How to Correctly Rotate Uploaded Images Based on EXIF Orientation using PHP?-PHP Tutorial-php.cn

How to Correctly Rotate Uploaded Images Based on EXIF Orientation using PHP?

Susan Sarandon

Release： 2024-10-31 14:28:02

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How to Correctly Rotate Uploaded Images Based on EXIF Orientation using PHP?

PHP read_exif_data and Adjust Orientation

When using exif_read_data to rotate uploaded jpeg images based on their orientation, it's important to interpret the data correctly. In the provided code, the orientation is being read but not applied accurately.

Reading EXIF Data

The EXIF data is extracted using exif_read_data($upload_path . $newfilename), which returns an array with various metadata. The "Orientation" key holds the value indicating the image's orientation.

Adjusting Orientation

To fix the rotation, use the following switch statement according to the "Orientation" value:

<code class="php">switch($ort)
{
    case 3: // Rotate 180 degrees left
        $image->imagerotate($upload_path . $newfilename, 180, -1);
        break;

    case 6: // Rotate 90 degrees right
        $image->imagerotate($upload_path . $newfilename, -90, -1);
        break;

    case 8: // Rotate 90 degrees left
        $image->imagerotate($upload_path . $newfilename, 90, -1);
        break;
}</code>

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Alternatively, consider these optimized functions for orientation adjustment:

GD Function

This function rotates the image without resampling:

<code class="php">function image_fix_orientation(&$image, $filename) {
    $exif = exif_read_data($filename);

    if (!empty($exif['Orientation'])) {
        switch ($exif['Orientation']) {
            case 3:
                $image = imagerotate($image, 180, 0);
                break;
            
            case 6:
                $image = imagerotate($image, 90, 0);
                break;
            
            case 8:
                $image = imagerotate($image, -90, 0);
                break;
        }
    }
}</code>

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One-line GD Version

<code class="php">function image_fix_orientation(&$image, $filename) {
    $image = imagerotate($image, array_values([0, 0, 0, 180, 0, 0, -90, 0, 90])[@exif_read_data($filename)['Orientation'] ?: 0], 0);
}</code>

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ImageMagick Function

This function handles image orientation within ImageMagick:

<code class="php">function image_fix_orientation($image) {
    if (method_exists($image, 'getImageProperty')) {
        $orientation = $image->getImageProperty('exif:Orientation');
    } else {
        $filename = $image->getImageFilename();

        if (empty($filename)) {
            $filename = 'data://image/jpeg;base64,' . base64_encode($image->getImageBlob());
        }

        $exif = exif_read_data($filename);
        $orientation = isset($exif['Orientation']) ? $exif['Orientation'] : null;
    }

    if (!empty($orientation)) {
        switch ($orientation) {
            case 3:
                $image->rotateImage('#000000', 180);
                break;

            case 6:
                $image->rotateImage('#000000', 90);
                break;

            case 8:
                $image->rotateImage('#000000', -90);
                break;
        }
    }
}</code>

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