[Lumiera] Lumiera Graphics

Michael R Fisher mfisher31 at gmail.com
Thu Dec 1 04:46:20 CET 2011

Good evening, morning or night!

I've added my external goocanvas, and graphics experiments back into the 
Lumiera tree.  Definitely interested in being educated on how to build a 
separate executable for testing.  There are actually two branches 
now...  mfisher31/goocanvas and the sparkling new mfisher31/graphics.

The purpose of the graphics branch is to explore the possibility of 
creating a Lumiera custom canvas widget and other Widgets that need to 
constantly draw something.  The broad concept in my head is this:  There 
a Gtk Canvas Widget which controls a Screen item that manages a tree of 
child Items to be drawn.  The Screen would internally manage some kind 
of "rendered image" that is drawn during the paint cycle.  The "rendered 
image" should be compatible with Cairo, OpenGL and/or cogl.  The Canvas 
Widget can tell the Screen to "paint", and then grab the rendered image 
and display it using conventional Gtk custom widget commands.  The Gtk 
Canvas should also forward Gdk events to the screen so it can deliver 
them to individual items, update itself, etc...

I think this kind of Widget / Screen separation could also facilitate 
more than just new Gui widgets.  Perhaps a Screen object could be 
utilised in simple plugins such as basic media generators like solid 
colors, gradient patterns, titlers, etc...  The GUI's for these plugins 
could use the Canvas as a "WYSIWYG" editor for the lowlevel processing 
side of it.  Not sure exactly how that would work, but it makes sense in 
my brain.

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