我有一个 jpg 图像，在矩形中有一个圆形物体，我想使圆形物体的环境透明...

(本例去除红色区域)

借助这个iOS make part of an UIImage transparent和“UIBezierPath bezierPathWithOvalInRect”我取得了一些成功，但这在我的对象周围形成了一条路径，我需要反转它，使路径的外部而不是内部透明..

我不确定我必须在哪里更改我的代码才能获得正确的结果..

Đây là mã của tôi:

//BezierPath
UIBezierPath *bezierPath = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, 100, 100)];  

// Create an image context containing the original UIImage.
UIGraphicsBeginImageContext(_imgTemp.image.size);
[_imgTemp.image drawAtPoint:CGPointZero];

// Clip to the bezier path and clear that portion of the image.
CGContextRef ngữ cảnh = UIGraphicsGetCurrentContext();
CGContextAddPath(context,bezierPath.CGPath);
CGContextClip(context);
CGContextClearRect(context,CGRectMake(0,0,self._imgTemp.image.size.width,self._imgTemp.image.size.height));

// Build a new UIImage from the image context.
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
self._imgTemp.image = newImage;

有人解决了吗？

1 Câu trả lời

要仅在黑色圆圈内绘制，您应该将 [_imgTemp.image drawAtPoint:CGPointZero]; Di chuyển đến CGContextClip(context); 之后，然后删除 CGContextClearRect( ... ) 完全调用:

//BezierPath
UIBezierPath *bezierPath = [UIBezierPath bezierPathWithOvalInRect:CGRectMake(0, 0, 100, 100)];  

// Create an image context containing the original UIImage.
UIGraphicsBeginImageContext(_imgTemp.image.size);

// Clip to the bezier path and clear that portion of the image.
CGContextRef ngữ cảnh = UIGraphicsGetCurrentContext();
CGContextAddPath(context,bezierPath.CGPath);
CGContextClip(context);

// Draw here when the context is clipped
[_imgTemp.image drawAtPoint:CGPointZero];

// Build a new UIImage from the image context.
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
self._imgTemp.image = newImage;

关于iOS:逆 UIBezierPath (bezierPathWithOvalInRect)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/10042087/