Image Management.Watermarks

    function getImageWithWatermark($imagePath, $watermarkPath) {
      list($sourceWidth, $sourceHeight) = getimagesize($imagePath);
      
      $resultImage = imagecreatetruecolor($sourceWidth, $sourceHeight);
      imagesavealpha($resultImage, true);
      $background = imagecolorallocatealpha($resultImage, 0, 0, 0, 127);
      imagefill($resultImage, 0, 0, $background);
    
      $sourceImage = imagecreatefrompng($imagePath);  
      imagecopy($resultImage, $sourceImage, 0, 0, 0, 0, $sourceWidth, $sourceHeight);
      
      $watermarkImage = imagecreatefrompng($watermarkPath);
      imagecopy($resultImage, $watermarkImage, 0, 0, 0, 0, imagesx($watermarkImage), imagesy($watermarkImage));
    
      ob_start();
      imagepng($resultImage);
      $imageData = ob_get_contents();
      ob_end_clean();
      
      return $imageData;
    }

        protected function doCustomRenderColumn($fieldName, $fieldData, $rowData, &$customText, &$handled)
        { 
            if ($fieldName == 'photo_large' && !empty($fieldData)) {
              $imagePath = sprintf('external_data/images/phone/iphone_large/%s', $fieldData);
              if (FileUtils::FileExists($imagePath)) {
                $watermarkPath = 'external_data/images/watermark.png';
                $imageData = base64_encode(getImageWithWatermark($imagePath, $watermarkPath));
                $src = 'data:image/png;base64,'.$imageData;
                $customText = str_replace($imagePath, $src, $customText);
                $handled = true;
              }
            }
        }