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gd_info> <iis_stop_service
Last updated: Mon, 26 Nov 2007

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Image 图像函数

简介

PHP 不仅限于只产生 HTML 的输出。还可以创建及操作多种不同图像格式的图像文件,包括 gif,png,jpg,wbmp 和 xpm。更方便的是,PHP 可以直接将图像流输出到浏览器。要处理图像,需要在编译 PHP 时加上图像函数的 GD 库。GD 和 PHP 还可能需要其它的库,视乎需要支持哪些图像格式而定。

可以在 PHP 中使用图像函数来得到 JPEGGIFPNGSWFTIFFJPEG2000 图像的大小。

Note: 阅读需求一节以了解怎样扩展图像能力来读取,写入和修改图像以及读取数码相机拍摄的照片中的元数据。

需求

如果有 GD 库(在 » http://www.libgd.org/),可以创建及操作图像。

所能处理的图像格式取决于所安装的 GD 版本,以及其它 GD 可能用到的来访问这些图像格式的库。低于 gd-1.6 版本的 GD 支持 GIF 图像格式,不支持 PNG,高于 gd-1.6 低于 gd-2.0.28 的版本支持 PNG,不支持 GIF。在 gd-2.0.28 中又重新支持 GIF 了。

Note: 自 PHP 4.3 起绑定了一个 GD 库的版本。这个绑定的版本具有一些附加的特色例如透明混色,应优先使用此版本,因为它的代码维护得更好以及更加稳定。

可能想要增加 GD 处理的图像格式。

所支持的图像格式
图像格式 要下载的库 注解
gif   仅在低于 gd-1.6 与高于 gd-2.0.28 的 GD 版本中支持。PHP 4.3.0 以及绑定的 GD 库中支持只读的 GIF。PHP 4.3.9 和 PHP 5.0.1 起支持写入
jpeg-6b » ftp://ftp.uu.net/graphics/jpeg/  
png » http://www.libpng.org/pub/png/libpng.html 仅在高于 gd-1.6 的 GD 版本中支持。
xpm » ftp://metalab.unc.edu/pub/Linux/libs/X/!INDEX.html 如果系统中安装了 X 环境,则很可能已经有了这个库。

可能想要增强 GD 处理不同字体的能力。支持下列字库:

所支持的字库
字库 下载位置 注解
FreeType 1.x » http://www.freetype.org/  
FreeType 2 » http://www.freetype.org/  
T1lib » ftp://sunsite.unc.edu/pub/Linux/libs/graphics/) 支持 Type 1 字体。

如果 PHP 编译时指定了 --enable-exif,就可以操作存储于 JPEGTIFF 图像文件头中的信息。这样就可以读取上面提到的数码相机生成的照片中的元数据。这些函数不需要 GD 库。

安装

要激活 GD 支持,配置 PHP 时加上 --with-gd[=DIR],DIR 是 GD 的基本安装目录。要使用推荐的绑定的 GD 库版本(首次绑定于 PHP 4.3.0),使用 --with-gd。要编译 GD 库,需要libpnglibjpeg

在 Windows 中,需要将 GD2 的 DLL 文件 php_gd2.dll 作为一个扩展包含在 php.ini 中。GD1 的 DLL 文件 php_gd.dll 在 PHP 4.3.2 中被删除了。此外要注意首选的真彩色图像函数,例如 imagecreatetruecolor(),需要 GD2。

Note: 要在 Windows 下启用 exif,在 php.ini 中 php_mbstring.dll 必须在 php_exif.dll 之前加载。

要在 PHP 3 中禁止 GD 支持,在配置时加上 --without-gd

要增强 GD 的能力以处理更多的图像格式,在配置 PHP 时指定 --with-XXXX 的配置开关。

所支持的图像格式
图像格式 配置开关
jpeg-6b 要激活 jpeg-6b 的支持,加上 --with-jpeg-dir=DIR.
png 要激活 png 的支持,加上 --with-png-dir=DIR。注意,libpng 需要 zlib library,因此配置中还要加上 --with-zlib-dir[=DIR]
xpm 要激活 xpm 的支持,加上 --with-xpm-dir=DIR。如果配置时提示找不到所需要的库,可以加上到 X11 库的路径。

