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gd_info> <Image
Last updated: Fri, 16 May 2008

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Image Functions

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gd_info> <Image
Last updated: Fri, 16 May 2008
 
add a note add a note User Contributed Notes
Image Functions
dev at kingthief dot com
28-Mar-2008 10:20
I've developed a well-documented, fairly rock-solid API for creating on the fly, anti-aliased, rounded corner images, including full alpha transparency support for all you PNG lovers.

go here to download the package:
http://sourceforge.net/projects/roundedphp/

go here for a live demo:
http://dev.kingthief.com/demos/roundedphp/

Installation is similar to PEAR.

Enjoy!
henry at corpocuisine dot com
17-Mar-2008 06:39
To troy,

Good demo of GD "tricks"

If safe mode is not: on;
then it will be better to:
instead of using putenv()
using the following which will work in any php.ini settings environment.

$fontpath='../../../WINDOWS/fonts/';

$font =$fontpath. 'arial.ttf';
troy --at-- goemr.com
14-Mar-2008 04:09
Here is a fun example Easter Egg drawing that uses a bunch of image functions.  Just in time for Easter 2008.  Enjoy.
<?php

$image = imagecreatetruecolor(400, 500);

$bg = imagecolorallocate($image, 10, 10, 150);
imagefill($image, 0, 0, $bg);

// allocate some colors
$white = imagecolorallocate($image, 255, 255, 255);
$grey = imagecolorallocate($image, 128, 128, 128);
$black = imagecolorallocate($image, 0, 0, 0);

// choose a color for the elipse
$col_ellipse = imagecolorallocate($image, 255, 200, 255);

// draw ellipse shadow
imagefilledellipse($image, 215, 265, 320, 400, $black);

// draw the ellipse
imagefilledellipse($image, 200, 250, 320, 400, $col_ellipse);

//draw arc where plastic egg opens
imagearc($image, 198, 235, 326, 100, 0, 180, $bg);

$colour = imagecolorallocate($image, 100, 0, 200);

$ca = rand(2,5);
$cb = rand(2,5);
$cc = rand(2,5);
$cd = rand(2,5);

${"colour".$ca} = imagecolorallocate($image, 153, 204, 255);
${"colour".$cb} = imagecolorallocate($image, 102, 0, 153);
${"colour".$cc} = imagecolorallocate($image, 204, 153, 204);
${"colour".$cd} = imagecolorallocate($image, 153, 0, 255);

//positions of stars relative to original position

$shift['x'][]=0;  //star 1
$shift['y'][]=0;
$star['color'][] = $colour;

$shift['x'][]=-80;  //star 2
$shift['y'][]=-120;
$star['color'][] = $colour2;

$shift['x'][]=-130; //star 3
$shift['y'][]=10;
$star['color'][] = $colour3;

$shift['x'][]=-10; //star 4
$shift['y'][]=-250;
$star['color'][] = $colour4;

$shift['x'][]=-160; //star 5
$shift['y'][]=-200;
$star['color'][] = $colour5;

for($ii=0; $ii < count($shift['x']); $ii++)
{

// set up array of points for polygon
$values = array(
            230,  330, 
            290,  390,
            280,  340,
            240, 380, 
            310, 370, 
            230,  330 
            );

    $shiftX = $shift['x'][$ii];
    $shiftY = $shift['y'][$ii];
   
    foreach ($values as &$val)
    {
        if($i == 1){    $val = $val+$shiftY;    $i++;    }
        else
        {    $val = $val+$shiftX;        $i = 1;    }
    }
   
   
    // draw a star filled in with a circle
    imagefilledpolygon($image, $values, 6, $star['color'][$ii]);
    imagefilledellipse($image, 273+$shiftX, 364+$shiftY, 35, 24, $star['color'][$ii]);
}//end for

// Rotate
$degrees = rand(0,360);

$image= imagerotate($image, $degrees, 0);

imagefilter($image, IMG_FILTER_MEAN_REMOVAL, 0);
imagefilter($image, IMG_FILTER_SMOOTH, 0);

//add some text
$text = 'Easter Egg by Troy Jordan 2008 using only php & gd';

//place font in same path as this script
putenv('GDFONTPATH=' . realpath('.'));

//change this font to the name of your font
$font = 'ACAKZIDE.TTF';

// Add some shadow to the text
imagettftext($image, 18, 0, 13, 21, $grey, $font, $text);

// Add the text
imagettftext($image, 18, 0, 12, 20, $white, $font, $text);

//resize the image
$width = imagesx($image);
$height = imagesy($image);

if($height > 0) { $ratio = $width/$height; }

$rand = rand(25,75);
$perc = $rand/100;

$newwidth = $width * $perc;
$newheight = $height * $perc;

$image2 = imagecreatetruecolor($newwidth, $newheight);

imagecopyresampled($image2, $image, 0, 0, 0, 0, $newwidth, $newheight, $width, $height);

header("Content-type: image/png");
imagepng($image2);

?>
somebody learning php
11-Mar-2008 10:34
This is regarding a note below titled "sampathperera at hotmail dot com - Sri Lanka". It is incomplete. A much better version is at (concat lines below to construct URL):

http://www.planet-source-code.com/vb/scripts/ShowCode.asp?
txtCodeId=739&lngWId=8

If the link is broken, google for Image Verification Tutorial by Darryl Porter.
ph_corp at yahoo dot fr
23-Dec-2007 04:19
<?php

/**
HSL/RGB conversion functions
very useful for a lot of applications
**/

function RBGtoHSL ( $R, $G, $B )
{

    $var_R = ( $R / 255 );
    $var_G = ( $G / 255 );
    $var_B = ( $B / 255 );

    $var_Min = min( $var_R, $var_G, $var_B )
    $var_Max = max( $var_R, $var_G, $var_B )
    $del_Max = $var_Max - $var_Min

    $L = ( $var_Max + $var_Min ) / 2;

    if ( $del_Max == 0 )
    {
       $H = 0
       $S = 0
    }
    else
    {
        if ( $L < 0.5 )
        {
            $S = $del_Max / ( $var_Max + $var_Min );
        }
        else
        {
            $S = $del_Max / ( 2 - $var_Max - $var_Min );
        }

        $del_R = ( ( ( $var_Max - $var_R ) / 6 ) + ( $del_Max / 2 ) ) / $del_Max;
        $del_G = ( ( ( $var_Max - $var_G ) / 6 ) + ( $del_Max / 2 ) ) / $del_Max;
        $del_B = ( ( ( $var_Max - $var_B ) / 6 ) + ( $del_Max / 2 ) ) / $del_Max;

        if ( $var_R == $var_Max )
        {
            $H = $del_B - $del_G;
        }
        else if ( $var_G == $var_Max )
        {
            $H = ( 1 / 3 ) + $del_R - $del_B;
        }
        else if ( $var_B == $var_Max )
        {
            $H = ( 2 / 3 ) + $del_G - $del_R;
        }

        if ( $H < 0 )
        {
            $H += 1;
        }
        if ( $H > 1 )
        {
            $H -= 1
        }

    }

    return array( $H, $S, $L );

}

function HuetoRGB( $v1, $v2, $vH )
{
    if ( $vH < 0 )
    {
        $vH += 1;
    }
    if ( $vH > 1 )
    {
        $vH -= 1;
    }
    if ( ( 6 * $vH ) < 1 )
    {
        return ( $v1 + ( $v2 - $v1 ) * 6 * $vH );
    }
    if ( ( 2 * $vH ) < 1 )
    {
        return ( $v2 );
    }
    if ( ( 3 * $vH ) < 2 )
    {
        return ( $v1 + ( $v2 - $v1 ) * ( ( 2 / 3 ) - $vH ) * 6 );
    }
    return ( $v1 )
}

function HSLtoRGB ( $H, $S, $L )
{

    if ( $S == 0 )
    {
        $R = $L * 255;
        $G = $L * 255;
        $B = $L * 255;
    }
    else
    {
        if ( $L < 0.5 )
        {
            $var_2 = $L * ( 1 + $S );
        }
        else
        {
            $var_2 = ( $L + $S ) - ( $S * $L );
        }

        $var_1 = 2 * $L - $var_2;

        $R = 255 * HuetoRGB( $var_1, $var_2, $H + ( 1 / 3 ) );
        $G = 255 * HuetoRGB( $var_1, $var_2, $H );
        $B = 255 * HuetoRGB( $var_1, $var_2, $H - ( 1 / 3 ) );
    }

    return array( $R, $G, $B );

}

function distance ( $R1, $G1, $B1, $R2, $G2, $B2 )
{
    $result = sqrt ( ( $R1 - $R2 )*( $R1 - $R2 ) + ( $G1 - $G2 )*( $G1 - $G2 ) + ( $B1 - $B2 )*( $B1 - $B2 ) );
    return ( $result );
}

?>
kangaroo232002 at yahoo dot co dot uk
14-Nov-2007 04:51
I have noticed that some functions use quite complicated resizing code, however if you want to specify just one dimension (e.g. resizing an image for a catalogue or social network etc) then you can do it my just getting the percentage reduction of one dimension of the image and applying it to the other, like so:

<?php

$new_width = 150;

//assuming you have already used imageSX(), imageSY() to get the dimensions.

$percentage_reduction = ($new_width / $old_width) * 100;
$new_height = ($old_height / 100) * $percentage_reduction;

?>

This means that images will not be stretched, but will be neater as they are the same width (e.g. facebook).
zilly at adminc dot org
20-Oct-2007 09:10
Here is an Example of what can be done using GD and Php.
There is a whole 3D-Dungeon realized and rendered in Real-Time using GD:
http://www.quizzen.de/labyrinth/
joachim dt werner a diggin-data dt de
29-Aug-2007 12:44
In reply to diggertadmin at gmail dot com:
I had the effect that my thumbnail script exceeded the memory limit, too.

However, as error_reporting was turned off, Firefox just printed out the script URL.

Internet Explorer was more helpful here.
maps at cwsol dot com
22-Apr-2007 01:28
If you are getting the generic error "The image cannot be displayed, because it contains errors.", comment out header("Content-type: image/png");.  This will enable PHP to display the real PHP errors.
felipe dot medeiros at kanashii dot com dot br
26-Mar-2007 11:41
Jonathon Reinhart, don't assume it.
.SO and .A files are libraries for dynamic and stactic linking when you compile a program. just to install <package> isn't enought to compile against it's libraries, as them may be only run-time libraries and give you some headache. The correct is to install <package>-devel, which will give you the right libraries for compile time.

And one final word... linux is by now a stable system with lots of working done... if the thing you're trying to do is too hard or unexplained it means that either you're trying something noone ever cared about spending his time on it or you didn't readed how to do it properly. Either way try to learn more about what you're trying.
Jonathon dot Reinhart at DONTSPAMgmail dot com
13-Mar-2007 12:48
I've seen a lot of issues with getting PHP compiled with jpeg and png support.  I built it under SuSE 10.2 and ./configure kept giving me "libjpeg.(a|so) not found".  I believe that's because my libjpeg was libjpeg.so.62.   It also did this for libpng (which mine was named libpng12.so)

Apparently ./config is looking only for the .so files.  To resolve this, I installed libjpeg-devel and libpng-devel, which then created symlinks:  libpng.so -> libpng12.so  and libjpeg.so -> libjpeg.so.62.0.0 .  I'm assuming creating these symlinks without installing the -devel packages will work just fine.
snagnever at gmail dot com
02-Mar-2007 12:38
A lot of GD effects in functions, like:
greyscale, sepia, filling, better-merging, fading
can be found here:
Examples Page:
http://beta.sn4g.net/gd.fillAndMerge.php
Source: http://url.sn4g.net/1u

They all work on PHP 4 and 5. Functions well documented, just copy and use it.

