“拼合”或“合并”石英2D绘制的线条

Question

我试图找出如何可以展平或合并在石英2D动态地画出的线条很多，

我上绘制随机线随着时间的推移我舞台上，我每次加新线坐标数组，并绘制阵列（我的drawRect我推在我的阵列定时器和setNeedDisplay新线acctually重绘以前所有的线条加上新）

现在的问题：一段时间后，它开始变得越来越慢，因为阵列越来越很长，所以我虽然我应该合并坐标转换为平面图像或东西，并清除阵列到k eep它记忆健康，但我该如何做到这一点？

这是我的当前工作流：

• 呼叫计时器

  [的NSTimer scheduledTimerWithTimeInterval：0.1目标：自选择器：@selector（drawdrawdraw）USERINFO：无重复：YES];

• 刷新的drawRect在我的 “drawdrawdraw” 功能

  - （无效）drawdrawdraw { [自setNeedsDisplay]; }

• 我的drawRect

  -(void)drawRect:(CGRect)rect{ 
      viewContext = UIGraphicsGetCurrentContext(); 
  
      int count = [mijnArray_r_x count]; 
  
      float r_x = (float)(random() % 768); 
      [mijnArray_r_x insertObject:[NSNumber numberWithFloat:r_x] atIndex:count]; 
  
      float r_y = (float)(random() % 1004); 
      [mijnArray_r_y insertObject:[NSNumber numberWithFloat:r_y] atIndex:count]; 
  
      float r_w = (float)(random() % 100); 
      [mijnArray_r_w insertObject:[NSNumber numberWithFloat:r_w] atIndex:count]; 
  
      float r_a = (float)(random() % 100); 
      [mijnArray_r_a insertObject:[NSNumber numberWithFloat:r_a] atIndex:count]; 
  
  
      CGContextSetLineWidth(viewContext, 2.0); 
      CGContextSetStrokeColorWithColor(viewContext, [UIColor blackColor].CGColor); 
      for (int k = 0; k <= count; k++) { 
  
       float temp_x = [[mijnArray_r_x objectAtIndex: k] floatValue]; 
       float temp_y = [[mijnArray_r_y objectAtIndex: k] floatValue]; 
       float temp_w = [[mijnArray_r_w objectAtIndex: k] floatValue]; 
       float temp_a = [[mijnArray_r_a objectAtIndex: k] floatValue]; 
  
       CGPoint pointpointpoint = CGPointMake(temp_x, temp_y); 
       CGPoint pointpointpointpoint = CGPointMake(temp_w, temp_a); 
       CGContextMoveToPoint(viewContext, pointpointpoint.x, pointpointpoint.y); 
       CGContextAddLineToPoint(viewContext, pointpointpoint.x - pointpointpointpoint.x, pointpointpoint.y + pointpointpointpoint.y); 
       CGContextStrokePath(viewContext); 
      } 
  } } 
  

Answer 1

您可以通过使用UIGraphicsBeginImageContext()画你的线条变成UIImage。通过这种方式，绘制将是恒定的，因为在每次迭代中你只绘制缓存图像作为位图和新行添加所需的时间。

- (void)drawRect:(CGRect)rect { 
    [self.currentImage drawInRect:[self bounds]]; 
    UIGraphicsBeginImageContext([self bounds].size); 
    CGContextRef cgContext = UIGraphicsGetCurrentContext(); 
    //Draw your lines into the cgContext here... 
    self.currentImage = UIGraphicsGetImageFromCurrentImageContext(); 
    UIGraphicsEndImageContext(); 
} 

这假定您已经声明UIImage类型的属性currentImage。