Question

我试图以编程方式创建UIImage并通过CGImageRef mask应用CGImageCreateWithMask()来屏蔽- (UIImage *)imageByMaskingHalfImage:(UIImage *)image { UIGraphicsBeginImageContextWithOptions((CGSize){image.size.width, image.size.height}, NO, image.scale); [[UIColor blackColor] setFill]; UIRectFill(CGRectMake(0, 0, image.size.width / 2, image.size.height)); [[UIColor whiteColor] setFill]; UIRectFill(CGRectMake(image.size.width / 2, 0, image.size.width / 2, image.size.height)); UIImage *maskImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); CGImageRef maskImageRef = CGImageMaskCreate(CGImageGetWidth(maskImage.CGImage), CGImageGetHeight(maskImage.CGImage), CGImageGetBitsPerComponent(maskImage.CGImage), CGImageGetBitsPerPixel(maskImage.CGImage), CGImageGetBytesPerRow(maskImage.CGImage), CGImageGetDataProvider(maskImage.CGImage), NULL, NO); CGImageRef imageRef = CGImageCreateWithMask(image.CGImage, maskImageRef); image = [UIImage imageWithCGImage:imageRef scale:image.scale orientation:image.imageOrientation]; CGImageRelease(maskImageRef); CGImageRelease(imageRef); return image; }。这是我的方法：

maskImage

预览image时，我可以看到它正确呈现：图像的一半是黑色，一半是白色。但是，生成的蒙版alertDialog.show(); try { TextView textView = (TextView)dialog.getWindow().getDecorView().findViewById(android.R.id.message); textView.setTextIsSelectable(true); } catch(Exception e) { // Oups! }保持不变，整个图像都可见。

我已阅读文档但无法找到问题。我的代码中肯定存在一些愚蠢的错误，或者我误解了某些内容。

Answer 1

这就是我在形状A中掩盖图像的方式

创建一个获取蒙版形状的方法，在我的情况下为形状A：

DestroyHandle()

上述方法在名为SHapeLayer的NSObject文件中声明。

并在视图控制器中调用此方法：

  -(void)shapeA:(CGRect)frame :(UIImageView*) testView {

    ////  Drawing
    UIBezierPath* textPath = UIBezierPath.bezierPath;
    [textPath moveToPoint: CGPointMake(CGRectGetMinX(frame) + 284.92, CGRectGetMinY(frame) + 243.03)];
    [textPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 230.48, CGRectGetMinY(frame) + 84.58)];
    [textPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 172.62, CGRectGetMinY(frame) + 243.03)];
    [textPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 284.92, CGRectGetMinY(frame) + 243.03)];
    [textPath closePath];
    [textPath moveToPoint: CGPointMake(CGRectGetMinX(frame) + 205.09, CGRectGetMinY(frame) + 31.36)];
    [textPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 260.02, CGRectGetMinY(frame) + 31.36)];
    [textPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 390.14, CGRectGetMinY(frame) + 390)];
    [textPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 336.92, CGRectGetMinY(frame) + 390)];
    [textPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 300.54, CGRectGetMinY(frame) + 282.58)];
    [textPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 158.7, CGRectGetMinY(frame) + 282.58)];
    [textPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 119.88, CGRectGetMinY(frame) + 390)];
    [textPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 70.08, CGRectGetMinY(frame) + 390)];
    [textPath addLineToPoint: CGPointMake(CGRectGetMinX(frame) + 205.09, CGRectGetMinY(frame) + 31.36)];
    [textPath closePath];

    CAShapeLayer *shapeLayer = [CAShapeLayer layer];
    shapeLayer.path = textPath.CGPath;
    shapeLayer.strokeColor   = [UIColor clearColor].CGColor;
    shapeLayer.fillColor     = [UIColor whiteColor].CGColor;

    [testView.layer setMask:shapeLayer];

}

现在在加载图片之前调用此方法-(void)callShape{ CGRect temp=self.imageView.bounds; ShapeLayer *sl=[[ShapeLayer alloc]init]; [sl shapeA:temp :self.imageView]; }。

以编程方式掩盖UIImage

1 个答案: