Web студия "GrandView"

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imagecreatefromjpeg

dmhouse at gmail dot com
08-Aug-2007 03:37


For a script that allows you to calculate the "fudge factor" discussed below by Karolis and Yaroukh, try the following. Grab a few images, preferably some large ones (the script should cope with images of up to 10 megapixels or so), some small ones, and some ones in between. Add their filenames to the $images array, then load the script in your browser.



<?php



header('Content-Type: text/plain');



ini_set('memory_limit', '50M');



function format_size($size) {

  if ($size < 1024) {

    return $size . ' bytes';

  }

  else {

    $size = round($size / 1024, 2);

    $suffix = 'KB';

    if ($size >= 1024) {

      $size = round($size / 1024, 2);

      $suffix = 'MB';

    }

    return $size . ' ' . $suffix;

  }

}



$start_mem = memory_get_usage();



echo <<<INTRO

The memory required to load an image using imagecreatefromjpeg() is a function 

of the image's dimensions and the images's bit depth, multipled by an overhead.

It can calculated from this formula: 

Num bytes = Width * Height * Bytes per pixel * Overhead fudge factor

Where Bytes per pixel = Bit depth/8, or Bits per channel * Num channels / 8.

This script calculates the Overhead fudge factor by loading images of 

various sizes.

INTRO;



echo "\n\n";



echo 'Limit: ' . ini_get('memory_limit') . "\n";

echo 'Usage before: ' . format_size($start_mem) . "\n";



// Place the images to load in the following array:

$images = array('image1.jpg', 'image2.jpg', 'image3.jpg');

$ffs = array();



echo "\n";



foreach ($images as $image) {

  $info = getimagesize($image);

  printf('Loading image %s, size %s * %s, bpp %s... ',

         $image, $info[0], $info[1], $info['bits']);

  $im = imagecreatefromjpeg($image);

  $mem = memory_get_usage();

  echo 'done' . "\n";

  echo 'Memory usage: ' . format_size($mem) . "\n";

  echo 'Difference: ' . format_size($mem - $start_mem) . "\n";

  $ff = (($mem - $start_mem) /

         ($info[0] * $info[1] * ($info['bits'] / 8) * $info['channels']));

  $ffs[] = $ff;

  echo 'Difference / (Width * Height * Bytes per pixel): ' . $ff . "\n";

  imagedestroy($im);

  $start_mem = memory_get_usage();

  echo 'Destroyed. Memory usage: ' . format_size($start_mem) . "\n";



  echo "\n";

}



echo 'Mean fudge factor: ' . (array_sum($ffs) / count($ffs));



?>

jhon at stockton dot com dot com
04-Jun-2007 01:02


// a function for resize the images(png,jpg,gif) in a directory

//for the png you must have the zlib actived



//$diror origin directory

//$dirdest destination directory

//$val value of resize(1,2,3..)

//$qual quality(80 if you don't know)



function imgres($diror,$dirdest,$val,$qual){

$q=$qual;

//open the directory

if (is_dir($diror)) {

   if ($dh = opendir($diror)) {

      while (($file = readdir($dh)) !== false) {

        if($file == "." || $file == ".."){continue;}

                 $k=explode(".",$file);

            if(strpos($k[1],"jpg")===0 || strpos($k[1],"jpeg")===0){

            $salva=$dirdest.$file;

                    $image=$diror.$file;

            $im =imagecreatefromjpeg("$image");

            $x=imagesx($im); 

            $y=imagesy($im);    

            $thumbnail=imagecreatetruecolor($x/$val,$y/$val);

            $im_ridimensionata=imagecopyresized( $thumbnail, $im, 0, 0, 0, 0, $x/$val,

            $y/$val, $x, $y);

            imagejpeg($thumbnail, $salva, $q);         

                    }

            elseif(strpos($k[1],"gif")===0){

            $salva=$dirdest.$file;

                    $image=$diror.$file;

            $im =imagecreatefromgif("$image");

            $x=imagesx($im); 

            $y=imagesy($im);    

            $thumbnail=imagecreatetruecolor($x/$val,$y/$val);

            $im_ridimensionata=imagecopyresized( $thumbnail, $im, 0, 0, 0, 0, $x/$val,

            $y/$val, $x, $y);

            imagegif($thumbnail, $salva, $q);

                }

            elseif(strpos($k[1],"png")===0){

            $salva=$dirdest.$file;

                    $image=$diror.$file;

            $im =imagecreatefrompng("$image");

            $x=imagesx($im); 

            $y=imagesy($im);    

            $thumbnail=imagecreatetruecolor($x/$val,$y/$val);

            $im_ridimensionata=imagecopyresized( $thumbnail, $im, 0, 0, 0, 0, $x/$val,

            $y/$val, $x, $y);

            imagepng($thumbnail, $salva, $q);

                }

            else{

                echo "File not compatible(no jpg,gif or png)";

            }    

            }

            closedir($dh);

            }

    }

}

huguowen at cn dot ibm dot com
16-May-2007 11:57


Tips for Windows User to Set up GD(dynamic graphic lib) with PHP.



Problem I meet:



When i run following function, which terminates at   



$img = @imagecreatefromjpeg($image_path);



error message is : undefined function imagecreatefromjpeg();



no other code of the script gets executed. 



Solution:



In one word, you need to turn on gd lib, 

which hold the implementation of imagecreatefromjpeg();



please follow below steps:



my php install dir is: c:/php/

first you must try to find:

c:/php/php.ini  

c:/php/ext/php_gd2.dll(php 5) 

c:/php/extension/php_gd2.dll(php 4)



The php_gd2.dll is included in a standard PHP installation for Windows, 

however, it's not enabled by default. 

