Pixmap question

[Colin Thomas <colin designresources co uk>]

Hi,

I am new to GUI programming, and would like some pointers to the 
best way in achieving something.

I need to develop Display window which can a number of coloured layers.
( the various layers used in IC design).

Where each layer overlaps another, I want to see the correct ANDING of
the colours.

I need to be able to repaint with an odd layer removed from display.

I can see that if I have multiple pixmaps (one for each layer to be
displayed), but just sending the desired pixmaps to the screen I should 
be able to achieve this.

Therefore..

1. Can multiple pixmaps be drawn to a single drawing area ?

2. Can the overlapping (colour ANDing) automatically achieved ?

I have somebooks on gtk+, and they talk about pixmaps having depth,
but never then explain how to use them :-( Is this route a potential
solution ??

I have tried painting different overlapping rectangles of different colours
(with opacity varied) to the same pixmap, and do not see any colour anding: the
last colour displayed alway oblitorates underlying colours.

I look forward to your combined wisdom...

Many thanks in advance..

Colin Thomas


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| Colin Thomas. 
| Email   : colin designresources co uk     
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