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I am using method described here to set a gradient background for vanilla UIView instance without creating a subclass. However the view comes out completely black. Here's my code:

UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0.0f, 0.0f, 315.0f, 44.0f)];

CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(NULL, 315.0, 44.0f, 8, 4 * 315, colorSpace, kCGImageAlphaNoneSkipFirst);

// Colors only for debugging purposes
CGColorRef startColor = (__bridge CGColorRef)[UIColor greenColor];
CGColorRef endColor = (__bridge CGColorRef)[UIColor redColor];
CFMutableArrayRef colors = CFArrayCreateMutable(kCFAllocatorDefault, 2, &kCFTypeArrayCallBacks);
CFArrayAppendValue(colors, startColor);
CFArrayAppendValue(colors, endColor);

CGGradientRef gradient = CGGradientCreateWithColors(colorSpace, colors, (const CGFloat []){0.25f, 0.75f});

CGContextDrawLinearGradient(context, gradient, CGPointZero, CGPointMake(0.0f, 44.0f), 0);

CGImageRef cgImage = CGBitmapContextCreateImage(context);

UIImage *backgroundGradient = [UIImage imageWithCGImage:cgImage];
[view setBackgroundColor:[UIColor colorWithPatternImage:backgroundGradient]];

CFRelease(colors);
CGGradientRelease(gradient);
CGImageRelease(cgImage);
CGColorSpaceRelease(colorSpace);
CGContextRelease(context);
return view;

I believe something might be wrong with the allocation of context since the created images are returned of desired size (315x44). What did I miss? What else can I check that would help me debug this problem?

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Eimantas
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1 Answers1

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That's not how you get a CGColorRef you need to do 

[UIColor redColor].CGColor
Paul.s
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  • That's another problem - I get a crash (using ARC) on those lines. No idea why. – Eimantas May 30 '12 at 06:33
  • You don't need this cast `(__bridge CGColorRef)`. Also check the answer here for potential ARC issue http://stackoverflow.com/questions/8155844/cg-gradient-runs-on-simulator-but-not-on-iphone – Paul.s May 30 '12 at 07:21