如何对相机胶卷中的照片进行方形切割? [英] How to perform square cut to the photos in camera roll?

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本文介绍了如何对相机胶卷中的照片进行方形切割?的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我想像 instagram 一样在 iPhone 上尝试一些图像过滤功能.我使用 imagePickerController 从相机胶卷中获取照片.我了解 imagePickerController 返回的图像已减少以节省内存.将原始图像加载到 UIImage 是不明智的.但是如何处理图像然后将其保存为原始像素?我使用 iPhone 4S 作为我的开发设备.

I would like to try some image filter features on iPhone like instagram does. I use imagePickerController to get photo from camera roll. I understand that the image return by imagePickerController was reduced to save memory. And it's not wise to load the original image to an UIImage. But how can I processe the image then save it back as the original pixels? I use iPhone 4S as my development device.

相机胶卷中的原始照片为 3264 * 2448.

The original photo in camera roll is 3264 * 2448.

UIImagePickerControllerOriginalImage 返回的图片是1920 * 1440

The image return by UIImagePickerControllerOriginalImage is 1920 * 1440

UIImagePickerControllerEditedImage 返回的图片是640 * 640

The image return by UIImagePickerControllerEditedImage is 640 * 640

imageViewOld(使用 UIImagePickerControllerCropRect [80,216,1280,1280] 裁剪 UIImagePickerControllerOriginalImage 返回的图片) 为 1280 * 1224

imageViewOld(use UIImagePickerControllerCropRect [80,216,1280,1280] to crop the image return by UIImagePickerControllerOriginalImage) is 1280 * 1224

imageViewNew(使用双倍大小的 UIImagePickerControllerCropRect [80,216,2560,2560] 裁剪 UIImagePickerControllerOriginalImage 返回的图像) 为 1840 * 1224.

imageViewNew(use double sized UIImagePickerControllerCropRect [80,216,2560,2560] to crop the image return by UIImagePickerControllerOriginalImage) is 1840 * 1224.

我通过instagram查看同一张照片是1280 * 1280

I check the same photo proceed by instagram is 1280 * 1280

我的问题是:

  1. 为什么 UIImagePickerControllerOriginalImage 不返回原始"照片?为什么要缩小到 1920 * 1440?

  2. 为什么 UIImagePickerControllerEditedImage 不返回 1280 * 1280 的图像?作为
    UIImagePickerControllerCropRect 显示它被 1280 * 1280 正方形切割?

  1. Why UIImagePickerControllerOriginalImage does not return the "Original" photo? Why reduced it to 1920 * 1440?

  2. Why UIImagePickerControllerEditedImage does not return the image by 1280 * 1280? As the
    UIImagePickerControllerCropRect shows it is cut by 1280 * 1280 square?

如何对原始照片进行方形切割以成为 2448 * 2448 的图像?

How can I do a square cut to original photo to be a 2448 * 2448 image?

提前致谢.以下是我的代码:

Thanks in advance. Below is my code:

  - (void)imagePickerController:(UIImagePickerController *)picker  didFinishPickingMediaWithInfo:(NSDictionary *)info
  {

   NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
   if ([mediaType isEqualToString:@"public.image"])
   {

    UIImage *imageEdited = [info objectForKey:UIImagePickerControllerEditedImage];
    UIImage *imagePicked = [info objectForKey:UIImagePickerControllerOriginalImage];

    CGRect cropRect;
    cropRect = [[info valueForKey:@"UIImagePickerControllerCropRect"] CGRectValue];

    NSLog(@"Original width = %f height= %f ",imagePicked.size.width, imagePicked.size.height);
    //Original width = 1440.000000 height= 1920.000000

    NSLog(@"imageEdited width = %f height = %f",imageEdited.size.width, imageEdited.size.height);
    //imageEdited width = 640.000000 height = 640.000000

    NSLog(@"corpRect %f %f %f %f", cropRect.origin.x, cropRect.origin.y , cropRect.size.width, cropRect.size.height);
    //corpRect 80.000000 216.000000 1280.000000 1280.000000

    CGRect rectNew = CGRectMake(cropRect.origin.x, cropRect.origin.y , cropRect.size.width*2, cropRect.size.height*2);

    CGRect rectOld = CGRectMake(cropRect.origin.x, cropRect.origin.y , cropRect.size.width, cropRect.size.height);

    CGImageRef imageRefNew = CGImageCreateWithImageInRect([imagePicked CGImage], rectNew);
    CGImageRef imageRefOld = CGImageCreateWithImageInRect([imagePicked CGImage], rectOld);

