Question

我注意到默认情况下，示例应用程序GLPaint带有二进制记录数据，并在启动时加载，它用于显示“摇我”文本。

我正在创建一个类似的绘画应用程序，我只是想知道实际记录这些笔划的最佳方法是什么，并在下次加载它们。

目前我尝试使用Core Data保存每个顶点的位置，然后在开始时它会再次读取并渲染所有点，但是我发现它太慢了。

有更好/更有效的方法吗？可以将整个viewBuffer保存为二进制文件然后重新加载吗？

Answer 1

如果查看Recording.data，您会注意到每一行都是它自己的数组。要捕获墨迹并播放它，您需要有一个数组数组。出于本演示的目的 - 声明一个可变数组 - writRay

    @synthesize writRay;
//init in code
 writRay = [[NSMutableArray alloc]init];

捕捉墨迹

// Handles the continuation of a touch.
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{  

 CGRect    bounds = [self bounds];
 UITouch*   touch = [[event touchesForView:self] anyObject];

 // Convert touch point from UIView referential to OpenGL one (upside-down flip)
 if (firstTouch) {
  firstTouch = NO;
  previousLocation = [touch previousLocationInView:self];
  previousLocation.y = bounds.size.height - previousLocation.y;
  /******************* create a new array for this stroke's points **************/
  [writRay addObject:[[NSMutableArray alloc]init]];
  /***** add 1st point *********/
  [[writRay objectAtIndex:[writRay count] -1]addObject:[NSValue valueWithCGPoint:previousLocation]];
 } else {
  location = [touch locationInView:self];
     location.y = bounds.size.height - location.y;
  previousLocation = [touch previousLocationInView:self];
  previousLocation.y = bounds.size.height - previousLocation.y;
  /********* add additional points *********/
  [[writRay objectAtIndex:[writRay count] -1]addObject:[NSValue valueWithCGPoint:previousLocation]];
 }

 // Render the stroke
 [self renderLineFromPoint:previousLocation toPoint:location];

}

播放墨水。

- (void)playRay{

 if(writRay != NULL){

  for(int l = 0; l < [writRay count]; l++){
    //replays my writRay -1 because of location point
   for(int p = 0; p < [[writRay objectAtIndex:l]count] -1; p ++){
    [self renderLineFromPoint:[[[writRay objectAtIndex:l]objectAtIndex:p]CGPointValue] toPoint:[[[writRay objectAtIndex:l]objectAtIndex:p + 1]CGPointValue]];
   }
  }
 }
}

为获得最佳效果，请摇动屏幕以清除并从AppController中的changeBrushColor调用playRay。

保存/加载样本GLPaint应用程序的笔划数据的最佳方法是什么？

1 个答案: