imagegd

(PHP 4 >= 4.0.7, PHP 5)

imagegd — Output GD image to browser or file

Description

bool imagegd ( resource $image [, string $filename ] )

Outputs a GD image to the given filename.

Parameters

image: An image resource, returned by one of the image creation functions, such as imagecreatetruecolor().
filename: The path to save the file to. If not set or NULL, the raw image stream will be outputted directly.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example #1 Outputting a GD image


<?php
// Create a blank image and add some text
$im = imagecreatetruecolor(120, 20);
$text_color = imagecolorallocate($im, 233, 14, 91);
imagestring($im, 1, 5, 5,  "A Simple Text String", $text_color);

// Output the image
imagegd($im);

// Free up memory
imagedestroy($im);
?>

Example #2 Saving a GD image


<?php
// Create a blank image and add some text
$im = imagecreatetruecolor(120, 20);
$text_color = imagecolorallocate($im, 233, 14, 91);
imagestring($im, 1, 5, 5,  "A Simple Text String", $text_color);

// Save the gd image
// The file format for GD images is .gd, see http://www.libgd.org/GdFileFormats
imagegd($im, 'simple.gd');

// Free up memory
imagedestroy($im);
?>

Notes

Note:
The GD format is commonly used to allow fast loading of parts of images. Note that the GD format is only usable in GD-compatible applications.


<?php



/*

* Captcha image for security 

*/



session_start();



class CaptchaSecurityImages {

 

   var $font = 'monofont.ttf';

 

   function generateCode($characters) {

      /* list all possible characters, similar looking characters and vowels have been removed */

      $possible = '23456789bcdfghjkmnpqrstvwxyz';

      $code = '';

      $i = 0;

      while ($i < $characters) { 

         $code .= substr($possible, mt_rand(0, strlen($possible)-1), 1);

         $i++;

      }

      return $code;

   }

 

   function CaptchaSecurityImages($width='120',$height='40',$characters='6') {

      $code = $this->generateCode($characters);

      /* font size will be 75% of the image height */

      $font_size = $height * 0.75;

      $image = imagecreate($width, $height) or die('Cannot initialize new GD image stream');

      /* set the colours */

      $background_color = imagecolorallocate($image, 255, 255, 255);

      $text_color = imagecolorallocate($image, 20, 40, 100);

      $noise_color = imagecolorallocate($image, 100, 120, 180);

      /* generate random dots in background */

      for( $i=0; $i<($width*$height)/3; $i++ ) {

         imagefilledellipse($image, mt_rand(0,$width), mt_rand(0,$height), 1, 1, $noise_color);

      }

      /* generate random lines in background */

      for( $i=0; $i<($width*$height)/150; $i++ ) {

         imageline($image, mt_rand(0,$width), mt_rand(0,$height), mt_rand(0,$width), mt_rand(0,$height), $noise_color);

      }

      /* create textbox and add text */

      $textbox = imagettfbbox($font_size, 0, $this->font, $code) or die('Error in imagettfbbox function');

      $x = ($width - $textbox[4])/2;

      $y = ($height - $textbox[5])/2;

      imagettftext($image, $font_size, 0, $x, $y, $text_color, $this->font , $code) or die('Error in imagettftext function');

      /* output captcha image to browser */

      header('Content-Type: image/jpeg');

      imagejpeg($image);

      imagedestroy($image);

      $_SESSION['security_code'] = $code;

   }

 

}

 

$width = isset($_GET['width']) && $_GET['width'] < 600 ? $_GET['width'] : '120';

$height = isset($_GET['height']) && $_GET['height'] < 200 ? $_GET['height'] : '40';

$characters = isset($_GET['characters']) && $_GET['characters'] > 2 ? $_GET['characters'] : '6';

 

$captcha = new CaptchaSecurityImages($width,$height,$characters);

 

?>

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