Others Proof of Concepts at http://beta.sn4g.net/
Skyeye
19-Aug-2006 04:04
In addition to %0A which you can use for making multiline text images, you can also use underlining and strikethrough.

For underlining use %0D and _, for example:

/image.php?text=Underline.%0D________

For strikethrough use %0D and %E2%80%93, for example:

/image.php?text=Strikethrough.%0D%E2%80%93%E2%80%93%E2%80%93%E2%80%93
%E2%80%93%E2%80%93%E2%80%93%E2%80%93%E2%80%93%E2%80%93

If you want to use both of them in one line you will have to use %20 to dispose the next block of modifying symbols:

/image.php?text=Underline%20and%20Strikethrough.%0D_______%20%20%20%20
%20%20%20%20%20%E2%80%93%E2%80%93%E2%80%93%E2%80%93%E2%80%93%E2%80%93
%E2%80%93%E2%80%93%E2%80%93%E2%80%93

As you see all modifying symbols for whole line are put after %0D in one string after the whole modifyable text and not after each modifyable word. This makes easy to put on and take off modifying string for whole line when it`s necessary.

If the text is on several lines, each line has its own disposition of modifying symbols:

/image.php?text=Underline%20and%0D_______%0AStrikethrough.%0D%E2%80%93
%E2%80%93%E2%80%93%E2%80%93%E2%80%93%E2%80%93%E2%80%93%E2%80%93
%E2%80%93%E2%80%93

Theese are only some examples how to use symbol combining. Using %0D and other symbols from Windows Charmap you can easy make images of characters which even doesn`t exist in any font.
Skyeye
18-Aug-2006 05:43
If you want to make an image through GET with text in several lines, use %0A for line separating, for example:

/image.php?text=Text%20string%0Ain%20several%0Alines.

As also you can make php generated images without other knowing that they are php-made. Simply add the image extension in Apache httpd.conf file:

AddType application/x-httpd-php .php .png

And call image as normal png image:

/somephpautogeneratedimage.png

Of course real .png files will be now treated as php, but if you don`t have png files on your webserver, this won`t be a problem. Or you can use this code for displaying real png images through php code:
<?php
   $filename = 'realpngfile.png';
   header('Content-type: image/png');
   header('Content-length: '.filesize($filename));
   readfile($filename);
?>
thomas at tgohome dot com
17-Aug-2006 05:01
I wrote this script to fetch details about a GIF image. I wanted to use it for avatar details on a CMS system, so I wrote it to return an array of details (instead of having to go through all of the functions)

Without further ado, here the script is:
<?
/*
 * Get GIF image data
 * Returns an array of data, including GIF image type, and
 * the width and height of the image, plus transparent colour
 * details and much more.
 *
 * Copyright 2006 Thomas Oldbury.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 */
 
/*
 * This function takes one argument, $file, a direct link to the image in
 * question. Perhaps in future versions it will get the file from an image
 * resource, but for now, it will have to do.
 */
function fetch_gif_data($file) {
 
    /*
     * First, we need to get the contents of the file in question, or we print
     * a warning using trigger_error().
     */
    $file_data = @file_get_contents($file) or trigger_error("File $file does not exist", E_USER_WARNING);
   
    /*
     * Now we need to fetch the gif image's version. We'll use strpos to fetch
     * gif89a, gif87a or if we don't get that then we will print an error.
     */
    $image_type = strpos($file_data, "g");
   
    /*
     * Now we check to see wether it is actually a GIF image, as it may not be
     * an image and if this is the case, problems could occur.
     */
    if($image_type === false) {
      trigger_error("File $file is not a gif89a or gif87a compatible image", E_USER_ERROR);
    }
   
    /*
     * Now, we need to fetch the image type by fetching the text at a certain
     * position, using PHP's function substr.
     */
    $image_info[version] = substr($file_data, 0, 6);
    $image_info[file_reg_version] = substr($file_data, 3, 3);
   
    /*
     * Let's get the total number of colours in this image using a special
     * piece of code, which fetches all the image's colours.
     */
    $im_gif = imagecreatefromgif($file);
    $image_info[total_pallete_colours] = imagecolorstotal($im_gif);
   
