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iphone - 如何对相机胶卷中的照片进行方形切割？

我想像instagram一样尝试在iPhone上使用某些图像过滤器功能。
我使用imagePickerController从相机胶卷获取照片。我了解减少了imagePickerController返回的图像以节省内存。并且将原始图像加载到UIImage是不明智的。但是，如何处理图像然后将其另存为原始像素呢？
我将iPhone 4S用作开发设备。

相机胶卷中的原始照片为3264 * 2448。

UIImagePickerControllerOriginalImage返回的图像为1920 * 1440

UIImagePickerControllerEditedImage返回的图像为640 * 640

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

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

我检查同一张照片，Instagram继续显示是1280 * 1280

我的问题是:

  • 为什么UIImagePickerControllerOriginalImage不返回“原始”照片？为什么将其减少到1920 * 1440？
  • 为什么UIImagePickerControllerEditedImage不能在1280 * 1280之前返回图像？作为
    UIImagePickerControllerCropRect显示它被削减1280 * 1280平方吗？
  • 如何将原始照片切成2448 * 2448的图像？

    • 提前致谢。
    下面是我的代码:
      - (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];

 }

    最佳答案

    如您所见，UIImagePickerController将返回按比例缩小的编辑图像，有时是640x640，有时是320x320(取决于设备)。

    你的问题:



    为此，您需要首先使用UIImagePickerControllerCropRect从使用信息字典的UIImagePickerControllerOriginalImage键获得的原始图像中创建一个新图像。使用Quartz Core方法CGImageCreateWithImageInRect，您可以创建一个仅包含由传递的rect界定的像素的新图像。在这种情况下，庄稼。您将需要考虑方向，以使其正常工作。然后，您只需要将图像缩放到所需的大小即可。重要的是要注意，正确定向后的裁剪矩形是相对于原始图像的，而不是因为它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的原因。

    我在上面使用了您的代码并将其设置为基于裁剪rect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)，这些值尚未解决。

  • 首先转换裁剪矩形，以考虑传入图像的方向和大小。此transformCGRectForUIImageOrientation函数来自NiftyBean
  • 创建裁剪到转换后的裁剪矩形的图像。
  • 将图像缩放(并旋转)到所需大小。即1280x1280。
  • 使用正确的比例和方向从CGImage创建UIImage。

    • 这是您所做的更改的代码:更新在此之下添加了新代码，该新代码应处理丢失的情况。
    - (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;
}
}

    更新我已经做了一些方法来处理其余的情况。
    步骤基本相同，但进行了一些修改。
  • 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
  • ，第二个是支持您可以从中获得的非方形裁剪UIImagePickerController。在这些情况下，正方形图像为
    充满您选择的颜色。

    • 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;

}

    10-07 18:34
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