Simple PlaceHolder API using Laravel and Intervention

PlaceHolderController.php

<?php

namespace App\Http\Controllers;

use Illuminate\Http\Request;

use App\Http\Requests;
use Intervention\Image\ImageManager;

class PlaceHolderController extends Controller
{
  public function serve($width,$height,$background_color = "#000",$text=NULL){
    if($width <= 0){
      return redirect()->action("ImageController@not_found");
    }

    if($height <= 0){
      return redirect()->action("ImageController@not_found");
    }

    $manager = new ImageManager();
    $img = $manager->canvas($width, $height, $background_color);

    if($text === NULL){
      $text = sprintf("%sx%s",$width,$height);
    }

    $font_size = 32;

    if($width <= 150 && $height <= 100){
      $font_size = 16;
    }

    if($width >= 60 && $height >= 30){

      $img->text($text, $width/2, $height/2, function($font) use($font_size) {
          $font->size($font_size);
          $font->color(array(255, 255, 255));
          $font->file(base_path('resources/assets/fonts/wt014.ttf'));
          $font->align('center');
          $font->valign('middle');
      });
    }


    return $img->response('jpg');
  }
}