如何淡化UIImageView的边angular/边界

我无法在论坛上find这个，所以我决定发布这个。

我有一个UIImageView与下面的代码淡化从另一个图像的代码。

- (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view. [[UIApplication sharedApplication] registerForRemoteNotificationTypes:(UIRemoteNotificationTypeBadge | UIRemoteNotificationTypeAlert | UIRemoteNotificationTypeSound)]; imageNames = [NSArray arrayWithObjects:@"image1.jpg", @"image2.jpg", @"image3.jpg", @"image4.jpg", @"image5.jpg", nil]; imageview.image = [UIImage imageNamed:[imageNames objectAtIndex:0]]; [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(transitionPhotos) userInfo:nil repeats:YES]; // Rounds corners of imageview CALayer *layer = [imageview layer]; [layer setMasksToBounds:YES]; [layer setCornerRadius:5]; } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } -(void)transitionPhotos{ if (photoCount < [imageNames count] - 1){ photoCount ++; }else{ photoCount = 0; } [UIView transitionWithView:imageview duration:2.0 options:UIViewAnimationOptionTransitionCrossDissolve animations:^{imageview.image = [UIImage imageNamed:[imageNames objectAtIndex:photoCount]]; } completion:NULL]; } 

我想实现一个代码，将淡入我的imageview的边界。

我知道我可以使用QuartzCore.framework，但是我无法find一个指南如何实现我想要的结果。

什么是最短的代码来做这样的方法？

Answer 1

有一个包含一个蒙版（透明背景模糊矩形）的图像：

 UIImage *mask = [UIImage imageNamed:@"mask.png"]; 

创build一个maskLayer：

 CALayer *maskLayer = [CALayer layer]; maskLayer.contents = (id)mask.CGImage; maskLayer.frame = imageView.bounds; 

并将其分配为您的imageView的掩码：

 imageView.layer.mask = maskLayer; 

编辑：您可以使用CALayer的阴影属性完全通过代码创build掩码。 只要玩shadowRadius和shadowPath ：

 CALayer *maskLayer = [CALayer layer]; maskLayer.frame = imageView.bounds; maskLayer.shadowRadius = 5; maskLayer.shadowPath = CGPathCreateWithRoundedRect(CGRectInset(imageView.bounds, 5, 5), 10, 10, nil); maskLayer.shadowOpacity = 1; maskLayer.shadowOffset = CGSizeZero; maskLayer.shadowColor = [UIColor whiteColor].CGColor; imageView.layer.mask = maskLayer; 

Answer 2

对于圆angular你需要修改下面的代码：

  imageView.layer.cornerRadius = 5; imageView.layer.clipsToBounds = YES; 

Answer 3

您也可以尝试使用GPUImage框架，就像在这里回答的那样。

代码如下：

 UIImage sourceImage = ... GPUImagePicture *imageSource = [[GPUImagePicture alloc] initWithImage:sourceImage]; GPUImageTransformFilter *transformFilter = [GPUImageTransformFilter new]; GPUImageFastBlurFilter *blurFilter = [GPUImageFastBlurFilter new]; //Force processing at scale factor 1.4 and affine scale with scale factor 1 / 1.4 = 0.7 [transformFilter forceProcessingAtSize:CGSizeMake(SOURCE_WIDTH * 1.4, SOURCE_WIDTH * 1.4)]; [transformFilter setAffineTransform:CGAffineTransformMakeScale(0.7, 0.7)]; //Setup desired blur filter [blurFilter setBlurSize:3.0f]; [blurFilter setBlurPasses:20]; //Chain Image->Transform->Blur->Output [imageSource addTarget:transformFilter]; [transformFilter addTarget:blurFilter]; [imageSource processImage]; UIImage *blurredImage = [blurFilter imageFromCurrentlyProcessedOutputWithOrientation:UIImageOrientationUp];