此包包含一些基本类和接口，有的用来描述图像文件内容（包括元数据和缩略图）(IIOImage)；
有的用来控制图像读取过程（ImageReader、ImageReadParam）和控制图像写入过程（ImageWriter 和 ImageWriteParam）；
详细 Java ImageIO处理图像的封装例子 http://www.gzhost.net/Artdetail-1609-649.html
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[*]package com.mapbar.graphics;
[*]
[*]import java.awt.Graphics;
[*]import java.awt.Image;
[*]import java.awt.Rectangle;
[*]import java.awt.image.BufferedImage;
[*]import java.io.File;
[*]import java.io.FileOutputStream;
[*]import java.io.IOException;
[*]import java.util.Arrays;
[*]import java.util.Iterator;
[*]
[*]import javax.imageio.ImageIO;
[*]import javax.imageio.ImageReadParam;
[*]import javax.imageio.ImageReader;
[*]import javax.imageio.metadata.IIOMetadata;
[*]import javax.imageio.stream.ImageInputStream;
[*]
[*]import com.sun.image.codec.jpeg.JPEGCodec;
[*]import com.sun.image.codec.jpeg.JPEGImageEncoder;
[*]
[*]/**
[*] *
[*] * Class ImageIOTest.java
[*] *
[*] * Description javax.imageio 操作
[*] *
[*] * Company mapbar
[*] *
[*] * author Chenll E-mail: Chenll@mapbar.com
[*] *
[*] * Version 1.0
[*] *
[*] * Date 2012-7-23 上午11:16:17
[*] */
[*]public class ImageIOTest {
[*]
[*] /**
[*] * Java Image I/O API 支持的读入，写出普通的格式，如果需要开发其它格式，还需要第三方插件，eg JIMI, JMagic
[*] */
[*] public void formatImageNames() {
[*]
[*] String[] imageFormats = ImageIO.getReaderFormatNames();
[*] //
[*] System.out.println(Arrays.asList(imageFormats));
[*]
[*] String[] imageFormats1 = ImageIO.getWriterFormatNames();
[*] //
[*] System.out.println(Arrays.asList(imageFormats1));
[*]
[*] }
[*]
[*] /**
[*] * Image I/O高级操作 ImageReader ImageWriter 通过ImageReader
[*] * 可以获取图片信息而不用把整张图片数据都读入内存。
[*] *
[*] * @throws IOException
[*] */
[*] public void imageReaderOp() throws IOException {
[*] Iterator<ImageReader> readers = ImageIO
[*] .getImageReadersByFormatName("JPG");
[*] ImageReader reader = readers.next();
[*] // 构造输入源
[*] File bigFile = new File("E:\\big.JPG");
[*] ImageInputStream iis = ImageIO.createImageInputStream(bigFile);
[*] // 输入源和ImageReader关联
[*] reader.setInput(iis, true);
[*] // 获取第一张图片的高度,试图解码文件的必要部分，去获取图片的宽度，而不用读取任何一个象素
[*] int imageIndex = 0;
[*] int width = reader.getWidth(imageIndex);
[*] }
[*]
[*] /**
[*] * 控制图片操作，ImageReadParam 可以让程序更好的控制内存，比如指定一个感兴趣的区域
[*] *
[*] * @throws IOException
[*] */
[*] public void imageReadParamOp() throws IOException {
[*] int imageIndex = 0;
[*] Iterator<ImageReader> readers = ImageIO
[*] .getImageReadersByFormatName("JPG");
[*] ImageReader reader = readers.next();
[*] File bigFile = new File("E:\\big.JPG");
[*] ImageInputStream iis = ImageIO.createImageInputStream(bigFile);
[*] reader.setInput(iis, true);
[*] ImageReadParam irp = reader.getDefaultReadParam();
[*] int halfWidth = reader.getWidth(imageIndex) / 2;
[*] int halfHeight = reader.getHeight(imageIndex) / 2;
[*] Rectangle rect = new Rectangle(0, 0, halfWidth, halfHeight);
[*] irp.setSourceRegion(rect);
[*] BufferedImage bi = reader.read(imageIndex, irp);
[*] ImageIO.write(bi, "JPG", new File("E:\\big_half.JPG"));
[*] }
[*]
[*] /**
[*] * 图片元信息
[*] *
[*] * @throws IOException
[*] */
[*] public void ImageMetadata() throws IOException {
[*] int imageIndex = 0;
[*] Iterator<ImageReader> readers = ImageIO
[*] .getImageReadersByFormatName("JPG");
[*] ImageReader reader = readers.next();
[*] File bigFile = new File("E:\\big.JPG");
[*] ImageInputStream iis = ImageIO.createImageInputStream(bigFile);
[*] reader.setInput(iis, true);
[*] IIOMetadata metadata = reader.getImageMetadata(imageIndex);
[*] }
[*]
[*] /**
[*] * 生成缩略图
[*] *
[*] * @throws IOException
[*] */
[*] public void generateSmall() throws IOException {
[*] File bigFile = new File("E:\\big.JPG");
[*] Image image = ImageIO.read(bigFile);
[*] int width = image.getWidth(null); // 3264
[*] int height = image.getHeight(null); // 2448
[*] BufferedImage buffi = new BufferedImage(width / 2, height / 2,
[*] BufferedImage.TYPE_INT_RGB);
[*] Graphics g = buffi.getGraphics();
[*] g.drawImage(image, 0, 0, width / 2, height / 2, null);
[*] g.dispose();
[*] ImageIO.write(buffi, "JPG", new File("E:\\small.JPG"));// width:1632 height:1224
[*] }
[*]
[*] public static void main(String[] args) throws IOException {
[*] ImageIOTest iot = new ImageIOTest();
[*] iot.generateSmall();
[*] iot.formatImageNames();
[*] iot.imageReaderOp();
[*] iot.imageReadParamOp();
[*] iot.ImageMetadata();
[*] }
[*]
[*]}
[*]
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