我正在开发一个应用程序,通过代码绘制UIView并使用UIColor进行填充。接下来,我想要加载一个mask.png文件(没有透明度,只有黑白)并对UIView进行遮罩以改变其外观。
有什么想法吗?
// 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>
很容易但我在任何地方都找不到答案!
iOS 8 引入了 maskView
属性,它允许您使用另一个视图来提供蒙版图像。在 Swift 中:
iOS 8 引入的 maskView
属性可以使用替代视图来提供蒙版图像。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;带有白色部分(用于不透明)和黑色部分(用于透明)的图像将无法使用。-(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 );
}
#import <UIKit/UIKit.h>
@interface UIView (ImageMask)
- (void) maskWithImage:(UIImage*) mask;
- (void) maskWithImage:(UIImage*)mask size:(CGSize)maskSize;
- (void) removeMask;
@end
#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
- (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];
}
Swift 2.0
将UIImage和掩码图像传递给此函数,您将获得一个遮罩图像作为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
}