title: How to display a JSON/base64 encoded image in FPDF?
body: <p>I'm storing signatures (using <a href="http://thomasjbradley.ca/lab/signature-to-image/" rel="nofollow">signaturepad</a> in my database <code>Coldfusion/MySQL 5.0.88</code> and would like to output the signature I'm taking onto a pdf which I'm generating with <code>fpdf</code>. However I can*t get it to work...</p>
  
  <p>Signatures are stored like this:</p>
  
  <pre><code>[{"lx":19,"ly":58,"mx":19,"my":57},{"lx":23,"ly":54,"mx":19,"my":58},{"lx":26,"ly":53,"mx":23,"my":54},{"lx":32,"ly":51,"mx":26,"my":53},{"lx":38,"ly":47,"mx":32,"my":51},{"lx":44,"ly":44,"mx":38,"my":47},{"lx":51,"ly":41,"mx":44,"my":44},{"lx":58,"ly":37,"mx":51,"my":41},{"lx":64,"ly":35,"mx":58,"my":37},{"lx":67,"ly":31,"mx":64,"my":35},{"lx":70,"ly":30,"mx":67,"my":31},{"lx":72,"ly":28,"mx":70,"my":30},{"lx":71,"ly":28,"mx":72,"my":28},{"lx":69,"ly":28,"mx":71,"my":28},{"lx":66,"ly":28,"mx":69,"my":28},{"lx":62,"ly":29,"mx":66,"my":28},{"lx":59,"ly":31,"mx":62,"my":29},{"lx":55,"ly":32,"mx":59,"my":31},{"lx":52,"ly":33,"mx":55,"my":32},{"lx":48,"ly":35,"mx":52,"my":33},{"lx":44,"ly":37,"mx":48,"my":35},{"lx":41,"ly":38,"mx":44,"my":37},{"lx":39,"ly":40,"mx":41,"my":38},{"lx":36,"ly":40,"mx":39,"my":40},{"lx":33,"ly":42,"mx":36,"my":40},{"lx":32,"ly":43,"mx":33,"my":42},{"lx":31,"ly":44,"mx":32,"my":43},{"lx":31,"ly":46,"mx":31,"my":44},{"lx":32,"ly":48,"mx":31,"my":46},{"lx":136,"ly":23,"mx":32,"my":48},{"lx":132,"ly":24,"mx":136,"my":23},{"lx":104,"ly":38,"mx":132,"my":24},{"lx":103,"ly":40,"mx":104,"my":38},{"lx":102,"ly":41,"mx":103,"my":40},{"lx":102,"ly":42,"mx":102,"my":41},{"lx":103,"ly":42,"mx":102,"my":42},{"lx":108,"ly":42,"mx":103,"my":42},{"lx":115,"ly":42,"mx":108,"my":42},{"lx":123,"ly":39,"mx":115,"my":42},{"lx":133,"ly":36,"mx":123,"my":39},{"lx":141,"ly":34,"mx":133,"my":36},{"lx":148,"ly":32,"mx":141,"my":34},{"lx":155,"ly":30,"mx":148,"my":32},{"lx":159,"ly":29,"mx":155,"my":30},{"lx":161,"ly":28,"mx":159,"my":29},{"lx":159,"ly":27,"mx":161,"my":28},{"lx":155,"ly":27,"mx":159,"my":27},{"lx":151,"ly":27,"mx":155,"my":27},{"lx":145,"ly":27,"mx":151,"my":27},{"lx":140,"ly":29,"mx":145,"my":27},{"lx":135,"ly":31,"mx":140,"my":29},{"lx":132,"ly":33,"mx":135,"my":31},{"lx":127,"ly":36,"mx":132,"my":33},{"lx":125,"ly":38,"mx":127,"my":36},{"lx":125,"ly":40,"mx":125,"my":38},{"lx":125,"ly":41,"mx":125,"my":40},{"lx":125,"ly":42,"mx":125,"my":41},{"lx":127,"ly":43,"mx":125,"my":42},{"lx":131,"ly":44,"mx":127,"my":43},{"lx":139,"ly":45,"mx":131,"my":44},{"lx":147,"ly":45,"mx":139,"my":45},{"lx":157,"ly":43,"mx":147,"my":45},{"lx":164,"ly":41,"mx":157,"my":43},{"lx":173,"ly":39,"mx":164,"my":41},{"lx":181,"ly":36,"mx":173,"my":39},{"lx":186,"ly":34,"mx":181,"my":36},{"lx":191,"ly":33,"mx":186,"my":34},{"lx":193,"ly":30,"mx":191,"my":33},{"lx":194,"ly":29,"mx":193,"my":30},{"lx":194,"ly":28,"mx":194,"my":29},{"lx":193,"ly":27,"mx":194,"my":28},{"lx":191,"ly":26,"mx":193,"my":27},{"lx":188,"ly":25,"mx":191,"my":26},{"lx":183,"ly":25,"mx":188,"my":25},{"lx":180,"ly":25,"mx":183,"my":25},{"lx":177,"ly":25,"mx":180,"my":25},{"lx":174,"ly":27,"mx":177,"my":25},{"lx":171,"ly":30,"mx":174,"my":27},{"lx":169,"ly":32,"mx":171,"my":30},{"lx":168,"ly":34,"mx":169,"my":32},{"lx":167,"ly":36,"mx":168,"my":34},{"lx":167,"ly":38,"mx":167,"my":36},{"lx":168,"ly":40,"mx":167,"my":38},{"lx":169,"ly":41,"mx":168,"my":40},{"lx":171,"ly":41,"mx":169,"my":41},{"lx":174,"ly":41,"mx":171,"my":41},{"lx":176,"ly":41,"mx":174,"my":41},{"lx":176,"ly":40,"mx":176,"my":41},{"lx":177,"ly":39,"mx":176,"my":40},{"lx":177,"ly":37,"mx":177,"my":39}]
  </code></pre>
  
