I've taken a look at this question: UIImage Shadow Trouble
But the accepted answer didn't work for me.
What I'm trying to do is take a UIImage and add a shadow to it, then return a whole new UIImage, shadow and all.
This is what I'm trying:
- (UIImage*)imageWithShadow {
CGColorSpaceRef colourSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef shadowContext = CGBitmapContextCreate(NULL, self.size.width, self.size.height + 1, CGImageGetBitsPerComponent(self.CGImage), 0,
colourSpace, kCGImageAlphaPremultipliedLast);
CGColorSpaceRelease(colourSpace);
CGContextSetShadow(shadowContext, CGSizeMake(0, -1), 1);
CGContextDrawImage(shadowContext, CGRectMake(0, 0, self.size.width, self.size.height), self.CGImage);
CGImageRef shadowedCGImage = CGBitmapContextCreateImage(shadowContext);
CGContextRelease(shadowContext);
UIImage * shadowedImage = [UIImage imageWithCGImage:shadowedCGImage];
CGImageRelease(shadowedCGImage);
return shadowedImage;
}
The result is that I get exactly the same image as before I put it through this method.
I am doing this the correct way, or is there something obvious I'm missing?
There are several problems with your code:
CGContextSetShadowWithColor
to define both the shadow and its color.By fixing these issues, the shadow should be drawn.
- (UIImage*)imageWithShadow {
CGColorSpaceRef colourSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef shadowContext = CGBitmapContextCreate(NULL, self.size.width + 10, self.size.height + 10, CGImageGetBitsPerComponent(self.CGImage), 0,
colourSpace, kCGImageAlphaPremultipliedLast);
CGColorSpaceRelease(colourSpace);
CGContextSetShadowWithColor(shadowContext, CGSizeMake(5, -5), 5, [UIColor blackColor].CGColor);
CGContextDrawImage(shadowContext, CGRectMake(0, 10, self.size.width, self.size.height), self.CGImage);
CGImageRef shadowedCGImage = CGBitmapContextCreateImage(shadowContext);
CGContextRelease(shadowContext);
UIImage * shadowedImage = [UIImage imageWithCGImage:shadowedCGImage];
CGImageRelease(shadowedCGImage);
return shadowedImage;
}