1 前言
使用 CGAffineTransformMakeScale/CGContextScaleCTM 函數創建一個仿射縮放變換。

2 代碼實例
ZYViewControllerView.m

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- (void)drawRect:(CGRect)rect{ 
    CGMutablePathRef path = CGPathCreateMutable(); 
    CGRect rectangle = CGRectMake(10.0f, 10.0f, 200.0f, 
                                  300.0f); 
    //將矩形縮放0.5 
    CGAffineTransform transform = CGAffineTransformMakeScale(0.5f, 0.5f); 
    /* Add the rectangle to the path */ 
    CGPathAddRect(path,&transform, rectangle); 
    /* Get the handle to the current context */ 
    CGContextRef currentContext = UIGraphicsGetCurrentContext(); 
    /* Add the path to the context */ 
    CGContextAddPath(currentContext,path); 
    /* Set the fill color to cornflower blue */ 
    [[UIColor colorWithRed:0.20f green:0.60f blue:0.80f alpha:1.0f] setFill]; 
    /* Set the stroke color to brown */ 
    [[UIColor brownColor] setStroke]; 
    /* Set the line width (for the stroke) to 5 */ 
    CGContextSetLineWidth(currentContext,5.0f); 
    /* Stroke and fill the path on the context */ 
    CGContextDrawPath(currentContext,kCGPathFillStroke); 
    /* Dispose of the path */ 
    CGPathRelease(path); 
}