Last updated: Sat, 17 Jul 2004

XLII. Image Functions

Introduction

PHP is not limited to creating just HTML output. It can also be used to create and manipulate image files in a variety of different image formats, including gif, png, jpg, wbmp, and xpm. Even more convenient, PHP can output image streams directly to a browser. You will need to compile PHP with the GD library of image functions for this to work. GD and PHP may also require other libraries, depending on which image formats you want to work with.

You can use the image functions in PHP to get the size of JPEG, GIF, PNG, SWF, TIFF and JPEG2000 images.

Not: Read requirements section about how to expand image capabilities to read, write and modify images and to read meta data of pictures taken by digital cameras.

Requirements

If you have the GD library (available at http://www.boutell.com/gd/) you will also be able to create and manipulate images.

The format of images you are able to manipulate depend on the version of GD you install, and any other libraries GD might need to access those image formats. Versions of GD older than gd-1.6 support GIF format images, and do not support PNG, where versions greater than gd-1.6 support PNG, not GIF.

Not: Since PHP 4.3 there is a bundled version of the GD lib. This bundled version has some additional features like alpha blending, and should be used in preference to the external library since its codebase is better maintained and more stable.

You may wish to enhance GD to handle more image formats.

Tablo 1. Supported image formats

Image format	Library to download	Notes
`gif`		Only supported in GD versions older than gd-1.6. Read-only GIF support is available with PHP 4.3.0 and the bundled GD-library.
`jpeg-6b`	ftp://ftp.uu.net/graphics/jpeg/
`png`	http://www.libpng.org/pub/png/libpng.html	Only supported in GD versions greater than gd-1.6.
`xpm`	ftp://metalab.unc.edu/pub/Linux/libs/X/!INDEX.html	It's likely you have this library already available, if your system has an installed X-Environment.

You may wish to enhance GD to deal with different fonts. The following font libraries are supported:

Tablo 2. Supported font libraries

Font library	Download	Notes
`FreeType 1.x`	http://www.freetype.org/
`FreeType 2`	http://www.freetype.org/
`T1lib`	ftp://sunsite.unc.edu/pub/Linux/libs/graphics/)	Support for Type 1 fonts.

If you have PHP compiled with --enable-exif you are able to work with information stored in headers of JPEG and TIFF images. This way you can read meta data generated by digital cameras as mentioned above. These functions do not require the GD library.

Not: PHP does not require any additional library for the exif module.

Installation

To enable GD-support configure PHP --with-gd[=DIR], where DIR is the GD base install directory. To use the recommended bundled version of the GD library (which was first bundled in PHP 4.3.0), use the configure option --with-gd.

In Windows, you'll include the GD2 DLL php_gd2.dll as an extension in php.ini. The GD1 DLL php_gd.dll was removed in PHP 4.3.2. Also note that the preferred truecolor image functions, such as imagecreatetruecolor(), require GD2.

Not: To enable exif support in Windows, php_mbstring.dll must be loaded prior to php_exif.dll in php.ini.

To disable GD support in PHP 3 add --without-gd to your configure line.

Enhance the capabilities of GD to handle more image formats by specifying the --with-XXXX configure switch to your PHP configure line.

Tablo 3. Supported image formats

Image Format	Configure Switch
`jpeg-6b`	To enable support for jpeg-6b add `--with-jpeg-dir=DIR`.
`png`	To enable support for png add `--with-png-dir=DIR`. Note, libpng requires the zlib library, therefore add `--with-zlib-dir[=DIR]` to your configure line.
`xpm`	To enable support for xpm add `--with-xpm-dir=DIR`. If configure is not able to find the required libraries, you may add the path to your X11 libraries.

Not: When compiling PHP with libpng, you must use the same version that was linked with the GD library.

Enhance the capabilities of GD to deal with different fonts by specifying the --with-XXXX configure switch to your PHP configure line.

Tablo 4. Supported font libraries

Font library	Configure Switch
`FreeType 1.x`	To enable support for FreeType 1.x add `--with-ttf[=DIR]`.
`FreeType 2`	To enable support for FreeType 2 add `--with-freetype-dir=DIR`.
`T1lib`	To enable support for T1lib (Type 1 fonts) add `--with-t1lib[=DIR]`.
`Native TrueType string function`	To enable support for native TrueType string function add `--enable-gd-native-ttf`.

