如何旋转UIImage以正确的方向在网站/ Facebook上发布照片？

Question

如果我使用iPhone相机拍摄照片，则会看到该照片旋转了90度。 例如，如果设备方向为UIDeviceOrientationPortrait，则UIImage方向为UIImageOrientationRight。 如何旋转UIIMage，以便将其发布在网站或Facebook上时，照片的方向是否正确？

Answer 1

我在UIImage类别中使用此功能：

- (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];
}

然后只需致电：

UIImage *myCameraRollImage = ..//image received from camera roll

UIImage *mFixedRotationImage = [myCameraRollImage resizedImageWithContentMode:UIViewContentModeScaleAspectFit bounds:CGSizeMake(width, height) interpolationQuality:kCGInterpolationHigh];

希望有帮助！