iOS uses UIScrollView to implement image scaling example code

This article introduces the example code for iOS using UIScrollView to implement image scaling, and share it with you:

Step 1: Add scrollView to the controllermiddle

  UIScrollView *scrollView = [[UIScrollView alloc] init];
   = CGRectMake(40, 250, 300, 200);
   = scrollView;
  [ addSubview:scrollView];

Step 2: Add image control to scrollView

Add image method one:

   UIImageView *imageView = [[UIImageView alloc] init];
    = [UIImage imageNamed:@"minion"];
    = CGRectMake(0, 0, , );

Adding image method two:

  UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"minion"]];
  [scrollView addSubview:imageView];

   = ;
   = imageView;

Step 3: Set the proxy and scaling ratio of scrollView

  // Set up a proxy   = self;

  // Set the scaling ratio   = 2.0;
   = 0.2;

Step 4: Implement the proxy method of scrollView so that its internal child controls can be scaled

  /**
   * The return value of this method determines the content to be scaled (the return value can only be a child control of UIScrollView)
   */
  - (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
  {
    return ;
  }

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