Hi.

>>Where should I take a look to see what's going on?
>Try this...
>
>     Paragraph allInstancesDo:
>          [:p | (p destinationForm class == DisplayScreen
>               and: [p destinationForm ~~ Display])
>               ifTrue: [p destinationForm: nil]]

I first made a select: of this and it came up empty. Ouch... not there.

>P.S.  Have you looked at the alpha-blend drawing demos in Squeak?  They 
actually provide a sliding 32-bit buffer with alpha blending and anti-aliasing 
for sketching.  The screen depth can even be 8 bits and they work.

Ouch again... I had looked at the alpha blending demo, but I didn't know 
why was it working and my stuff wasn't. So I changed the bitDepth to 32 and the 
plotters worked fine, so I assumed it was my fault anyway but later got so 
excited by the function plotters that I forgot the whole thing...

The plotting engine writes to aFormCanvas, which later is asked for its 
form to copy it to the morph world's canvas in drawOn:. But it wouldn't display 
translucent colors...

>Also, note that Squeak 2.2 introduced a new bitBlt mode supporting 
copyBits of any source form at a given alpha value into EITHER 16 or 32 bits, so you 
can do some alpha blend experiments now without having to go to 32 bits. 
[more]

Hmmm... interesting... I was thinking about layerizing the function plotter 
so every function plot will have a different layer and all of them will be 
rendered into a single form for FunctionPlotterMorph>>drawOn:, and this will 
come in handy.

I have another problem with the plotters. The form copying stuff is very 
slow, imagine a 640 at 480 form being copied over and over... no way. So I wanted 
to make plotting directly over the morph world canvas (and then keeping the 
form corresponding to the plotter's bounds in such canvas to allow fast 
dragging). It works and it looks great with alpha blending! But if the plotter's 
morph is not included in the world's box... say for instance if the world has a 
canvas from 0 at 0 to 640 at 480, the plotter has a bound size of 640 at 480 but its 
position in the world is 100 at 100 and the right lower part falls outside, then 
it won't draw correctly in the visible portion of the morph. It will draw 
correctly say in the first 320 at 200 of the morph's bounds, the other parts will 
remain the same and when I later ask the world's canvas for a copy of the 
morph's bounds, I also get stuff outside the world's window...

I would like it to work properly, but I still haven't figured out how. It's 
pretty rude on Morphic but the results are very nice.

Big thanks!
Andres.