java 图像处理两例：图像缩放与圆角图片的制作

package test;    import java.awt.AlphaComposite;  import java.awt.Color;  import java.awt.Graphics2D;  import java.awt.Image;  import java.awt.RenderingHints;  import java.awt.geom.RoundRectangle2D;  import java.awt.image.BufferedImage;  import java.io.File;  import java.io.IOException;    import javax.imageio.ImageIO;        public class ChangeImage {        public static BufferedImage makeRoundedCorner(BufferedImage image,              int cornerRadius) {          int w = image.getWidth();          int h = image.getHeight();          BufferedImage output = new BufferedImage(w, h,                  BufferedImage.TYPE_INT_ARGB);            Graphics2D g2 = output.createGraphics();            // This is what we want, but it only does hard-clipping, i.e. aliasing          // g2.setClip(new RoundRectangle2D ...)            // so instead fake soft-clipping by first drawing the desired clip shape          // in fully opaque white with antialiasing enabled...          g2.setComposite(AlphaComposite.Src);          g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,                  RenderingHints.VALUE_ANTIALIAS_ON);          g2.setColor(Color.WHITE);          g2.fill(new RoundRectangle2D.Float(0, 0, w, h, cornerRadius,                  cornerRadius));            // ... then compositing the image on top,          // using the white shape from above as alpha source          g2.setComposite(AlphaComposite.SrcAtop);          g2.drawImage(image, 0, 0, null);            g2.dispose();            return output;      }        public static BufferedImage createResizedCopy(Image originalImage, int scaledWidth,              int scaledHeight, boolean preserveAlpha) {          int imageType = preserveAlpha ? BufferedImage.TYPE_INT_RGB                  : BufferedImage.TYPE_INT_ARGB;          BufferedImage scaledBI = new BufferedImage(scaledWidth, scaledHeight,                  imageType);          Graphics2D g = scaledBI.createGraphics();          if (preserveAlpha) {              g.setComposite(AlphaComposite.Src);          }          g.drawImage(originalImage, 0, 0, scaledWidth, scaledHeight, null);          g.dispose();          return scaledBI;      }        public static void main(String[] args) throws IOException {          BufferedImage icon = ImageIO.read(new File("/home/june/桌面/mm.jpg"));          BufferedImage rounded = makeRoundedCorner(icon, 30);          ImageIO.write(rounded, "png", new File("/home/june/桌面/mm_rounded.png"));                    BufferedImage pic = ImageIO.read(new File("/home/june/桌面/zhang.jpg"));          BufferedImage resized = createResizedCopy(pic, 250, 250*768/1024, true);          ImageIO.write(resized, "jpg", new File("/home/june/桌面/zhang_small.jpg"));      }    }