我想用羽毛圈裁剪图像。我使用它来裁剪图像,但它只是裁剪成方形。
CGImageRef imref = CGImageCreateWithImageInRect([newImage CGImage], faceRect);
newSubImage = [UIImage imageWithCGImage:imref];
我想要的是羽毛边缘裁剪?我应该用什么来实现它?
答案 0 :(得分:3)
此代码段将创建带有羽毛边缘的圆形剪裁
第一个featherLocations
变量可能是您需要调整的唯一变量
- (UIImage *) featheredImageWithImage:(UIImage *) image
{
// Locations of where the feather starts and ends (0 -> 1)
const CGFloat featherLocations[] = {0.9, 1};
UIGraphicsBeginImageContextWithOptions(image.size, NO, image.scale);
CGContextRef ctx = UIGraphicsGetCurrentContext();
// Draw the original image
[image drawInRect:CGRectMake(0, 0, image.size.width, image.size.height)];
// A 'knock-out' gradient is used to generate a feather effect,
// the alpha channel on the colors defines the alpha of the drawn image
NSArray *gradientColors = @[(id)[UIColor colorWithWhite:0 alpha:1].CGColor,
(id)[UIColor colorWithWhite:0 alpha:0].CGColor];
CGGradientRef gradient = CGGradientCreateWithColors(CGImageGetColorSpace(image.CGImage), (__bridge CFArrayRef)gradientColors, featherLocations);
// Because we're changing the draw mode below,
// take a snapshot of the current draw settings so we can reset them after
CGContextSaveGState(ctx);
// The kCGBlendModeDestinationIn blend mode will provide a'knock-out' effect on
// the previously drawn content, using the alpha channels of the gradient's colors
CGContextSetBlendMode(ctx, kCGBlendModeDestinationIn);
const CGPoint gradientCenter = CGPointMake(image.size.width / 2, image.size.height / 2);
// The gradient will start at the center (0) and extend to the closest edge (horizontal or vertical)
const CGFloat startRadius = 0;
const CGFloat endRadius = MIN(image.size.width,
image.size.height) / 2;
// Draw the gradient to eliminate the pixels we don't want
CGContextDrawRadialGradient(ctx, gradient, gradientCenter, startRadius, gradientCenter, endRadius, (kCGGradientDrawsAfterEndLocation));
CGGradientRelease(gradient);
gradient = NULL;
// Finally, restore state
// (note that in this example CGContextSaveGState and CGContextRestoreGState
// are optional because no further drawing happens after this point)
CGContextRestoreGState(ctx);
// Get the UIImage version
UIImage *featheredImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return featheredImage;
}
答案 1 :(得分:0)
这个怎么样......首先围绕图像:
//round the image
UIImageView *roundView = [[UIImageView alloc] initWithImage:smallImage];
UIGraphicsBeginImageContextWithOptions(roundView.bounds.size, NO, [UIScreen mainScreen].scale);
[[UIBezierPath bezierPathWithRoundedRect:roundView.bounds
cornerRadius:roundView.frame.size.width/2] addClip];
[smallImage drawInRect:roundView.bounds];
UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
然后将它再次圆圈但是用一个较小的圆圈并将bezier路径颜色再次设置为白色但通过调整alpha使其半透明...