使用Java调整图像大小而不会失去透明度

2 回答

• 1

  这就是我解决问题的方法：

  public static BufferedImage convertRGBAToIndexed(BufferedImage src) {
      BufferedImage dest = new BufferedImage(src.getWidth(), src.getHeight(), BufferedImage.TYPE_BYTE_INDEXED);
      Graphics g = dest.getGraphics();
      g.setColor(new Color(231, 20, 189));
      g.fillRect(0, 0, dest.getWidth(), dest.getHeight());
      dest = makeTransparent(dest, 0, 0);
      dest.createGraphics().drawImage(src, 0, 0, null);
      return dest;
  }
  
  public static BufferedImage makeTransparent(BufferedImage image, int x, int y) {
      ColorModel cm = image.getColorModel();
      if (!(cm instanceof IndexColorModel))
          return image; // sorry...
      IndexColorModel icm = (IndexColorModel) cm;
      WritableRaster raster = image.getRaster();
      int pixel = raster.getSample(x, y, 0);
      int size = icm.getMapSize();
      byte[] reds = new byte[size];
      byte[] greens = new byte[size];
      byte[] blues = new byte[size];
      icm.getReds(reds);
      icm.getGreens(greens);
      icm.getBlues(blues);
      IndexColorModel icm2 = new IndexColorModel(8, size, reds, greens, blues, pixel);
      return new BufferedImage(icm2, raster, image.isAlphaPremultiplied(), null);
  }
  
  public static Dimension getScaledDimension(Dimension imgSize, Dimension boundary) {
      int original_width = imgSize.width;
      int original_height = imgSize.height;
      int bound_width = boundary.width;
      int bound_height = boundary.height;
      int new_width = 0;
      int new_height = 0;
  
      if (original_width > original_height) {
          new_width = bound_width;
          new_height = (new_width*original_height)/original_width;
      } else {
          new_height = bound_height;
          new_width = (new_height*original_width)/original_height;
      }
  
      return new Dimension(new_width, new_height);
  }
  
  public static void resizeImage(File original_image, File resized_image, int IMG_SIZE) {
      try {
          BufferedImage originalImage = ImageIO.read(original_image);
  
          String extension = Files.getFileExtension(original_image.getName());
  
          int type = extension.equals("gif") || (originalImage.getType() == 0) ? BufferedImage.TYPE_INT_ARGB : originalImage.getType();
  
          Dimension new_dim = getScaledDimension(new Dimension(originalImage.getWidth(), originalImage.getHeight()), new Dimension(IMG_SIZE,IMG_SIZE));
  
          BufferedImage resizedImage = new BufferedImage((int) new_dim.getWidth(), (int) new_dim.getHeight(), type);
          Graphics2D g = resizedImage.createGraphics();
          g.drawImage(originalImage, 0, 0, (int) new_dim.getWidth(), (int) new_dim.getHeight(), null);
          g.dispose();            
  
          if (!extension.equals("gif")) {
              ImageIO.write(resizedImage, extension, resized_image);
          } else {
              // Gif Transparence workarround
              ImageIO.write(convertRGBAToIndexed(resizedImage), "gif", resized_image);
          }
  
      } catch (IOException e) {
          Utils.log("resizeImage", e.getMessage());
      }
  }
  

  回复于 2024-04-27T00:45:50+08:00
• 1

  在resarch之后我发现只有将它保存为BufferedImage而不将其转换为ImageIcon时才能调整缓冲区图像的大小

  我像这样解决问题：

  public class NewJFrame extends javax.swing.JFrame {
  
  /**
   * Creates new form NewJFrame
   */
  public NewJFrame()  {
      try {
          initComponents();
          BufferedImage c = ImageIO.read(new File("60_Personnel.png"));
          JLabel lblMains = new JLabel( new ImageIcon(c));
          this.add(lblMains);                                       //add real size
          this.add(new JLabel(new ImageIcon((resize(c, 150)))));    //add converting image
          this.pack();
          this.setLocationRelativeTo(null);
          this.setVisible(true);
      } catch (IOException ex) {
          Logger.getLogger(NewJFrame.class.getName()).log(Level.SEVERE, null, ex);
      }
  
  }
  
  public static BufferedImage resize(Object img, int percent) {
      BufferedImage buff = (BufferedImage) img;
      return resize(buff, buff.getWidth() * percent / 100, buff.getWidth() * percent / 100);
  }
  
  public static BufferedImage resize(BufferedImage img, int newW, int newH) {
      Image tmp = img.getScaledInstance(newW, newH, Image.SCALE_SMOOTH);
      BufferedImage dimg = new BufferedImage(newW, newH, BufferedImage.TYPE_INT_ARGB);
      Graphics2D g2d = dimg.createGraphics();
      g2d.drawImage(tmp, 0, 0, null);
      g2d.dispose();
      return dimg;
  }
  

  }

  回复于 2024-04-27T00:45:50+08:00