檢查 GD 並產生縮圖的函式

這是經常使用的GD縮圖函式

//檢查 GD

function checkGD(){

    $error = false;

    $gd = array();   

    if (!extension_loaded('gd')) {

        if (strtoupper(substr(PHP_OS, 0, 3)) == 'WIN') {

            if (!dl('php_gd.dll')) {

                $error = true;

            }

        } else {

            if (!dl('gd.so')) {

                $error = true;

            }

        }

    }

    if ($error) {

        return false;

    } else {

        $gdInfo                   = gd_info();

        $gd['version']           = stristr($gdInfo['GD Version'], '2.') ? 2 : 1;

        $gd['formats']['gif'] = $gdInfo['GIF Read Support'];

        $gd['formats']['jpg'] = $gdInfo['JPEG Support']; //小心，不是 JPG Support

        $gd['formats']['png'] = $gdInfo['PNG Support'];       

        return $gd;

    }   

}

// 製作縮圖 createImage(來源檔名路徑, 格式, 縮圖檔名路徑, 縮圖寬, 縮圖高)

function createImage($file, $format, $fileDest, $outputX, $outputY){

    // Get information about the installed GD.

    $gdInfo    = checkGD();

    $gdVersion = $gdInfo['version'];   

    if ($gdInfo == false) {

        return false;

    }   

    // Ensure the given format is supported.

    if ($gdInfo['formats'][$format] != 1) {

        return false;

    }   

    // Get the image dimensions.

    $dimensions = @getimagesize($file);

    $width        = $dimensions[0];

    $height        = $dimensions[1];   

    // thumbs mode.   

    $quality  = 85;       

    $deltaX   = 0;

    $deltaY   = 0;

    $portionX = $width;

    $portionY = $height;

    // Get the source image in gif format.

    if ($format == 'gif') {

        $imageSrc  = @imagecreatefromgif($file);

    }   

    // Get the source image in jpg format.

    if ($format == 'jpg') {

        $imageSrc  = @imagecreatefromjpeg($file);

    }   

    // Get the source image in png format.

    if ($format == 'png') {

        $imageSrc  = @imagecreatefrompng($file);

    }

    // The thumbnail creation with GD1.x functions does the job.

    if ($gdVersion == 1) {       

        // Create an empty thumbnail image.

        $imageDest = @imagecreate($outputX, $outputY);       

        // Try to create the thumbnail from the source image.

        if (@imagecopyresized($imageDest, $imageSrc, 0, 0, $deltaX, $deltaY, $outputX, $outputY, $portionX, $portionY)) {           

            // save the thumbnail image into a file.

            @imagejpeg($imageDest, $fileDest, $quality);           

            // Delete both image resources.

            @imagedestroy($imageSrc);

            @imagedestroy($imageDest);           

            return true;           

        }       

    }   

    // The recommended approach is the usage of the GD2.x functions.

    if ($gdVersion == 2) {       

        // Create an empty thumbnail image.

        $imageDest = @imagecreatetruecolor($outputX, $outputY);       

        // Try to create the thumbnail from the source image.

        if (@imagecopyresampled($imageDest, $imageSrc, 0, 0, $deltaX, $deltaY, $outputX, $outputY, $portionX, $portionY)) {           

            // save the thumbnail image into a file.

            @imagejpeg($imageDest, $fileDest, $quality);

            // Delete both image resources.

            @imagedestroy($imageSrc);

            @imagedestroy($imageDest);           

            return true;           

        }       

    }

    return false;

}