Can't create Retina images with CGContextDrawImage - iphone

Question

I'm creating an image by combining two other images, using CGContext. Even if I have the #2x images, I can't succeed to create an retina image.
Here's my code. Could you please help ?
-(UIImage*)makePinImageWithImage:(UIImage*)icon {
UIImage * pin = [UIImage imageNamed:#"defaultPin.png"]; // I have the #2x one.
int w = pin.size.width;
int h = pin.size.height;
CGRect iconRect = CGRectMake(16, 47, 24, 26); // the frame where mix icon in pin
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(NULL, w, h, 8, 8 * w, colorSpace, kCGImageAlphaPremultipliedFirst);
// Drawing pin in context
CGContextDrawImage(context, CGRectMake(0, 0, w, h), pin.CGImage);
CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1);
// Drawing icon in context
CGContextDrawImage(context, iconRect, icon.CGImage);
CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1);
// Getting back the final image
CGImageRef imageCG = CGBitmapContextCreateImage(context);
CGContextRelease(context);
CGColorSpaceRelease(colorSpace);
UIImage * createdImage = [UIImage imageWithCGImage:imageCG];
CGImageRelease(imageCG);
return createdImage;
}
Thanks

Answer 1

This code is done in a text window, should more or less do what you want.
(UIImage*)makePinImageWithImage:(UIImage*)icon // this code assumes this image is #2x if the device is
{
UIImage *pin = [UIImage imageNamed:#"defaultPin.png"]; // I have the #2x one.
CGFloat w = rintf(pin.size.width);
CGFloat h = rintf(pin.size.height);
UIGraphicsBeginImageContextWithOptions(CGSizeMake(w, h), YES, 0); // 0 means let iOS deal with scale for you
CGContextRef context = UIGraphicsGetCurrentContext();
CGAffineTransform flipVertical = CGAffineTransformMake(1, 0, 0, -1, 0, h);
CGContextConcatCTM(context, flipVertical);
CGRect iconRect = CGRectMake(16, 47, 24, 26); // the frame where mix icon in pin
// Drawing pin in context
CGContextDrawImage(context, CGRectMake(0, 0, w, h), [pin CGImage]); // CGImage is a method, not a property
//CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1); // this does not do anything does it? You never do a FillRect...
// Drawing icon in context
CGContextDrawImage(context, iconRect, [icon CGImage]);
//CGContextSetRGBFillColor(context, 0.0, 0.0, 1.0, 1); // this does not do anything does it? You never do a FillRect...
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image; // will be either normally sized or retina sized depending on environment
}