    UIImageView *imageViewNew = [[UIImageView alloc] initWithImage:[UIImage imageWithCGImage:imageRefNew]];
    CGImageRelease(imageRefNew);

    UIImageView *imageViewOld = [[UIImageView alloc] initWithImage:[UIImage imageWithCGImage:imageRefOld]];
    CGImageRelease(imageRefOld);


    NSLog(@"imageViewNew width = %f height = %f",imageViewNew.image.size.width, imageViewNew.image.size.height);
    //imageViewNew width = 1840.000000 height = 1224.000000

    NSLog(@"imageViewOld width = %f height = %f",imageViewOld.image.size.width, imageViewOld.image.size.height);
    //imageViewOld width = 1280.000000 height = 1224.000000

     UIImageWriteToSavedPhotosAlbum(imageEdited, nil, nil, NULL);

     UIImageWriteToSavedPhotosAlbum([imageViewNew.image imageRotatedByDegrees:90.0], nil, nil, NULL);
     UIImageWriteToSavedPhotosAlbum([imageViewOld.image imageRotatedByDegrees:90.0], nil, nil, NULL);


    //assign the image to an UIImage Control
    self.imageV.contentMode = UIViewContentModeScaleAspectFit;
    self.imageV.frame = CGRectMake(0, 0, self.view.bounds.size.width, self.view.bounds.size.width);
    self.imageV.image = imageEdited;


  }

  [self dismissModalViewControllerAnimated:YES];

 }

推荐答案

正如您所观察到的，UIImagePickerController 有时会返回一个缩小的编辑图像，有时为 640x640，有时为 320x320(取决于设备).

As you have observed the UIImagePickerController will return a scaled down edited image sometimes 640x640 sometimes 320x320 (device dependent).

你的问题:

如何对原始照片进行方形切割以成为 2448 * 2448 的图像?

How can I do a square cut to original photo to be a 2448 * 2448 image?

为此，您需要首先使用 UIImagePickerControllerCropRect 从使用 info 字典的 UIImagePickerControllerOriginalImage 键获得的原始图像创建新图像.使用 Quartz Core 方法，CGImageCreateWithImageInRect 你可以创建一个新的图像，它只包含被传递的 rect 包围的像素；在这种情况下，作物矩形.您需要考虑方向才能使其正常工作.然后，您只需要将图像缩放到您想要的大小.重要的是要注意，裁剪矩形在正确定向后是相对于原始图像的，而不是从相机或照片库中出来的.这就是为什么当我们开始使用 Quartz 方法创建新图像等时，我们需要转换裁剪矩形以匹配方向.

To do this you need to first use the UIImagePickerControllerCropRect to create a new image from the original image obtained using the UIImagePickerControllerOriginalImage key of the info dictionary. Using the Quartz Core method, CGImageCreateWithImageInRect you can create a new image that only contains the pixels bounded by the passed rect; in this case the crop rect. You will need to take into account orientation in order for this to work properly. Then you need only scale the image to your desired size. It's important to note that the crop rect is relative to the original image when after it has been oriented correctly, not as it comes out of the camera or photo library. This is why we need to transform the crop rect to match the orientation when we start using Quartz methods to create new images, etc.

我采用了您上面的代码并将其设置为根据裁剪矩形从原始图像创建 1280x1280 图像.这里仍然存在一些边缘情况，即考虑到裁剪矩形有时可能具有负值(代码假定为方形裁剪矩形)尚未解决.

I took your code above and set it up to create a 1280x1280 image from the original image based on the crop rect. There are still some edge cases here, i.e. taking into account that the crop rect can sometimes have negative values, (the code assumes a square cropping rect) that have not been addressed.

  1. 首先转换裁剪矩形以考虑传入图像的方向和大小.这个 transformCGRectForUIImageOrientation 函数来自 NiftyBean
  2. 创建一个裁剪为转换后的裁剪矩形的图像.
  3. 将图像缩放(和旋转)到所需大小.即1280x1280.
  4. 从具有正确比例和方向的 CGImage 创建 UIImage.

以下是您的代码进行了更改:更新已在此下方添加了新代码，应处理丢失的情况.

Here is your code with the changes: UPDATE New code has been added below this that should take care of the missing cases.

- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info {
NSString *mediaType = [info objectForKey:UIImagePickerControllerMediaType];
if ([mediaType isEqualToString:@"public.image"])
{

    UIImage *imageEdited = [info objectForKey:UIImagePickerControllerEditedImage];
    UIImage *imagePicked = [info objectForKey:UIImagePickerControllerOriginalImage];

    CGRect cropRect;
    cropRect = [[info valueForKey:@"UIImagePickerControllerCropRect"] CGRectValue];

    NSLog(@"Original width = %f height= %f ",imagePicked.size.width, imagePicked.size.height);
    //Original width = 1440.000000 height= 1920.000000

    NSLog(@"imageEdited width = %f height = %f",imageEdited.size.width, imageEdited.size.height);
    //imageEdited width = 640.000000 height = 640.000000

    NSLog(@"corpRect %@", NSStringFromCGRect(cropRect));
    //corpRect 80.000000 216.000000 1280.000000 1280.000000

    CGSize finalSize = CGSizeMake(1280,1280); 
    CGImageRef imagePickedRef = imagePicked.CGImage;

    CGRect transformedRect = transformCGRectForUIImageOrientation(cropRect, imagePicked.imageOrientation, imagePicked.size);
    CGImageRef cropRectImage = CGImageCreateWithImageInRect(imagePickedRef, transformedRect);
    CGColorSpaceRef colorspace = CGImageGetColorSpace(imagePickedRef);
    CGContextRef context = CGBitmapContextCreate(NULL, 
                                                 finalSize.width, 
                                                 finalSize.height,
                                                 CGImageGetBitsPerComponent(imagePickedRef),
                                                 CGImageGetBytesPerRow(imagePickedRef),
                                                 colorspace,
                                                 CGImageGetAlphaInfo(imagePickedRef));
    CGContextSetInterpolationQuality(context, kCGInterpolationHigh); //Give the context a hint that we want high quality during the scale
    CGContextDrawImage(context, CGRectMake(0, 0, finalSize.width, finalSize.height), cropRectImage);
    CGImageRelease(cropRectImage);

    CGImageRef instaImage = CGBitmapContextCreateImage(context);
    CGContextRelease(context);

    //assign the image to an UIImage Control
    UIImage *image = [UIImage imageWithCGImage:instaImage scale:imagePicked.scale orientation:imagePicked.imageOrientation];
    self.imageView.contentMode = UIViewContentModeScaleAspectFit;
    self.imageView.image = image;
    CGImageRelease(instaImage);

    UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
}

[self dismissModalViewControllerAnimated:YES];

}

CGRect transformCGRectForUIImageOrientation(CGRect source, UIImageOrientation orientation, CGSize imageSize) {
switch (orientation) {
    case UIImageOrientationLeft: { // EXIF #8
        CGAffineTransform txTranslate = CGAffineTransformMakeTranslation(imageSize.height, 0.0);
        CGAffineTransform txCompound = CGAffineTransformRotate(txTranslate,M_PI_2);
        return CGRectApplyAffineTransform(source, txCompound);
    }
    case UIImageOrientationDown: { // EXIF #3
        CGAffineTransform txTranslate = CGAffineTransformMakeTranslation(imageSize.width, imageSize.height);
        CGAffineTransform txCompound = CGAffineTransformRotate(txTranslate,M_PI);
        return CGRectApplyAffineTransform(source, txCompound);
    }
    case UIImageOrientationRight: { // EXIF #6
        CGAffineTransform txTranslate = CGAffineTransformMakeTranslation(0.0, imageSize.width);
        CGAffineTransform txCompound = CGAffineTransformRotate(txTranslate,M_PI + M_PI_2);
        return CGRectApplyAffineTransform(source, txCompound);
    }
    case UIImageOrientationUp: // EXIF #1 - do nothing
    default: // EXIF 2,4,5,7 - ignore
        return source;
}
}

更新我已经做了几个方法来处理其余的情况.步骤基本相同，只是稍作修改.

UPDATE I have made a couple of methods that will take care of the rest of the cases. The steps are basically the same, with a couple of modifications.

  1. 第一个修改是正确转换和缩放上下文以处理传入图像的方向，
  2. 第二个是支持您可以从中获得的非方形作物UIImagePickerController.在这些情况下，方形图像是填充您选择的颜色.
  1. First modification is to correctly transform and scale the context to handle the orientation of the incoming image,
  2. and the second is to support the non square crops you can get from the UIImagePickerController. In these cases the square image is filled with a color of your choosing.

