学步园

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- (void)drawRect:(CGRect)rect {
	
    //Get the current drawing context   
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    //Set the line color and width
    CGContextSetStrokeColorWithColor(context, [UIColor colorWithRed:0.0f green:0.0f blue:0.0f alpha:0.2f].CGColor);
    CGContextSetLineWidth(context, 1.0f);
    
    
    //Start a new Path
    CGContextBeginPath(context);
	
    //Find the number of lines in our textView + add a bit more height to draw lines in the empty part of the view
    NSUInteger numberOfLines = (self.contentSize.height + self.bounds.size.height) / self.font.leading;
	
    //Set the line offset from the baseline. (I'm sure there's a concrete way to calculate this.)
    CGFloat baselineOffset = 6.0f;
	
    //iterate over numberOfLines and draw each line
    for (int x = 1; x < numberOfLines; x++) {
        
        //0.5f offset lines up line with pixel boundary
        CGContextMoveToPoint(context, self.bounds.origin.x+10, self.font.leading*x + 0.5f + baselineOffset);
        CGContextAddLineToPoint(context, self.bounds.size.width-10, self.font.leading*x + 0.5f + baselineOffset);
    }
	
    //Close our Path and Stroke (draw) it
    CGContextClosePath(context);
    CGContextStrokePath(context);
}