我正在一个应用程序,我通过代码绘制UIView,并用UIColor填充它。接下来我想加载一个mask.png文件(不透明,只是黑白),并掩盖UIView以改变其视觉外观。如何掩盖UIView
任何想法如何做到这一点?
我正在一个应用程序,我通过代码绘制UIView,并用UIColor填充它。接下来我想加载一个mask.png文件(不透明,只是黑白),并掩盖UIView以改变其视觉外观。如何掩盖UIView
任何想法如何做到这一点?
您可能能够使用CGContextClipToMask:
-(void) drawRect:(CGRect)dirty {
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGContextClipToMask(context , [self bounds] , [self maskImage]);
[super drawRect:dirty]; // or draw your color manually
CGContextRestoreGState(context);
}
感谢drawnonward,
结束了此功能:
- (UIImage*) maskImage:(UIView *)image withMask:(UIImage *)maskImage {
UIGraphicsBeginImageContext(image.bounds.size);
[image.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRef maskRef = maskImage.CGImage;
CGImageRef mask = CGImageMaskCreate(CGImageGetWidth(maskRef),
CGImageGetHeight(maskRef),
CGImageGetBitsPerComponent(maskRef),
CGImageGetBitsPerPixel(maskRef),
CGImageGetBytesPerRow(maskRef),
CGImageGetDataProvider(maskRef), NULL, false);
CGImageRef masked = CGImageCreateWithMask([viewImage CGImage], mask);
return [UIImage imageWithCGImage:masked];
}
// Create your mask layer
CALayer* maskLayer = [CALayer layer];
maskLayer.frame = CGRectMake(0,0,yourMaskWidth ,yourMaskHeight);
maskLayer.contents = (__bridge id)[[UIImage imageNamed:@"yourMaskImage.png"] CGImage];
// Apply the mask to your uiview layer
yourUIView.layer.mask = maskLayer;
记得导入QuartzCore并添加框架
#import <QuartzCore/QuartzCore.h>
这很容易,但我没有在任何地方找到答案!
我已创建与上述代码的类别:
的UIView + ImageMask.h:
#import <UIKit/UIKit.h>
@interface UIView (ImageMask)
- (void) maskWithImage:(UIImage*) mask;
- (void) maskWithImage:(UIImage*)mask size:(CGSize)maskSize;
- (void) removeMask;
@end
的UIView + ImageMask.m:
#import <QuartzCore/QuartzCore.h>
#import "UIView+ImageMask.h"
@implementation UIView (ImageMask)
- (void) maskWithImage:(UIImage*) mask {
[self maskWithImage:mask size:mask.size];
}
- (void) maskWithImage:(UIImage*)mask size:(CGSize)maskSize {
CALayer* maskLayer = [CALayer layer];
maskLayer.frame = CGRectMake(0, 0, maskSize.size.width, maskSize.size.height);
maskLayer.contents = (__bridge id)[mask CGImage];
// Apply the mask to your uiview layer
self.layer.mask = maskLayer;
}
- (void) removeMask {
self.layer.mask = nil;
}
@end
iOS 8的介绍maskView
属性它允许您使用替代视图来提供遮罩图像。在Swift中:
if let maskImage = UIImage(named: "MaskImage") {
myView.maskView = UIImageView(image: maskImage)
}
请注意,您需要提供实际具有透明度的图像;具有白色部分(用于不透明)和黑色部分(用于透明)的图像将不起作用。
任何想法为什么这可能会崩溃与EXC_BAD_ACCESS? ( - [UIImageView _maskView]:发送到释放实例的消息) – Yaroslav 2016-05-07 18:17:38
雨燕2.0
传递一个UIImage和遮掩图像这个功能,你会得到一个遮盖的图像作为一个UIImage。
func maskImage(image:UIImage, mask:(UIImage))->UIImage{
let imageReference = image.CGImage
let maskReference = mask.CGImage
let imageMask = CGImageMaskCreate(CGImageGetWidth(maskReference),
CGImageGetHeight(maskReference),
CGImageGetBitsPerComponent(maskReference),
CGImageGetBitsPerPixel(maskReference),
CGImageGetBytesPerRow(maskReference),
CGImageGetDataProvider(maskReference), nil, true)
let maskedReference = CGImageCreateWithMask(imageReference, imageMask)
let maskedImage = UIImage(CGImage:maskedReference!)
return maskedImage
}
应该首选任何使用Core Animation而不是Core Graphics的答案。 CA的API更易于理解和使用。 – zakdances 2013-04-24 05:15:37