利用 ImageMagick 检测 EXIF 方向和旋转图像

Use the auto-orient option of ImageMagick's convert to do this.

convert your-image.jpg -auto-orient output.jpg

Or use mogrifyto do it in place

mogrify -auto-orient your-image.jpg

The PHP Imagick way would be to test the image orientation and rotate/flip the image accordingly:

function autorotate(Imagick $image)
{
switch ($image->getImageOrientation()) {
case Imagick::ORIENTATION_TOPLEFT:
break;
case Imagick::ORIENTATION_TOPRIGHT:
$image->flopImage();
break;
case Imagick::ORIENTATION_BOTTOMRIGHT:
$image->rotateImage("#000", 180);
break;
case Imagick::ORIENTATION_BOTTOMLEFT:
$image->flopImage();
$image->rotateImage("#000", 180);
break;
case Imagick::ORIENTATION_LEFTTOP:
$image->flopImage();
$image->rotateImage("#000", -90);
break;
case Imagick::ORIENTATION_RIGHTTOP:
$image->rotateImage("#000", 90);
break;
case Imagick::ORIENTATION_RIGHTBOTTOM:
$image->flopImage();
$image->rotateImage("#000", 90);
break;
case Imagick::ORIENTATION_LEFTBOTTOM:
$image->rotateImage("#000", -90);
break;
default: // Invalid orientation
break;
}
$image->setImageOrientation(Imagick::ORIENTATION_TOPLEFT);
}

The function might be used like this:

$img = new Imagick('/path/to/file');
autorotate($img);
$img->stripImage(); // if you want to get rid of all EXIF data
$img->writeImage();