Generating QR Code on a Background Image with Text Using PHP

This guide explains how to create a QR code, place it on a background picture, render custom text onto the same image, and finally output the merged result using PHP. It includes a full class implementation with methods for QR generation, text rendering, image compositing, and file saving.

Key steps:

Construct the base image from a JPEG source.

Generate a QR code image with configurable error correction level, size, and margin.

Overlay the QR code onto the base image at a specified position.

Render custom text with chosen font, size, and color, centered horizontally.

Save the final image as a JPEG file.

Below is the complete PHP class used in the tutorial:

class codeImg {
    private $date,$img,$main,$width,$height,$target,$white;

    public function constr($source) {
        $this->date   = '' . date('Ymd') . '/';
        $this->img    = $this->date . md5($source) . '.jpg';
        $this->main   = imagecreatefromjpeg($source);
        $this->width  = imagesx($this->main);
        $this->height = imagesy($this->main);
        $this->target = imagecreatetruecolor($this->width, $this->height);
        $this->white  = imagecolorallocate($this->target, 255, 255, 255);
        imagefill($this->target, 0, 0, $this->white);
        imagecopyresampled($this->target, $this->main, 0, 0, 0, 0, $this->width, $this->height, $this->width, $this->height);
    }

    /**
     * Generate QR code
     * @param string $website   URL to encode
     * @param string $filename  Output file name (optional)
     * @param string $level     Error correction level (L, M, Q, H)
     * @param int    $size      Module size (default 4)
     * @param int    $margin    Margin size (default 2)
     */
    public function qrencode($website, $filename = false, $level = "L", $size = 4, $margin = 2) {
        include "./phpqrcode/qrlib.php";
        QRcode::png($website, $filename, $level, $size, $margin);
    }

    /**
     * Add text to the image
     */
    public function generateFont($source, $text1, $textwidth, $textherght, $fontSize = 18, $cate1 = 255, $cate2 = 250, $cate3 = 250, $font = './font/fangsong_GB2312.ttf') {
        $this->constr($source);
        $fontColor = imagecolorallocate($this->target, $cate1, $cate2, $cate3);
        $fontBox   = imagettfbbox($fontSize, 0, $font, $text1);
        imagettftext($this->target, $fontSize, 0, $textwidth, $textherght, $fontColor, $font, $text1);
        $this->createImg();
        return $this->img;
    }

    /**
     * Merge QR code onto background image
     */
    public function generateImg($source, $codeurl, $sourcewidth, $sourceheight, $codewidth = 100, $codeheight = 100) {
        $this->constr($source);
        $child1 = imagecreatefrompng($codeurl);
        $codewidth  = $codewidth  > 0 ? $codewidth  : imagesx($child1);
        $codeheight = $codeheight > 0 ? $codeheight : imagesy($child1);
        imagecopyresampled($this->target, $child1, $sourcewidth, $sourceheight, 0, 0, $codewidth, $codeheight, imagesx($child1), imagesy($child1));
        imagedestroy($child1);
        $this->createImg();
        return $this->img;
    }

    private function createImg() {
        @mkdir('./' . $this->date);
        imagejpeg($this->target, './' . $this->img, 95);
        imagedestroy($this->main);
        imagedestroy($this->target);
    }
}

// Example usage
$source   = "./img/1000.jpg";
$codeImg  = new codeImg($source);
$website  = "http://www.baidu.com";
$codeurl  = "./temp/code.png";
$codeImg->qrencode($website, $codeurl);
$text         = "开始了开始了hahhah呵呵";
$textwidth    = 100;
$textherght   = 50;
$generateFont = $codeImg->generateFont($source, $text, $textwidth, $textherght);
$sourcewidth  = 200;
$sourceheight = 150;
$generateImg  = $codeImg->generateImg($generateFont, $codeurl, $sourcewidth, $sourceheight);
echo "<img src='" . $generateImg . "'>";

The example demonstrates initializing the class with a background image, creating a QR code for a URL, adding a text label, positioning the QR code on the background, and finally outputting the composed image in an HTML <img> tag.