How to set up a user Quartz2D coordinate system with scaling that avoids fuzzy drawing?

Question

This topic has been scratched once or twice, but I am still puzzled. And Google was not friendly either.

Since Quartz allows for arbitrary coordinate systems using a

Answer 1

Well, as often, explaining the issue lead me to a solution.

The problem is that the view transform property is applied to it after it has been drawn into a bit buffer. The scaling transform has to be applied before drawing, ie. in the drawRect method. So scratch the awakeFromNib I gave, and here is a correct drawRect:

- (void)drawRect:(CGRect)rect {
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGAffineTransform scale = CGAffineTransformMakeScale(6.0, 6.0);
    CGContextConcatCTM(context, scale);
    CGRect r = CGRectMake(10., 10., 10., 10.);
    CGFloat lineWidth = 0.1;
    CGContextStrokeRectWithWidth(context, r, lineWidth);
}