PHP GD Library Generate verification code

1. Introduction of GD Library, in the php.ini bar Extension=php_gd2.dll in front; Print_r (Gd_info ()); Print out the relevant information.

Learn GD library weight in understanding, 1. Process of Drawing 2, computer coordinate system GD library drawing typical flow 1. Create Canvas imagecreatetruecolor ();  You can also open a picture of a painting cloth imagecreatefromjpeg ($path); 2. Create Pigment imagecolorcate (); 3. Paint the Ink to render Imagefill (); Draw a straight line Imageline () 4. Keep Imagepng () imagejpeg () imagegif (); 5. Destroy the canvas and release the Resource Imagedestroy ($IMG);

PHP GD Library Generate verification code