Note: 当把 PHP 和 libpng 一起编译时,必须使用和 GD 库连接的同一个版本。

要增强 GD 的能力以处理更多的字体,在配置 PHP 时指定 --with-XXXX 的配置开关。

所支持的字库
字库 配置开关
FreeType 1.x 要激活 FreeType 1.x 的支持,加上 --with-ttf[=DIR]
FreeType 2 要激活 FreeType 2 的支持,加上 --with-freetype-dir=DIR
T1lib 要激活 T1lib(Type 1 字体),加上 --with-t1lib[=DIR]
本地 TrueType 字符串函数 要激活本地 TrueType 字符串函数的支持,加上 --enable-gd-native-ttf

运行时配置

没有 image 特定的配置选项。不过可以参考 exif 扩展库配置指令。

资源类型

本扩展模块未定义任何资源类型。

预定义常量

以下常量由本扩展模块定义,因此只有在本扩展模块被编译到 PHP 中,或者在运行时被动态加载后才有效。

IMG_GIF (integer)
IMG_JPG (integer)
IMG_JPEG (integer)
IMG_PNG (integer)
IMG_WBMP (integer)
IMG_XPM (integer)
IMG_COLOR_TILED (integer)
IMG_COLOR_STYLED (integer)
IMG_COLOR_BRUSHED (integer)
IMG_COLOR_STYLEDBRUSHED (integer)
IMG_COLOR_TRANSPARENT (integer)
IMG_ARC_ROUNDED (integer)
IMG_ARC_PIE (integer)
IMG_ARC_CHORD (integer)
IMG_ARC_NOFILL (integer)
IMG_ARC_EDGED (integer)
IMAGETYPE_GIF (integer)
IMAGETYPE_JPEG (integer)
IMAGETYPE_PNG (integer)
IMAGETYPE_SWF (integer)
IMAGETYPE_PSD (integer)
IMAGETYPE_BMP (integer)
IMAGETYPE_WBMP (integer)
IMAGETYPE_XBM (integer)
IMAGETYPE_TIFF_II (integer)
IMAGETYPE_TIFF_MM (integer)
IMAGETYPE_IFF (integer)
IMAGETYPE_JB2 (integer)
IMAGETYPE_JPC (integer)
IMAGETYPE_JP2 (integer)
IMAGETYPE_JPX (integer)
IMAGETYPE_SWC (integer)

范例

Example#1 用 PHP 创建 PNG 图像

<?php

header
("Content-type: image/png");
$string $_GET['text'];
$im     imagecreatefrompng("images/button1.png");
$orange imagecolorallocate($im22021060);
$px     = (imagesx($im) - 7.5 strlen($string)) / 2;
imagestring($im3$px9$string$orange);
imagepng($im);
imagedestroy($im);

?>
本例应该在一个具有类似:<img src="button.php?text=text"> 标记的页面中被调用。上述的 button.php 脚本会取得 "text" 字符串将其覆盖在原图上(本例中的 "images/button1.png")并输出作为结果的图像。用此方法可以很方便地修改按钮上的文字从而避免了每次都要新画一个按钮的图像。用此方法就可以动态生成了。

Table of Contents



gd_info> <iis_stop_service
Last updated: Mon, 26 Nov 2007
 
add a note add a note User Contributed Notes
Image
bryan dot spirit at gmail dot com
08-Jun-2008 05:40
to troy and henry:
not $fontpath='../../../WINDOWS/fonts/';
but $fontpath = 'C:/Windows/fonts/';

its more likely to work with everyone on a windows.
dev at kingthief dot com
29-Mar-2008 12:20
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 08:39
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
15-Mar-2008 06:09
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(
           
230330
           
290390,
           
280340,
           
240, 380
           
310, 370
           
230330 
           
);

   
$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
12-Mar-2008 12:34
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 07:19
<?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 07:51
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 11:10
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
30-Aug-2007 02:44
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
23-Apr-2007 03:28
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
27-Mar-2007 01:41
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 02:48
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
03-Mar-2007 03:38
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
20-Aug-2006 06:04
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
19-Aug-2006 07:43
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
18-Aug-2006 07:01
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
21-Jul-2006 01:04
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
20-Jul-2006 04:39
<?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
20-Jul-2006 04:36
<?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
22-Apr-2006 11:19
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;