[wxPython-users] Drawing question

[Christopher Barker]

Dj Gilcrease wrote:
> 4) It uses a mix of ClientDC and MemoryDC (I have not figured out yet
> why it uses one over the other in places)

Well,  Memory DC draws to an of-screen bitmap. A ClientDC draws to the 
screen immediately.

> 1) Would it be better to make a Canvas wide DC that each "layer" uses
> when it wants to draw and not delete the DC

I think so. It sure seems like overkill to create a new dc for each 
object. However, it is considered a bad idea to keep DCs around forever.

Usually, one creates a DC, draws everything to it, then throws it away, 
creating a new one when the drawing needs to be updated.

> 2) How is the new Graphics Device better / worse then using ClientDC
> and MemoryDC?

The new graphics device supports alpha blending, anti-aliasing, and more 
sophisticated path-based drawing.

Make sure you read the relevant Wiki pages:
http://wiki.wxpython.org/index.cgi/RecipesImagesAndGraphics

and you might want to check out wx.lib.floatcanvas for an involved example.

-Chris





-- 
Christopher Barker, Ph.D.
Oceanographer

Emergency Response Division
NOAA/NOS/OR&R            (206) 526-6959   voice
7600 Sand Point Way NE   (206) 526-6329   fax
Seattle, WA  98115       (206) 526-6317   main reception

Chris.Barker at noaa.gov