    /*
     * Now, the next thing we need to do is get the width and height of the
     * image in question by using imagesx(); and imagesy();
     */
    $image_info[width] = imagesx($im_gif);
    $image_info[height] = imagesy($im_gif);
    
    /*
     * Let's fetch the transparent color of the image, if there is one.
     */
    $id = imagecolortransparent($im_gif);
    $image_info[transparent_color_id] = $id;
    $image_info[transparent_color_values] = imagecolorsforindex($im_gif, $id);
   
    /*
     * Now, we return all the data.
     */
    return $image_info;
}
/*
 * Usage Example:
 */
 
echo '<pre>';
print_r(fetch_gif_data("hello.gif"));
echo '</pre>';
?>

This script returns something like:

Array
(
    [version] => GIF89a
    [file_reg_version] => 89a
    [total_pallete_colours] => 251
    [width] => 100
    [height] => 100
    [transparent_color_id] => 16
    [transparent_color_values] => Array
        (
            [red] => 0
            [green] => 0
            [blue] => 0
            [alpha] => 127
        )

)

Tested on PHP 5.1.2, but should work on older versions.
sampathperera at hotmail dot com - Sri Lanka
20-Jul-2006 11:04
I have used following function to generate Security Images to authenticate users are real humans. Need to have GD graphic library with FreeType enabled.

Used a gif file as background, put random text on it & creates a new gif file as output.
<?php
function createImage(){
//         creates the images, writes the file
        $fileRand = md5(rand(100000,999999));
        $string_a = array("A","B","C","D","E","F","G","H","J","K",
"L","M","N","P","R","S","T","U","V","W","X","Y","Z",
"2","3","4","5","6","7","8","9");
        $keys = array_rand($string_a, 6);
        foreach($keys as $n=>$v){
            $string .= $string_a[$v];
         }
$backgroundimage = "security_background.gif";
$im=imagecreatefromgif($backgroundimage);
$colour = imagecolorallocate($im, rand(0,255), rand(0,255), rand(0,255));
$font = 'Arial';
$angle = rand(-5,5);
// Add the text
imagettftext($im, 16, $angle, 15, 25, $colour, $font, $string);
$outfile= "$fileRand.gif";
imagegif($im,$outfile);
return $outfile;
}
echo "<IMG SRC=".createImage()." name=secimg>";

?>
g8z at yahoo dot com
19-Jul-2006 02:39
<?php
/**
chunk_image breaks an image into roughly equal chunks horizontally (which are returned in an array of image resources)

parameters:
$image = image resource to work on
$chunks = number of chunks to break the image into

Courtesy of the $5 Script Achive: http://www.tufat.com
**/

function chunk_image_horizontally ($image, $chunks = 1)
{
    $image_width = imagesx($image);
    $image_height = imagesy($image);

    // calculate required chunk size
    $chunk_size = round($image_width / $chunks);

    // do all but the last chunk
    for ($current_chunk = 1; $current_chunk < $chunks; $current_chunk++) {
        // create image resource to store chunk
        $chunk_images[$current_chunk - 1] = imagecreate($chunk_size, $image_height);

        // copy chunk to chunk images array
        imagecopy($chunk_images[$current_chunk - 1], $image, 1, 1, $chunk_size * ($current_chunk - 1) + 1 , 1, $chunk_size, $image_height);
    }

    // get last chunk
    $chunk_images[$chunks - 1] = imagecreate($chunk_size, $image_height);
    imagecopy($chunk_images[$chunks - 1], $image, 1, 1, $chunk_size * ($chunks - 1) + 1 , 1, $image_width, $image_height);

    // return array
    return $chunk_images;
}

//Example:

// read in test.jpg, and break it into 4 chunks using our function
$in_image = imagecreatefromjpeg('./image.jpg');
$images = chunk_image_horizontally($in_image, 4);
$count = 0;

// save chunks to files
foreach ($images as $image) {
    $count++;
    imagejpeg($image, './test_chunk'.$count.'.jpg');
}
?>
g8z at yahoo dot com
19-Jul-2006 02:36
<?php
/**
change_color replaces $old_color with $new_color. $threshold allows you to specify how far away from the specified color a pixel can be and still be considered a match. $old_color and $new_color must be decimal color values.

