在滚动视图中缩放图像iOS sdk

Question

在滚动视图中缩放图像具有适当比例的iOS sdk。当它放大滚动视图时，如何保持图像的比例。

Answer 1

Declare following variable in .h file. 

UIScrollView *scrollViewPhoto; 
UIImageView *imvPhoto; 

put the following code in .m file and call set image method when setting the image in imageView. 


#pragma mark - set Image view 
-(void)setImage:(UIImage *)imageV 
{ 
    scrollViewPhoto.zoomScale = 1; 
    scrollViewPhoto.hidden = NO; 
    toolbar.hidden = NO; 
    UIImage* image = imageV; 
    imvPhoto.image = imageV; 

    float width = scrollViewPhoto.frame.size.width/image.size.width; 
    if (image.size.width<self.view.frame.size.width) { 
     width = 1; 
    } 

    float height = scrollViewPhoto.frame.size.height/image.size.height; 
    if (image.size.height<self.view.frame.size.height) { 
     height = 1; 
    } 

    float f = 0; 

    if (width < height) 
    { 
     f = width; 
    } 
    else 
    { 
     f = height; 
    } 

    imvPhoto.frame = CGRectMake(0, 0, image.size.width*f, image.size.height*f); 


    CGRect frame = scrollViewPhoto.frame; 
    scrollViewPhoto.contentSize = frame.size; 
    imvPhoto.center = CGPointMake(frame.size.width/2, frame.size.height/2); 
} 

-(void)setImageViewCenter{ 
    CGRect frame = scrollViewPhoto.frame; 
    imvPhoto.center = CGPointMake(imvPhoto.center.x , frame.size.height/2); 
} 


- (void)scrollViewDidZoom:(UIScrollView *)scrollView 
{ 

    float width = 0; 
    float height = 0; 

    if (imvPhoto.frame.size.width < scrollView.frame.size.width) 
    { 
     width = scrollView.frame.size.width; 

     if (imvPhoto.frame.size.height < scrollView.frame.size.height) 
     { 
      height = scrollView.frame.size.height; 
     } 
     else 
     { 
      height = scrollView.contentSize.height; 
     } 
    } 
    else 
    { 
     width = scrollView.contentSize.width; 

     if (imvPhoto.frame.size.height < scrollView.frame.size.height) 
     { 
      height = scrollView.frame.size.height; 
     } 
     else 
     { 
      height = scrollView.contentSize.height; 
     } 

    } 

    imvPhoto.center = CGPointMake(width/2, height/2); 

} 


-(UIView *) viewForZoomingInScrollView:(UIScrollView *)scrollView { 
return imvPhoto; 
} 

Answer 2

我觉得这个链接可以帮到你！ mwphotobrowser