新代码

// CropRect is assumed to be in UIImageOrientationUp, as it is delivered this way from the UIImagePickerController when using AllowsImageEditing is on.
// The sourceImage can be in any orientation, the crop will be transformed to match
// The output image bounds define the final size of the image, the image will be scaled to fit,(AspectFit) the bounds, the fill color will be
// used for areas that are not covered by the scaled image. 
-(UIImage *)cropImage:(UIImage *)sourceImage cropRect:(CGRect)cropRect aspectFitBounds:(CGSize)finalImageSize fillColor:(UIColor *)fillColor {

CGImageRef sourceImageRef = sourceImage.CGImage;

//Since the crop rect is in UIImageOrientationUp we need to transform it to match the source image.
CGAffineTransform rectTransform = [self transformSize:sourceImage.size orientation:sourceImage.imageOrientation];
CGRect transformedRect = CGRectApplyAffineTransform(cropRect, rectTransform);

//Now we get just the region of the source image that we are interested in.
CGImageRef cropRectImage = CGImageCreateWithImageInRect(sourceImageRef, transformedRect);

//Figure out which dimension fits within our final size and calculate the aspect correct rect that will fit in our new bounds
CGFloat horizontalRatio = finalImageSize.width / CGImageGetWidth(cropRectImage);
CGFloat verticalRatio = finalImageSize.height / CGImageGetHeight(cropRectImage);
CGFloat ratio = MIN(horizontalRatio, verticalRatio); //Aspect Fit
CGSize aspectFitSize = CGSizeMake(CGImageGetWidth(cropRectImage) * ratio, CGImageGetHeight(cropRectImage) * ratio);


CGContextRef context = CGBitmapContextCreate(NULL,
                                             finalImageSize.width,
                                             finalImageSize.height,
                                             CGImageGetBitsPerComponent(cropRectImage),
                                             0,
                                             CGImageGetColorSpace(cropRectImage),
                                             CGImageGetBitmapInfo(cropRectImage));

if (context == NULL) {
    NSLog(@"NULL CONTEXT!");
}

//Fill with our background color
CGContextSetFillColorWithColor(context, fillColor.CGColor);
CGContextFillRect(context, CGRectMake(0, 0, finalImageSize.width, finalImageSize.height));

//We need to rotate and transform the context based on the orientation of the source image.
CGAffineTransform contextTransform = [self transformSize:finalImageSize orientation:sourceImage.imageOrientation];
CGContextConcatCTM(context, contextTransform);

//Give the context a hint that we want high quality during the scale
CGContextSetInterpolationQuality(context, kCGInterpolationHigh); 

//Draw our image centered vertically and horizontally in our context.
CGContextDrawImage(context, CGRectMake((finalImageSize.width-aspectFitSize.width)/2, (finalImageSize.height-aspectFitSize.height)/2, aspectFitSize.width, aspectFitSize.height), cropRectImage);

//Start cleaning up..
CGImageRelease(cropRectImage);

CGImageRef finalImageRef = CGBitmapContextCreateImage(context);
UIImage *finalImage = [UIImage imageWithCGImage:finalImageRef];

CGContextRelease(context);
CGImageRelease(finalImageRef);
return finalImage;
}

//Creates a transform that will correctly rotate and translate for the passed orientation.
//Based on code from niftyBean.com
- (CGAffineTransform) transformSize:(CGSize)imageSize orientation:(UIImageOrientation)orientation {

CGAffineTransform transform = CGAffineTransformIdentity;
switch (orientation) {
    case UIImageOrientationLeft: { // EXIF #8
        CGAffineTransform txTranslate = CGAffineTransformMakeTranslation(imageSize.height, 0.0);
        CGAffineTransform txCompound = CGAffineTransformRotate(txTranslate,M_PI_2);
        transform = txCompound;
        break;
    }
    case UIImageOrientationDown: { // EXIF #3
        CGAffineTransform txTranslate = CGAffineTransformMakeTranslation(imageSize.width, imageSize.height);
        CGAffineTransform txCompound = CGAffineTransformRotate(txTranslate,M_PI);
        transform = txCompound;
        break;
    }
    case UIImageOrientationRight: { // EXIF #6
        CGAffineTransform txTranslate = CGAffineTransformMakeTranslation(0.0, imageSize.width);
        CGAffineTransform txCompound = CGAffineTransformRotate(txTranslate,-M_PI_2);
        transform = txCompound;
        break;
    }
    case UIImageOrientationUp: // EXIF #1 - do nothing
    default: // EXIF 2,4,5,7 - ignore
        break;
}
return transform;

}

这篇关于如何对相机胶卷中的照片进行方形切割?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！

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