如何在JPanel

Question

中顯示的矩形區域內的圖像上寫文字，以便在圖像上繪製文字。在第一次鼠標點擊一個矩形區域顯示時，只要輸入文本，文本應該在矩形shap中繪製，矩形應該自動調整大小與附加圖像中顯示的文本。

Answer 1

的基本概念是像任何正常搖擺形式。你只需要添加一些額外的工作來將它們放在一起。

你需要決定的第一件事是你想要多行支持嗎？

下面的示例簡單地使用JLayeredPane來提供自由佈局，並使用自定義JTextArea來提供可編輯字段。

對此的整潔的事情是調整大多是照顧你，因爲是「重新編輯」，只需點擊文本，你會明白我的意思。

我會離開重新定位給你;）

public class TextOverImage { 

    public static void main(String[] args) { 
     new TextOverImage(); 
    } 

    public TextOverImage() { 
     EventQueue.invokeLater(new Runnable() { 
      @Override 
      public void run() { 
       try { 
        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName()); 
       } catch (ClassNotFoundException ex) { 
       } catch (InstantiationException ex) { 
       } catch (IllegalAccessException ex) { 
       } catch (UnsupportedLookAndFeelException ex) { 
       } 

       JFrame frame = new JFrame("Test"); 
       frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
       frame.setLayout(new BorderLayout()); 
       frame.add(new ImagePane()); 
       frame.pack(); 
       frame.setLocationRelativeTo(null); 
       frame.setVisible(true); 
      } 

     }); 
    } 

    public class ImagePane extends JLayeredPane { 

     private BufferedImage background; 

     public ImagePane() { 
      setFocusable(true); 
      try { 
       background = ImageIO.read(new File("Your/image/here")); 
      } catch (Exception e) { 
       e.printStackTrace(); 
      } 
      addMouseListener(new MouseAdapter() { 
       @Override 
       public void mouseClicked(MouseEvent e) { 
        Component focusOwner = FocusManager.getCurrentKeyboardFocusManager().getFocusOwner(); 
        if (!(focusOwner instanceof OverlayEditor)) { 
         OverlayEditor field = new OverlayEditor(); 
         field.setLocation(e.getPoint()); 
         add(field); 
         invalidate(); 
         repaint(); 
         field.requestFocusInWindow(); 
        } else { 
         requestFocusInWindow(); 
        } 
       } 

      }); 
      InputMap im = getInputMap(WHEN_IN_FOCUSED_WINDOW); 
      ActionMap am = getActionMap(); 
      im.put(KeyStroke.getKeyStroke(KeyEvent.VK_ESCAPE, 0), "cancel"); 
      am.put("cancel", new AbstractAction() { 
       @Override 
       public void actionPerformed(ActionEvent e) { 
        Component focusOwner = FocusManager.getCurrentKeyboardFocusManager().getFocusOwner(); 
        if (focusOwner instanceof OverlayEditor) { 
         remove(focusOwner); 
         invalidate(); 
         repaint(); 
        } 
       } 

      }); 
     } 

     @Override 
     public Dimension getPreferredSize() { 
      return new Dimension(400, 400); 
     } 

     @Override 
     protected void paintComponent(Graphics g) { 
      super.paintComponent(g); 
      if (background != null) { 
       int x = (getWidth() - background.getWidth()); 
       int y = (getHeight() - background.getHeight()); 
       g.drawImage(background, x, y, this); 
      } 
     } 

    } 

    public class OverlayEditor extends JTextArea { 

     public OverlayEditor() { 
      super(1, 10); 
      setBorder(null); 
      setForeground(Color.WHITE); 
      setOpaque(false); 
      setSize(getPreferredSize()); 

      getDocument().addDocumentListener(new DocumentListener() { 
       public void update() { 
        setSize(getPreferredSize()); 
       } 

       @Override 
       public void insertUpdate(DocumentEvent e) { 
        update(); 
       } 

       @Override 
       public void removeUpdate(DocumentEvent e) { 
        update(); 
       } 

       @Override 
       public void changedUpdate(DocumentEvent e) { 
        update(); 
       } 

      }); 

      addFocusListener(new FocusListener() { 
       @Override 
       public void focusGained(FocusEvent e) { 
        setBorder(new LineBorder(Color.WHITE)); 
        repaint(); 
       } 

       @Override 
       public void focusLost(FocusEvent e) { 
        setBorder(null); 
        repaint(); 
       } 

      }); 
     } 

     @Override 
     protected void paintComponent(Graphics g) { 
      super.paintComponent(g); 
      Graphics2D g2d = (Graphics2D) g.create(); 
      if (hasFocus()) { 
       g2d.setColor(new Color(0, 0, 0, 32)); 
       g2d.fill(new Rectangle(getWidth(), getHeight())); 
      } 
      g2d.dispose(); 
     } 

    } 

}