在scrollView中的ImageView中裁剪缩放图像 [英] crop a zoomed image in ImageView inside scrollView

问题描述

我已经从我身边做了很多努力。最后我需要帮助。谢谢

I already do Lot of efforts from my Side. finally I need help. thanks

目标：
1）我如何在ScrollView中使用imageView

Goal : 1) How I fit imageView inside ScrollView

2）我如何裁剪内部scrollView中的缩放图像。

2) How I crop a zoomed Image in inside scrollView.

我在Scroll View中有一个imageView。我希望缩放后的裁剪图像显示在scrollview边界内。我已经裁剪了图像，但它与我想要的完全相同。

I have a imageView inside Scroll View. I wants crop image after zoomed which is display inside scrollview boundary. I cropped image already but it not exactly same which i wants.

这里我将backgroundColor Black设置为我的scrollView。当我在其中放置imageView时，它不适合。

Here I set backgroundColor Black to my scrollView. And when I place imageView inside it, it's not fit.

和裁剪图像后

我的代码在这里：

- (void)viewDidLoad
{
    [super viewDidLoad];

    CGRect frame1 = CGRectMake(50,50,200,200);

    CGRect frame2 = CGRectMake(50,50,200,200);

    imageView1=[[UIImageView alloc]initWithFrame:frame1];

   imageView1.image= [UIImage imageNamed:@"back.jpeg"];

   imageView1.backgroundColor=[UIColor brownColor];

   imageView1.contentMode = UIViewContentModeScaleAspectFit;



   scroll=[[UIScrollView alloc]initWithFrame:frame2];

   scroll.backgroundColor=[UIColor blackColor];

  [scroll addSubview:imageView1];

  scroll.delegate=self;

 [self.view addSubview:scroll];

 [self setContentSizeForScrollView];

 self.imageView1.userInteractionEnabled = YES;

}

设置滚动视图contentSize

setting scroll view contentSize

-(void)setContentSizeForScrollView
{
 // scroll.contentSize = CGSizeMake(imageView1.frame.size.width,imageView1.frame.size.height);

    scroll.contentSize = CGSizeMake(200, 200);
   scroll.minimumZoomScale = .50;
  scroll.maximumZoomScale = 1.5;
}

我的裁剪逻辑是

-(IBAction)cropButtonClicked
{
    //Calculate the required area from the scrollview

CGRect rect = CGRectMake(50, 50, 200,200);


UIImage *image = [self imageByCropping:imageView1.image toRect:rect];

imageView1.image=image;


imageView1.contentMode = UIViewContentModeScaleAspectFit;


 }

此方法裁剪图片：

- (UIImage*)imageByCropping:(UIImage *)myImage toRect:(CGRect)cropToArea{
    CGImageRef cropImageRef = CGImageCreateWithImageInRect(myImage.CGImage, cropToArea);
    UIImage* cropped = [UIImage imageWithCGImage:cropImageRef];

    CGImageRelease(cropImageRef);
    return cropped;
}

推荐答案

我的回答问题：经过多方努力，我找到了我的两个问题的答案。

Answer of my own Question : After many efforts i found the answer of both of my questions.

这对我有用。我在这里分享，可能对某人有帮助。 ：）

and it work good for me. I share here, may be it help someone. :)

1）在Scroll View中调整图像视图。我使用这个链接

1) Fit image View inside Scroll View. I use this link

- (void)centerScrollViewContents {

CGSize boundsSize = scroll.bounds.size;
CGRect contentsFrame = self.imageView1.frame;

if (contentsFrame.size.width < boundsSize.width) {
contentsFrame.origin.x = (boundsSize.width - contentsFrame.size.width) / 2.0f;
} 
else {
contentsFrame.origin.x = 0.0f;
}

if (contentsFrame.size.height < boundsSize.height) {
    contentsFrame.origin.y = (boundsSize.height - contentsFrame.size.height) / 2.0f;
} 
else {
contentsFrame.origin.y = 0.0f;
}

self.imageView1.frame = contentsFrame;
}

2）在内部scrollView中裁剪缩放的图像。我使用这个链接

2) Crop a zoomed Image in inside scrollView. I use this link

    UIGraphicsBeginImageContext(CGSizeMake(200, 200));

    [scroll.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage *fullScreenshot = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    imageView1.contentMode = UIViewContentModeScaleAspectFill;

    UIImageWriteToSavedPhotosAlbum(fullScreenshot, nil, nil, nil);

    return fullScreenshot;

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