[self-interest] Scaling in canvases

Michael Latta lattam at mac.com
Sat Jun 19 01:15:06 UTC 2004

Before I run off half cocked I could use comments on the following 

1) It appears that each window has its own back buffer that gets damage 
drawn onto it.
2) When multiple users access a system they get their own windows, so 
drawing can occur once per user for the same damage area.
3) I would have liked to see the canvas abstract out the buffering so 
worldMorph would not need to keep paired lists of canvases to do 
buffering.  That would also make it easier to substitute hardware or OS 

For my needs I would like to see a drawing subsystem that supports 
scaling (of shapes and text) with the traditional transforms available 
from one morph to the children.  If this was making use of hardware 
transformation it should not cost much, and FSAA in hardware only costs 
about 10%.  But it looks like the entire complex of canvas, display, 
and worldMorph will be impacted heavily to do this.

Has this been considered?  Was it just not the focus of the research, 
or was there a reason from the shared X11 perspective that this would 
be a bad idea?  The large work area that the Self UI supports would be 
a perfect place to add a zooming interface type control for navigation, 
rather than scrolling in 1/3 screen increments.


On Jun 18, 2004, at 5:24 PM, Michael Latta wrote:

> I know I am on my own here, but the protocol for canvas supports
> scaling, but not the pixmapCanvas for the Mac.  I will see what I can
> do to correct this.  If it takes work in the C code I could use a
> pointer.
> Thanks,
> Michael
> Yahoo! Groups Links

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