如何縮小圖像並保持它在滾動視圖的中心

在我的應用程序中，我需要用cam捕捉圖像，然後將其傳遞給imageView，該圖像用作ScrollView的子視圖。如何縮小圖像並保持它在滾動視圖的中心

要求是「圖像必須方便縮小的1/4尺寸和放大的尺寸的3倍」。

現在的問題是，當我縮小這張圖片時，圖片縮小了，但它並沒有保持在中間的位置。它會根據手指觸摸設置其位置。（沒有雙抽頭變焦是存在的，而不是必需的也行）

下面是代碼..，

- (void)viewDidLoad

{ [超級viewDidLoad中];

UIImage* tmpImage = nil; 
tmpImage = [roomImage resizedImage:imageScrollView.frame.size interpolationQuality:0]; 
imageView = [[UIImageView alloc] initWithImage:tmpImage]; 
imageView.contentMode = UIViewContentModeScaleAspectFit; 

imageScrollView.delegate = self; 
imageScrollView.canCancelContentTouches = NO; 
imageScrollView.minimumZoomScale = 0.25; 
imageScrollView.maximumZoomScale = 3.00; 


imageScrollView.clipsToBounds = YES; 

[imageView sizeToFit]; 
[imageScrollView addSubview:imageView]; 

imageScrollView.contentSize = imageView.frame.size; 
    imageScrollView.contentMode = UIViewContentModeScaleAspectFit; 
    imageScrollView.contentOffset = CGPointMake(imageScrollView.frame.size.width/2, imageScrollView.frame.size.height/2); 
imageScrollView.autoresizesSubviews = YES; 
imageScrollView.autoresizingMask = UIViewAutoresizingFlexibleHeight |  UIViewAutoresizingFlexibleWidth | 
UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin | 
UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin; 


CGFloat f,x,y; 

if(tmpImage.size.height > tmpImage.size.width) 
{ 
    f = (imageScrollView.frame.size.height/tmpImage.size.height); 
} 
else 
{ 
    f = (imageScrollView.frame.size.width/tmpImage.size.width); 
} 

x = (imageScrollView.frame.size.width - tmpImage.size.width*f)/2; 
y = (imageScrollView.frame.size.height - tmpImage.size.height*f)/2; 

imageView.bounds = CGRectMake(x, y,tmpImage.size.width, tmpImage.size.height); 
[imageView setNeedsDisplay]; 
[imageScrollView setZoomScale:f animated:YES]; 
[imageScrollView setNeedsDisplay]; 

jpgPath = nil; 
[roomImage release]; 
roomImage = nil;

}

希望任何人能幫助我..，

在此先感謝..，

來源

2010-09-01 viral

如果我理解你正確地，你可以繼承的UIScrollView的和有類似於layoutSubviews方法中的以下內容以保持其內容居中：

-(void)layoutSubviews { 

[super layoutSubviews]; 

CGSize boundsSize = self.bounds.size; 
CGRect contentViewFrame = contentView.frame; 

if (contentViewFrame.size.width < boundsSize.width) { 

    contentViewFrame.origin.x = (boundsSize.width - contentViewFrame.size.width)/2; 

} else { 

    contentViewFrame.origin.x = 0; 

} 

if (contentViewFrame.size.height < boundsSize.height) { 

    contentViewFrame.origin.y = (boundsSize.height - contentViewFrame.size.height)/2; 

} else { 

    contentViewFrame.origin.y = 0; 

} 

contentView.frame = contentViewFrame;

}

contentView變量是一個iVar，它表示您在scrollView中想要的imageView。希望這有助於:-)

來源

2011-05-18 09:08:42 menab0t

如何縮小圖像並保持它在滾動視圖的中心

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