PHP: imagecreatefromgif

Description

resource imagecreatefromgif ( string filename )

imagecreatefromgif() returns an image identifier representing the image obtained from the given filename.

imagecreatefromgif() returns an empty string on failure. It also outputs an error message, which unfortunately displays as a broken link in a browser. To ease debugging the following example will produce an error GIF:

Przykład 1. Example to handle an error during creation (courtesy vic at zymsys dot com)


<?php

function LoadGif ($imgname) 

{

    $im = @imagecreatefromgif ($imgname); /* Attempt to open */

    if (!$im) { /* See if it failed */

        $im = imagecreate (150, 30); /* Create a blank image */

        $bgc = imagecolorallocate ($im, 255, 255, 255);

        $tc = imagecolorallocate ($im, 0, 0, 0);

        imagefilledrectangle ($im, 0, 0, 150, 30, $bgc);

        /* Output an errmsg */

        imagestring ($im, 1, 5, 5, "Error loading $imgname", $tc);

    }

    return $im;

}

?>

Notatka: GIF support was removed from the GD library in Version 1.6, and added back in Version 2.0.28. This function is not available between these versions.

Podpowiedź: Jeśli włączona jest dyrektywa konfiguracyjna fopen wrappers, możliwe jest podanie jako nazwy pliku adresu URL. Zobacz opis funkcji fopen() aby dowiedzieć się jak przekazać nazwę pliku, oraz fopen wrappers aby uzyskać listę obsługiwanych protokołów.

Ostrzeżenie

PHP w wersji starszej niż 4.3.0, pracujące pod kontrolą systemów Windows, nie obsługują dostępu do zdalnych plików w tej funkcji, nawet jeśli opcja allow_url_fopen jest włączona.

User Contributed Notes


this function will convert gif image to jpeg. it take three parameter as argument. two argument are optional

first will take the gif file name. second for file name to save the converted file. third argument is an color array



function gif2jpeg($p_fl, $p_new_fl='', $bgcolor=false){

  list($wd, $ht, $tp, $at)=getimagesize($p_fl);

  $img_src=imagecreatefromgif($p_fl);

  $img_dst=imagecreatetruecolor($wd,$ht);

  $clr['red']=255;

  $clr['green']=255;

  $clr['blue']=255;

  if(is_array($bgcolor)) $clr=$bgcolor;

  $kek=imagecolorallocate($img_dst,

                  $clr['red'],$clr['green'],$clr['blue']);

  imagefill($img_dst,0,0,$kek);

  imagecopyresampled($img_dst, $img_src, 0, 0, 

                  0, 0, $wd, $ht, $wd, $ht);

  $draw=true;

  if(strlen($p_new_fl)>0){

    if($hnd=fopen($p_new_fl,'w')){

      $draw=false;

      fclose($hnd);

    }

  }

  if(true==$draw){

    header("Content-type: image/jpeg");

    imagejpeg($img_dst);

  }else imagejpeg($img_dst, $p_new_fl);

  imagedestroy($img_dst);

  imagedestroy($img_src);

}



EXAMPLE:

$fl='http://www.suchona.com/test/testgif.gif';

$c['red']=255;

$c['green']=0;

$c['blue']=0;

gif2jpeg($fl, '', $c);



Thanks

Md. Shahadat Hossain Khan Razon

razon.phpxperts.com


I have written this code to detect if a gif file is animated or not.  I thought I would share it :-)



<?php



function is_ani($filename)

{

        $filecontents=file_get_contents($filename);



        $str_loc=0;

        $count=0;

        while ($count < 2) # There is no point in continuing after we find a 2nd frame

        {



                $where1=strpos($filecontents,"\x00\x21\xF9\x04",$str_loc);

                if ($where1 === FALSE)

                {

                        break;

                }

                else

                {

                        $str_loc=$where1+1;

                        $where2=strpos($filecontents,"\x00\x2C",$str_loc);

