「拼合」或「合併」石英2D繪製的線條

Question

我試圖找出如何可以展平或合併在石英2D動態地畫出的線條很多，

我上繪製隨機線隨着時間的推移我舞臺上，我每次加新線座標數組，並繪製陣列（我的drawRect我推在我的陣列定時器和setNeedDisplay新線acctually重繪以前所有的線條加上新）

現在的問題：一段時間後，它開始變得越來越慢，因爲陣列越來越很長，所以我雖然我應該合併座標轉換爲平面圖像或東西，並清除陣列到k eep它記憶健康，但我該如何做到這一點？

這是我的當前工作流：

• 呼叫計時器

  [的NSTimer scheduledTimerWithTimeInterval：0.1目標：自選擇器：@selector（drawdrawdraw）USERINFO：無重複：YES];

• 刷新的drawRect在我的 「drawdrawdraw」 功能

  - （無效）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

您可以通過使用UIGraphicsBeginImageContext()畫你的線條變成UIImage。通過這種方式，繪製將是恆定的，因爲在每次迭代中你只繪製緩存圖像作爲位圖和新行添加所需的時間。

- (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(); 
} 

這假定您已經聲明UIImage類型的屬性currentImage。