Cómo acercar el área específica de la imagen en el lienzo en Swing

Question

Quiero ampliar el área específica de la imagen. que es seleccionado por el usuario. visualización de imágenes en lienzo usando Swing. Ya hice zoom de imagen completa sobre lienzo pero no puedo implementar el zoom de área específica. por favor ayuda

Answer 1

Lienzo es awt no swing. Pruebe JPanel en su lugar. Example.

Pero si ya ha hecho el zoom completo de la imagen, intente hacer lo mismo en un sub-image.

BufferedImage.getSubimage(x, y, w, h); 

EDITAR

import java.awt.*; 
import java.awt.event.*; 
import java.awt.image.BufferedImage; 
import javax.swing.*; 

public class Example { 

    private Point startPoint = new Point(0, 0); 
    private Point rectLocale = new Point(); 
    private Dimension rectSize = new Dimension(); 
    private int zoom = 80; 
    private BufferedImage capture = null; 
    private BufferedImage raw; 

    public Example() throws Exception { 
     raw = new Robot().createScreenCapture(new Rectangle(
       Toolkit.getDefaultToolkit().getScreenSize())); 
     MouseBehavior behavior = new MouseBehavior(); 
     JPanel b = new JPanel() { 

      private static final long serialVersionUID = 1L; 

      @Override 
      public Dimension getMinimumSize() { 
       return new Dimension(500, 500); 
      } 

      @Override 
      public Dimension getPreferredSize() { 
       return new Dimension(500, 500); 
      } 

      @Override 
      protected void paintComponent(Graphics g) { 
       super.paintComponent(g); 
       Graphics2D g2d = ((Graphics2D) g); 
       g2d.drawImage(raw, 0, 0, null); 
       if (capture != null) { 
        int width2 = (int) (rectSize.width + rectSize.width * (zoom/500d)); 
        int height2 = (int) (rectSize.height + rectSize.height * (zoom/500d)); 
        int x2 = rectLocale.x - ((width2 - rectSize.width)/2); 
        int y2 = rectLocale.y - ((height2 - rectSize.height)/2); 
        Image scaledInstance = capture.getScaledInstance(
          width2, height2, Image.SCALE_AREA_AVERAGING); 
        g2d.drawImage(scaledInstance, x2, y2, null); 
        g2d.drawRect(x2, y2, width2, height2); 
       } else { 
        g2d.draw(new Rectangle(rectLocale, rectSize)); 
       } 
      } 
     }; 
     b.addMouseMotionListener(behavior); 
     b.addMouseListener(behavior); 
     b.addMouseWheelListener(behavior); 
     JFrame f = new JFrame(); 
     f.setLocation(10, 10); 
     f.setDefaultCloseOperation(3); 
     f.add(b); 
     f.pack(); 
     f.setVisible(true); 
    } 

    private class MouseBehavior extends MouseAdapter { 

     @Override 
     public void mousePressed(MouseEvent e) { 
      startPoint = e.getPoint(); 
      rectLocale = new Point(); 
      rectSize = new Dimension(); 
      capture = null; 
      if (e.getSource() instanceof JComponent) { 
       ((JComponent) e.getSource()).repaint(); 
      } 
     } 

     @Override 
     public void mouseDragged(MouseEvent e) { 
      Point currentPoint = e.getPoint(); 
      rectSize.width = Math.abs(currentPoint.x - startPoint.x); 
      rectSize.height = Math.abs(currentPoint.y - startPoint.y); 
      if (e.isShiftDown()) { 
       rectSize.width = rectSize.height = Math.min(
         rectSize.width, rectSize.height); 
       int dx = startPoint.x - rectSize.width; 
       int dy = startPoint.y - rectSize.height; 
       rectLocale.x = startPoint.x < currentPoint.x ? startPoint.x 
         : Math.max(dx, dy); 
       rectLocale.y = startPoint.y < currentPoint.y ? startPoint.y 
         : Math.min(dx, dy); 
      } else { 
       rectLocale.x = Math.min(currentPoint.x, startPoint.x); 
       rectLocale.y = Math.min(currentPoint.y, startPoint.y); 
      } 
      if (e.getSource() instanceof JComponent) { 
       ((JComponent) e.getSource()).repaint(); 
      } 
     } 

     @Override 
     public void mouseReleased(MouseEvent e) { 
      if (rectSize.width <= 0 || rectSize.height <= 0) { 
       capture = null; 
      } else { 
       capture = raw.getSubimage(Math.max(0, rectLocale.x), 
         Math.max(0, rectLocale.y), rectSize.width, rectSize.height); 
      } 
      if (e.getSource() instanceof JComponent) { 
       ((JComponent) e.getSource()).repaint(); 
      } 
     } 

     @Override 
     public void mouseWheelMoved(MouseWheelEvent e) { 
      zoom = Math.min(2000, Math.max(0, zoom + e.getUnitsToScroll() * 10)); 
      if (e.getSource() instanceof JComponent) { 
       ((JComponent) e.getSource()).repaint(); 
      } 
     } 
    } 

    public static void main(String[] args) { 
     EventQueue.invokeLater(new Runnable() { 

      @Override 
      public void run() { 
       try { 
        Example example = new Example(); 
       } catch (Exception e) { 
        e.printStackTrace(); 
       } 
      } 
     }); 
    } 
}