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PHP ICO to PNG conversion

A few posts ago I wrote about using a PHP class to convert an ICO image to a PNG (or GIF or JPG). I just discovered a bug in the class.

I ran into a problem where some red and orange ICO images turned blue during the conversion. Reading this forum post made me realize that the red and blue values were switched somewhere in class.ico.php. With some experimentation I found it:

In class.ico.php, lines 264-267 need to be changed from

$c[$i] = $this->AllocateColor($im, $this->formats[$index]['colors'][$i]['red'],
         $this->formats[$index]['colors'][$i]['green'],
         $this->formats[$index]['colors'][$i]['blue'],
         round($this->formats[$index]['colors'][$i]['reserved'] / 255 * 127));

to

$c[$i] = $this->AllocateColor($im, $this->formats[$index]['colors'][$i]['blue'],
         $this->formats[$index]['colors'][$i]['green'],
         $this->formats[$index]['colors'][$i]['red'],
         round($this->formats[$index]['colors'][$i]['reserved'] / 255 * 127));

(Note that the blue and red values are indeed switched.) After changing this, it works like a charm for me.

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This entry was posted on Tuesday, February 17th, 2009 at 10:24 pm and is filed under Computers, Web Development. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

5 Responses to “PHP ICO to PNG conversion”

  1. secret :) says:
    March 11, 2009 at 4:25 pm

    Great! keep the good work!

    For the convenient of others, here’s a quote from the first post:
    ————
    Here’s how you use the class:
    GetIcon(0))) die(“Could not load ICO.”);
    else {
    header(“Content-Type: image/png”);
    imagepng($r);
    }
    ?>
    ————

    And I’ve modified a bit your class, sometimes I just want to get the best quality icon (that’s usually the last icon in the file) so I’ve replaced this:
    ———–
    function &GetIcon($index) {
    if (!isset($this->formats[$index])) {
    ———–
    with this:
    ———–
    function &GetIcon($index=null) {
    if (is_null($index)) {
    $index = count($this->formats)-1;
    }
    if (!isset($this->formats[$index])) {
    ———–
    so I can omit the $index parameter and get the best icon (assuming he’s the last one)

    Good luck everyone!

  2. Dp76 says:
    May 29, 2009 at 9:57 am

    Hello, First of all thanks for your work :)
    But, please, update zip file as well.
    Your zip file have previous version without fixes.

  3. GarykPatton says:
    June 16, 2009 at 7:42 am

    Hello, can you please post some more information on this topic? I would like to read more.

  4. CrisBetewsky says:
    July 6, 2009 at 2:29 pm

    I’m glad that after surfing the web for uch a long time I have found out this information. I’m really lucky.

  5. KonstantinMiller says:
    July 6, 2009 at 4:32 pm

    I have been looking looking around for this kind of information. Will you post some more in future? I’ll be grateful if you will.

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