实现原理

参考 iOS手指涂抹位置变马赛克的实现 实现 mac osx 版本

图片马赛克实现

借助CoreImage 库中的 CIFilter 滤镜，我们可以轻易实现图片的马赛克 代码如下

NSImage * img1 = [NSImage imageNamed:@"1.png"];
CGImageSourceRef source = CGImageSourceCreateWithData((__bridge  CFDataRef)img1.TIFFRepresentation, nil);
CGImageRef inImage = CGImageSourceCreateImageAtIndex(source, 0, nil);
CIImage *ciImage  = [[CIImage alloc] initWithCGImage:inImage];
CIFilter *filter  = [CIFilter filterWithName:@"CIPixellate"];
[filter setDefaults];
[filter setValue:ciImage forKey:kCIInputImageKey];
[filter setValue:@(10.f) forKey:kCIInputScaleKey];
CIImage * outPutImg = [filter outputImage];
NSCIImageRep * rep = [NSCIImageRep imageRepWithCIImage:outPutImg];
NSImage *img2 = [[NSImage alloc] initWithSize:[outPutImg extent].size];
[img2 addRepresentation:rep];

CAShapeLayer

通过图层遮罩来实现 根据Path 显示马赛克

    //mac 使用layer 必须设置wantsLayer = YES，默认是NO
    self.view.wantsLayer = YES;
    //添加layer（imageLayer）到self上
    self.imageLabyer = [CALayer layer];
    self.imageLabyer.frame = self.view.bounds;
    [self.view.layer addSublayer:self.imageLabyer];
    
    self.shapeLayer = [CAShapeLayer layer];
    self.shapeLayer.frame = self.view.bounds;
    self.shapeLayer.lineCap = kCALineCapRound;
    self.shapeLayer.lineJoin = kCALineJoinRound;
    self.shapeLayer.lineWidth = 40.0f;
    self.shapeLayer.strokeColor = [[NSColor blueColor] CGColor];
    self.shapeLayer.fillColor = nil;
    [self.view.layer addSublayer:self.shapeLayer];
    
    //设置mask
    self.imageLabyer.mask = self.shapeLayer;
    self.path = CGPathCreateMutable();
    //设置马赛克图片
    self.imageLabyer.contents = img2;
    //设置底图
    self.view.layer.contents = img1;

鼠标响应处理

设置View 监听鼠标移动消息
[self.view addTrackingRect:self.view.bounds owner:self userData:nil assumeInside:YES];

处理鼠标移动消息

- (void)mouseDown:(NSEvent *)event
{
   CGPoint pt = event.locationInWindow;
   CGPathMoveToPoint(self.path, NULL, pt.x, pt.y);
   CGMutablePathRef path = CGPathCreateMutableCopy(self.path);
   self.shapeLayer.path = path;
   CGPathRelease(path);
   NSLog(@"mouseDown");
}

-(void)mouseUp:(NSEvent *)event
{
    NSLog(@"mouseUp");
}
-(void)mouseDragged:(NSEvent *)event
{
   CGPoint pt = event.locationInWindow;
   CGPathAddLineToPoint(self.path, NULL,pt.x, pt.y);
   CGMutablePathRef path = CGPathCreateMutableCopy(self.path);
   self.shapeLayer.path = path;
   CGPathRelease(path);
   NSLog(@"mouseDragged");
}

效果图

效果图

源码

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