27

我正在开发一个应用程序,我通过代码绘制 UIView 并用 UIColor 填充它。接下来我要加载一个 mask.png 文件(没有透明度,只有黑色和白色)并屏蔽 UIView 以更改其视觉外观。

知道怎么做吗?

4

6 回答 6

52
// 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,但我在任何地方都找不到答案!

于 2012-03-08T09:37:28.680 回答
12

iOS 8 引入了maskView允许您使用备用视图来提供遮罩图像的属性。在斯威夫特:

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;带有白色部分(用于不透明)和黑色部分(用于透明)的图像将不起作用。

于 2015-03-19T16:37:47.050 回答
5

您也许可以使用 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 );
}
于 2010-06-17T07:36:58.440 回答
4

我用上面的代码创建了一个类别:

UIView+ImageMask.h:

#import <UIKit/UIKit.h>

@interface UIView (ImageMask)

- (void) maskWithImage:(UIImage*) mask;
- (void) maskWithImage:(UIImage*)mask size:(CGSize)maskSize;
- (void) removeMask;

@end

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
于 2013-07-07T16:13:10.783 回答
3

谢谢提请,

结束了这个功能:

- (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];

}
于 2010-06-17T08:07:54.060 回答
0

斯威夫特 2.0

将 UIImage 和蒙版图像传递给此函数,您将获得蒙版图像作为 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
}
于 2016-04-20T08:35:01.040 回答