如何在沒有UIScrollView的情況下放大或縮小UIImageView？

Question

我正在爲這個應用程序開發iOS 4.2，iPhone應用程序，我下載圖像並將它們保存在內部存儲（NSDocuments）中。

那麼，我在UIImageView中顯示第一個圖像。用戶可以在UIImageView（TouchesMoved）上拖動他們的手指，當用戶這樣做時，我加載其他圖像。如果用戶拖下來，我加載一個圖像，如果向上拖動，我加載其他圖像，並且還向右和向左。

這一切都完成了。但我想實現縮放。這是我的代碼，直到現：

initialDistance - >是在第一觸摸的手指之間的距離
finalDistance - >是手指之間的距離在每次移動
×時間 - >爲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 - 

非常感謝！

PD：如果UIScrollView有一種方法可以在不同的圖像之間移動，我也可以打開看一看。

Answer 1

好的。您可以考慮使用UIScrollView，只是爲了使用它的縮放功能。

假設我們有一個scrollView和一個imageView，它們都具有相同的邊界。添加imageView作爲scrollView的子視圖。

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

僅支持縮放和在scrollView你viewController不是不平移將不得不採取UIScrollViewDelegate協議。

// 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; 
} 

現在我們有縮放可用。對於滑動，您可以使用適當配置的UISwipeGestureRecognizers。創建一個手勢來處理每個滑動方向並將其添加到滾動視圖。

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

和檢索基於手勢適當的圖像，並使用imageView.image = yourImage;設置。

Answer 2

最後，在Deepak的幫助下，我使用UIImageView的transform屬性進行縮放。

我使用CGFloat在CGAffineTransform矩陣中的位置[0,0]來設置限制。我必須在放大時將CGFloat傳遞給字符串，因爲當我將它與0進行比較時，這總是如此。

最後這是我在touchesMoved代碼，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]; 
      } 
     } 

和當然，有很多感謝迪帕克的。