How to Draw an BufferedImage to a JPanel

Question

I am trying to use some sort of draw method to draw a sprite image to my subclass of JPanel called AnimationPanel. I have created a Spritesheet class which can generate a Bu

Answer 1

Here's some generic code for drawing an image to a JPanel. This method is called to paint your JPanel component.

public void paintComponent (Graphics g)
{ 
     super.paintComponent(g);
     //I would have image be a class variable that gets updated in your run() method
     g.drawImage(image, 0, 0, this); 
} 

I may also modify run() to look something like this:

public void run() {
  BufferedImage[] frames = sheet.getAllSprites();
  currentFrame = 0;
  while (true) {
    image = frames[currentFrame];
    this.repaint(); //explicitly added "this" for clarity, not necessary.
    currentFrame++;
    if (currentFrame >= frames.length) {
        currentFrame = 0;
    }
  }
}

In regards to only repainting part of the component, it gets a little more complicated

public void run() {
  BufferedImage[] frames = sheet.getAllSprites();
  currentFrame = 0;
  while (true) {
    image = frames[currentFrame];
    Rectangle r = this.getDirtyRect();
    this.repaint(r); 
    currentFrame++;
    if (currentFrame >= frames.length) {
        currentFrame = 0;
    }
  }
}

public Rectangle getDirtyRect() {
  int minX=0; //calculate smallest x value affected
  int maxX=0; //calculate largest x value affected
  int minY=0; //calculate smallest y value affected
  int maxY=0; //calculate largest y value affected 
  return new Rectangle(minX,minY,maxX,maxY);
}