[英]How to remove UIImage Background color and make it transparent?
我想删除 UIImage 背景颜色并使其透明...
我试过了,但下面的代码只是将白色背景颜色更改为黑色。
UIImage* createColorMaskedImage(UIImage* originalImage){
float maskingColors[6] = {0xEE, 0xFF, 0xEE, 0xFF, 0xEE, 0xFF};
CGImageRef maskedImageRef = CGImageCreateWithMaskingColors(originalImage.CGImage, maskingColors);
UIImage* maskedImage = [UIImage imageWithCGImage:maskedImageRef];
CGImageRelease(maskedImageRef);
return maskedImage;
}
UIImage *watchImage = [UIImage imageNamed:@"watch2.jpg"];
// Mask image
colorMaskImage_ = createColorMaskedImage(watchImage);
//create image view and set its poistion.
UIImageView* maskImageView = [[UIImageView alloc] initWithImage:colorMaskImage_];
CGRect frame = maskImageView.frame;
frame.origin = CGPointMake(80,60);
maskImageView.frame = frame;
maskImageView.backgroundColor = [UIColor clearColor];
[self.view addSubview:maskImageView];
[maskImageView release];
迅捷版
func makeTransparent(image: UIImage) -> UIImage? {
guard let rawImage = image.cgImage else { return nil}
let colorMasking: [CGFloat] = [255, 255, 255, 255, 255, 255]
UIGraphicsBeginImageContext(image.size)
if let maskedImage = rawImage.copy(maskingColorComponents: colorMasking),
let context = UIGraphicsGetCurrentContext() {
context.translateBy(x: 0.0, y: image.size.height)
context.scaleBy(x: 1.0, y: -1.0)
context.draw(maskedImage, in: CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height))
let finalImage = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return finalImage
}
return nil
}
您的watch2.jpg
可能没有 alpha 值,这将使它具有透明区域。
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