Courtesy of the $5 Script Achive: http://www.tufat.com
*/

function change_color($image, $old_color, $new_color, $threshold = 15)
{
    $image_width = imagesx($image);
    $image_height = imagesy($image);

    // iterate through x axis
    for ($x = 0; $x < $image_width; $x++) {

        // iterate through y axis
        for ($y = 0; $y < $image_height; $y++) {

            // look at current pixel
            $pixel_color = imagecolorat($image, $x, $y);

            if (($pixel_color <= $old_color + $threshold) && ($pixel_color >= $old_color - $threshold)) {
                // replace with new color
                imagesetpixel($image, $x, $y, $new_color);
            }
        }
    }
}

// EXAMPLE:

// convert all red in the image to green
$image = imagecreatefromjpeg('./test.jpg');
$red_rbg = 16646146;
$green_rbg = 65341;
change_color($image, $red_rbg, $green_rbg, 15);
imagejpeg($image, './test_changed.jpg');
?>
php at synvb dot com
21-Apr-2006 09:19
Here is a single-function to flip, based on the one below.

<?php
  function flipImage($image, $vertical, $horizontal) {
    $w = imagesx($image);
    $h = imagesy($image);

    if (!$vertical && !$horizontal) return $image;

    $flipped = imagecreatetruecolor($w, $h);

    if ($vertical) {
      for ($y=0; $y<$h; $y++) {
        imagecopy($flipped, $image, 0, $y, 0, $h - $y - 1, $w, 1);
      }
    }

    if ($horizontal) {
      if ($vertical) {
        $image = $flipped;
        $flipped = imagecreatetruecolor($w, $h);
      }

      for ($x=0; $x<$w; $x++) {
        imagecopy($flipped, $image, $x, 0, $w - $x - 1, 0, 1, $h);
      }
    }

    return $flipped;
  }
?>
shd at earthling dot net
28-Mar-2006 05:44
If you happen to need a way to output a Windows BMP file (e.g. when using the PEAR ExcelWriter), feel free to use the following code:

<?php
function imagebmp ($im, $fn = false)
{
    if (!$im) return false;
           
    if ($fn === false) $fn = 'php://output';
    $f = fopen ($fn, "w");
    if (!$f) return false;
           
    //Image dimensions
    $biWidth = imagesx ($im);
    $biHeight = imagesy ($im);
    $biBPLine = $biWidth * 3;
    $biStride = ($biBPLine + 3) & ~3;
    $biSizeImage = $biStride * $biHeight;
    $bfOffBits = 54;
    $bfSize = $bfOffBits + $biSizeImage;
           
    //BITMAPFILEHEADER
    fwrite ($f, 'BM', 2);
    fwrite ($f, pack ('VvvV', $bfSize, 0, 0, $bfOffBits));
           
    //BITMAPINFO (BITMAPINFOHEADER)
    fwrite ($f, pack ('VVVvvVVVVVV', 40, $biWidth, $biHeight, 1, 24, 0, $biSizeImage, 0, 0, 0, 0));
           
    $numpad = $biStride - $biBPLine;
    for ($y = $biHeight - 1; $y >= 0; --$y)
    {
        for ($x = 0; $x < $biWidth; ++$x)
        {
            $col = imagecolorat ($im, $x, $y);
            fwrite ($f, pack ('V', $col), 3);
        }
        for ($i = 0; $i < $numpad; ++$i)
            fwrite ($f, pack ('C', 0));
    }
    fclose ($f);
    return true;
}
?>

It works the same way as regular imagejpeg/imagepng do and only supports GD2.0 true colour bitmaps (which is what's required by ExcelWriter).
felipensp at gmail dot com
12-Mar-2006 10:17
Representation decimal of a color in hexadecimal for use on functions of library GD.

