如何在没有UIScrollView的情况下放大或缩小UIImageView？

Question

我正在为这个应用程序开发iOS 4.2，iPhone应用程序，我下载图像并将它们保存在内部存储（NSDocuments）中。

那么，我在UIImageView中显示第一个图像。用户可以在UIImageView（TouchesMoved）上拖动他们的手指，当用户这样做时，我加载其他图像。如果用户拖下来，我加载一个图像，如果向上拖动，我加载其他图像，并且还向右和向左。

这一切都完成了。但我想实现缩放。这是我的代码，直到现：

initialDistance - >是在第一触摸的手指之间的距离
finalDistance - >是手指之间的距离在每次移动
×时间 - >为0
y - >是0

// this method calculate the distance between 2 fingers 
    - (CGFloat)distanceBetweenTwoPoints:(CGPoint)fromPoint toPoint:(CGPoint)toPoint { 
     float xPoint = toPoint.x - fromPoint.x; 
     float yPoint = toPoint.y - fromPoint.y; 

     return sqrt(xPoint * xPoint + yPoint * yPoint); 
    } 

     //------------------- Movimientos con los dedos ------------------------------------ 
     #pragma mark - 
     #pragma mark UIResponder 

      // First Touch 
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{ 

NSSet *allTouches = [event allTouches]; 

switch ([allTouches count]) { 
    case 1: { //Single touch 

     //Get the first touch. 
     UITouch *touch1 = [[allTouches allObjects] objectAtIndex:0]; 

     switch ([touch1 tapCount]) 
     { 
      case 1: //Single Tap. 
      { 
       // Guardo la primera localización del dedo cuando pulsa por primera vez 
       //inicial = [touch1 locationInView:self.view]; 

      } break; 
      case 2: {//Double tap. 
       //Track the initial distance between two fingers. 
       //if ([[allTouches allObjects] count] >= 2) { 

       // oculto/o no, la barra de arriba cuando se hace un dobleTap 
       //[self switchToolBar]; 

      } break; 
     } 
    } break; 
    case 2: { //Double Touch 

     // calculo la distancia inicial que hay entre los dedos cuando empieza a tocar 
     UITouch *touch1 = [[allTouches allObjects] objectAtIndex:0]; 
     UITouch *touch2 = [[allTouches allObjects] objectAtIndex:1]; 

     initialDistance = [self distanceBetweenTwoPoints:[touch1 locationInView:[self view]] 
               toPoint:[touch2 locationInView:[self view]]]; 
    } 
    default: 
     break; 
} 
} 

// when the finger/s move to 
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event 
{ 

NSSet *allTouches = [event allTouches]; 

switch ([allTouches count]) 
{ 
    case 1: { 



    } break; 
    case 2: { 
     //The image is being zoomed in or out. 

     UITouch *touch1 = [[allTouches allObjects] objectAtIndex:0]; 
     UITouch *touch2 = [[allTouches allObjects] objectAtIndex:1]; 

     //Calculate the distance between the two fingers. 
     CGFloat finalDistance = [self distanceBetweenTwoPoints:[touch1 locationInView:[self view]] 
                 toPoint:[touch2 locationInView:[self view]]]; 

     NSLog(@"Distancia Inicial :: %.f, Ditancia final :: %.f", initialDistance, finalDistance); 

     float factorX = 20.0; 
     float factorY = 11.0; 

     // guardo la posicion de los 2 dedos 
     //CGPoint dedo1 = [[[touches allObjects] objectAtIndex:0] locationInView:self.view]; 
     //CGPoint dedo2 = [[[touches allObjects] objectAtIndex:1] locationInView:self.view]; 

     // comparo para saber si el usuario esta haciendo zoom in o zoom out 
     if(initialDistance < finalDistance) { 
      NSLog(@"Zoom In"); 

      float newWidth = imagen.frame.size.width + (initialDistance - finalDistance + factorX); 
      float newHeight = imagen.frame.size.height + (initialDistance - finalDistance + factorY); 

      if (newWidth <= 960 && newHeight <= 640) { 
       /* 
       if (dedo1.x >= dedo2.x) { 
       x = (dedo1.x + finalDistance/2); 
       y = (dedo1.y + finalDistance/2); 
       } else { 
       x = (dedo2.x + finalDistance/2); 
       y = (dedo2.y + finalDistance/2); 
       } 
       */ 

       //x = (dedo1.x); 
       //y = (dedo1.y); 

       imagen.frame = CGRectMake(x, y, newWidth, newHeight); 
      } else { 
       imagen.frame = CGRectMake(x, y, 960, 640); 
      } 



