Balloon Issues
Michael Latta
lattam at mac.com
Sat Jan 8 17:42:26 UTC 2005
I have been digging into the use of Balloon and transfromations. The
diagrams I would like to use with Connectors 2.0 would be larger than
would fit at full scale on a monitor. I am working with the released
3.7 full image. If the newer images deal with these issues please let
me know. The scope and nature of the issues make it hard to see moving
forward with Squeak.
1) BalloonCanvas does not really provide transformed drawing, but
rather transforms coordinates and draws to those new coordinates.
There are numerous drawing methods that do not deal with
transformations properly: all text drawing, framing of rectangles,
others.
2) The performance is borderline. Most of the time is spent in
fastCopyLoop which does the rendering using primitives. I have not
looked at the primitives yet to see how optimal they are, but that
would be an involved effort.
3) I am seeing some issues with fills in scaled areas as well.
The biggest issue is the handling of text. While I have had some
success substituting one TT font for another to get close to scaling,
this does not produce real scaling. I would have to replace the
current use of cached bitmaps with rendering using outlines. This
would most likely require more performance work.
While Smalltalk makes many of these tasks possible, it represents work
not related to the project. It currently looks like a virtual rewrite
of Balloon and font rendering would be required to achieve a graphics
model like that found in PostScript, Quartz, or Java2D.
It is possible I will continue to "play" with Squeak, but using it on a
project would yield more consistent time and motivation.
Michael
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