CGContextEOFillPath + CGContextDrawLinearGradient - objective-c

Question

I have succeeded in drawing a rectangle which has a hole inside of the shape of a rounded rectangle using CGContextEOFillPath. I can change the colour of my shape. However, I would like to use a gradient, I suppose that I have got to use CGContextDrawLinearGradient, however, I can't make it work. It keep painting the entire rectangle, hole included.
Here is the code that I am using
- (void)drawRect:(CGRect)rect
{
[super drawRect:rect];
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSaveGState(context);
CGFloat frameWidth = 1; //[CQMFloatingContentOverlayView frameWidth];
CGFloat radius = [self cornerRadius];
CGSize viewSize = [self frame].size;
CGPathRef path = CQMPathCreateRoundingRect(CGRectMake(frameWidth, frameWidth,
viewSize.width - frameWidth * 2,
viewSize.height - frameWidth * 2),
radius, radius, radius, radius);
CGContextAddRect(context, CGRectMake(0, 0, viewSize.width, viewSize.height));
CGContextAddPath(context, path);
CGContextEOFillPath(context);
CGPathRelease(path);
CGContextRestoreGState(context);
}
CGPathRef CQMPathCreateRoundingRect(CGRect rect, CGFloat blRadius, CGFloat brRadius, CGFloat trRadius, CGFloat tlRadius) {
CGPoint tlPoint = rect.origin;
CGPoint brPoint = CGPointMake(rect.origin.x + rect.size.width,
rect.origin.y + rect.size.height);
CGMutablePathRef path = CGPathCreateMutable();
CGPathMoveToPoint(path, NULL, tlPoint.x + tlRadius, tlPoint.y);
CGPathAddArcToPoint(path, NULL,
brPoint.x, tlPoint.y,
brPoint.x, tlPoint.y + trRadius,
trRadius);
CGPathAddArcToPoint(path, NULL,
brPoint.x, brPoint.y,
brPoint.x - brRadius, brPoint.y,
brRadius);
CGPathAddArcToPoint(path, NULL,
tlPoint.x, brPoint.y,
tlPoint.x, brPoint.y - blRadius,
blRadius);
CGPathAddArcToPoint(path, NULL,
tlPoint.x, tlPoint.y,
tlPoint.x + tlRadius, tlPoint.y,
tlRadius);
CGPathCloseSubpath(path);
return path;
}
I don't know where to put the gradient code, I have tried before and after the CGContextEOFillPath but could not reach my objective.

Answer 1

This code should make what you want (check for syntax and typos, code is directly written in answer)
- (void)drawRect:(CGRect)rect {
CGContextRef context = UIGraphicsGetCurrentContext();
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGFloat gradientColors[] =
{
0.1, 0.1, 0.5, 1.00,
0.9, 0.9, 1.0, 1.00,
};
CGGradientRef gradient = CGGradientCreateWithColorComponents(colorSpace, gradientColors, NULL, sizeof(gradientColors)/(sizeof(gradientColors[0])*4));
CGColorSpaceRelease(colorSpace);
CGContextSaveGState(context);
CGFloat frameWidth = 1; //[CQMFloatingContentOverlayView frameWidth];
CGFloat radius = [self cornerRadius];
CGSize viewSize = [self frame].size;
CGPathRef path = CQMPathCreateRoundingRect(CGRectMake(frameWidth, frameWidth,
viewSize.width - frameWidth * 2,
viewSize.height - frameWidth * 2),
radius, radius, radius, radius);
CGContextAddRect(context, CGRectMake(0, 0, viewSize.width, viewSize.height));
CGContextAddPath(context, path);
CGContextEOClip(context);
CGContextDrawLinearGradient(context, gradient, CGPointMake(0, 0), CGPointMake(viewSize.width, viewSize.height), kCGGradientDrawsBeforeStartLocation);
CGPathRelease(path);
CGContextRestoreGState(context);
}