Convert jpg to webp using imagewebp

Question

I'm having trouble using imagewebp to convert an image to webp.

I use this code:

$filename = dirname(__FILE__) .'/example.jpg';

$im = imagecreatefromjpeg($filename);

$webp =imagewebp($im, str_replace('jpg', 'webp', $filename));
imagedestroy($im);

var_dump($webp);

$webp returns true but when I try to view the webp-image in Chrome it just shows blank, but with the correct size. If I instead load the image and set headers with PHP (see below) it shows up, but with wrong colors (too much yellow).

$im = imagecreatefromwebp('example.webp');
header('Content-Type: image/webp');
imagewebp($im);
imagedestroy($im);

If I convert the same image with command line it works as expected.

cwebp -q 100 example.jpg -o example.webp

I'm testing this on Ubuntu 14, Apache 2.4.7 and PHP 5.5.9-1ubuntu4.4.

Answer 1

I user this

function webpConvert2($file, $compression_quality = 80)
{
    // check if file exists
    if (!file_exists($file)) {
        return false;
    }
    $file_type = exif_imagetype($file);
    //https://www.php.net/manual/en/function.exif-imagetype.php
    //exif_imagetype($file);
    // 1    IMAGETYPE_GIF
    // 2    IMAGETYPE_JPEG
    // 3    IMAGETYPE_PNG
    // 6    IMAGETYPE_BMP
    // 15   IMAGETYPE_WBMP
    // 16   IMAGETYPE_XBM
    $output_file =  $file . '.webp';
    if (file_exists($output_file)) {
        return $output_file;
    }
    if (function_exists('imagewebp')) {
        switch ($file_type) {
            case '1': //IMAGETYPE_GIF
                $image = imagecreatefromgif($file);
                break;
            case '2': //IMAGETYPE_JPEG
                $image = imagecreatefromjpeg($file);
                break;
            case '3': //IMAGETYPE_PNG
                    $image = imagecreatefrompng($file);
                    imagepalettetotruecolor($image);
                    imagealphablending($image, true);
                    imagesavealpha($image, true);
                    break;
            case '6': // IMAGETYPE_BMP
                $image = imagecreatefrombmp($file);
                break;
            case '15': //IMAGETYPE_Webp
               return false;
                break;
            case '16': //IMAGETYPE_XBM
                $image = imagecreatefromxbm($file);
                break;
            default:
                return false;
        }
        // Save the image
        $result = imagewebp($image, $output_file, $compression_quality);
        if (false === $result) {
            return false;
        }
        // Free up memory
        imagedestroy($image);
        return $output_file;
    } elseif (class_exists('Imagick')) {
        $image = new Imagick();
        $image->readImage($file);
        if ($file_type === "3") {
            $image->setImageFormat('webp');
            $image->setImageCompressionQuality($compression_quality);
            $image->setOption('webp:lossless', 'true');
        }
        $image->writeImage($output_file);
        return $output_file;
    }
    return false;
}

Answer 2

It works:

$jpg=imagecreatefromjpeg('filename.jpg');
$w=imagesx($jpg);
$h=imagesy($jpg);
$webp=imagecreatetruecolor($w,$h);
imagecopy($webp,$jpg,0,0,0,0,$w,$h);
imagewebp($webp, 'filename.webp', 80);
imagedestroy($jpg);
imagedestroy($webp);

Answer 3

I had same problem, my solution is:

$file='hnbrnocz.jpg';
$image=  imagecreatefromjpeg($file);
ob_start();
imagejpeg($image,NULL,100);
$cont=  ob_get_contents();
ob_end_clean();
imagedestroy($image);
$content =  imagecreatefromstring($cont);
imagewebp($content,'images/hnbrnocz.webp');
imagedestroy($content);