Convert images to webp files under 250kB

convertToWebP.php

<?php

//Convert PNG and JPEG images to WebP
function convertToWebp($source, $destination, $quality = 80) {
    $startTime = microtime(true);
    $info = getimagesize($source);
    if ($info['mime'] == 'image/jpeg' || $info['mime'] == 'image/jpg' || $info['mime'] == 'image/jfif') {
        echo "Original image is jpeg<br>";
        // Load the JPEG file
        $image = imagecreatefromjpeg($source);
        // Read the EXIF data to get the orientation
        $exif = exif_read_data($source);
        if (!empty($exif['Orientation'])) {
            switch ($exif['Orientation']) {
                case 3:
                    echo "Rotate 180 degrees<br>";
                    $image = imagerotate($image, 180, 0);
                    break;
                case 6:
                    echo "Rotate -90 degrees<br>";
                    $image = imagerotate($image, -90, 0);
                    break;
                case 8:
                    echo "Rotate 90 degrees<br>";
                    $image = imagerotate($image, 90, 0);
                    break;
            }
        }
    } elseif ($info['mime'] == 'image/png') {
        echo "Original image is png<br>";
        $image = imagecreatefrompng($source);
        if ($image) {
            // Preserve transparency
            imagepalettetotruecolor($image);
            imagealphablending($image, true);
            imagesavealpha($image, true);
        } else {
            echo "Corrupt file, not converting to webp.<br>";
            return false;
        }
    } else if ($info['mime'] == 'image/webp') {
        echo "Original image is webp<br>";
        $image = imagecreatefromwebp($source);
    } else {
        echo "Unsupported file type " . $info['mime'] . "<br>";
        return false;
    }

    // Convert to WebP
    $result = imagewebp($image, $destination, $quality);

    // Free up memory
    imagedestroy($image);

    $endTime = microtime(true);
    $duration = $endTime - $startTime;
    echo __FUNCTION__ . " took " . round($duration, 3) . " seconds to execute.<br>";

    return $result;
}

function resizeWebP($sourceFile, $destinationFile, $targetWidth, $targetHeight) {
    $startTime = microtime(true);
    // Create an image resource from the source WebP file
    $sourceImage = imagecreatefromwebp($sourceFile);
    if (!$sourceImage) {
        die('Failed to load source image');
    }

    // Get the dimensions of the source image
    list($sourceWidth, $sourceHeight) = getimagesize($sourceFile);

    // Create a new image resource with the target dimensions
    $targetImage = imagecreatetruecolor($targetWidth, $targetHeight);

    // Preserve transparency in case the source image has it
    imagecolortransparent($targetImage, imagecolorallocatealpha($targetImage, 0, 0, 0, 127));
    imagealphablending($targetImage, false);
    imagesavealpha($targetImage, true);

    // Copy and resize the source image to the target image
    imagecopyresampled(
        $targetImage,    // Destination image
        $sourceImage,    // Source image
        0, 0, // Destination x, y
        0, 0, // Source x, y
        $targetWidth,    // Destination width
        $targetHeight,   // Destination height
        $sourceWidth,    // Source width
        $sourceHeight    // Source height
    );

    // Save the resized image to the destination file
    imagewebp($targetImage, $destinationFile);

    // Free up memory
    imagedestroy($sourceImage);
    imagedestroy($targetImage);

    $endTime = microtime(true);
    $duration = $endTime - $startTime;
    echo __FUNCTION__ . " took " . round($duration, 3) . " seconds to execute.<br>";

    return filesize($destinationFile);
}

$scriptStartTime = microtime(true);
//$directoryPath = 'c:/xampp/htdocs/image/product/';
$directoryPath = 'c:/xampp_8_2_12/htdocs/image/product/';
$filesAndFolders = glob($directoryPath . '*'); // some files don't have extension
// Check if any images were found.
$nFiles = 0;
if ($filesAndFolders !== false) {
    echo "Found " . count($filesAndFolders) . " files and folders<br>";
    $maxSizeReduction = 1;
    $maxReducedFile = "";
    foreach ($filesAndFolders as $i => $source) {
        if (is_file($source)) { // exclude directories
            $nFiles++;
            echo "<br>" . $nFiles . ". " . $source . "<br>";
            $filePath = pathinfo($source, PATHINFO_DIRNAME);
            $filenameWithoutExt = pathinfo($source, PATHINFO_FILENAME);
            $destinationWebP = $filePath . '/webp/' . $filenameWithoutExt . '.webp';
            if (convertToWebp($source, $destinationWebP, 80)) {
                $fileSizeOriginal = filesize($source);
                $fileSizeWebP = filesize($destinationWebP);
                $sizeReductionFromWebPConversion = $fileSizeOriginal / $fileSizeWebP;
                echo "fileSizeOriginal: " . $fileSizeOriginal . " bytes, fileSizeWebP: " . $fileSizeWebP . " bytes (" . round($sizeReductionFromWebPConversion, 1) . "x reduction)<br>";
                $maxSizeBytes = 250 * 1024; //250kB
                $sizeReductionFromWidthHeightChange = 1;
                if ($fileSizeWebP > $maxSizeBytes) {
                    $imageInfo = getimagesize($destinationWebP);
                    if ($imageInfo !== false) {
                        $width = $imageInfo[0];
                        $height = $imageInfo[1];
                        $reductionFactor = sqrt($maxSizeBytes / $fileSizeWebP); // Width and height reduction to get desired file size is an approximation because the actual size after reduction also depends on the image content, compression efficiency, and specific format characteristics
                        $reducedWidth = (int)round($reductionFactor * $width);
                        $reducedHeight = (int)round($reductionFactor * $height);
                        echo "width: " . $width . ", height: " . $height . ", reductionFactor: " . round($reductionFactor, 3) . ", reducedWidth: " . $reducedWidth .
                            ", reducedHeight: " . $reducedHeight . "<br>";
                        clearstatcache(true, $destinationWebP); // To get up-to-date file size of $destinationWebP after resizeWebP
                        $reducedSize = resizeWebP($destinationWebP, $destinationWebP, $reducedWidth, $reducedHeight);
                        if ($reducedSize) {
                            $sizeReductionFromWidthHeightChange = $fileSizeWebP / $reducedSize;
                            echo 'Image resized successfully to ' . $reducedSize . ' bytes (' . round($sizeReductionFromWidthHeightChange, 1) . 'x resize reduction, ' .
                                round($fileSizeOriginal / $reducedSize, 1) . 'x total reduction)<br>';
                        } else {
                            echo 'Failed to resize image.<br>';
                        }
                    } else {
                        echo "Failed to get image dimensions.<br>";
                    }
                }
                $totalSizeReduction = $sizeReductionFromWebPConversion * $sizeReductionFromWidthHeightChange;
                if ($totalSizeReduction > $maxSizeReduction) {
                    $maxSizeReduction = $totalSizeReduction;
                    $maxReducedFile = $source;
                }
            }
        }
    }
    echo "<br><b>maxSizeReduction: " . round($maxSizeReduction, 1) . ", maxReducedFile: " . $maxReducedFile . "</b><br>";
} else {
    echo "No files found in " . $directoryPath . "<br>";
}

$scriptEndTime = microtime(true);
$scriptDuration = $scriptEndTime - $scriptStartTime;
echo "For " . $nFiles . " files, it took " . round($scriptDuration / 60, 3) . " minutes.<br>";