2D Rendering Advice

Java 2D
#1

I am writing an application that decodes image data from a network stream and then renders it. I need two rendering modes, one for on screen rendering and one for image rendering to disk. Because the data is often raw pixels, I am currently using the code below to allow access to the pixel data directly and then copy the changed pixels to the regular BufferedImage. When the data stream has a line or rectangle encoded, I draw directly to the BufferedImage. Is there a faster/smarter way to do this? I have tried accessing the pixels stored in the DataBufferInt rather than using the pixel[] below and performance is horrendous.

Thanks in advance for any suggestions.

pixels = new int[width * height];
memImageSrc = new MemoryImageSource(width, height, colorModel, pixels, 0, width);
memImageSrc.setAnimated(true);

memImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
memGraphics = memImage.getGraphics();
pixelsSource = new MemoryImageSource(width, height, colorModel, pixels, 0, width);
pixelsSource.setAnimated(true);
rawPixelsImage = Toolkit.getDefaultToolkit().createImage(pixelsSource);

#2

Not sure if this will help, but here’s code for accessing pixel[] arrays in a BufferedImage quickly, so you don’t have to copy from a MemoryImageSource.


        int w = getWidth();
        int h = getHeight();
        int[] pixels = new int[w * h];
        
        DirectColorModel colorModel = 
            new DirectColorModel(24, 0xff0000, 0x00ff00, 0x0000ff);

        SampleModel sampleModel = new SinglePixelPackedSampleModel(
            DataBuffer.TYPE_INT, w, h, new int[] { 0xff0000, 0x00ff00, 0x0000ff }); 
        
        DataBuffer dataBuffer = new DataBufferInt(pixels, w * h);
        
        WritableRaster raster = Raster.createWritableRaster(
            sampleModel, dataBuffer, new Point(0,0));
        
        awtImage = new BufferedImage(colorModel, raster, true, new Hashtable());
#3

And does that end up being quicker than using the WritableRaster that is supplied by the BufferedImage automatically? I tried


int[] pixels = ((DataBufferInt)memImage.getRaster().getDataBuffer()).getData(0);

and it ends up being much slower than the version I have now

#4

My two cents:

I recommend never ever touching the DataBuffer of an image. I explain why here:

I’ve had good performance with:
bi.getRaster().setDataElements(x,y,w,h,data)

But “good” is a vague word depending on the size of the animation, the minimum system specs of your app, etc.

#5

It ends up being much faster than what is supplied by BufferedImage automatically. You actually write directly to the pixels[] buffer