Name: skT88420 Date: 06/02/99


Create a custom cursor, set this cursor for a component, damage and repaint the area under the cursor while tracking mouse drag events. The cursor and the area under the custom cursor are not redrawn properly.

In my application I use a magnifying glass cursor when in "zoom in" mode. This bug makes the screen look awful. There is so much "trash" drawn that the user can't tell where the zoom will occur.

This is a regression - the same code works fine in 1.2 and 1.2.1.

I'm running on an IBM ThinkPad 770x with Windows 98.

The source code for a small example that demonstrates the problem is included below. If you also need the cursor gif file, please send me e-mail and I'll send it as an attachment.


-------- Source Code ------------

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class Bug {
    
    public static class Paper extends JComponent {
        
        public boolean minimumArea_;
        public int x_;
        public int y_;
        
        public void paintComponent(Graphics graphics) {
            graphics.setColor(getBackground());
            graphics.fillRect(0, 0, getWidth(), getHeight());
            graphics.setColor(getForeground());
            graphics.drawLine(x_, y_, x_ + 31, y_);
            graphics.drawLine(x_ + 32, y_, x_ + 32, y_ + 31);
            graphics.drawLine(x_ + 32, y_ + 32, x_ + 1, y_ + 32);
            graphics.drawLine(x_, y_ + 32, x_, y_ + 1);
        }
        
        void repaintRect(int x, int y) {
            RepaintManager repaintManager = RepaintManager.currentManager(this);
            repaintManager.paintDirtyRegions();
            repaint(x, y, 31 + 1, 1);
            repaintManager.paintDirtyRegions();
            repaint(x + 32, y, 1, 31 + 1);
            repaintManager.paintDirtyRegions();
            repaint(x + 1, y + 32, 31 + 1, 1);
            repaintManager.paintDirtyRegions();
            repaint(x, y + 1, 1, 31 + 1);
            repaintManager.paintDirtyRegions();
        }
        
        public void update(int newX, int newY) {
            if (minimumArea_) {
                int oldX = x_;
                int oldY = y_;
                x_ = newX;
                y_ = newY;
                repaintRect(newX, newY);
                repaintRect(oldX, oldY);
            } else {
                repaint();
                x_ = newX;
                y_ = newY;
                repaint();
            }
        }
        
    }
    
    public static void main(String[] args) {
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        Image image = toolkit.createImage(Bug.class.getResource("ZoomToCursor-32x32.gif"));
        Cursor cursor = toolkit.createCustomCursor(image, new Point(8, 8), "custom");

        final Paper paper = new Paper();
        paper.minimumArea_ = args.length > 0;
        paper.setCursor(cursor);
        paper.addMouseMotionListener(
            new MouseMotionAdapter() {
                public void mouseDragged(MouseEvent event) {
                    paper.update(event.getX(), event.getY());
                }
            }
        );
        
        JFrame frame = new JFrame("Bug");
        frame.getContentPane().add(paper);
        frame.setBounds(0, 0, 200, 200);
        frame.show();
    }
    
}
(Review ID: 83819)
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