Runtime Configuration

The behaviour of these functions is affected by settings in php.ini.

Exif supports automatically conversion for Unicode and JIS character encodings of user comments when module mbstring is available. This is done by first decoding the comment using the specified characterset. The result is then encoded with another characterset which should match your HTTP output.

Tablo 5. Exif configuration options

Name	Default	Changeable
exif.encode_unicode	"ISO-8859-15"	PHP_INI_ALL
exif.decode_unicode_motorola	"UCS-2BE"	PHP_INI_ALL
exif.decode_unicode_intel	"UCS-2LE"	PHP_INI_ALL
exif.encode_jis	""	PHP_INI_ALL
exif.decode_jis_motorola	"JIS"	PHP_INI_ALL
exif.decode_jis_intel	"JIS"	PHP_INI_ALL

For further details and definition of the PHP_INI_* constants see ini_set().

Here's a short explanation of the configuration directives.

exif.encode_unicode string: exif.encode_unicode defines the characterset UNICODE user comments are handled. This defaults to ISO-8859-15 which should work for most non Asian countries. The setting can be empty or must be an encoding supported by mbstring. If it is empty the current internal encoding of mbstring is used.
exif.decode_unicode_motorola string: exif.decode_unicode_motorola defines the image internal characterset for Unicode encoded user comments if image is in motorola byte order (big-endian). This setting cannot be empty but you can specify a list of encodings supported by mbstring. The default is UCS-2BE.
exif.decode_unicode_intel string: exif.decode_unicode_intel defines the image internal characterset for Unicode encoded user comments if image is in intel byte order (little-endian). This setting cannot be empty but you can specify a list of encodings supported by mbstring. The default is UCS-2LE.
exif.encode_jis string: exif.encode_jis defines the characterset JIS user comments are handled. This defaults to an empty value which forces the functions to use the current internal encoding of mbstring.
exif.decode_jis_motorola string: exif.decode_jis_motorola defines the image internal characterset for JIS encoded user comments if image is in motorola byte order (big-endian). This setting cannot be empty but you can specify a list of encodings supported by mbstring. The default is JIS.
exif.decode_jis_intel string: exif.decode_jis_intel defines the image internal characterset for JIS encoded user comments if image is in intel byte order (little-endian). This setting cannot be empty but you can specify a list of encodings supported by mbstring. The default is JIS.

Resource Types

This extension has no resource types defined.

Predefined Constants

The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.

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)

Examples

�rnek 1. PNG creation with PHP


<?php

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

    $string = $_GET['text'];

    $im     = imagecreatefrompng("images/button1.png");

    $orange = imagecolorallocate($im, 220, 210, 60);

    $px     = (imagesx($im) - 7.5 * strlen($string)) / 2;

    imagestring($im, 3, $px, 9, $string, $orange);

    imagepng($im);

    imagedestroy($im);

?>

This example would be called from a page with a tag like: <img src="button.php?text=text">. The above button.php script then takes this "text" string and overlays it on top of a base image which in this case is "images/button1.png" and outputs the resulting image. This is a very convenient way to avoid having to draw new button images every time you want to change the text of a button. With this method they are dynamically generated.

