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我有一个带有 UIImageView 的视图和一个为其设置的图像。我想像在 Photoshop 中用橡皮擦一样擦除图像。我如何实现这一目标？另外，如何撤消擦除？

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3 回答 3

8

如果您知道要擦除的区域，则可以创建一个相同大小的新图像，将蒙版设置为完整图像减去要擦除的区域，将完整图像绘制到新图像中，并将其用作新图片。要撤消，只需使用上一个图像。

编辑

示例代码。假设您要从图像视图imgView中删除的区域由 by 指定erasePath：

- (void) clipImage 
{
    UIImage *img = imgView.image;
    CGSize s = img.size;
    UIGraphicsBeginImageContext(s);
    CGContextRef g = UIGraphicsGetCurrentContext();
    CGContextAddPath(g,erasePath);
    CGContextAddRect(g,CGRectMake(0,0,s.width,s.height));
    CGContextEOClip(g);
    [img drawAtPoint:CGPointZero];
    imageView.image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
}
于 2009-09-28T16:34:10.670 回答
1 
UIGraphicsBeginImageContext(imgBlankView.frame.size);
[imgBlankView.image drawInRect:CGRectMake(0, 0, imgBlankView.frame.size.width, imgBlankView.frame.size.height)];

CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(),lineWidth);
CGContextSetBlendMode(UIGraphicsGetCurrentContext(), kCGBlendModeClear);

CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), red, green, blue, 1.0);
CGContextBeginPath(UIGraphicsGetCurrentContext());  
CGContextSetShouldAntialias(UIGraphicsGetCurrentContext(), YES);

CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint1.x, lastPoint1.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
CGContextStrokePath(UIGraphicsGetCurrentContext());
imgBlankView.image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();
于 2011-12-08T09:41:58.700 回答
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斯威夫特 5.2 版本

        UIGraphicsBeginImageContextWithOptions(imageView.frame.size, false, 1.0)
        let currentContext = UIGraphicsGetCurrentContext()
        currentContext?.addPath(shapeLayer.path!)
        currentContext?.addRect(CGRect(x: 0, y: 0, width: imageView.frame.size.width, height: imageView.frame.size.height))
        currentContext?.clip(using: .evenOdd)
        
        imageView.image?.draw(at: .zero)
        
        let imageTeemp = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext()
于 2021-02-05T10:22:53.393 回答