<?php

    // Representation hexadecimal
    $var = '#FFFFFF';

    function getRgbFromGd($color_hex) {

        return array_map('hexdec', explode('|', wordwrap(substr($color_hex, 1), 2, '|', 1)));

    }
   
    print_r(getRgbFromGd($var));

    // Output: Array ( [0] => 255 [1] => 255 [2] => 255 )

?>
andrew dot barlow at gmail dot com
28-Feb-2006 10:47
To create a simple transparent gif with black text with any TrueType Font...

Simple put this script into a PHP file and call it with the usual IMG tag.

You can also specify the font size for the IMG tag too.

Change the $font to your own font and upload it to the same directory as this script.

<?php
// Set the content-type
header("Content-type: image/gif");

$fontsize = 18;
if(@$_GET['fontsize']) {
    $fontsize = $_GET['fontsize'];
}
$font = 'yourcustomfont.ttf';
$text = @$_GET['text'];

// Create the image
$size = imagettfbbox($fontsize, 0, $font, $text);
$width = $size[2] + $size[0] + 8;
$height = abs($size[1]) + abs($size[7]);

$im = imagecreate($width, $height);

$colourBlack = imagecolorallocate($im, 255, 255, 255);
imagecolortransparent($im, $colourBlack);

// Create some colors
$white = imagecolorallocate($im, 255, 255, 255);
$black = imagecolorallocate($im, 0, 0, 0);

// Add the text
imagefttext($im, $fontsize, 0, 0, abs($size[5]), $black, $font, $text);

// Using imagepng() results in clearer text compared with
imagegif($im);
imagedestroy($im);
?>
relsqui at chiliahedron dot com
17-Feb-2006 12:14
<?php
// This is a correction to the image-flipping function I posted previously.
// The bitwise ands (&) were incorrectly written as logical ands (&&).
// Needless to say, that breaks the function in obnoxious--if amusing--ways.

define("VERTICAL", 1);
define("HORIZONTAL", 2);

function imageflip($image, $mode) {
       $w = imagesx($image);
       $h = imagesy($image);
       $flipped = imagecreate($w, $h);
       if ($mode & VERTICAL) {
               for ($y = 0; $y < $h; $y++) {
                       imagecopy($flipped, $image, 0, $y, 0, $h - $y - 1, $w, 1);
               }
       }
       if ($mode & HORIZONTAL) {
               for ($x = 0; $x < $w; $x++) {
                       imagecopy($flipped, $image, $x, 0, $w - $x - 1, 0, 1, $h);
               }
       }
       return $flipped;
}
?>
relsqui at chiliahedron dot com
14-Feb-2006 04:22
On the offchance someone else should need one, here's a function you can use to randomly "mix" two colors, resulting in a "child" color with components of both. You might use it to come up with ideas for a color scheme, for example; the image section seemed as good a place for it as any.

<?php
// $mom and $dad should be integers, quite possibly the output of hexdec().
// Similarly, the return value $child will be an integer suitable for feeding to dechex().

breed_colors($mom, $dad) {
        do { $maskhex .= rand()&1 ? "f" : "0"; } while (strlen($maskhex) < 6);
        $mask = hexdec($maskhex);
        $inversemask = $mask ^ 16777215;
        $child = ($mom & $mask) | ($dad & $inversemask);
        return $child;
}

// For example:
breed_colors(hexdec("012345"), hexdec("6789ab"));

// Let's say the random mask was ff0f0f.
// The inverse mask is therefore 00f0f0.
// $mom & $mask == 010305.
// $dad & $inversemask == 0080a0.
// Those two |ed together make 0183a5, which combines the traits of the parents into one $child.

?>
jan at anh dot sk
15-Jan-2006 05:03
When outputing an image from a script to a browser, use header("Content-Length: XYZ") together with Content-Type header. This avoids problems rendering-displaying the image with some browsers (f.i. MSIE) - fixes random image cutting of image bottom parts. Image from cache example:

<?php
$cache_file = "imageca