DirectColorModel issues

Java 2D
#1

It seems that if I use anything but 8 bits per colour channel I get much decreased performance with DirectColorModel and MemoryImageSource in my applet. For example, if I wanted 5 remaining bits for a 32 bit mode I’d do something like this:

new DirectColorModel(32, 0x7fe00000, 0x001ffc00, 0x000003ff)

This gives 10.11.10. Using that model to display is much slower than a standard 8 bits per colour. If I were to guess, I would say it has something to do with the fact that when the Producer requests the RGB, the Colour Model has to scale the values to 0-255 first if you don’t use the standard 8. Funny thing is, it doesn’t seem to happen in 1.1, only in later versions, especially 1.4. Can anybody back me up on that? I also wonder if you could overcome this by writing your own colour model?

Abs

#2

This is really an AWT/2D API issue, not a tuning issue per se.

I think you’ll probably get faster response if you post over in the 2D section.

#3

It’s slow because Java2D doesn’t have optimized loops for your custom color model, so we have to go through generic routines, which often has several method calls per pixel.

Are you sure you need that custom color model? Take a look at the predefined image types (see BufferedImage class).