後でキャンバスの中に描画してイメージを保存する方法は？

Question

私はキャンバスに何かを描くことができる自由な手描きのJavaアプレットを実装しようとしています（キャンバスは優先事項ではありません。後でボタンを押した後に別の場所に表示するには、他の解決策もあります））。私は描くことができるコードを見つけましたが、今はキャンバスの中に絵を描くことに問題があります...そして、私はすでに結果を出さずに数日を過ごしました。

import java.awt.*; 
import java.awt.event.*; 
import java.awt.event.ActionEvent; 
import java.awt.event.ActionListener; 
import java.awt.event.MouseEvent; 
import java.awt.event.MouseListener; 
import java.awt.event.MouseMotionListener; 
import javax.swing.*; 
import java.applet.*; 

public class paintMozApplet extends Applet implements ActionListener 
{ 
    int xPressed,yPressed; 
    int xReleased,yReleased; 
    int xDragged,yDragged; 
    private GridLayout gL; 
    private JPanel buttons; 
    private JPanel panel; 
    private Button clear, createMoz; 
    private Label result_here; 
    private javax.swing.JPanel drawing; 
    private JPanel moz; 
    private Canvas canvas; 
    private draw draw; 

    public paintMozApplet() 
    { 
     draw = new draw(); 

     gL = new GridLayout(1, 0);   

     buttons = new JPanel(); 
     drawing = new JPanel(); 
     moz = new JPanel(); 
     canvas = new Canvas(); 

     clear = new Button("clear"); 
     createMoz = new Button("Create Moz"); 

     buttons.add(clear); 
     buttons.add(createMoz); 

     result_here = new Label("Result here!"); 

     moz.add(result_here); 
     drawing.add(canvas); 

     clear.addActionListener(this); 
     //canvas.add(draw); 
     //canvas.addMouseMotionListener(this); 

     canvas.setPreferredSize(new Dimension(200, 200)); 
     canvas.setBackground(Color.green); 

     add(drawing); 
     add(buttons); 
     add(moz); 
     add(draw); 
     setPreferredSize(new Dimension(1000, 1000)); 

     setSize(1000, 1000); 
     setLayout(gL); 
    } 

    public void actionPerformed(ActionEvent e) 
    { 
     if(e.getSource()==clear) 
     { 
      //setOpaque(false); 
      repaint(); 
     } 
    } 

} 
class draw extends JFrame implements MouseListener, MouseMotionListener, ActionListener { 

    int xPressed,yPressed; 
    int xReleased,yReleased; 
    int xDragged,yDragged; 
    private JButton clear; 
    public draw() 
    { 
     setPreferredSize(new Dimension(1200, 500)); 
     setBounds(0, 0, 480, 500); 
     clear=new JButton("CLEAR"); 
     add(clear); 
     clear.setBounds(540, 5, 100, 25); 
     clear.addActionListener(this); 
     addMouseListener(this); 
     addMouseMotionListener(this); 
    }   

    protected void paintComponent(Graphics g) 
    { 
     g.drawLine(xPressed,yPressed,xDragged,yDragged); 
     xPressed=xDragged; 
     yPressed=yDragged; 
    } 

    @Override 
    public void mouseDragged(MouseEvent arg0) { 
     Graphics g = getGraphics(); 
     g.drawLine(xPressed, yPressed, arg0.getX(), arg0.getY()); 
     xDragged = arg0.getX(); 
     yDragged = arg0.getY(); 
     repaint(); 
    } 

    @Override 
    public void mouseMoved(MouseEvent arg0) { 
    } 
    @Override 
    public void mouseClicked(MouseEvent arg0) { 
    } 
    @Override 
    public void mouseEntered(MouseEvent arg0) { 
    } 
    @Override 
    public void mouseExited(MouseEvent arg0) { 
    } 
    @Override 
    public void mousePressed(MouseEvent arg0) { 
     xPressed = arg0.getX(); 
     yPressed = arg0.getY(); 
    } 
    @Override 
    public void mouseReleased(MouseEvent arg0) { 
    } 

