将CMYK彩色空间的图片转换为RGB彩色空间的图片
? 最近给网站(http://www.30buy.com/?source=2355)增加一个会员头像的功能,这就必然的会有用户上传图片然后压缩啊，剪裁啊?什么什么的。
?? 做出来了，自己独自测试，通过了。然后交由老大验收，结果他在测试的时候，上传了一张比较大的jpg格式的图片，然后程序运行不通过了。我原本以为是图片太大导致，自己又重新测试，用了一张更大的图，通过了。这是为毛呢。然后看了看报错，Unsupport Image Type .度娘&谷哥后，原来是CMYK这么个东西，就是我自己测试的时候用的全是RGB的图片，老大测试的时候用的那张是CMYK的，然后就出现了这结果。 于是，继续度娘&谷哥，找到了一些将CMYK的图片转为RGB的源代码，COPY测试不通过。经过对几种方法的测试和"研究".ND 终于将这个问题搞定了。下面给出代码：
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package com.test.common;import com.sun.image.codec.jpeg.JPEGCodec;import com.sun.image.codec.jpeg.JPEGImageEncoder;import java.awt.Transparency;import java.awt.color.ColorSpace;import java.awt.image.BufferedImage;import java.awt.image.ColorModel;import java.awt.image.ComponentColorModel;import java.awt.image.DataBuffer;import java.awt.image.DataBufferByte;import java.awt.image.Raster;import java.awt.image.WritableRaster;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;import java.util.Iterator;import javax.imageio.IIOException;import javax.imageio.ImageIO;import javax.imageio.ImageReader;import javax.imageio.stream.ImageInputStream;/** * * @author Dsmart */public class CMYK { public void readImage(String filename) throws IOException { File file = new File(filename); ImageInputStream input = ImageIO.createImageInputStream(file); Iterator readers = ImageIO.getImageReaders(input); if(readers == null || !readers.hasNext()) { throw new RuntimeException("1 No ImageReaders found"); } ImageReader reader = (ImageReader) readers.next(); reader.setInput(input); String format = reader.getFormatName() ; BufferedImage image; if ( "JPEG".equalsIgnoreCase(format) ||"JPG".equalsIgnoreCase(format) ) { try { // 尝试读取图片 (包括颜色的转换). image = reader.read(0); //RGB } catch (IIOException e) { // 读取Raster (没有颜色的转换). Raster raster = reader.readRaster(0, null);//CMYK image = createJPEG4(raster); } image.getGraphics().drawImage(image, 0, 0, null); String newfilename = filename.substring(0,filename.lastIndexOf("."))+"_rgb"+filename.substring(filename.lastIndexOf(".")); File newFile = new File(newfilename); FileOutputStream out = new FileOutputStream(newFile); JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out); encoder.encode(image); out.flush(); out.close(); } } private static BufferedImage createJPEG4(Raster raster) { int w = raster.getWidth(); int h = raster.getHeight(); byte[] rgb = new byte[w * h * 3]; //彩色空间转换 float[] Y = raster.getSamples(0, 0, w, h, 0, (float[]) null); float[] Cb = raster.getSamples(0, 0, w, h, 1, (float[]) null); float[] Cr = raster.getSamples(0, 0, w, h, 2, (float[]) null); float[] K = raster.getSamples(0, 0, w, h, 3, (float[]) null); for (int i = 0, imax = Y.length, base = 0; i < imax; i++, base += 3) { float k = 220 - K[i], y = 255 - Y[i], cb = 255 - Cb[i], cr = 255 - Cr[i]; double val = y + 1.402 * (cr - 128) - k; val = (val - 128) * .65f + 128; rgb[base] = val < 0.0 ? (byte) 0 : val > 255.0 ? (byte) 0xff : (byte) (val + 0.5); val = y - 0.34414 * (cb - 128) - 0.71414 * (cr - 128) - k; val = (val - 128) * .65f + 128; rgb[base + 1] = val < 0.0 ? (byte) 0 : val > 255.0 ? (byte) 0xff : (byte) (val + 0.5); val = y + 1.772 * (cb - 128) - k; val = (val - 128) * .65f + 128; rgb[base + 2] = val < 0.0 ? (byte) 0 : val > 255.0 ? (byte) 0xff : (byte) (val + 0.5); } raster = Raster.createInterleavedRaster(new DataBufferByte(rgb, rgb.length), w, h, w * 3, 3, new int[]{0, 1, 2}, null); ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_sRGB); ColorModel cm = new ComponentColorModel(cs, false, true, Transparency.OPAQUE, DataBuffer.TYPE_BYTE); return new BufferedImage(cm, (WritableRaster) raster, true, null); } public static void main(String[] args) throws IOException { String filename = "h:/img/test.jpg"; CMYK cm = new CMYK(); cm.readImage(filename); } }??
由于CMYK和RGB的不同，所以在转换后会出现颜色变亮。
如果觉得这个不错，请点击(http://www.30buy.com/?source=2355)，看看也好
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