objective-c - 如何用 UIImage 填充 CGContext？

Question

我继承了UIView，我覆盖了-drawRect:，我通过CGContext画了一个图形。现在我想用 UIImage 填充这个图。知道怎么做吗？

编辑:

我的代码来自 -drawRect:

CGContextBeginPath(ctx);
//here I draw my figure
CGContextClosePath(ctx);
CGContextClip(ctx);

//this doesn't work
UIImage * image = [UIImage imageNamed:@"blackbackground.jgp"];
[image drawInRect:rect];

//this neither
CGImageRef cgImage = image.CGImage;
CGContextDrawImage(ctx, rect,  cgImage);

Answer 1

将图像绘制到 CGContext 的正确方法是这样的:

UIImage *_originalImage = // your image

UIGraphicsBeginImageContext(_originalImage.size);
CGContextRef _context = UIGraphicsGetCurrentContext(); // here you don't need this reference for the context but if you want to use in the future for drawing anything else on the context you could get it for it
[_originalImage drawInRect:CGRectMake(0.f, 0.f, _originalImage.size.width, _originalImage.size.height)];

UIImage *_newImage = UIGraphicsGetImageFromCurrentImageContext();    
UIGraphicsEndImageContext();