     } 
     else { 
      NSLog(@"Zoom Out"); 

      float newWidth = imagen.frame.size.width - (finalDistance - initialDistance + factorX); 
      float newHeight = imagen.frame.size.height - (finalDistance - initialDistance + factorY); 

      if (newWidth >= 480 && newHeight >= 320) { 
       /* 
       if (dedo1.x >= dedo2.x) { 
       x = (dedo1.x + finalDistance/2); 
       y = (dedo1.y + finalDistance/2); 
       } else { 
       x = (dedo2.x + finalDistance/2); 
       y = (dedo2.y + finalDistance/2); 
       } 
       */ 
       //x -= (finalDistance - initialDistance + factorX); 
       //y -= (finalDistance - initialDistance + factorX); 

       //x = (dedo1.x); 
       //y = (dedo1.y); 

       imagen.frame = CGRectMake(x, y, newWidth, newHeight); 
      } else { 
       imagen.frame = CGRectMake(0, 0, 480, 320); 
      } 



     } 

     initialDistance = finalDistance; 

    } break; 
} 
} 

#pragma mark - 

非常感谢！

PD：如果UIScrollView有一种方法可以在不同的图像之间移动，我也可以打开看一看。

Answer 1

好的。您可以考虑使用UIScrollView，只是为了使用它的缩放功能。

假设我们有一个scrollView和一个imageView，它们都具有相同的边界。添加imageView作为scrollView的子视图。

[scrollView addSubview:imageView]; 
scrollView.contentSize = imageView.frame.size; 

仅支持缩放和在scrollView你viewController不是不平移将不得不采取UIScrollViewDelegate协议。

// Disabling panning/scrolling in the scrollView 
scrollView.scrollEnabled = NO; 

// For supporting zoom, 
scrollView.minimumZoomScale = 0.5; 
scrollView.maximumZoomScale = 2.0; 

... 

// Implement a single scroll view delegate method 
- (UIView*)viewForZoomingInScrollView:(UIScrollView *)aScrollView { 
    return imageView; 
} 

现在我们有缩放可用。对于滑动，您可以使用适当配置的UISwipeGestureRecognizers。创建一个手势来处理每个滑动方向并将其添加到滚动视图。

UISwipeGestureRecognizer *rightSwipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self selector:@selector(handleRightSwipe:)]; 
rightSwipe.direction = UISwipeGestureRecognizerDirectionRight; 
rightSwipe.numberOfTouchesRequired = 1; 
[scrollView addGesture:rightSwipe]; 
[rightSwipe release]; 

和检索基于手势适当的图像，并使用imageView.image = yourImage;设置。

Answer 2

最后，在Deepak的帮助下，我使用UIImageView的transform属性进行缩放。

我使用CGFloat在CGAffineTransform矩阵中的位置[0,0]来设置限制。我必须在放大时将CGFloat传递给字符串，因为当我将它与0进行比较时，这总是如此。

最后这是我在touchesMoved代码，如果它是有用的人：

// comparo para saber si el usuario esta haciendo zoom in o zoom out 
     if(initialDistance < finalDistance) { 
      NSLog(@"Zoom Out"); 

      CGAffineTransform transformer = CGAffineTransformScale(imagen.transform, 1.05, 1.05); 

      NSLog(@"transformer :: A: %.f, B: %.f, C: %.f, D: %.f", imagen.transform.a, imagen.transform.b, imagen.transform.c, imagen.transform.d); 

      if (transformer.a < 5) { 
       [UIView beginAnimations:nil context:NULL]; 
       [UIView setAnimationDuration: 0.2]; 
       imagen.transform = transformer; 
       [UIView setAnimationDelegate:self]; 
       [UIView commitAnimations]; 
      } 
     } 
     else { 
      NSLog(@"Zoom In"); 

      CGAffineTransform transformer = CGAffineTransformScale(imagen.transform, 0.95, 0.95); 

      NSLog(@"transformer :: A: %.f, B: %.f, C: %.f, D: %.f", transformer.a, transformer.b, transformer.c, transformer.d); 

      NSString *num = [NSString stringWithFormat:@"%.f", transformer.a]; 

      if (![num isEqualToString:@"0"]) { 
       [UIView beginAnimations:nil context:NULL]; 
       [UIView setAnimationDuration: 0.2]; 
       imagen.transform = transformer; 
       [UIView setAnimationDelegate:self]; 
       [UIView commitAnimations]; 
      } 
     } 

和当然，有很多感谢迪帕克的。