PaintPanel.java

From: Into Java - Part XVI

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

public class PaintPanel extends JPanel
                        implements MouseMotionListener {

    /* static class variables to determine shapes */
    public static int LINE = 0;
    public static int RECTANGLE = 1;
    public static int OVAL = 2;

    private boolean filledShape = true;
    private int shape = 1; // default is rectangle
    private int startX;
    private int startY;
    private int stopX;
    private int stopY;
    private Color paintColor;
    private boolean mousePressed;
    private PaintShape tempShape;
    private Vector storedShapes;

    public PaintPanel() {
        super(true); // being double buffered

        paintColor = Color.black;
        storedShapes = new Vector();

        addMouseListener(new MouseAdapter() {
            public void mousePressed(MouseEvent mp) {
                if ((mp.getModifiers()
                            & InputEvent.BUTTON1_MASK) != 0) {

                    startX = mp.getX();
                    startY = mp.getY();
                    mousePressed = true;
                }
            }

            public void mouseReleased(MouseEvent mr) {
                if ((mr.getModifiers()
                            & InputEvent.BUTTON1_MASK) != 0) {

                    mousePressed = false;
                    stopX = mr.getX();
                    stopY = mr.getY();
                    tempShape = new PaintShape(filledShape,
                            paintColor, shape, startX, startY);
                    tempShape.setStop(stopX, stopY);
                    storedShapes.addElement(tempShape);
                    repaint();
                }
            }

            public void mouseClicked(MouseEvent mc) {
                if (mc.getClickCount() > 1 && (mc.getModifiers()
                            & InputEvent.BUTTON3_MASK) != 0) {

                    Point p = new Point(mc.getX(), mc.getY());
                    removeShape(p);
                }
            }
        });
        addMouseMotionListener(this);
    }

    private void removeShape(Point xy) {
        for (int i = 0; i < storedShapes.size(); i++) {
            PaintShape tempS = (PaintShape)
                storedShapes.elementAt(i);
            if (tempS.contains(xy)) {
                storedShapes.removeElement(tempS);
                repaint();
                break;
            }
        }
    }

    public void mouseMoved(MouseEvent skipIt) { /* empty */ }

    public void mouseDragged(MouseEvent me) {
        stopX = me.getX();
        stopY = me.getY();
        repaint();
    }

    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        for(int i = 0; i < storedShapes.size(); i++) {
            PaintShape tempObj = (PaintShape)storedShapes.elementAt(i);
            tempObj.paintComponent(g);
        }
        Color oldColor = g.getColor();
        g.setColor(paintColor);

        if (shape == 0) { // that is line
            g.drawLine(startX, startY, stopX, stopY);
        } else {
            /* make four temp variables to avoid trouble */
            int startXX = startX;
            int startYY = startY;
            int width = stopX - startX;
            int height = stopY - startY;
            if (width < 0) { // not good
                startXX = stopX;
                width = -width;
            } else {
                startXX = startX;
            }
            if (height < 0) { // not good
                startYY = stopY;
                height = -height;
            } else {
                startYY = startY;
            }

            if (shape == 1) { // that is rectangle
                if (filledShape) {
                    g.fillRect(startXX, startYY, width, height);
                } else {
                    g.drawRect(startXX, startYY, width, height);
                }
            } else { // remaining is oval
                if (mousePressed) {
                    g.drawRect(startXX, startYY, width, height);
                }
                if (filledShape) {
                    g.fillOval(startXX, startYY, width, height);
                } else {
                    g.drawOval(startXX, startYY, width, height);
                }
            }
        }
        g.setColor(oldColor);
    }

    public void setFilled(boolean b) {
        filledShape = b;
    }

    public void setShape(int sh) {
        shape = sh;
    }

    public void setColor(Color c) {
        paintColor = c;
    }
}