iphone - 多点裁剪后的UIImage如何保存？

Question

我想在图像上进行多点裁剪(参见图像)。它工作正常。我的问题是裁剪图像后如何保存 UIImage。我正在使用 CAShapeLayer 来裁剪图像。下面的代码用于多点裁剪。

- (void)multiPointCrop:(CGPoint)cropPoint
{
    UIBezierPath *aPath = [UIBezierPath bezierPath];
    [aPath moveToPoint:cropPoint];

    for (NSString *pointString in self.touchPoints) { 
        if ([self.touchPoints indexOfObject:pointString] != 0)
            [aPath addLineToPoint:CGPointFromString(pointString)];
    }
    [aPath addLineToPoint:cropPoint];
    [aPath closePath];

    [self setClippingPath:aPath andView:self];
    [self setNeedsDisplay];
}

- (void)setClippingPath:(UIBezierPath *)clippingPath andView:(UIView *)view;
{
    if (![[view layer] mask])
        [[view layer] setMask:[CAShapeLayer layer]];

    [(CAShapeLayer*) [[view layer] mask] setPath:[clippingPath CGPath]];
}

如何从 CAShapeLayer 保存 UIImage？如果这是多重裁剪的正确方法或任何其他简单的方法来实现这一点。请提供您的想法、建议、源代码等。任何内容都欢迎。

Answer 1

尝试将图层渲染到上下文中并从该上下文创建图像。

CALayer *layer = view.layer;
CGSize s = layer.frame.size;
// create context
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(NULL, s.width, s.height,
                                             8, (s.width * 4),
                                             colorSpace, kCGImageAlphaPremultipliedLast);

// flip Y
CGContextTranslateCTM(context, 0.0, s.height);    
CGContextScaleCTM(context, 1.0, -1.0);

// render layer
[layer renderInContext:context];

CGImageRef imgRef = CGBitmapContextCreateImage(context);
// here is your image
UIImage *img = [UIImage imageWithCGImage:imgRef];  

// release owned memory
CGImageRelease(imgRef);
CGColorSpaceRelease(colorSpace);
CGContextRelease(context);