1.2 Quartz 2D 記憶體管理

 1 - (void)drawRect:(CGRect)rect
 2 {
 3     // 1.獲取上下文(layer)
 4     CGContextRef ctx = UIGraphicsGetCurrentContext();
 5 
 6     // 2.拼接路徑
 7     CGMutablePathRef path = CGPathCreateMutable();
 8     CGPathMoveToPoint(path, NULL, 50, 50);
 9     CGPathAddLineToPoint(path, NULL, 100, 100);
10 
11     // 3.把路徑添加到上下文當中
12     CGContextAddPath(ctx, path);
13 
14     // 4.渲染
15     CGContextStrokePath(ctx);
16 
17     // 釋放
18     CGPathRelease(path);  //方法1
19     CFRelease(path);      //方法2
20 }