    @Override 
    public void actionPerformed(ActionEvent e) { 
    } 

}  

は、だから私の考えは1を描き、他のすべての場所を作成するために描画するために使用し、他の2つのクラスを作成することです。ここで私は今では持っているコードとそれ以下の説明です。私はたくさんのことを試してきましたが、今私はここにいて、キャンバス上の描画クラスをどのようにしてそれを描画するのかを理解することはできません。私がすべてのものを1つのクラスに入れて、キャンバスにマウスイベントを呼び出す前に。結果は、キャンバスをクリックしたときにのみ描画されるという結果でしたが、マウスを手放さずキャンバスからドラッグしないと、実際の描画もキャンバスから外れました。また、キャンバスに描画されませんでしたが、アプレットの背景に、少なくともそれはそのように見えました。

私は自分の理解を説明してくれることを願っています。オンラインのソリューションがたくさんあるので簡単に解決できますが、私が意図したとおりに動作するものは見つけられないようです。

Answer 1

私はこのソースは非常にまだらである

import java.awt.*; 
import java.awt.RenderingHints.Key; 
import java.awt.event.*; 
import java.awt.image.BufferedImage; 
import java.io.File; 
import java.io.IOException; 
import java.util.HashMap; 
import java.util.Map; 

import javax.imageio.ImageIO; 
import javax.swing.*; 
import javax.swing.border.*; 
import javax.swing.event.ChangeEvent; 
import javax.swing.event.ChangeListener; 
import javax.swing.filechooser.FileFilter; 
import javax.swing.filechooser.FileNameExtensionFilter; 

public class BasicPaint { 

    /** Reference to the original image. */ 
    private BufferedImage originalImage; 
    /** Image used to make changes. */ 
    private BufferedImage canvasImage; 
    /** The main GUI that might be added to a frame or applet. */ 
    private JPanel gui; 
    /** The color to use when calling clear, text or other 
    * drawing functionality. */ 
    private Color color = Color.WHITE; 
    /** General user messages. */ 
    private JLabel output = new JLabel("You DooDoodle!"); 

    private BufferedImage colorSample = new BufferedImage(
      16,16,BufferedImage.TYPE_INT_RGB); 
    private JLabel imageLabel; 
    private int activeTool; 
    public static final int SELECTION_TOOL = 0; 
    public static final int DRAW_TOOL = 1; 
    public static final int TEXT_TOOL = 2; 

    private Point selectionStart; 
    private Rectangle selection; 
    private boolean dirty = false; 
    private Stroke stroke = new BasicStroke(
      3,BasicStroke.CAP_ROUND,BasicStroke.JOIN_ROUND,1.7f); 
    private RenderingHints renderingHints; 

    public JComponent getGui() { 
     if (gui==null) { 
      Map<Key, Object> hintsMap = new HashMap<RenderingHints.Key,Object>(); 
      hintsMap.put(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY); 
      hintsMap.put(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_ENABLE); 
      hintsMap.put(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON); 
      renderingHints = new RenderingHints(hintsMap); 

      setImage(new BufferedImage(320,240,BufferedImage.TYPE_INT_RGB)); 
      gui = new JPanel(new BorderLayout(4,4)); 
      gui.setBorder(new EmptyBorder(5,3,5,3)); 

      JPanel imageView = new JPanel(new GridBagLayout()); 
      imageView.setPreferredSize(new Dimension(480,320)); 
      imageLabel = new JLabel(new ImageIcon(canvasImage)); 
      JScrollPane imageScroll = new JScrollPane(imageView); 
      imageView.add(imageLabel); 
      imageLabel.addMouseMotionListener(new ImageMouseMotionListener()); 
      imageLabel.addMouseListener(new ImageMouseListener()); 
      gui.add(imageScroll,BorderLayout.CENTER); 

      JToolBar tb = new JToolBar(); 
      tb.setFloatable(false); 
      JButton colorButton = new JButton("Color"); 
      colorButton.setMnemonic('o'); 
      colorButton.setToolTipText("Choose a Color"); 
      ActionListener colorListener = new ActionListener() { 
       public void actionPerformed(ActionEvent arg0) { 
        Color c = JColorChooser.showDialog(
          gui, "Choose a color", color); 
        if (c!=null) { 
         setColor(c); 
        } 
       } 
      }; 
      colorButton.addActionListener(colorListener); 
      colorButton.setIcon(new ImageIcon(colorSample)); 
      tb.add(colorButton); 

      setColor(color); 

