JScrollPane 및 확대/축소 이미지

Question

JPanel에서 확장하여 이미지를 확대 및 축소하고 최상위 레벨에서 JScrollPane을 사용하여 누군가가 확대/축소 된 영역을 가로 질러 앞뒤로 스크롤 할 수있게하는 간단한 클래스를 작성하려고합니다. 영상. JScrollPane 부분에 문제가 있습니다.

확대/축소 버튼 중 하나를 클릭하면 JScrollBars가 나타나거나 재설정 버튼이 사라질 때까지 버튼을 두 번 클릭해야합니다. 계속해서 확대하거나 축소하는 경우에도 막대가 나타나기 시작한 후에도 막대가 새로운 확대/축소 수준에 따라 업데이트되지 않습니다. 창 크기를 조정하면이 문제가 해결되지만 좀 더 구체적인 해결책을 찾고 있습니다.

ImagePanel 번호 :

package com.zephyr.graphics; 

import java.awt.Color; 
import java.awt.Container; 
import java.awt.Dimension; 
import java.awt.Graphics; 
import java.awt.Image; 
import java.awt.image.BufferedImage; 
import java.beans.PropertyChangeEvent; 
import java.beans.PropertyChangeListener; 
import java.io.File; 
import java.io.IOException; 

import javax.imageio.ImageIO; 
import javax.swing.JPanel; 

public class ImagePanel extends JPanel implements PropertyChangeListener{ 

    private File imageFile; 

    private BufferedImage image; 

    private double zoomMultiplier; 

    public ImagePanel() 
    { 
     imageFile = null; 

     image = null; 

     zoomMultiplier = 1; 
    } 

    public ImagePanel(File imageFile) 
    { 
     this.imageFile = imageFile; 

     try { 
      image = ImageIO.read(imageFile); 
     } catch (IOException e) { 
      image = null; 
     } 

     zoomMultiplier = 1; 
    } 

    public void setImageFile(File imageFile) 
    { 
     this.imageFile = imageFile; 

     if(imageFile == null) 
     { 
      image = null; 
     } 
     else 
     { 
      try { 
       image = ImageIO.read(imageFile); 
      } catch (IOException e) { 
       image = null; 
      } 
     } 

     zoomMultiplier = 1; 

     this.revalidate(); 
     this.repaint(); 
    } 

    public File getImageFile() 
    { 
     return imageFile; 
    } 

    public void paintComponent(Graphics g) 
    { 
     g.clearRect(0, 0, this.getWidth(), this.getHeight()); 

     if(image == null) 
     { 
      this.setPreferredSize(new Dimension(this.getParent().getWidth(), this.getParent().getHeight())); 
      g.setColor(Color.black); 
      g.fillRect(0, 0, this.getWidth(), this.getHeight()); 
     } 
     else 
     { 
      double preferredWidth = this.getParent().getWidth() * zoomMultiplier; 
      double preferredHeight = this.getParent().getHeight() * zoomMultiplier; 

      this.setPreferredSize(new Dimension((int)preferredWidth, (int)preferredHeight)); 

      Image scaled = image.getScaledInstance((int)preferredWidth, (int)preferredHeight, Image.SCALE_DEFAULT); 

      g.drawImage(scaled, 0, 0, null); 
     } 
    } 

    @Override 
    public void propertyChange(PropertyChangeEvent evt) { 
     if(evt.getPropertyName().equals("Image File")) 
     { 
      setImageFile((File)evt.getNewValue()); 
     } 
     else if(evt.getPropertyName().equals("Zoom In")) 
     { 
      double additive = ((Number)evt.getNewValue()).doubleValue(); 

      zoomMultiplier += additive; 

      this.revalidate(); 
      this.repaint(); 
     } 
     else if(evt.getPropertyName().equals("Zoom Out")) 
     { 
      double subtractive = ((Number)evt.getNewValue()).doubleValue(); 

      zoomMultiplier -= subtractive; 

