imagecreatefromwebp

(PHP 5 >= 5.4.0, PHP 7, PHP 8)

imagecreatefromwebp — 由文件或 URL 创建一个新图象。

说明

imagecreatefromwebp ( string $filename ) : resource

imagecreatefromwebp() 返回从给定文件名创建的图像标示符。

Tip

如已启用fopen 包装器，在此函数中， URL 可作为文件名。关于如何指定文件名详见 fopen()。各种 wapper 的不同功能请参见支持的协议和封装协议，注意其用法及其可提供的预定义变量。

参数

filename: WebP 图像文件路径。

返回值

成功后返回图象资源,失败后返回 false。

范例

Example #1 Convert an WebP image to a jpeg image using imagecreatefromwebp()


<?php
// 加载 WebP 文件
$im = imagecreatefromwebp('./example.webp');

// 以 100% 的质量转换成 jpeg 格式
imagejpeg($im, './example.jpeg', 100);
imagedestroy($im);
?>

User Contributed Notes

kawewong at gmail dot com 23-Jul-2021 09:43


PHP GD and WebP support:



Normal WebP (VP8): supported since PHP 5.4

Transparent WebP or alpha transparency (VP8X, VP8L): supported since PHP 7.0

Animated WebP (VP8X): not supported at all.



You can use the images from here https://developers.google.com/speed/webp/gallery2

here https://ezgif.com/help/alternative-animated-image-formats

and here https://developers.google.com/speed/webp/gallery1



Test with imagecreatefromwebp('your-image.webp'); and see the errors.



You can detect animated or transparent webp using this code.



<?php

/**

 * Get WebP file info.

 * 

 * @link https://www.php.net/manual/en/function.pack.php unpack format reference.

 * @link https://developers.google.com/speed/webp/docs/riff_container WebP document.

 * @param string $file

 * @return array|false Return associative array if success, return `false` for otherwise.

 */

function webpinfo($file) {

    if (!is_file($file)) {

        return false;

    } else {

        $file = realpath($file);

    }



    $fp = fopen($file, 'rb');

    if (!$fp) {

        return false;

    }



    $data = fread($fp, 90);



    fclose($fp);

    unset($fp);



    $header_format = 'A4Riff/' . // get n string

        'I1Filesize/' . // get integer (file size but not actual size)

        'A4Webp/' . // get n string

        'A4Vp/' . // get n string

        'A74Chunk';

    $header = unpack($header_format, $data);

    unset($data, $header_format);



    if (!isset($header['Riff']) || strtoupper($header['Riff']) !== 'RIFF') {

        return false;

    }

    if (!isset($header['Webp']) || strtoupper($header['Webp']) !== 'WEBP') {

        return false;

    }

    if (!isset($header['Vp']) || strpos(strtoupper($header['Vp']), 'VP8') === false) {

        return false;

    }



    if (

        strpos(strtoupper($header['Chunk']), 'ANIM') !== false || 

        strpos(strtoupper($header['Chunk']), 'ANMF') !== false

    ) {

        $header['Animation'] = true;

    } else {

        $header['Animation'] = false;

    }



    if (strpos(strtoupper($header['Chunk']), 'ALPH') !== false) {

        $header['Alpha'] = true;

    } else {

        if (strpos(strtoupper($header['Vp']), 'VP8L') !== false) {

            // if it is VP8L, I assume that this image will be transparency

            // as described in https://developers.google.com/speed/webp/docs/riff_container#simple_file_format_lossless

            $header['Alpha'] = true;

        } else {

            $header['Alpha'] = false;

        }

    }



    unset($header['Chunk']);

    return $header;

}// webpinfo

?>



Reference: https://stackoverflow.com/a/68491679/128761



Usage:



<?php

$info = webpinfo('your-image.webp');

if (isset($info['Animation']) && $info['Animation'] === true) {

    echo 'It is animated webp.';

} 

if (isset($info['Alpha']) && $info['Alpha'] === true) {

    echo 'It is transparent webp.';

} 

?>