Jussi Laako wrote:
Canvases give you much more than just rendering. They also manage the
graphical objects that you created and, if anything changes, rerendering
the changed parts happens automatically.
That's usually bad and undesirable for any real time graphics rendering,
like audio UIs often are. For example with proper interfaces I can now
get full screen scrolling spectrogram at 50-100 fps without huge CPU
load.
I agree on that, I surely wouldn't want to draw waves or 3D
visualizations using a canvas widget either. ;-) But computer music
applications also need complex object views (scores, tracks,
arrangements, etc.) which can be manipulated by the user (selections,
drag and drop, etc.). Canvases are indispensable for that (well, you
certainly don't have to use an existing canvas implementation, but then
you probably end up doing your own).
--
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email: [EMAIL PROTECTED], [EMAIL PROTECTED]
WWW: http://www.musikinformatik.uni-mainz.de/ag
