PHP: imagecreatefromstring

imagecreatefromstring

kanzure at gmail dot com
11-Jul-2006 09:18


Generating graphs in an external program (in this case, gnuplot) may cause problems. This is a solution hacked together in the late hours of night.



<?php

// get the values from, say, a database

$vals = "1 2\\\\n4 8\\\\n"; # etc

// construct the gnuplot_call variable, something like:

$gnuplot_call = "echo \"set term png; plot '<echo -e \\\"$vals\\\" ' ti 'Updated with' with line ; \" | gnuplot";

ob_start();

passthru($gnuplot_call, $gnuplot_call_output);

$image = imagecreatefromstring(ob_get_contents());

ob_end_clean();

imagepng($image); # display

?>

junkmail at pmobl dot com
25-Feb-2006 02:37


I know a lot of people have been having trouble using images from the Sprint PPC6700 with GD.  The jpeg library always thows an error about 16 bytes of extraneous data.  I decided to poke around in a hex editor and found those extraneous bytes occur right at the end of the exif data.



By removing this extraneous data, images can easily be manipulated by GD and the EXIF extension as a normal images.  This also removes any problems using the images with GIMP which must rely on the same jpeg libraries.



Here is a function that will check to see if an image is from the PPC6700 and then remove the extraneous data for you.  The result can successully be used with imagecreatefromstring



Author: Paul Visco

IM: paulsidekick

Created: 2-12-06



function checkFixPPC6700($orig){



    //get the file contents

    $data = file_get_contents($orig);



    //if its a PPC 6700 image cut out the extraneous 16 bits

    if(strstr($data, "\x41\x70\x61\x63\x68\x65\x00\x48")){

//this next line can all be one string I split it up so the form on php.net would accept it

        $bad_data ="\x00\x10\x4A\x46" . "\x49\x46\x00\x01\x01" . "\x00\x00\x01\x00\x01\x00\x00";

        return substr_replace($data, "", strpos($data, $bad_data),

        strlen($bad_data));

    } else {

        //if not from a PPC 6700 return data unaltered

         return $data;

    }



}

kakail at aei dot ca
26-Nov-2005 06:07


I found out that in PHP 4.3.2 and 4.3.4 that the 'imagecreatefromstring' function use a lot of memory when working with big image...

Try this piece of code with a big image (like 1Meg or more)

<?php

$loadFile = "http://bigimage.jpg";//Try with a big image 

$im = imagecreatefromstring(file_get_contents($loadFile));

imagejpeg($im);

?>



With a 400k image. I run with a 16M Mem_limit but for a 1.4M image, the mem_limit required jump to more that 32M

alexandrebr at ignorethis dot gmail dot com
28-Aug-2005 05:08


An easy example to help understanding this function...



<?

$loadFile = "http://static.php.net/images/php.gif";



$im = imagecreatefromstring(file_get_contents($loadFile));

// identical to imagecreatefromgif($loadFile);

imagegif($im);

?>



The function will try to auto-determine file format (jpg, gif, png....), and will return false if fails.

paul at epeeps dot net
25-Jul-2005 07:39


I run a blogging site that allowed users to publish images from their cell phones.  For some reason, the nokia 3220 produces jpegs with extrandeous data before the EOF 0xFFF9



I wrote this class to allow you to fix the images so that they can be used with GD to resize and manipulate.  Without applying the fix both GD and gimp report errors for the file.  If basically keeps eating bytes from the junk part till the file is a valid jpeg.  Here is an example bunk pic written by a nokia 3220 that you cna test it with http://www.shawnrider.com/moblog/cache/0854747001121624103.jpg



/*

Author: Paul Visco

Hompage: http://www.elmwoodstrip.com?u=paul

AIM: paulsidekick

Notes:  The file allows you fix the jpegs created by the Nokia 3220 picture phone so that they can be manipulated using the GD library with PHP.



Usage:  Simply instanitiate the class and then call the fix method for each image.

e.g. 