                        if ($where2 === FALSE)

                        {

                                break;

                        }

                        else

                        {

                                if ($where1+8 == $where2)

                                {

                                        $count++;

                                }

                                $str_loc=$where2+1;

                        }

                }

        }



        if ($count > 1)

        {

                return(true);



        }

        else

        {

                return(false);

        }

}



exec("ls *gif" ,$allfiles);

foreach ($allfiles as $thisfile)

{

        if (is_ani($thisfile))

        {

                echo "$thisfile is animated<BR>\n";

        }

        else

        {

                echo "$thisfile is NOT animated<BR>\n";

        }

}

?>



It could quite easily be modified to count the number of frames if you required.


thanks yamasoft for the gif to png lib.  it works!  but, there is one bug.  i changed line 1003 to this:



if(isset($this->m_img->m_bTrans) && $this->m_img->m_bTrans && ($nColors > 0)) {



because i was getting an error that m_bTrans is undefined.  i think this is because my gif has no transparency.  after i updated this line, there were no problems.



thanks!



-j


I just installed gif2png on my server, and it took a little research on my part to figure out that this...



passthru("$path/gif2png -O $image_path/image.gif")



will not work if safe mode is on. If you're on a shared server, it probably is. You don't need to turn safe mode off, however, just set the safe_mode_exec_dir variable in your php.ini file to the directory where you installed gif2png. Then you'll be able to execute the program from your PHP script.


function LoadGif ($imgname) {

    $im = @ImageCreateFromGIF ($imgname); /* Attempt to open */

    if (!$im) { /* See if it failed */

        $im = ImageCreate (150, 30); /* Create a blank image */

        $bgc = ImageColorAllocate ($im, 255, 255, 255);

        $tc  = ImageColorAllocate ($im, 0, 0, 0);

        ImageFilledRectangle ($im, 0, 0, 150, 30, $bgc); 

        /* Output an errmsg */

        ImageString($im, 1, 5, 5, "Error loading $imgname", $tc); 

    }

    return $im;

}


re: 09-May-2002 11:31



Seems gif2png is no longer at http://www.tuxedo.org/~esr/gif2png/

I found a Win32 version at http://www.r1ch.net/stuff/gif2png/

(for the Unix and source, see http://catb.org/~esr/gif2png/ )



In Win32,

  passthru("gif2png $filename");

works fine if gif2png.exe is in the path.

It will overwrite the file with .png extension, so be careful,or use temp files as in the post referenced above (without the  -O; type "gif2png" at the command line for the options).



I had a problem with exceeding the default 30 second execution time limit in PHP, so I added this line

  set_time_limit(0); // some odd gifs take a long time (example, a 25K gif, 700x700, mostly blank)


For users who just want GIF read (not write) support but:

1) Don't want to patch GD libs

2) Don't want to recompile something

3) Don't have permissions to install conversion packages

4) Any other reason...



I created a small php script (around 25KB) which lets you load a GIF from a file (you even can specify the image index on animated GIFs) and then convert it to a PNG or BMP file.



If I take one example:



<?

include("gif.php");



$gif = gif_loadFile("./test.gif");



if($gif) {

    // GIF file successfully opened

    if(gif_outputAsPNG($gif, "./test.png")) {

        // Now, just use ImageCreateFromPng...

        $img = ImageCreateFromPng("./test.png");



        if($img) {

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

            ImageJPEG($img);

            ImageDestroy($img);

        }

        else {

            // Could NOT open PNG

        }

    }

    else {

        // Could NOT convert GIF to PNG...

    }

}

else {

    // GIF not loaded...

}

?>



Of course, it's slower than using appropriate software and/or libraries but it's quite useful for reading occasionaly some GIF files.



You'll find the gif.php source code at: http://www.yamasoft.com/php-gif.zip



Fabien


FreeBSD users are lucky to have the option of compiling GIF support in GD2.x through the ports system.