      final SpinnerNumberModel strokeModel = 
        new SpinnerNumberModel(3,1,16,1); 
      JSpinner strokeSize = new JSpinner(strokeModel); 
      ChangeListener strokeListener = new ChangeListener() { 
       @Override 
       public void stateChanged(ChangeEvent arg0) { 
        Object o = strokeModel.getValue(); 
        Integer i = (Integer)o; 
        stroke = new BasicStroke(
          i.intValue(), 
          BasicStroke.CAP_ROUND, 
          BasicStroke.JOIN_ROUND, 
          1.7f); 
       } 
      }; 
      strokeSize.addChangeListener(strokeListener); 
      strokeSize.setMaximumSize(strokeSize.getPreferredSize()); 
      JLabel strokeLabel = new JLabel("Stroke"); 
      strokeLabel.setLabelFor(strokeSize); 
      strokeLabel.setDisplayedMnemonic('t'); 
      tb.add(strokeLabel); 
      tb.add(strokeSize); 

      tb.addSeparator(); 

      ActionListener clearListener = new ActionListener() { 
       public void actionPerformed(ActionEvent arg0) { 
        int result = JOptionPane.OK_OPTION; 
        if (dirty) { 
         result = JOptionPane.showConfirmDialog(
           gui, "Erase the current painting?"); 
        } 
        if (result==JOptionPane.OK_OPTION) { 
         clear(canvasImage); 
        } 
       } 
      }; 
      JButton clearButton = new JButton("Clear"); 
      tb.add(clearButton); 
      clearButton.addActionListener(clearListener); 

      gui.add(tb, BorderLayout.PAGE_START); 

      JToolBar tools = new JToolBar(JToolBar.VERTICAL); 
      tools.setFloatable(false); 
      JButton crop = new JButton("Crop"); 
      final JRadioButton select = new JRadioButton("Select", true); 
      final JRadioButton draw = new JRadioButton("Draw"); 
      final JRadioButton text = new JRadioButton("Text"); 

      tools.add(crop);    
      tools.add(select);   
      tools.add(draw);    
      tools.add(text); 

      ButtonGroup bg = new ButtonGroup(); 
      bg.add(select); 
      bg.add(text); 
      bg.add(draw); 
      ActionListener toolGroupListener = new ActionListener() { 
       @Override 
       public void actionPerformed(ActionEvent ae) { 
        if (ae.getSource()==select) { 
         activeTool = SELECTION_TOOL; 
        } else if (ae.getSource()==draw) { 
         activeTool = DRAW_TOOL; 
        } else if (ae.getSource()==text) { 
         activeTool = TEXT_TOOL; 
        } 
       } 
      }; 
      select.addActionListener(toolGroupListener); 
      draw.addActionListener(toolGroupListener); 
      text.addActionListener(toolGroupListener); 

      gui.add(tools, BorderLayout.LINE_END); 

      gui.add(output,BorderLayout.PAGE_END); 
      clear(colorSample); 
      clear(canvasImage); 
     } 

     return gui; 
    } 

    /** Clears the entire image area by painting it with the current color. */ 
    public void clear(BufferedImage bi) { 
     Graphics2D g = bi.createGraphics(); 
     g.setRenderingHints(renderingHints); 
     g.setColor(color); 
     g.fillRect(0, 0, bi.getWidth(), bi.getHeight()); 

     g.dispose(); 
     imageLabel.repaint(); 
    } 

    public void setImage(BufferedImage image) { 
     this.originalImage = image; 
     int w = image.getWidth(); 
     int h = image.getHeight(); 
     canvasImage = new BufferedImage(w,h,BufferedImage.TYPE_INT_ARGB); 

     Graphics2D g = this.canvasImage.createGraphics(); 
     g.setRenderingHints(renderingHints); 
     g.drawImage(image, 0, 0, gui); 
     g.dispose(); 

     selection = new Rectangle(0,0,w,h); 
     if (this.imageLabel!=null) { 
      imageLabel.setIcon(new ImageIcon(canvasImage)); 
      this.imageLabel.repaint(); 
     } 
     if (gui!=null) { 
      gui.invalidate(); 
     } 
    } 

    /** Set the current painting color and refresh any elements needed. */ 
    public void setColor(Color color) { 
     this.color = color; 
     clear(colorSample); 
    } 

    private JMenu getFileMenu(boolean webstart){ 
     JMenu file = new JMenu("File"); 
     file.setMnemonic('f'); 

