CGContext problems
- by Peyman
Hi
I have a CALayer tree hierarchy
A
B
C
D
where A is the view's root layer (and I create and add B,C and D layers. I am using the same delegate method
`- (void) drawLayer:(CALayer *) theLayer inContext:(CGContextRef)context
to provide content to each of these layers (implemented through a switch statement in the above method). At initiation A's content is drawn (A.contents) sequentially through these methods
`- (void) drawLayer:(CALayer *) theLayer inContext:(CGContextRef)context
-(void) drawCircle:(CALayer *) theLayer inContext:(CGContextRef)context
where drawCircle does
CGContextSaveGState(context);
/ draws circle and other paths here /
CGContextRestoreGState(context);
CGImageRef contentImage = CGBitmapContextCreateImage(context);
theLayer.contents = (id) contentImage;
CGImageRelease(contentImage);
(i.e I save the Context, do the drawing, restore the context, make a bitmap of the context, update the layer's contents, in this case A's, then release the contentimage).
When the user then clicks somewhere in the circle at touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event delegate method I then try to paint the content of B by (still in touchesEnded:)
CGContextRef context = UIGraphicsGetCurrentContext();
[self drawLayer:self.B inContext:context];
[self.B setNeedsDisplay];
the setNeedsDisplay call the delegate - drawLayer:(CALayer *) theLayer inContext:(CGContextRef)context again but this time the switch statement (using a layer flag) calls
[self drawCircle:theLayer inContext:context];
with color red. The problem I am facing is that when -drawCircle: inContext: is called I get a long list of CGContext errors, starting with
<Error>: CGContextSaveGState: invalid context
and ending with
CGBitmapContextCreateImage: invalid context
I played around with making context the view's ivar and it worked so i am sure the context is the problem but I don't know what. I've tried CGContextFlush but it didn't help.
Any help would be appreciated
thank you
