Op Fri, 16 Sep 2011 00:57:14 +0200 schreef Lee Privett
<[email protected]>:

A fading transparency is what I was originally referring to


One way to achieve this could be:
1. Create 3 psa buffers in memory,
2. copy the screen part you want to overlay in buffer 1,
3. copy the overlapping picture in buffer 2,
4. use George's example from Quanta (v27i4) to calculate the merged
colours and store in buffer 3,
5. copy this result to the screen,
6. change the alpha value and repeat step 4 to 6.

You may not need to go through all alpha steps from 1 to 254.
Also to do this in SBasic may be too slow, depending on your machine but
you need some delay to show the fading effect.
Maybe buffer 3 could be limited to one line at the time.

The tools/keywords to manipulate psa buffers can be found in EasyPTR4,
QPTR or George's TurboPTR, although each does it a bit different.
Another example of what can be done with psa buffers can be seen in QCP
(QL Colour Picker) where I use it to scroll a picture of the 3D borders
into a menu window (just hit the button at the bottom).

Bob

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