iOS Can't draw on my CALayer!

[srg39]

Hi All,

I'm new to mac programming and I'm having some problems trying to draw on a CALayer. I'm creating my layer in a viewcontroller using the function (below). This is called in the -viewDidLoad of my viewcontroller.

-(void)setupLayers {
	myHelper = [[ViewDelegateHelper alloc] init]; //an object containing only my drawLayerinContext delegate
	
	//Layer 1
	Layer1 = [CALayer layer];
	Layer1.frame = CGRectMake(50.0, 50.0, 50.0, 50.0);
	Layer1.name = @"BarOneLayer";
	[Layer1 setDelegate:myHelper];
	[[self.view layer] addSublayer:Layer1];
}

myHelper is an object that only contains the delegate (below) I'm using to do the drawing:

- (void)drawLayer:(CALayer *)myLayer inContext:(CGContextRef)myContext{

	CALayer *theLayer = [CALayer layer];
	*theLayer = *myLayer;
	
	CGRect rectOne = CGRectMake(40, 150, 50, 300 );
	theLayer.frame = CGRectMake(0, 0, 320,480 );
			
	//change background layer color
	float components[4] = {0, 0, 1, 0.5};
	CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
	CGColorRef transparentColor = CGColorCreate( colorSpace, components);
	theLayer.backgroundColor = transparentColor;

	//draw rectangle on layer
	CGContextSetRGBFillColor (myContext, 1, 1, 0, 1);
	CGContextFillRect (myContext, rectOne);
}

When I run the app, I see the new background color of the layer but I can't seem to be able to get it to draw my rectangle. Does anyone know what I'm missing?

Thanks,
srg39.

 

[kainjow]

Where is barRect and are you sure it's within the layer's bounds? Can you confirm the draw method is being called?

I'm not following what you're doing with theLayer. I think that's just unnecessary. Use myLayer directly.

 

[srg39]

Thanks for the help kainjow!

I've added two lines to -setupLayers:

	Layer1.bounds = CGRectMake(0, 0, 320, 480);
	Layer1.position = CGPointMake(0,0);

and removed two lines from -drawLayerInContext:

	CALayer *theLayer = [CALayer layer];
	*theLayer = *myLayer;

and it's all working fine now.

I had convinced myself that I was looking for something a lot more subtle. All I was missing was setting the bounds of the Layer.