Sub-Layers Disappear when Changing UIView Transform

Gillies · 07-10-2009, 05:13 AM

Hey

I have a strange problem when trying to rotate a UIView. I wonder if anyone can help me.

I have a UIView to which I add a number of subviews:

Code:

// Set the pickLayers up in a vector
pickLayers.resize( maxDivisions, 0 );
for( unsigned int i = 0; i < maxDivisions; ++i ) 
{
	// Create a new layer
	pickLayers[i] = [[CALayer layer] retain];
	
	// Set up the properties that will be reusable
	pickLayers[i].opaque = NO;
	pickLayers[i].backgroundColor = CGColorCreateGenericRGB( 1.0f, 1.0f, 1.0f, ( ( float )i / ( float )maxDivisions ) )
	// Show the layer
	pickLayers[i].hidden = NO;
	pickLayers[i].frame = CGRectMake( 0.0f, ( divisionHeight * i ), divisionWidth, divisionHeight );
	
	// Add this to the view
	[pickerView.layer addSublayer:pickLayers[i]];
}

When I show and hide the view all works well. I get a set of sublayers arranged correctly on the view.

However if I try to rotate the view:

Code:

pickerView.transform = CGAffineTransformMakeRotation( M_PI / 2.0f );

...I can't see the sub layers any more. I have tried resetting their positions after the rotate but it doesn't help.

Setting the transform to identity instead of the above is fine:

Code:

pickerView.transform = CGAffineTransformIdentity;

Has anyone come across this?

Am I doing something fundamentally wrong?

Thank you

Gillies · 07-10-2009, 06:12 AM

Sorry folks.
I was making a mistake setting the frame property in parallel with this.
Still don't get the transform/centre/bounds/frame relationship.