CGContext giving unexpected line width

Question

I'm trying to draw a L shape, the code works but the lines are not of the right width and is 5 pixels thick for vertical lines and some are 3 pixels thick despite me explicitly telling it to use 3 pixel as line width,what am I doing wrong? here's my code:

CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextClearRect(ctx, rect);
CGContextAddPath(ctx, pathi);
CGContextSetStrokeColorWithColor(ctx, [UIColor redColor].CGColor);
CGContextSetLineWidth(ctx, 3.0);
CGContextSetLineCap(ctx, kCGLineCapRound);
CGContextSetShouldAntialias(ctx, NO);
CGContextStrokePath(ctx);

I have already calculated path "pathi" The path is working fine.

Answer 1

The lines are actually not thick, the half of the lines gets cutoff while drawing. You should apply padding equal to the half of the width( inn your case, 3/2 => 1.5) because the drawing always start from the mid of the points provided.