ios - How to create a UIImage from the current graphics context?

Question

I'd like to create a UIImage object from the current graphics context. More specifically, my use case is a view that the user can draw lines on. They may draw incrementally. After they are done, I'd like to create a UIImage to represent their drawing.

Here is what drawRect: looks like for me now:

- (void)drawRect:(CGRect)rect
{
CGContextRef c = UIGraphicsGetCurrentContext();

CGContextSaveGState(c);
CGContextSetStrokeColorWithColor(c, [UIColor blackColor].CGColor);
CGContextSetLineWidth(c,1.5f);

for(CFIndex i = 0; i < CFArrayGetCount(_pathArray); i++)
{
    CGPathRef path = CFArrayGetValueAtIndex(_pathArray, i);
    CGContextAddPath(c, path);
}

CGContextStrokePath(c);

CGContextRestoreGState(c);
}

... where _pathArray is of type CFArrayRef, and is populated every time touchesEnded: is invoked. Also note that drawRect: may be invoked several times, as the user draws.

When the user is done, I'd like to create a UIImage object that represents the graphics context. Any suggestions on how to do this?

Answer 1

You need to setup the graphics context first:

UIGraphicsBeginImageContext(myView.bounds.size);
[myView.layer renderInContext:UIGraphicsGetCurrentContext()];
viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();