     JMenuItem newImageItem = new JMenuItem("New"); 
     newImageItem.setMnemonic('n'); 
     ActionListener newImage = new ActionListener() { 
      @Override 
      public void actionPerformed(ActionEvent arg0) { 
       BufferedImage bi = new BufferedImage(
         360, 300, BufferedImage.TYPE_INT_ARGB); 
       clear(bi); 
       setImage(bi); 
      } 
     }; 
     newImageItem.addActionListener(newImage); 
     file.add(newImageItem); 

     if (webstart) { 
      //TODO Add open/save functionality using JNLP API 
     } else { 
      //TODO Add save functionality using J2SE API 
      file.addSeparator(); 
      ActionListener openListener = new ActionListener() { 
       @Override 
       public void actionPerformed(ActionEvent arg0) { 
        if (!dirty) { 
         JFileChooser ch = getFileChooser(); 
         int result = ch.showOpenDialog(gui); 
         if (result==JFileChooser.APPROVE_OPTION) { 
          try { 
           BufferedImage bi = ImageIO.read(
             ch.getSelectedFile()); 
           setImage(bi); 
          } catch (IOException e) { 
           showError(e); 
           e.printStackTrace(); 
          } 
         } 
        } else { 
         // TODO 
         JOptionPane.showMessageDialog(
           gui, "TODO - prompt save image.."); 
        } 
       } 
      }; 
      JMenuItem openItem = new JMenuItem("Open"); 
      openItem.setMnemonic('o'); 
      openItem.addActionListener(openListener); 
      file.add(openItem); 

      ActionListener saveListener = new ActionListener() { 

       @Override 
       public void actionPerformed(ActionEvent e) { 
        JFileChooser ch = getFileChooser(); 
        int result = ch.showSaveDialog(gui); 
        if (result==JFileChooser.APPROVE_OPTION) { 
         try { 
          File f = ch.getSelectedFile(); 
          ImageIO.write(BasicPaint.this.canvasImage, "png", f); 
          BasicPaint.this.originalImage = BasicPaint.this.canvasImage; 
          dirty = false; 
         } catch (IOException ioe) { 
          showError(ioe); 
          ioe.printStackTrace(); 
         } 
        } 
       } 
      }; 
      JMenuItem saveItem = new JMenuItem("Save"); 
      saveItem.addActionListener(saveListener); 
      saveItem.setMnemonic('s'); 
      file.add(saveItem); 
     } 

     if (canExit()) { 
      ActionListener exit = new ActionListener() { 
       @Override 
       public void actionPerformed(ActionEvent arg0) { 
        // TODO Auto-generated method stub 
        System.exit(0); 
       } 
      }; 
      JMenuItem exitItem = new JMenuItem("Exit"); 
      exitItem.setMnemonic('x'); 
      file.addSeparator(); 
      exitItem.addActionListener(exit); 
      file.add(exitItem); 
     } 

     return file; 
    } 

    private void showError(Throwable t) { 
     JOptionPane.showMessageDialog(
       gui, 
       t.getMessage(), 
       t.toString(), 
       JOptionPane.ERROR_MESSAGE); 
    } 

    JFileChooser chooser = null; 

    public JFileChooser getFileChooser() { 
     if (chooser==null) { 
      chooser = new JFileChooser(); 
      FileFilter ff = new FileNameExtensionFilter("Image files", ImageIO.getReaderFileSuffixes()); 
      chooser.setFileFilter(ff); 
     } 
     return chooser; 

    } 

    public boolean canExit() { 
     boolean canExit = false; 
     SecurityManager sm = System.getSecurityManager(); 
     if (sm==null) { 
      canExit = true; 
     } else { 
      try { 
       sm.checkExit(0); 
       canExit = true; 
      } catch(Exception stayFalse) { 
      } 
     } 

     return canExit; 
    } 

    public JMenuBar getMenuBar(boolean webstart){ 
     JMenuBar mb = new JMenuBar(); 
     mb.add(this.getFileMenu(webstart)); 
     return mb; 
    } 

    public static void main(String[] args) { 
     Runnable r = new Runnable() { 
      @Override 
      public void run() { 
       try { 
        UIManager.setLookAndFeel(
          UIManager.getSystemLookAndFeelClassName()); 
       } catch (Exception e) { 
        // use default 
       } 
       BasicPaint bp = new BasicPaint(); 

