Question

我一直在使用Trent的UIImage包来调整图像大小以适应我的UIImage尺寸320 * 320.当我使用截图或网页中的任何图片时，垂直和水平都很好。但是，当我使用iPhone 5相机拍摄的照片时，垂直拍摄将像水平一样旋转（水平照片保持水平幸运）。我把它缩小到我的代码中发生的时候，Trent的代码是有道理的，但我不知道是什么原因导致垂直相机图片这样做？有什么想法吗？

我的代码：

    UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];
        // Resizes the image, but unfortunately the below code also rotates it if vertical from an iPhone 5
UIImage *scaledImage = [image resizedImageWithContentMode:UIViewContentModeScaleAspectFill bounds:CGSizeMake(pic.frame.size.width, pic.frame.size.height) interpolationQuality:kCGInterpolationHigh];

特伦特的代码：

- (UIImage *)resizedImageWithContentMode:(UIViewContentMode)contentMode
                                  bounds:(CGSize)bounds
                    interpolationQuality:(CGInterpolationQuality)quality {
    CGFloat horizontalRatio = bounds.width / self.size.width;
    CGFloat verticalRatio = bounds.height / self.size.height;
    CGFloat ratio;

    switch (contentMode) {
        case UIViewContentModeScaleAspectFill:
            ratio = MAX(horizontalRatio, verticalRatio);
            break;

        case UIViewContentModeScaleAspectFit:
            ratio = MIN(horizontalRatio, verticalRatio);
            break;

        default:
            [NSException raise:NSInvalidArgumentException format:@"Unsupported content mode: %d", contentMode];
    }

    CGSize newSize = CGSizeMake(self.size.width * ratio, self.size.height * ratio);

    return [self resizedImage:newSize interpolationQuality:quality];
}

更新：以下是“来自Trent代码的调整后的图片：

- (UIImage *)resizedImage:(CGSize)newSize interpolationQuality:(CGInterpolationQuality)quality {
    BOOL drawTransposed;
    CGAffineTransform transform = CGAffineTransformIdentity;

    // In iOS 5 the image is already correctly rotated. See Eran Sandler's
    // addition here: http://eran.sandler.co.il/2011/11/07/uiimage-in-ios-5-orientation-and-resize/

    if ( [[[UIDevice currentDevice] systemVersion] floatValue] >= 5.0 ) 
    {
        drawTransposed = NO;  
    } 
    else 
    {    
        switch ( self.imageOrientation ) 
        {
            case UIImageOrientationLeft:
            case UIImageOrientationLeftMirrored:
            case UIImageOrientationRight:
            case UIImageOrientationRightMirrored:
                drawTransposed = YES;
                break;
            default:
                drawTransposed = NO;
        }

        transform = [self transformForOrientation:newSize];
    } 

    return [self resizedImage:newSize transform:transform drawTransposed:drawTransposed interpolationQuality:quality];
}

这是变换......但我已经知道这不是实际问题所在：

- (CGAffineTransform)transformForOrientation:(CGSize)newSize {
    CGAffineTransform transform = CGAffineTransformIdentity;

    switch (self.imageOrientation) {
        case UIImageOrientationDown:           // EXIF = 3
        case UIImageOrientationDownMirrored:   // EXIF = 4
            transform = CGAffineTransformTranslate(transform, newSize.width, newSize.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;

        case UIImageOrientationLeft:           // EXIF = 6
        case UIImageOrientationLeftMirrored:   // EXIF = 5
            transform = CGAffineTransformTranslate(transform, newSize.width, 0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;

        case UIImageOrientationRight:          // EXIF = 8
        case UIImageOrientationRightMirrored:  // EXIF = 7
            transform = CGAffineTransformTranslate(transform, 0, newSize.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        default:
            break;
    }

    switch (self.imageOrientation) {
        case UIImageOrientationUpMirrored:     // EXIF = 2
        case UIImageOrientationDownMirrored:   // EXIF = 4
            transform = CGAffineTransformTranslate(transform, newSize.width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;

        case UIImageOrientationLeftMirrored:   // EXIF = 5
        case UIImageOrientationRightMirrored:  // EXIF = 7
            transform = CGAffineTransformTranslate(transform, newSize.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
        default:
            break;
    }

    return transform;
}

Answer 1

解决了它

   - (UIImage *)resizedImage:(CGSize)newSize interpolationQuality:(CGInterpolationQuality)quality {
        BOOL drawTransposed;
        switch ( self.imageOrientation )
        {
            case UIImageOrientationLeft:
                        case UIImageOrientationLeftMirrored:
                        case UIImageOrientationRight:
                        case UIImageOrientationRightMirrored:
                      drawTransposed = YES;
                      break;
                        default:
                      drawTransposed = NO;
                }
        CGAffineTransform transform = [self transformForOrientation:newSize];

        return [self resizedImage:newSize transform:transform drawTransposed:drawTransposed interpolationQuality:quality];
    }

仅在调整相机图片大小时UIImage会旋转，但在截屏图片时工作正常

1 个答案: