我有一个图标,它悬停在一个按钮上。这个图标是黑白的,我想通过编程“剪切”黑色区域。
请问如何通过编程将图标的黑色区域转换为透明?
请见下方图片:
请问如何通过编程将图标的黑色区域转换为透明?
请见下方图片:
![enter image description here](https://istack.dev59.com/lO6lY.webp)
CIMaskToAlpha
。-(void)setImage:(UIImage *)image_
{
UIImage *entryImage = image_;
CIContext *context = [CIContext contextWithOptions:nil];
CIImage *image = [CIImage imageWithCGImage:[entryImage CGImage]];
CIFilter *filter = [CIFilter filterWithName:@"CIMaskToAlpha"];
[filter setDefaults];
[filter setValue:image forKey:kCIInputImageKey];
// CIImage *result = [filter valueForKey:kCIOutputImageKey];
CIImage *result = [filter outputImage];
CGImageRef cgImage = [context createCGImage:result fromRect:[result extent]];
UIImage *newImage = [UIImage imageWithCGImage:cgImage scale:[entryImage scale] orientation:UIImageOrientationUp];
CGImageRelease(cgImage);
[super setImage:newImage];
}
该图像将是原始图像大小的透明正方形,完全黑色区域应被遮罩成白色。当我们将这个遮罩图像覆盖在实际的正方形图像上时,输出将是一个期望的图像。
一旦您准备好了遮罩图像,就实现遮罩图像的功能。
//遮罩缩略图像
+(UIImage*) maskImage:(UIImage *)thumbImage withMask:(UIImage *)maskImage
{
CGImageRef maskRef = maskImage.CGImage;
CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef),
CGImageGetHeight(maskRef),
CGImageGetBitsPerComponent(maskRef),
CGImageGetBitsPerPixel(maskRef),
CGImageGetBytesPerRow(maskRef),
CGImageGetDataProvider(maskRef), NULL, false);
CGImageRef masked = CGImageCreateWithMask([thumbImage CGImage], mask);
CGImageRelease(mask);
UIImage *maskedImage = [UIImage imageWithCGImage:masked];
CGImageRelease(masked);
return maskedImage;
}