       JFrame f = new JFrame("DooDoodle!"); 
       f.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); 
       f.setLocationByPlatform(true); 

       f.setContentPane(bp.getGui()); 
       f.setJMenuBar(bp.getMenuBar(false)); 

       f.pack(); 
       f.setMinimumSize(f.getSize()); 
       f.setVisible(true); 
      } 
     }; 
     SwingUtilities.invokeLater(r); 
    } 

    public void text(Point point) { 
     String text = JOptionPane.showInputDialog(gui, "Text to add", "Text"); 
     if (text!=null) { 
      Graphics2D g = this.canvasImage.createGraphics(); 
      g.setRenderingHints(renderingHints); 
      g.setColor(this.color); 
      g.setStroke(stroke); 
      int n = 0; 
      g.drawString(text,point.x,point.y); 
      g.dispose(); 
      this.imageLabel.repaint(); 
     } 
    } 

    public void draw(Point point) { 
     Graphics2D g = this.canvasImage.createGraphics(); 
     g.setRenderingHints(renderingHints); 
     g.setColor(this.color); 
     g.setStroke(stroke); 
     int n = 0; 
     g.drawLine(point.x, point.y, point.x+n, point.y+n); 
     g.dispose(); 
     this.imageLabel.repaint(); 
    } 

    class ImageMouseListener extends MouseAdapter { 

     @Override 
     public void mousePressed(MouseEvent arg0) { 
      // TODO Auto-generated method stub 
      if (activeTool==BasicPaint.SELECTION_TOOL) { 
       selectionStart = arg0.getPoint(); 
      } else if (activeTool==BasicPaint.DRAW_TOOL) { 
       // TODO 
       draw(arg0.getPoint()); 
      } else if (activeTool==BasicPaint.TEXT_TOOL) { 
       // TODO 
       text(arg0.getPoint()); 
      } else { 
       JOptionPane.showMessageDialog(
         gui, 
         "Application error. :(", 
         "Error!", 
         JOptionPane.ERROR_MESSAGE); 
      } 
     } 

     @Override 
     public void mouseReleased(MouseEvent arg0) { 
      if (activeTool==BasicPaint.SELECTION_TOOL) { 
       selection = new Rectangle(
         selectionStart.x, 
         selectionStart.y, 
         arg0.getPoint().x, 
         arg0.getPoint().y); 
      } 
     } 
    } 

    class ImageMouseMotionListener implements MouseMotionListener { 

     @Override 
     public void mouseDragged(MouseEvent arg0) { 
      reportPositionAndColor(arg0); 
      if (activeTool==BasicPaint.SELECTION_TOOL) { 
       selection = new Rectangle(
         selectionStart.x, 
         selectionStart.y, 
         arg0.getPoint().x-selectionStart.x, 
         arg0.getPoint().y-selectionStart.y); 
      } else if (activeTool==BasicPaint.DRAW_TOOL) { 
       draw(arg0.getPoint()); 
      } 
     } 

     @Override 
     public void mouseMoved(MouseEvent arg0) { 
      reportPositionAndColor(arg0); 
     } 

    } 

    private void reportPositionAndColor(MouseEvent me) { 
     String text = ""; 
     if (activeTool==BasicPaint.SELECTION_TOOL) { 
      text += "Selection (X,Y:WxH): " + 
        (int)selection.getX() + 
        "," + 
        (int)selection.getY() + 
        ":" + 
        (int)selection.getWidth() + 
        "x" + 
        (int)selection.getHeight(); 
     } else { 
      text += "X,Y: " + (me.getPoint().x+1) + "," + (me.getPoint().y+1); 
     } 
     output.setText(text); 
    } 
} 

...塗装面などBufferedImageの周りに基づいて、このアプローチで始まる示唆しています。

• それはdirty属性が宣言されていますが、何らかの意味のある方法で使用されることはありません// TODO
• で多くの部分を持っています。 ..

これは私が今日一緒にハッキングしたものであり、投稿制限に達する前に表示する必要があります。

ああ、私は中に何も入れていないので、どんな「OOデザイン」も探していない。何かがあれば、それは偶然でしかない。このコードは、可能なことと、それをやり始める方法を示すことを目的としています。