$nokia = new nokia;

$nokia->debug ="y";

$nokia->fix("yourpic.jpg");

*/



class nokia

{

    public $file;

    public $debug = "n";

    public $dir_name = "";

    private $img; //the image created from the string

    private $str;

    

    function fix($file)

    {

        

        //set the file to fix

        $this->file = $file;

    

        //load the file into a string

        $this->str = file_get_contents($this->file);

        

        //test to see if it is a nokia image or if it has been corrupted previously

        if (substr_count($this->str, chr(0x28).chr(0x36).chr(0x28).chr(0x2B)) == 0 || @imagecreatefromstring($this->str)) 

        { 

            if ($this->debug =="y")

            {

                echo "\n<br />".$this->file." is not a corrupted Nokia pic";

            }

            

            return true;

        }

        

        //make a directory for fixed images if it doesn't exist and is specified

        if(!empty($this->dir_name) && !is_dir($this->dir_name))

        {

            @mkdir($this->dir_name, 0777);

        }

        

        //strip out the funk e crap from the file

        $this->eat($this->str);

        

        //write the file back to itself

        file_put_contents($this->dir_name.$this->file, $this->str);



        //return true for fixed

        return true;



    }

    

    function eat()

    {

    

        //check the image

        $this->img = @imagecreatefromstring($this->str);

        

        //if the image doesn't work then keep striping out crap

        while(!$this->img)

        {

            //cut off the bad bytes one by one

            $this->str= substr_replace($this->str, "", -3, -2);

            

            //check the image again

            $this->img = @imagecreatefromstring($this->str);

        }  

        

        if ($this->debug =="y")

        {

            //notify the user it's fixed

            echo "\n<br />Nasty bits eaten!! ".$this->file." is fixed now thanks to p:labs!";

        }

        return true;

    }



}

not given
03-Aug-2003 02:14


A note to the previous question (if you still don't know it :))...



GIF's are 256 colors (or 8 bit), and the resample function needs true color I guess... that's why it works with JPG's and not with GIF's.



Next thing... you take a string, write it to file, open the file (imagecreatefromgif), and delete the file again.



if you do imagecreatefromstring($string) you can skip the temporary file part.

shiehj at yahoo dot com
11-Apr-2003 09:44


Here is the code I did to create a thumbnail image from the database blob field. The trick is to use "imagecreatefromstring()" to create an image file.



Jack Shieh



<?php

require("dbconfig.inc");



$id = $_GET['id'];



if($id) {



    $link = @mysql_connect($host, $user, $password) or die("Could not connect: " . mysql_error());

    @mysql_select_db($dbname, $link);



    $query = "select filetype, image from pictures where id = $id";

    $result = @mysql_query($query);



    $data = @mysql_result($result,0,"image");

    $type = @mysql_result($result,0,"filetype");

    

    Header( "Content-type: $type");    

    

    $size = 150;  // new image width

    $src = imagecreatefromstring($data); 

    $width = imagesx($src);

    $height = imagesy($src);

    $aspect_ratio = $height/$width;



    if ($width <= $size) {

      $new_w = $width;

      $new_h = $height;

    } else {

      $new_w = $size;

      $new_h = abs($new_w * $aspect_ratio);

    }



    $img = imagecreatetruecolor($new_w,$new_h); 

    imagecopyresized($img,$src,0,0,0,0,$new_w,$new_h,$width,$height);

 

    // determine image type and send it to the client    

    if ($type == "image/pjpeg") {    

      imagejpeg($img); 

    } else if ($type == "image/x-png") {

      imagepng($img);

    } else if ($type == "image/gif") {

      imagegif($img);

    }

    imagedestroy($img); 

    mysql_close($link);

};

?>

adrian_schmidt at yahoo dot com
05-Mar-2003 04:04


I'm trying to get the imagecreatefromstring to work with GIFs. Of course, it won't.

I've read the tips but can't get them to work either.

The following is what I tried, based on above tips:



---



    header('Content-Type: image/gif');

    header('Content-Disposition: inline; filename=file.gif');



    $temp = tmpfile();

    fwrite($temp, $line['image']);

    $src_img = imagecreatefromgif($temp);

    fclose($temp); // this removes the file

    $dst_img = imagecreatetruecolor(100, 100);

    imagecopyresampled($dst_img, $src_img, 0,0,0,0, 100,100, imagesx($src_img), imagesy($src_img));

    

    imagegif($dst_img);



---



where $line['image'] is the gif as taken from my MySQL database...



If anyone that has been able to make something like this work could give me a working piece of code I'd be really greatful!



I would be great if the tempfile could be excluded too...



Below is a working piece of code for jpeg:



---



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

    header('Content-Disposition: inline; filename=file.jpg');

    

    $src_img = imagecreatefromstring($line['image']);

    $dst_img = imagecreatetruecolor(100, 100);

    imagecopyresampled($dst_img, $src_img, 0,0,0,0, 100,100, imagesx($src_img), imagesy($src_img));

    

    imagejpeg($dst_img);

imagecreatefromstring

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