gistfile1.m

- (void)drawLinesInRect:(CGRect)rect forFont:(UIFont *)font
{
    CGFloat maxLineHeight = 30.0f;
    CGFloat fontLineHeight = roundf(font.lineHeight);
    CGFloat fontBaselineAdjustment = roundf(-font.descender);
        
    CGFloat startY = fmodf(yOffset, fontLineHeight);
    
    CGFloat totalDrawnLines = (int)(floorf(CGRectGetHeight(rect) / fontLineHeight));
    for (NSUInteger drawnLine = 0; drawnLine < totalDrawnLines; drawnLine++) {
        CGFloat lineY = startY + (drawnLine + 1) * fontLineHeight - fontBaselineAdjustment;
        
        CGRect lineRect = CGRectMake(0.0f,
                                     roundf(lineY),
                                     CGRectGetWidth(rect),
                                     -1.0f);
        
        CGContextFillRect(UIGraphicsGetCurrentContext(), lineRect);
    }
}