      this.revalidate(); 
      this.repaint(); 
     } 
     else if(evt.getPropertyName().equals("Zoom Reset")) 
     { 
      zoomMultiplier = 1; 

      this.revalidate(); 
      this.repaint(); 
     } 
    } 
} 

메인 클래스

package com.zephyr.graphics; 

import java.awt.BorderLayout; 
import java.awt.Dimension; 
import java.awt.FlowLayout; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.beans.PropertyChangeSupport; 
import java.io.File; 

import javax.swing.JButton; 
import javax.swing.JFileChooser; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.JScrollPane; 

public class Main { 

    public static void main(String[] args) 
    { 
     PropertyChangeSupport pcs = new PropertyChangeSupport(Main.class); 

     JFileChooser chooser = new JFileChooser(System.getProperty("user.home")); 
     chooser.setDialogTitle("Select an image"); 
     chooser.setFileSelectionMode(JFileChooser.FILES_ONLY); 

     File file = null; 

     if(chooser.showOpenDialog(null) == JFileChooser.APPROVE_OPTION) 
     { 
      file = chooser.getSelectedFile(); 
     } 
     else 
     { 
      System.err.println("NO FILE WAS SELECTED OR THE WINDOW WAS CLOSED"); 
      return; 
     } 

     JFrame frame = new JFrame("ImagePanel Tester"); 
     frame.setLocationRelativeTo(null); 
     frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 

     ImagePanel iPanel = new ImagePanel(file); 
     pcs.addPropertyChangeListener(iPanel); 

     JScrollPane iScroll = new JScrollPane(iPanel, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED); 
     iScroll.setPreferredSize(new Dimension(1024, 768)); 

     JPanel controlPanel = new JPanel(); 
     controlPanel.setLayout(new FlowLayout(FlowLayout.CENTER)); 

     JButton zoomIn = new JButton("Zoom In"); 
     zoomIn.addActionListener(new ActionListener() { 

      @Override 
      public void actionPerformed(ActionEvent arg0) { 
       pcs.firePropertyChange("Zoom In", null, new Double(.25)); 
       frame.revalidate(); 
       frame.repaint(); 
      } 

     }); 
     controlPanel.add(zoomIn); 

     JButton zoomOut = new JButton("Zoom Out"); 
     zoomOut.addActionListener(new ActionListener() { 

      @Override 
      public void actionPerformed(ActionEvent e) { 
       pcs.firePropertyChange("Zoom Out", null, new Double(.25)); 
       frame.revalidate(); 
       frame.repaint(); 
      } 

     }); 
     controlPanel.add(zoomOut); 

     JButton zoomReset = new JButton("Zoom Reset"); 
     zoomReset.addActionListener(new ActionListener() { 

      @Override 
      public void actionPerformed(ActionEvent e) { 
       pcs.firePropertyChange("Zoom Reset", null, null); 
       frame.revalidate(); 
       frame.repaint(); 
      } 

     }); 
     controlPanel.add(zoomReset); 

     JButton changeImage = new JButton("Change Image"); 
     changeImage.addActionListener(new ActionListener() { 

      @Override 
      public void actionPerformed(ActionEvent e) { 
       if(chooser.showOpenDialog(frame) == JFileChooser.APPROVE_OPTION) 
       { 
        File tempFile = chooser.getSelectedFile(); 
        pcs.firePropertyChange("Image File", null, tempFile); 
        frame.revalidate(); 
        frame.repaint(); 
       } 
      } 

     }); 
     controlPanel.add(changeImage); 

     frame.add(iScroll, BorderLayout.CENTER); 
     frame.add(controlPanel, BorderLayout.SOUTH); 
     frame.pack(); 
     frame.setVisible(true); 
     frame.revalidate(); //Shouldn't really be necessary, but seems to be helping 

    } 
} 

Answer 1

일부 무거운 파고 후, 스크롤 인터페이스는 저를 저장했다. 이를 구현하고이 example 다음의 각각의 메서드와 paintComponent에서 preferredSize 참조를 제거하면 내가 가지고있는 문제가 해결됩니다.