PHP Unconference Europe 2015

imagecreatefromgif

(PHP 4, PHP 5)

imagecreatefromgifCrée une nouvelle image depuis un fichier ou une URL

Description

resource imagecreatefromgif ( string $filename )

imagecreatefromgif() retourne un identifiant d'image qui représente l'image obtenue à partir du fichier dont le nom est donné par filename.

Astuce

Vous pouvez utiliser une URL comme nom de fichier avec cette fonction, si le gestionnaire fopen a été activé. Voyez fopen() pour plus de détails sur la façon de spécifier le nom du fichier. Reportez-vous aux Liste des protocoles et des gestionnaires supportés pour plus d'informations sur les capacités des différents gestionnaires, les notes sur leur utilisation, ainsi que les informations sur leurs variables prédéfinies fournies.

Liste de paramètres

filename

Chemin vers l'image GIF.

Valeurs de retour

Retourne un identifiant de ressource d'image en cas de succès, ou FALSE si une erreur survient.

Exemples

Exemple #1 Exemple de prise en charge d'une erreur lors du chargement d'une image GIF

<?php
function LoadGif($imgname)
{
    
/* Tente d'ouvrir l'image */
    
$im = @imagecreatefromgif($imgname);

    
/* Traitement si l'ouverture à échouer */
    
if(!$im)
    {
        
/* Création d'une image vide */
        
$im imagecreatetruecolor (15030);
        
$bgc imagecolorallocate ($im255255255);
        
$tc imagecolorallocate ($im000);

        
imagefilledrectangle ($im0015030$bgc);

        
/* Affiche un message d'erreur dans l'image */
        
imagestring ($im155'Error loading ' $imgname$tc);
    }

    return 
$im;
}

header('Content-Type: image/gif');

$img LoadGif('bogus.image');

imagegif($img);
imagedestroy($img);
?>

L'exemple ci-dessus va afficher quelque chose de similaire à :

Affichage de l'exemple : imagecreatefromgif()

Notes

Note:

Le support du GIF a été supprimé de la bibliothèque GD dans sa version 1.6 et a été rajouté depuis la version 2.0.28. Cette fonction n'est donc pas disponible entre ces deux versions.

Note:

Lors de la lecture en mémoire de fichiers GIF animés, seule la première frame est retournée au pointeur de ressource de l'image.

Avertissement

Les versions Windows de PHP antérieures à la version 4.3.0 ne supportent pas l'accès aux fichiers distants avec cette fonction, même si allow_url_fopen est activé.

add a note add a note

User Contributed Notes 18 notes

up
3
frank at huddler dot com
3 years ago
An updated is_ani based on issues reported here and elsewhere

<?php
function is_ani($filename) {
    if(!(
$fh = @fopen($filename, 'rb')))
        return
false;
   
$count = 0;
   
//an animated gif contains multiple "frames", with each frame having a
    //header made up of:
    // * a static 4-byte sequence (\x00\x21\xF9\x04)
    // * 4 variable bytes
    // * a static 2-byte sequence (\x00\x2C) (some variants may use \x00\x21 ?)
   
    // We read through the file til we reach the end of the file, or we've found
    // at least 2 frame headers
   
while(!feof($fh) && $count < 2) {
       
$chunk = fread($fh, 1024 * 100); //read 100kb at a time
       
$count += preg_match_all('#\x00\x21\xF9\x04.{4}\x00(\x2C|\x21)#s', $chunk, $matches);
   }
   
   
fclose($fh);
    return
$count > 1;
}
?>
up
2
ZeBadger
8 years ago
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.
up
2
Anonymous
1 year ago
Using the following script to generate(keep) animated GIF, it fixs GD lib animation problem.
http://www.gdenhancer.com/
up
1
Malcolm Murphy
3 years ago
Hopefully this might save someone a headache when using functions to check for animated GIFs.

I have come across some some GIFs use the a different frame separator sequence, \x00\x21, instead of the official standard \x00\x2C. This seems to be happening with animated GIFs saved in Photoshop CS5, although I'm not quite sure if that's where the issue is originating from.

Anyway, I've been using the pattern:
"#\x00\x21\xF9\x04.{4}\x00(\x2C|\x21)#s"
which seems to cover all GIFs, hopefully without misinterpreting.

Cheers.
up
2
ZeBadger
1 year ago
The version of is_ani that reads the file in 100Kb chunks is flawed as the end of frame marker might be split in between 2 chunks - so be careful.
up
1
moxley at moxleydata dot com
8 years ago
I wanted to find out if a GIF is Black & White or Color, but I didn't want to wait around for imagecreatefromgif() to parse a 200k file (about 1 second) to get the color map, so I wrote this function to get a list of all the colors in the GIF. Hope it is useful for you.

<?php
function getGIFColorMap($file)
{
  
$fp = fopen($file, 'r');
  
$buf = fread($fp, 1024);
  
fclose($fp);
     
  
// Calculate number of colors
   // buf[10] is the color info byte
  
$color_byte = ord($buf[10]);
  
$has_color_map = ($color_byte >> 7) & 1;
  
$color_res = (($color_byte >> 4) & 7) + 1;
  
$bits_per_pixel = ($color_byte & 7) + 1;
  
$color_count = 1 << $bits_per_pixel;
     
   if (!
$has_color_map) return null;
     
  
// buf[13] is the beginning of the color map
  
$color_map_index = 13;
  
$map = array();
   for (
$i=0; $i < $color_count; $i++) {
      
$index = $color_map_index + $i*3;
      
$r = ord($buf[$index]);
      
$g = ord($buf[$index + 1]);
      
$b = ord($buf[$index + 2]);
      
$map[$i] = array($r, $g, $b);
   }
   return
$map;
}
?>
up
0
steve at stevedix dot de
9 years ago
If anyone is looking for the Yamasoft gif conversion utility :

Although Yamasoft's website is long gone, the code can be found on the following websites :
http://www.fpdf.org/phorum/read.php?f=1&i=9418&t=7568#9418

http://www.fpdf.org/download/php-gif.zip

http://phpthumb.sourceforge.net/index.php?source=phpthumb.gif.php
up
0
jason at null dot zzz
10 years ago
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
up
0
josh [ a t ] OnlineComics [ d o t ] net
11 years ago
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.
up
0
Anonymous
11 years ago
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;
}
up
0
Anonymous
11 years ago
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)
up
0
geoffrey at poulet dot org
11 years ago
After hours of search, I've finally found a program which can convert JPG to GIF.
IJG - The Independent JPEG Group's JPEG software
Version 6 which support GIF (read and write with LZW)
and the version 6b which support GIF (write only without LZW)

The name of the file is: jpegsrc.v6.tar.gz
up
0
fezber at yamasoft dot com
11 years ago
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
up
0
Ady at freebsd dot ady dot ro
11 years ago
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!
up
0
unknown at hotmail dot com
11 years ago
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
up
0
senbei at terra dot es
12 years ago
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.
up
0
anthony dot atkins at vt dot edu
14 years ago
<?php

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);
}

?>
up
-1
chuckg at infinite9 dot com
13 years ago
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)
To Top