Fast Image - Slow Image

Question

Hi
In my game I load a 2D landscape from a gif image. The image consists of mostly two colors. If I use this image in my game, the game runs fast. as it should.
But to make the graphics nicer, I have drawn a second, small image with lots of colors and details. The idea is to replace one of the colors in the image (the ground) with this image. This method do that:
     public static BufferedImage changeColor (Image image, Color fromColor, Image toImage) {
           BufferedImage ri = new BufferedImage (image.getWidth(null), image.getHeight(null),BufferedImage.TYPE_4BYTE_ABGR);
           BufferedImage bImage = new BufferedImage (toImage.getWidth(null), toImage.getHeight(null),BufferedImage.TYPE_4BYTE_ABGR);
           bImage.getGraphics().drawImage(toImage,0,0,null);
           if (toImage.getWidth(null)<2 || toImage.getHeight(null)<2) return null;
           Graphics g = ri.getGraphics();
           int fromRGB = fromColor.getRGB();
            g.drawImage (image, 0, 0, null);
           for (int a=0; a < image.getWidth(null); a++)
              for (int b=0; b < image.getHeight(null); b++)
                 if (ri.getRGB(a,b)==fromRGB) {
                      int x=a, y=b;
                      while (x<0 || x>=toImage.getWidth(null) || y <0 || y>= toImage.getHeight(null)) {
                           if (x<0) x+=toImage.getWidth(null);
                           if (x>=toImage.getWidth(null)) x-=toImage.getWidth(null);
                           if (y<0) y+=toImage.getHeight(null);
                           if (y>=toImage.getHeight(null)) y-=toImage.getHeight(null);
                        ri.setRGB(a,b,bImage.getRGB(x,y));
          return ri;
    }This method returns a BufferedImage. But when I use this BufferedImage in the game, the game becomes really slow.
So, I don't know why this happens. Is it always slower to draw an image whith many colors than an image with few colors? Or is BufferedImages always slower than images returned from Toolkit.getImage()? Or do I use the wrong type of BufferedImage?
cccB

Answer 1

new BufferedImage(....) are not managed (cached in vram)
Images loaded from toolkit.getImage() are managed.
Also, the color model BufferedImage.TYPE_4BYTE_ABGR is not an efficient colormodel.
It will require conversion to the displays colormodel (which is probably TYPE_INT_RGB/ARGB/BGR)
Change your BufferedImage creation so it uses graphicsConfiguration.createCompatibleImage(...)
The BufferedImage returned will be a colormodel compatible with the display, and will be managed (cachable in vram)