iOS Quartz2D - 画矩形

- (void)drawRect:(CGRect)rect {
   
    //1.获得图形上下文
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    
    //2.画矩形框
    CGContextAddRect(ctx, CGRectMake(10, 10, 100, 100));
    
    //3.绘制图形
    CGContextStrokePath(ctx);
//    CGContextFillPath(ctx);
}