Bug 3789 - [CoreImage] Radial Gradient creates a blank image
Summary: [CoreImage] Radial Gradient creates a blank image
Status: RESOLVED FIXED
Alias: None
Product: iOS
Classification: Xamarin
Component: Xamarin.iOS.dll ()
Version: 5.2
Hardware: PC Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Miguel de Icaza [MSFT]
URL:
Depends on:
Blocks:
 
Reported: 2012-03-07 13:39 UTC by Eric Beisecker
Modified: 2012-03-07 18:12 UTC (History)
1 user (show)

Tags:
Is this bug a regression?: ---
Last known good build:

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Status:
RESOLVED FIXED

Description Eric Beisecker 2012-03-07 13:39:01 UTC
Current Behavior: The CIRadialGradient class produces a blank image.

Expected Behavior: The CIRadialGradient should produce an image similar to 
https://developer.apple.com/library/mac/documentation/graphicsimaging/reference/CoreImageFilterReference/Art/CIRadialGradient.gif
Sample Code:

public CIImage RadialGradient()
{
	var center = new CIVector(100, 100); // Default [150 150]
	var radGradient = new CIRadialGradient()
	{
		Center = center,
		Radius0 = 10F, // Default 5
		Radius1 = 150F, // Default 100
		Color0 = new CIColor(new CGColor(0, 255F, 0)), // Green
		Color1 = new CIColor(new CGColor(0, 0, 0)) // Black
	};
	
	return radGradient.OutputImage;
}
Comment 1 Miguel de Icaza [MSFT] 2012-03-07 18:12:46 UTC
This was a bug in the sample.

It turns out that for filters that generate images without an input image there
is no region defined for the filter, so we must manually call Crop on the
resulting image to render.