In this AWT Tutorial, we will perform rubber banding of Line and Rectangle drawing while dragging the mouse. We will also see setXORMode() and its usage while performing the rubber banding.
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package AwtDemoPkg; import java.awt.BorderLayout; import java.awt.Button; import java.awt.Checkbox; import java.awt.Color; import java.awt.Font; import java.awt.Frame; import java.awt.Graphics; import java.awt.GridLayout; import java.awt.Label; import java.awt.Panel; import java.awt.Point; 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 java.awt.event.WindowEvent; import java.awt.event.WindowListener; //Sample 01: Implement the Listeneres public class FrameWin extends Frame implements WindowListener, ActionListener, MouseListener, MouseMotionListener { //Sample 02: Member Variables String DrawMode = ""; Point FirstPoint = new Point(0,0); Point SecondPoint = new Point(0,0); Label lblModeDisplay; Checkbox chkDragMode; public FrameWin(String FrameTitle) { //Display the Frame Window super(FrameTitle); setSize(600, 300); setLocation(100,100); addWindowListener(this); //Sample 03: Prepare Command Panel Panel CommandPanel = new Panel(new GridLayout(6,1)); CommandPanel.setBackground(new Color(240, 240, 240)); //3.1 Prepare Button & Checkbox Button btnDrawLine = new Button("Draw Line"); Button btnDrawRect = new Button("Draw Rect"); Button btnFreeHand = new Button("Free Hand"); btnDrawLine.setActionCommand("LineD"); btnDrawRect.setActionCommand("RectD"); btnFreeHand.setActionCommand("FreeH"); btnDrawLine.addActionListener(this); btnDrawRect.addActionListener(this); btnFreeHand.addActionListener(this); chkDragMode = new Checkbox("Rubber Band"); //3.2 Prepare Labels Label lblMode = new Label("Mode"); lblModeDisplay = new Label(); Font f1 = new Font("Verdana", Font.PLAIN, 20); lblMode.setFont(f1); lblModeDisplay.setFont(f1); lblModeDisplay.setForeground(Color.BLUE); //3.3 Pack the Panel & give to Frame CommandPanel.add(btnDrawLine); CommandPanel.add(btnDrawRect); CommandPanel.add(btnFreeHand); CommandPanel.add(chkDragMode); CommandPanel.add(lblMode); CommandPanel.add(lblModeDisplay); add(BorderLayout.EAST, CommandPanel); //Sample 07: Register with Mouse Listener addMouseListener(this); //Sample 12: Register Mouse Motion Listener addMouseMotionListener(this); } public void windowOpened(WindowEvent e) {} public void windowClosed(WindowEvent e) {} public void windowIconified(WindowEvent e) {} public void windowDeiconified(WindowEvent e) {} public void windowActivated(WindowEvent e) {} public void windowDeactivated(WindowEvent e) {} public void windowClosing(WindowEvent e) { this.dispose(); } public void mouseDragged(MouseEvent e) { //Sample 14: Perform Free Hand Drawing if (DrawMode.compareTo("FreeH") == 0) { if (SecondPoint.x != 0 && SecondPoint.y != 0) { FirstPoint.x = SecondPoint.x; FirstPoint.y = SecondPoint.y; } SecondPoint.setLocation(e.getX(), e.getY()); paint(getGraphics()); } //Sample 15: Draw Line Rubber-Banding if(DrawMode.compareTo("LineD") == 0 && chkDragMode.getState() == true) { Graphics gr = getGraphics(); gr.setColor(Color.LIGHT_GRAY); //Sample 16: Resolve Rubber Banding Issue => if (SecondPoint.x != 0 && SecondPoint.y != 0) { gr.setXORMode(getBackground()); gr.drawLine( FirstPoint.x, FirstPoint.y, SecondPoint.x, SecondPoint.y); } //Sample 16 <= SecondPoint.setLocation(e.getX(), e.getY()); paint(gr); } //Sample 17: Draw Rect Rubber-Banding if(DrawMode.compareTo("RectD") == 0 && chkDragMode.getState() == true) { Graphics gr = getGraphics(); gr.setColor(Color.LIGHT_GRAY); if (SecondPoint.x != 0 && SecondPoint.y != 0) { gr.setXORMode(getBackground()); Point TopLeft = GetTopLeft(); int width = Math.abs(SecondPoint.x - FirstPoint.x); int height = Math.abs(SecondPoint.y - FirstPoint.y); gr.drawRect(TopLeft.x, TopLeft.y, width, height); } SecondPoint.setLocation(e.getX(), e.getY()); paint(gr); } } public void mouseMoved(MouseEvent e) { } public void mouseClicked(MouseEvent e) {} public void mousePressed(MouseEvent e) { //Sample 05: Set First Point FirstPoint.setLocation(0, 0); SecondPoint.setLocation(0, 0); FirstPoint.setLocation(e.getX(), e.getY()); } public void mouseReleased(MouseEvent e) { //Sample 06: Set Second Point //Sample 13: Introduce the Condition if (DrawMode.compareTo("FreeH") != 0) { SecondPoint.setLocation(e.getX(), e.getY()); repaint(); } } public void mouseEntered(MouseEvent e) {} public void mouseExited(MouseEvent e) {} public void actionPerformed(ActionEvent e) { //Sample 04: Set the Draw Mode DrawMode = e.getActionCommand(); lblModeDisplay.setText(DrawMode); FirstPoint.setLocation(0, 0); SecondPoint.setLocation(0, 0); } public void paint(Graphics g) { if (FirstPoint.equals(SecondPoint)) return; switch(DrawMode) { case "LineD": //Sample 08: Draw Line g.drawLine( FirstPoint.x, FirstPoint.y, SecondPoint.x, SecondPoint.y); break; case "RectD": //Sample 10: Draw Rectangle Point TopLeft = GetTopLeft(); int width = Math.abs(SecondPoint.x - FirstPoint.x); int height = Math.abs(SecondPoint.y - FirstPoint.y); g.drawRect(TopLeft.x, TopLeft.y, width, height); break; case "FreeH": //Sample 11: Free Hand Drawing g.drawLine( FirstPoint.x, FirstPoint.y, SecondPoint.x, SecondPoint.y); break; } } //Sample 09: Relocate Rectangle Start Point private Point GetTopLeft() { Point TopLeft = new Point(); TopLeft.x = Math.min(FirstPoint.x,SecondPoint.x ); TopLeft.y = Math.min(FirstPoint.y,SecondPoint.y ); return TopLeft; } } |
Categories: AWT-Tube
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