All you need to do is to export the "WITH_LZW=yes" global variable when compiling the graphics/gd2 port, e.g.:



# cd /usr/ports/graphics/gd2

# export WITH_LZW=yes

# make && make install



Then recompile and (re)install the www/mod_php4 port and you are in business... :)



Good luck!


If GD doesn't support GIFs & gif2png is not available & you are not an administrator, you can install it in your account like this:



create do.php:

<? 

  global $do;

  passthru($do);

?>



then upload gif2png-2.4.6.tar.gz, unpack and install it:

do.php?do=tar+-xvzf+gif2png-2.4.6.tar.gz

do.php?do=gif2png-2.4.5/configure

do.php?do=make



Then remove all files except gif2png. Don't forget to remove do.php as it is a serious security hole in your system. 



Njoy!



Anze


Since gif support is removed from the more recent GD libraries, you can still use it via an external program.


I've read somewhere about using ImageMagick and I tried myself but it's a quite big package and needs the X11 libs which are not available in some servers.


The other option I found is to use a little prog "gif2png" http://www.tuxedo.org/~esr/gif2png/


to convert gif files to png ones. It works under Unix and dos/win32/winnt and is very straightforward.


If you need to modify an user uploaded gif file to save it into your site just use this:





$path=$_FILES["photo"]["tmp_name"];


passthru("/usr/bin/gif2png -d -O ".$path);


$src_img=imagecreatefrompng( dirname($path)."/".basename($path, ".gif").".png");





This will convert the gif to a png and delete the gif file, then it will open the png with the GDlib so you can perform any operation on it.


I just thought I'd let you guys know of a workaround for the lack of Gif support in the latest GD...aside from adding the patch.  It works just as good, from what I can tell, and is quite nice ;)





Here goes:


<?


//Just grab some general image info


$img = "path/to/image.gif";


$imageInfo = GetImagesize($img);





if ( $imageInfo[2] == 1 ) {


   //it's a gif


   $file = fread(fopen($path, "r"), filesize($path));





   $fileHeader = "image/gif";


   Header("Content-Type: ".$fileHeader);


   echo $file;


   fclose($file);


}


?>





basically what that does is reads the file..through the "GetImageSize", which still returns if it's a GIF or not, (thank god), then if it's a gif, opens the file through normal filestream, sets the header to image type "gif" then prints it out.  Same as doing "ImageCreateFromGif($img)" and "ImageGif($img)", except that it doesn't require GD Gif support.  If you have any questions just ask me via email (chuckg@infinite9.com)


<pre>


function myImageCreateFromGif($file_or_url) {





        $dummy_file = "/tmp/dummy.gif";





        # if this is a url, use fopen to get the file data, then 


        # save it to a dummy file


        if (preg_match("/(http|ftp):\/\//i", $file_or_url)) {


                # open the file using fopen, which supports remote URLs


                $input = fopen($file_or_url, "rb");





                # read the contents of the file


                # will accept files up to 10Mb, but will probably get 


                # and EOF before that, we have to do it this way because


                # filesize isn't designed to work with URLs.  sigh.


                $image_data = fread($input, 10000000);





                fclose($input);





                # write the contents to a dummy file


                $output = fopen("$dummy_file", "wb");


                fwrite($output, $image_data);


                fclose($output);





                # create the gif from the dummy file


                $image = ImageCreateFromGif($dummy_file);





                # get rid of the dummy file


                unlink($dummy_file);





        }





        # if it's not a URL, we can simply open the image directly


        else {


                $image = ImageCreateFromGif($file_or_url);


        }





        if ($image) { return $image; }


        else { return 0; }


}








if (!$url) { $url = "http://scholar.lib.vt.edu/images/cornholio.gif";}


$image = myImageCreateFromGif($url);





if ($image == "" || $image == 0) {


        print "<p>No Image data was returned...</p>\n";


}


else { 


        header("Content-Type: image/gif\n\n");


        ImageGif($image);


}





?>


</pre>