exif数据没有方向 - PHP图像上传

问题描述

一直试图从iPhone上检测上传图片的图像方向，然后从中调整它们的方向。

been trying to detect the image orientation of uploaded images from iPhones and then adjust their orientation from that.

我正在尝试解决在potrait中拍摄的图像的问题，以-90度旋转上传。我尝试了许多无效的switch语句，因此决定在我的JSON返回中返回exif数据。

I am trying to fix the issue where images taken in potrait, are uploaded with a -90 degree rotate. I tried numerous switch statements which were not working, so decided to return the exif data in my JSON return.

我看到的问题是他们在exif中没有方向数据。

The issue i see is that their is no orientation in the exif data.

我这样做：

$imagefile = $fileToUpload["tmp_name"];
$destinationImage = imagecreatefromstring(file_get_contents($imagefile));
$exif = exif_read_data($imagefile);
$moveUploadedFile = imagejpeg($destinationImage, $this->uploadDir . "/" . $newFileName, 100);
imagedestroy($destinationImage);

if ($moveUploadedFile) {
  $return['ort'] = $exif;
  echo json_encode($return);
}

我在回程中看到的（使用firebug）是：

What i am seeing in my return (using firebug) is:

FileName:"phpUQZFHh"
FileDateTime:1410465904
FileSize:473421
FileType:2
MimeType:"image/jpeg"
SectionsFound:"COMMENT"

Computed: OBJECT:
Height:700
Width:933
IsColor:1

Comment: ARRAY:
0:"CREATOR: gd-jpeg v1.0 (using IJG JPEG v62), quality = 100"

我希望能够像这样使用exif数据：

I want to be able use the exif data like so:

    if (!empty($exif['Orientation'])){
        //get the orientation
        $ort = $exif['Orientation'];
        //determine what oreientation the image was taken at
        switch($ort){
            case 2: // horizontal flip
                break;
            case 3: // 180 rotate left
                $destinationImage = imagerotate($destinationImage, 180, -1);
                break;
        }
    }

任何帮助？

编辑：下载已上传的图像并检查其属性后，似乎在上传过程中删除了所有exif数据。

After downloaded an image that had been uploaded and checking its properties it appears that all exif data was removed in the upload process.

这仍然让我感到困惑的是为什么在上传/上传之前轮换它/如何解决这个问题。

This still baffles me as to why it is rotated before / during upload / how to fix this.

推荐答案

我遇到了同样的问题。事实证明一些图像确实没有任何exif数据 Orientation - 通常具有正确方向的图像没有它。我尝试用iPhone拍摄一张风景图像，然后就有了。

I ran into the same problem. Turns out some images really did not have any exif data on Orientation at all -- usually ones with the "correct" orientation do not have it. I tried one landscape image taken with an iPhone and there was.

在你的情况下，照片可能首先没有exif数据。我也有一些这样的照片（旋转-90度，但没有方向信息）。我可能错了，但没有exif数据，没有编程方式可以知道图像是否定向错误。

In your case, the photos may have had no exif data in the first place. I had some photos like that as well (rotated -90 degrees but no Orientation info). I could be wrong but without exif data, there's no programmatic way to know if an image is incorrectly oriented.

对于没有方向错误定向的照片 info，我建议您确保用户看到（预览）要上传的内容。 IME，大多数用户都非常愿意为了解决油漆/ photoshop /等问题。只是为了确保他们有漂亮的照片。

For incorrectly oriented photos without Orientation info, I suggest you just make sure the user sees (gets a preview) of what about to be uploaded. IME, most users are more than willing to get out of their way to fire up paint/photoshop/etc. just to ensure they have good looking photos.

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