Re: Graphics "playback" suggestion?
Re: Graphics "playback" suggestion?
- Subject: Re: Graphics "playback" suggestion?
- From: Ken Thomases <email@hidden>
- Date: Tue, 6 Jan 2009 21:44:08 -0600
On Jan 5, 2009, at 11:09 PM, Robert Monaghan wrote:
I am trying to figure out what the best method is, to playback
"generated" graphics.
I am downloading image data over ethernet, and then processing the
imagery.
Currently I am creating a NSBitmapImageRep, and populating the
buffer with my pixel data.
I then draw this inside an NSView.
If I create a for loop, the imagery isn't been updated in the view,
even if I do a "setNeedsDisplay".
Is there a better way to do this?
-setNeedsDisplay: only _marks_ a view as needing display. The actual
display doesn't happen until you return control to the AppKit so it
has a chance to update any windows needing display (or containing
views needing display).
What you should be doing is receiving the image data asynchronously.
You get a message each time a chunk of data is received. You collect
them as they come but you return to the main event loop after handling
each one. When an image is complete, you process it into a bitmap
object and call -setNeedsDisplay: on your view. Again, you return to
the event loop after doing this. The event loop will notice that your
view needs display and will call your drawRect: method to redraw it.
You can read more:
Cocoa Drawing Guide: Views and Drawing
http://developer.apple.com/documentation/Cocoa/Conceptual/CocoaDrawingGuide/DrawingEnviron/chapter_2_section_6.html
Cocoa Drawing Guide: Using NSTimer for Animated Content
http://developer.apple.com/documentation/Cocoa/Conceptual/CocoaDrawingGuide/AdvancedDrawing/chapter_9_section_5.html
Cocoa Drawing Guide: Using Cocoa Animation Objects
http://developer.apple.com/documentation/Cocoa/Conceptual/CocoaDrawingGuide/AdvancedDrawing/chapter_9_section_6.html
View Programming Guide for Cocoa
http://developer.apple.com/documentation/Cocoa/Conceptual/CocoaViewsGuide/
Cheers,
Ken
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