[PHP] reCaptcha Image Merging

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      [PHP] reCaptcha Image Merging

      Mit ein bisschen Raffinesse lassen sich die reCaptcha Bilder in eigene Bilder hineinkopieren - ohne den weißen Hintergrund.

      Benötigt wird ein Webserver mit PHP und aktiver GD Erweiterung (Ist zu 99% immer aktiviert)

      so könnte es zb aussehen:

      Folgenden Code kopieren, die 2 Funktionen ggf in andere Dateien auslagern, Keys eintragen und Rest ebenfalls nach Wunsch anpassen

      PHP-Quellcode

      1. <?php
      3. ///////////////////////////////////////
      5. // additional recaptcha functions
      7. function recaptcha_load_challange($publicKey)
      8. {
      9. $recaptchaStateJS = @file_get_contents("http://www.google.com/recaptcha/api/challenge?k=$publicKey");
      10. if (!$recaptchaStateJS) die("recaptcha_load_challange: cannot load file");
      11. if (!preg_match("/challenge\s*?\:\s*?\'([^\']+)\'/", $recaptchaStateJS, $recaptchaChallange)) die("recaptcha_load_challange: cannot find field");
      12. return $recaptchaChallange[1];
      13. }
      15. function recaptcha_merge_images($challange, $targetImage, $targetStartX, $targetStartY)
      16. {
      18. if (!is_string($challange)) die("recaptcha_merge_images: challange is no string");
      19. if (!is_resource($targetImage)) die("recaptcha_merge_images: targetImage is no resource");
      20. if (!is_numeric($targetStartX)) die("recaptcha_merge_images: targetStartX is no number");
      21. if (!is_numeric($targetStartY)) die("recaptcha_merge_images: targetStartY is no number");
      23. $targetStartX = (int)round($targetStartX);
      24. $targetStartY = (int)round($targetStartY);
      26. $recaptchaImage = @file_get_contents("http://www.google.com/recaptcha/api/image?c=$challange");
      27. if (!$recaptchaImage) die("recaptcha_merge_images: cannot load image");
      29. $recaptchaImage = imagecreatefromstring($recaptchaImage);
      30. if (!$recaptchaImage) die("recaptcha_merge_images: cannot read image");
      32. $recaptchaWidth = imagesx($recaptchaImage);
      33. $recaptchaHeight = imagesy($recaptchaImage);
      35. $targetWidth = imagesx($targetImage);
      36. $targetHeight = imagesy($targetImage);
      37. $targetWidth = ($recaptchaWidth+$targetStartX >= $targetWidth) ? $targetWidth-$targetStartX : $recaptchaWidth;
      38. $targetHeight = ($recaptchaHeight+$targetStartY >= $targetHeight) ? $targetHeight-$targetStartY : $recaptchaHeight;
      40. $recaptchaStartX = ($targetStartX < 0) ? $targetStartX*-1 : 0;
      41. $recaptchaStartY = ($targetStartY < 0) ? $targetStartY*-1 : 0;
      43. if ($targetWidth <= 0 || $targetHeight <= 0) die("err 5");
      45. function rgba2int($r, $g, $b, $a=0)
      46. {
      47. return ($a << 24) + ($r << 16) + ($g << 8) + $b;
      48. }
      50. function int2rgba($int)
      51. {
      52. return array(
      53. 3 => ($int >> 24) & 0xFF,
      54. 0 => ($int >> 16) & 0xFF,
      55. 1 => ($int >> 8) & 0xFF,
      56. 2 => $int & 0xFF
      57. );
      58. $a = ($int >> 24) & 0xFF;
      59. $r = ($int >> 16) & 0xFF;
      60. $g = ($int >> 8) & 0xFF;
      61. $b = $int & 0xFF;
      62. return array($r, $g, $b, $a);
      63. }
      65. function distance($r, $g, $b)
      66. {
      67. return sqrt($r*$r + $g*$g + $b*$b);
      68. }
      70. $maxDistance = 441.6729559300637098;
      71. for ($x=$recaptchaStartX; $x<$targetWidth; $x++)
      72. for ($y=$recaptchaStartY; $y<$targetHeight; $y++)
      73. {
      74. $targetColor = int2rgba(imagecolorat($targetImage, $x+$targetStartX, $y+$targetStartY));
      75. $recaptchaColor = int2rgba(imagecolorat($recaptchaImage, $x, $y));
      76. $percent = 1 / $maxDistance * distance($recaptchaColor[0], $recaptchaColor[1], $recaptchaColor[2]);
      77. imagesetpixel(
      78. $targetImage,
      79. $x+$targetStartX,
      80. $y+$targetStartY,
      81. rgba2int(
      82. round(min(255, $recaptchaColor[0]*(1-$percent) + $targetColor[0]*$percent)),
      83. round(min(255, $recaptchaColor[1]*(1-$percent) + $targetColor[1]*$percent)),
      84. round(min(255, $recaptchaColor[2]*(1-$percent) + $targetColor[2]*$percent))
      85. )
      86. );
      87. }
      88. imagedestroy($recaptchaImage);
      89. return $targetImage;
      90. }
      92. ///////////////////////////////////////
      94. $recaptchaPublic = "oOoOo0o0ooOoooO0OoOOoOO0OO0o0oO0O0Ooo";
      95. $recaptchaPrivate = "li1II1II1IlIII1iIililli1i11ilIi1";
      97. if (isset($_GET["go"]))
      98. switch($_GET["go"])
      99. {
      101. case "image":
      103. if (!isset($_GET["challange"])) die("...");
      105. $image = recaptcha_merge_images(
      106. $_GET["challange"],
      107. imagecreatefrompng("preview.png"),
      108. 50, // start x
      109. 50 // start y
      110. );
      112. // keep alpha
      113. imagealphablending($image, true);
      114. imagesavealpha($image, true);
      116. // output
      117. header('Content-Type: image/png');
      118. imagepng($image);
      119. imagedestroy($image);
      121. // and exit
      122. exit();
      124. break;
      126. case "verify":
      128. if (!isset($_POST["challange"])) die("...");
      129. if (!isset($_POST["answer"])) die("...");
      131. require_once('recaptchalib.php');
      132. $resp = recaptcha_check_answer(
      133. $recaptchaPrivate,
      134. $_SERVER["REMOTE_ADDR"],
      135. $_POST["challange"],
      136. $_POST["answer"]
      137. );
      139. if (!$resp->is_valid) {
      140. die ("The reCAPTCHA wasn't entered correctly. Go back and try it again." .
      141. "(reCAPTCHA said: " . $resp->error . ")");
      142. } else {
      143. echo "answer was correct";
      144. // Your code here to handle a successful verification
      145. }
      147. exit();
      148. break;
      150. }
      152. $challange = recaptcha_load_challange($recaptchaPublic);
      154. ?>
      156. <html>
      157. <body>
      158. <form method="post" action="?go=verify">
      159. <img src="?go=image&challange=<?php echo $challange; ?>">
      160. <input type="hidden" name="challange" value="<?php echo $challange; ?>" />
      161. <input type="text" name="answer" />
      162. <input type="submit" />
      163. </form>
      164. </body>
      165. </html>


      Weiß nich unter welchen Bedingungen ich dies veröffentlichen darf, daher gibs das ma als Example-SourceCode und nich in meiner WebLib =)

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