I'm trying to build Paint app and I doing something wrong in DrawingArea class. The problem is when I try to draw second shape , the first shape or figure is auto deleting so I need to some idea about how to solve this.All answers acceptable. THANKS FOR HELP.
There is part of DrawingArea.class codes :
@Override // GETTING FIRST (STARTING) COORDINATE WHEN THE MOUSE PRESSED
public void mousePressed(MouseEvent e) {
oldX = e.getX();
oldY = e.getY();
repaint();
}
@Override // GETTING RELEASED COORDINATE TO DRAW LINE.
public void mouseReleased(MouseEvent e) {
lastX = e.getX();
lastY = e.getY();
repaint();
}
public void mouseClicked(MouseEvent e) {
clickedX = true;
COUNT = e.getClickCount();
}
// GETTING COORDINATE TO DRAW FILLEDRECT,FILLEDOVAL,OVAL,RECT.
public void mouseDragged(MouseEvent e) {
draggedX = e.getX();
draggedY = e.getY();
repaint();
width = Math.abs(oldX - draggedX);
height = Math.abs(oldY - draggedY);
x = Math.min(draggedX, oldX);
y = Math.min(draggedY, oldY);
}
public void mouseMoved(MouseEvent e) {
}
public void mouseEntered(MouseEvent e) {
}
public void mouseExited(MouseEvent e) {
}
// CLEAR THE ALL SHAPES DRAWED ON DRAW AREA.
public void clear() {
g2.setColor(Color.WHITE);
g2.fillRect(0, 0, (int) this.getWidth() + 55, (int) this.getHeight() + 55);
super.repaint();
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
if (image == null) {
image = new BufferedImage((int) this.getWidth(), (int) this.getHeight(), BufferedImage.TYPE_INT_ARGB);
g2 = (Graphics2D) image.getGraphics();
g2.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
clear();
}
g2.drawImage(image, 0, 0, getWidth(), getHeight(), this);
g2.dispose();
g.setColor(initialColor);
if (shape == Shapers.PENCIL) {
g.setColor(currentColor);
g.fillOval(draggedX, draggedY, thickness, thickness);
} else if (shape == Shapers.OVAL) {
g.setColor(currentColor);
g.drawOval(oldX, oldY, draggedX, draggedX);
} else if (shape == Shapers.FILLEDOVAL) {
g.setColor(currentColor);
g.fillOval(oldX, oldY, draggedX, draggedY);
} else if (shape == Shapers.RECT) {
g.setColor(currentColor);
g.drawRect(x, y, width, height);
} else if (shape == Shapers.FILLEDRECT) {
g.setColor(currentColor);
g.fillRect(x, y, width, height);
} else if (shape == Shapers.LINE) {
g.setColor(currentColor);
g.drawLine(oldX, oldY, draggedX, draggedY);
oldX = draggedX;
oldY = draggedY;
} else if (shape == Shapers.ERASER) {
g.setColor(Color.WHITE);
g.fillRect(draggedX, draggedY, thickness, thickness);
} else if (shape == Shapers.TEXT) {
if (clickedX == true || COUNT == 2) {
String str = JOptionPane.showInputDialog("Write Your Text Here : ");
g.setFont(myFont);
g.setColor(currentColor);
if (str != null) {
g.drawString(str, oldX, oldY);
COUNT = 0;
} else {
return;
}
}
} else {
COUNT = 0;
return;
}
}
}
You need to either:
- Store shapes to be painted in a List and then in the paintComponent() method you paint all the shapes in the List, or
- Paint your shapes to a BufferedImage and then just paint the BufferedImage
Check out Custom Painting Approaches for working examples of both approaches and use the approach that best meets your requirement.
来源：https://stackoverflow.com/questions/39660946/how-to-draw-multiple-shapes-on-jcomponent-or-jpanel