Drawing Rectangles（绘制矩形）

绘制过程:

    创建路径 －CGMutablePathRef  CGPathCreateMutable (void);  //CGMutablePathRef path = CGPathCreateMutable();

    设置矩形 －CGRect CGRectMake (CGFloat x,CGFloat y,CGFloat width,CGFloat height);

    将所要绘制的图形（矩形）加入路径 

        加入单个矩形 －void  CGPathAddRect (CGMutablePathRef path,const CGAffineTransform *m,CGRect rect); //第二个参数:NULL

        加入多个矩形 －void  CGPathAddRects (CGMutablePathRef path,const CGAffineTransform *m,const CGRect rects[],size_t count);

    创建上下文环境 －CGContextRef  UIGraphicsGetCurrentContext (void); //CGContextRef currentContext = UIGraphicsGetCurrentContext();

        在环境中添加路径 －void  CGContextAddPath (CGContextRef context,CGPathRef path); 

    设置相关属性 - (void)setFill  //填充颜色

               - (void)setStroke  //边界颜色

              － void  CGContextSetLineWidth (CGContextRef c,CGFloat width); //线宽

    绘制路径 －void  CGContextDrawPath (CGContextRef c,CGPathDrawingMode mode);

    释放 －void  CGPathRelease (CGPathRef path);

- (void)drawRect:(CGRect)rect{  

    /* Create the path */

   CGMutablePathRef path = CGPathCreateMutable();

    

   CGRect rectangle = CGRectMake(10.0f,30.0f,200.0f,300.0f);

   CGPathAddRect(path, NULL,rectangle);

    

   // CGRect rectangle1 = CGRectMake(10.0f,30.0f,200.0f,300.0f);

   // CGRect rectangle2 = CGRectMake(40.0f,100.0f,90.0f,300.0f);

   // CGRect rectangles[2] = {rectangle1, rectangle2};

   // CGPathAddRects(path,NULL,(const CGRect *)&rectangles,2);

    /* 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);

    

}