You have to turn it on, 

You may simply uncomment the line "extension=php_gd2.dll" in php.ini and restart the PHP extension. 



Change: 

,extension=php_gd2.dll



To: 

extension=php_gd2.dll



You may also have to correct the extension directory setting 

from: 

extension_dir = "./"

extension_dir = "./extensions"

To (FOR WINDOWS): 

extension_dir = "c:/php/extensions"(php 4)

extension_dir = "c:/php/ext"(php 5)



Cheers!

sales at wholehogsoftware dot com
02-May-2007 09:10


I've found a bug in CentOS 4.x that, while previously addressed, does not seem to be directly addressed here as far as the nature of the bug is concerned.



If you are having a problem getting this function to work on CentOS 4.4 (may appear earlier) and are receiving this error:



Call to undefined function imagecreatefromjpeg()



This is because the installation *does* support JPG by default if you have libjpeg installed. However, the config script finds libjpeg in /usr/lib but it is never successfully added to the PHP build.



To fix this, you should recompile PHP and be absolutely sure to add '--with-jpeg-dir' to the config command. This should appear BEFORE the --with-gd option. Example:



'--with-jpeg-dir' '--with-gd'



If you don't put it before --with-gd, the option is completely ignored.



As always, be sure to do a 'make clean' before a 'make install'. I made the mistake of forgetting to check and wasted 30 minutes trying to resolve this problem simply because I forgot to clean up after myself previously.

henk_vd_bosch at planet dot nl
26-Jan-2007 04:41


When i run following function dis function terminates at the  

13th line where is says:

$img = @imagecreatefromjpeg($image_path);



no other code of the script gets executed. can anyone help me. i use PHP5 with GD lib support



function convertLQ($image_path)

{

  ClearStatCache();

  $file = basename($image_path);

  $dirname = dirname ($image_path);

  // set save path + name

  $save_path = $dirname.'/LQ/'.$file;

  // Load image

  $img = null;

  $ext = strtolower(end(explode('.', $image_path)));

  $image_path = htmlentities($image_path);

  if ($ext == 'jpg' || $ext == 'jpeg')

  {

    $img = @imagecreatefromjpeg($image_path);

  }

  else if ($ext == 'png')

  {

    $img = @imagecreatefrompng($image_path);

  }

  else if ($ext == 'gif')

  {

    $img = @imagecreatefromgif($image_path);

  }

  // If an image was successfully loaded, test the image for size

  if ($img)

  {

    // Get image size and scale ratio

    $width = imagesx($img);

    $height = imagesy($img);

    $scale = maxHeightLQ/$height;

    // If the image is larger than the max shrink it

    if ($scale < 1)

    {

      $new_width = floor($scale*$width);

      $new_height = floor($scale*$height);

      // Create a new temporary image

      $tmp_img = imagecreatetruecolor($new_width, $new_height);

      // Copy and resize old image into new image

      imagecopyresized($tmp_img, $img, 0, 0, 0, 0, $new_width, $new_height, $width, $height);

      imagedestroy($img);

      $img = $tmp_img;

    }

  }

  // Create error image if necessary

  if (!$img)

  {

    $img = imagecreate(witdhErrorImage,heightErrorImage);

    $backgroundcolor = imagecolorallocate($img,70,70,70);

    $c = imagecolorallocate($img,70,70,70);

    $red = ImageColorAllocate($img,255,0,0);

    imageline($img,0,0,witdhErrorImage,heightErrorImage,$red);

    imageline($img,witdhErrorImage,0,0,heightErrorImage,$red);

    imagejpeg($img,$save_path,85);

    imagedestroy($img);

    return false;

  }

  // Save the image

  if ($ext == 'jpg' || $ext == 'jpeg')

  {

    imagejpeg($img,$save_path,85);

  }

  else if ($ext == 'png')

  {

    imagePng($img,$save_path);

  }

   else if ($ext == 'gif')

  {

    ImageGif($img,$save_path);

  }

  else

  {

    imagejpeg($img,$save_path,85);

  }

  imagedestroy($img);

  return true;

}

hvozda at ack dot org
30-Oct-2006 03:42


If imagecreatefromjpeg() fails with "PHP Fatal error:  Call to undefined function:  imagecreatefromjpeg()", it does NOT necessarily mean that you don't have GD installed.



If phpinfo() shows GD, but not JPEG support, then that's the problem.  You would think that --with-gd would do the right thing since it does check for the existance of libjpeg (and finds it) and add that feature to GD, but it doesn't in v4.4.4 at least on RHEL v2.1, RHEL v3, CentOS v2.1 or CentOS v4.3.



On those platforms, it's *important* that --with-jpeg-dir be *before* --with-gd.  If it's not, GD won't build with jpeg support as if --with-jpeg-dir had never been specified...

info at daleconsulting dot com dot au
29-Aug-2006 06:34


In a post by Angel Leon, an example script was given that forms a thumbnail gallery using imagecreatefromjpeg.  I am fairly new to php scripts, but I found that the script did not display the table of thumbnail images if the row wasn't "filled" with images.. i.e. if there were 5 images in the folder and the script specified 3 rows in the table, then the page would only display the thumbnails for the first row and only three images were shown.  I found that if you specified the variable row with this equation, then the table would display properly:



$row = intval(count($files)+($row_size-1));



(This is the first line in the createThumbTable function.)

kapishonas at yahoo dot com
11-Jul-2006 04:56


script for nokia photos which end with FF D9 and still imagecreatefromjpeg() returns error.



<?php



error_reporting( 32 );

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



$imgPath = 'att.jpg';



// Atdod atpaka

imagecreatefromjpeg

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