[linux-audio-dev] Re: Which widgets?

[Albert Graef]

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:  Dr.Graef at t-online.de, ag at muwiinfa.geschichte.uni-mainz.de
WWW:    http://www.musikinformatik.uni-mainz.de/ag