imagettftext不适合我

I have a function that takes for images and combines them into a single wide image. That seems to work. Now I am trying to put some text on the images and that is not.

The five lines after: // Allocate A Color For The Text, are the ones i added to create the text. Is there something I'm missing? I don't see any errors when I run the code.

 function merge($filename_w, $filename_x, $filename_y, $filename_z,$filename_result, $text) {
  // Get dimensions for specified images
 list($width_w, $height_w) = getimagesize($filename_w);
 list($width_x, $height_x) = getimagesize($filename_x);
 list($width_y, $height_y) = getimagesize($filename_y);
 list($width_z, $height_z) = getimagesize($filename_z);
 // Create new image with desired dimensions
 $image = imagecreatetruecolor($width_w + $width_x + $width_y + $width_z, $height_x);
 // Load images and then copy to destination image
$image_w = imagecreatefromjpeg($filename_w);
 $image_x = imagecreatefromjpeg($filename_x);
 $image_y = imagecreatefromjpeg($filename_y);
$image_z = imagecreatefromjpeg($filename_z);
 imagecopy($image, $image_w, 0, 0, 0, 0, $width_w, $height_w);
 imagecopy($image, $image_x, $width_w, 0, 0, 0, $width_x, $height_x);
 imagecopy($image, $image_y, $width_w + $width_x, 0, 0, 0, $width_y, $height_y);
 imagecopy($image, $image_z, $width_w + $width_x + $width_y, 0, 0, 0, $width_z, $height_z);
      // Allocate A Color For The Text
      $white = imagecolorallocate($image, 255, 255, 255);
      // Set Path to Font File
      $font_path = './tahoma.ttf';
      // Print Text On Image
      imagettftext($image, 25, 0, 75, 300, $white, $font_path, "Test text");
 // Save the resulting image to disk (as JPEG)
 imagejpeg($image, $filename_result);
 // Clean up
 imagedestroy($image);
 imagedestroy($image_w);
 imagedestroy($image_x);
 imagedestroy($image_y);
 imagedestroy($image_z);
}