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POMouseEvent on JPanel - wrong coordinate
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  1. POMouseEvent on JPanel - wrong coordinate
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    copied!<p>I have written the following micro-paintbrush program in Java: </p> <pre><code>import java.awt.BorderLayout; import java.awt.Color; import java.awt.Container; import java.awt.Graphics; import java.awt.GridLayout; import java.awt.event.MouseEvent; import java.awt.event.MouseListener; import java.awt.event.MouseMotionListener; import javax.swing.BorderFactory; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JOptionPane; import javax.swing.JPanel; class AuxClass1 extends JFrame implements MouseListener, MouseMotionListener{ private JPanel panel1 = new JPanel(); private JPanel panel2 = new JPanel(); private JLabel label1_x = new JLabel(); private JLabel label1_y = new JLabel(); private JLabel label1_x_info = new JLabel(""); private JLabel label1_y_info = new JLabel(""); //add a container keep panels with widgets private Container con1 = getContentPane(); private int xval1; private int yval1; private GridLayout layout1 = new GridLayout(2,2,2,2); private JOptionPane info1 = new JOptionPane(); //get the class that controls the mouse public AuxClass1(){ super("Mouse Experiment"); panel1.setBackground(Color.WHITE); panel1.setLayout(layout1); label1_x.setText("X Location"); label1_x.setBorder(BorderFactory.createLineBorder(Color.BLUE, 2)); label1_y.setBorder(BorderFactory.createLineBorder(Color.BLUE, 2)); label1_x_info.setBorder(BorderFactory.createLineBorder(Color.RED, 2)); label1_y_info.setBorder(BorderFactory.createLineBorder(Color.RED, 2)); label1_y.setText("Y Location"); panel1.add(label1_x); panel1.add(label1_y); panel1.add(label1_x_info); panel1.add(label1_y_info); con1.add(panel1, BorderLayout.NORTH); panel2.setBackground(new Color(100,200,200)); panel2.setBorder(BorderFactory.createLineBorder(new Color(255,255,0), 2)); panel2.addMouseListener(this); panel2.addMouseMotionListener(this); con1.add(panel2, BorderLayout.CENTER); setDefaultCloseOperation(EXIT_ON_CLOSE); setSize(500, 500); setLocationRelativeTo(null); setVisible(true); } @Override public void mouseClicked(MouseEvent arg0) { } @Override public void mouseMoved(MouseEvent arg0) { // TODO Auto-generated method stub if (arg0.getSource()==panel2){ x_var = arg0.getX(); y_var = arg0.getY(); label1_x_info.setText(Integer.toString(x_var)); label1_y_info.setText(Integer.toString(y_var)); } } @Override public void mouseDragged(MouseEvent e) { // TODO Auto-generated method stub if (e.getSource()==panel2){ //info1.showMessageDialog(this, "This is an awesome Mouse toolbox!"); xval1 = e.getX(); yval1= e.getY(); AuxClass2 Inst2 = new AuxClass2(xval1, yval1); Inst2.paintComponent(getGraphics()); } } @Override public void mouseEntered(MouseEvent arg0) { // TODO Auto-generated method stub } @Override public void mouseExited(MouseEvent arg0) { if (arg0.getSource()==panel2){ label1_x_info.setText(""); label1_y_info.setText(""); } // TODO Auto-generated method stub } @Override public void mousePressed(MouseEvent arg0) { // TODO Auto-generated method stub } @Override public void mouseReleased(MouseEvent arg0) { // TODO Auto-generated method stub } } class AuxClass2 extends JPanel{ //JOptionPane info2 = new JOptionPane(); private int xval2; private int yval2; public AuxClass2(int input1, int input2){ xval2 = input1; yval2 = input2; setSize(500,500); } @Override public void paintComponent(Graphics g){ super.paintComponents(g); g.setColor(Color.BLUE); g.fillRect(xval2, yval2+70, 5, 5); } } public class MainClass{ private static AuxClass1 Inst1; public static void main(String args[]){ Inst1 = new AuxClass1(); } } </code></pre> <p>It works alright except for the Y coordinate of the mouseDragged method (see paintComponent method in class t3_aux2). For some reason the Y coordinate used by the method is ~70 pixels less than the actual one in panel2. I suspect this is something to do with the inherited JPanel method in t3_aux2 class but not too sure.</p> <p>If someone could clarify this point, it would be cool. Thanks. </p> <p>UPD: If anyone has suggestions on how to improve style and/or optimize code, that would be massively appreciated too. </p> <p>UPD2: Changed the names to comply with Java naming conventions. </p>
 

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