Java对图片的处理---缩放图像、图像切割、图像类型转换、彩色转为黑白
import java.io.*;import java.awt.*;import java.awt.image.*;import java.awt.Graphics;import java.awt.color.ColorSpace;import javax.imageio.ImageIO;public class ChangeImageSize{ /** *//** * 缩放图像 * @param srcImageFile 源图像文件地址 * @param result 缩放后的图像地址 * @param scale 缩放比例 * @param flag 缩放选择:true 放大; false 缩小; */ public static void scale(String srcImageFile, String result, int scale, boolean flag) { try { BufferedImage src = ImageIO.read(new File(srcImageFile)); // 读入文件 int width = src.getWidth(); // 得到源图宽 int height = src.getHeight(); // 得到源图长 if (flag) { // 放大 width = width * scale; height = height * scale; } else { // 缩小 width = width / scale; height = height / scale; } Image image = src.getScaledInstance(width, height, Image.SCALE_DEFAULT); BufferedImage tag = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); Graphics g = tag.getGraphics(); g.drawImage(image, 0, 0, null); // 绘制缩小后的图 g.dispose(); ImageIO.write(tag, "JPEG", new File(result));// 输出到文件流 } catch (IOException e) { e.printStackTrace(); } } /** *//** * 图像切割 * @param srcImageFile 源图像地址 * @param descDir 切片目标文件夹 * @param destWidth 目标切片宽度 * @param destHeight 目标切片高度 */ public static void cut(String srcImageFile, String descDir, int destWidth, int destHeight) { try { Image img; ImageFilter cropFilter; // 读取源图像 BufferedImage bi = ImageIO.read(new File(srcImageFile)); int srcWidth = bi.getHeight(); // 源图宽度 int srcHeight = bi.getWidth(); // 源图高度 if (srcWidth > destWidth && srcHeight > destHeight) { Image image = bi.getScaledInstance(srcWidth, srcHeight, Image.SCALE_DEFAULT); destWidth = 200; // 切片宽度 destHeight = 150; // 切片高度 int cols = 0; // 切片横向数量 int rows = 0; // 切片纵向数量 // 计算切片的横向和纵向数量 if (srcWidth % destWidth == 0) { cols = srcWidth / destWidth; } else { cols = (int) Math.floor(srcWidth / destWidth) + 1; } if (srcHeight % destHeight == 0) { rows = srcHeight / destHeight; } else { rows = (int) Math.floor(srcHeight / destHeight) + 1; } // 循环建立切片 // 改进的想法:是否可用多线程加快切割速度 for (int i = 0; i < rows; i++) { for (int j = 0; j < cols; j++) { // 四个参数分别为图像起点坐标和宽高 // 即: CropImageFilter(int x,int y,int width,int height) cropFilter = new CropImageFilter(j * 200, i * 150, destWidth, destHeight); img = Toolkit.getDefaultToolkit().createImage( new FilteredImageSource(image.getSource(), cropFilter)); BufferedImage tag = new BufferedImage(destWidth, destHeight, BufferedImage.TYPE_INT_RGB); Graphics g = tag.getGraphics(); g.drawImage(img, 0, 0, null); // 绘制缩小后的图 g.dispose(); // 输出为文件 ImageIO.write(tag, "JPEG", new File(descDir + "pre_map_" + i + "_" + j + ".jpg")); } } } } catch (Exception e) { e.printStackTrace(); } } /** *//** * 图像类型转换 GIF->JPG GIF->PNG PNG->JPG PNG->GIF(X) */ public static void convert(String source, String result) { try { File f = new File(source); f.canRead(); f.canWrite(); BufferedImage src = ImageIO.read(f); ImageIO.write(src, "JPG", new File(result)); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** *//** * 彩色转为黑白 * @param source * @param result */ public static void gray(String source, String result) { try { BufferedImage src = ImageIO.read(new File(source)); ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_GRAY); ColorConvertOp op = new ColorConvertOp(cs, null); src = op.filter(src, null); ImageIO.write(src, "JPEG", new File(result)); } catch (IOException e) { e.printStackTrace(); } } /** *//** * @param args */ public static void main(String[] args) { scale("c:\\test\\456.jpg","C:\\test\\image1.jpg",2,false); cut("c:\\test\\456.jpg","C:\\test\\image2.jpg",64,64); gray("c:\\test\\456.jpg","C:\\test\\image4.jpg"); }}
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