  <p>There is a custom function included in siganturepad (<a href="http://thomasjbradley.ca/lab/signature-to-image/" rel="nofollow">signature to image</a>) to convert the above back into an image. Like so:</p>
  
  <pre><code>&lt;?php
  require_once '../../signature-to-image.php';
  $img = sigJsonToImage(file_get_contents('sig-output.json'));
  
  // Output to browser
  header('Content-Type: image/png');
  imagepng($img);
  
  imagedestroy($img);
  &gt;
  </code></pre>
  
  <p>But if I try this on my fpdf page, the whole page breaks ( I guess because I want to embed the image in a cell not output only the image to the browser) and I get this:</p>
  
  <p>Resource id #10‰PNG  IHDRÆ7Ø7¢¶±IDATxœí›iP[×Ç/’a6±£'ŒÀk0›ëÝ†6)NÒÆ‰Ý¸µM2î´nf:“d2gq“Æušq–Ió! ŽSâÄNJgRÛñ ’@1KOFf±õ´ ÀfÖÖ/}y‘Ä`çþ>x¬û®Gºÿ{Î=ç…¹.Pm¡ €Ük@IA(J B1PRŠ’‚P”„b ¤ %¡()Å@IA(J B1PRŠ’‚P”„b ¤ %¡()Å@IA(J B1PRŠ’‚Pc¡ €üÀðèT³Æ Pa­×L'^z02œ¾Ð”Ô£·Œ+ÔX‹S¨0íÍb¼«wpåòô4,h ¤vK†ê¿Õe¨þÆà1Á óÓ¥bŽTÌÉËN™ÃL#u ªƒÇ•¾§­Y‘±27½ZÂg%{^ ƒ? œNÚoQ¨°A†ê‡F­nâ–Dìyà¾=÷ß¹ >¿¤ýËáÆ[Óþ¿¥€—ºwKá/Ëy4Z1%*lvG{¹YmÀãÚØ”mÆiþ‹i|êN}c÷7­}ß´öûiÃoÖ×dº-¹'“VÛSïž?)ïTKxÏ?.‰aFø˜ßÞcúJ¡;¥¼>:y°±ˆ{è÷kÙ‰1øÕ»XR£“wZÔ˜Å”ZÃ·Z£ÛUuíîäø¨y6iÒjSjJ­A†êÛºMV›ƒ¸ÄCX"Äîp6u}ìüS‡Î\× ªoìž°Î¬Kß¼³wÃ£k>lÞvàk9Š±¢#_ß³vKEŽŸ·¶9ŽžS½Qßj™xò+^Ýý3|ü®””idâí/ÛjOw:œ^fkÉ³[KçÁ˜‘qk‹ÚÐ¬6ÈP}WŸÅîpâãaa@ÌM–ˆ2[*æho¿ö™RŽbÀo1án©®AõÝõA|„‡...</p>
  
  <p>If I'm doing this:</p>
  
  <pre><code>if( strlen($unterschrift) &gt; 0){
      $img = sigJsonToImage( $unterschrift );
  };
  </code></pre>
  
  <p>and try to output:</p>
  
  <pre><code>if ( $imgProceed == "true" ){
      $pdf-&gt;imagepng($img);
  } else {
      $pdf-&gt;Cell(50,4,'',0,1);
  }
  </code></pre>
  
  <p>all I'm getting is:</p>
  
  <pre><code>`Call to undefined method PDF::imagepng() `/ `strpos() expects parameter 1 to be string, resource` 
  </code></pre>
  
  <p>Can someone explain to me, what I'm doing wrong or what I need to do to include the image in a cell in fpdf? I'm clueless. </p>
  
  <p>Thanks!</p>