��indekiler
exif_imagetype -- Determine the type of an image
exif_read_data -- Reads the EXIF headers from JPEG or TIFF. This way you can read meta data generated by digital cameras.
exif_thumbnail -- Retrieve the embedded thumbnail of a TIFF or JPEG image
gd_info -- Retrieve information about the currently installed GD library
getimagesize -- Get the size of an image
image_type_to_extension -- Get file extension for image type
image_type_to_mime_type -- Get Mime-Type for image-type returned by getimagesize, exif_read_data, exif_thumbnail, exif_imagetype
image2wbmp -- Output image to browser or file
imagealphablending -- Set the blending mode for an image
imageantialias -- Should antialias functions be used or not
imagearc -- Draw a partial ellipse
imagechar -- Draw a character horizontally
imagecharup -- Draw a character vertically
imagecolorallocate -- Allocate a color for an image
imagecolorallocatealpha -- Allocate a color for an image
imagecolorat -- Get the index of the color of a pixel
imagecolorclosest -- Get the index of the closest color to the specified color
imagecolorclosestalpha -- Get the index of the closest color to the specified color + alpha
imagecolorclosesthwb -- Get the index of the color which has the hue, white and blackness nearest to the given color
imagecolordeallocate -- De-allocate a color for an image
imagecolorexact -- Get the index of the specified color
imagecolorexactalpha -- Get the index of the specified color + alpha
imagecolormatch -- Makes the colors of the palette version of an image more closely match the true color version
imagecolorresolve -- Get the index of the specified color or its closest possible alternative
imagecolorresolvealpha -- Get the index of the specified color + alpha or its closest possible alternative
imagecolorset -- Set the color for the specified palette index
imagecolorsforindex -- Get the colors for an index
imagecolorstotal -- Find out the number of colors in an image's palette
imagecolortransparent -- Define a color as transparent
imagecopy -- Copy part of an image
imagecopymerge -- Copy and merge part of an image
imagecopymergegray -- Copy and merge part of an image with gray scale
imagecopyresampled -- Copy and resize part of an image with resampling
imagecopyresized -- Copy and resize part of an image
imagecreate -- Create a new palette based image
imagecreatefromgd2 -- Create a new image from GD2 file or URL
imagecreatefromgd2part -- Create a new image from a given part of GD2 file or URL
imagecreatefromgd -- Create a new image from GD file or URL
imagecreatefromgif -- Create a new image from file or URL
imagecreatefromjpeg -- Create a new image from file or URL
imagecreatefrompng -- Create a new image from file or URL
imagecreatefromstring -- Create a new image from the image stream in the string
imagecreatefromwbmp -- Create a new image from file or URL
imagecreatefromxbm -- Create a new image from file or URL
imagecreatefromxpm -- Create a new image from file or URL
imagecreatetruecolor -- Create a new true color image
imagedashedline -- Draw a dashed line
imagedestroy -- Destroy an image
imageellipse -- Draw an ellipse
imagefill -- Flood fill
imagefilledarc -- Draw a partial ellipse and fill it
imagefilledellipse -- Draw a filled ellipse
imagefilledpolygon -- Draw a filled polygon
imagefilledrectangle -- Draw a filled rectangle
imagefilltoborder -- Flood fill to specific color
imagefilter -- Applies Filter an image using a custom angle
imagefontheight -- Get font height
imagefontwidth -- Get font width
imageftbbox -- Give the bounding box of a text using fonts via freetype2
imagefttext -- Write text to the image using fonts using FreeType 2
imagegammacorrect -- Apply a gamma correction to a GD image
imagegd2 -- Output GD2 image
imagegd -- Output GD image to browser or file
imagegif -- Output image to browser or file
imageinterlace -- Enable or disable interlace
imageistruecolor -- Finds whether an image is a truecolor image.
imagejpeg -- Output image to browser or file
imagelayereffect -- Set the alpha blending flag to use the bundled libgd layering effects
imageline -- Draw a line
imageloadfont -- Load a new font
imagepalettecopy -- Copy the palette from one image to another
imagepng -- Output a PNG image to either the browser or a file
imagepolygon -- Draw a polygon
imagepsbbox -- Give the bounding box of a text rectangle using PostScript Type1 fonts
imagepscopyfont -- Make a copy of an already loaded font for further modification
imagepsencodefont -- Change the character encoding vector of a font
imagepsextendfont -- Extend or condense a font
imagepsfreefont -- Free memory used by a PostScript Type 1 font
imagepsloadfont -- Load a PostScript Type 1 font from file
imagepsslantfont -- Slant a font
imagepstext -- To draw a text string over an image using PostScript Type1 fonts
imagerectangle -- Draw a rectangle
imagerotate -- Rotate an image with a given angle
imagesavealpha -- Set the flag to save full alpha channel information (as opposed to single-color transparency) when saving PNG images.
imagesetbrush -- Set the brush image for line drawing
imagesetpixel -- Set a single pixel
imagesetstyle -- Set the style for line drawing
imagesetthickness -- Set the thickness for line drawing
imagesettile -- Set the tile image for filling
imagestring -- Draw a string horizontally
imagestringup -- Draw a string vertically
imagesx -- Get image width
imagesy -- Get image height
imagetruecolortopalette -- Convert a true color image to a palette image
imagettfbbox -- Give the bounding box of a text using TrueType fonts
imagettftext -- Write text to the image using TrueType fonts
imagetypes -- Return the image types supported by this PHP build
imagewbmp -- Output image to browser or file
imagexbm -- Output XBM image to browser or file
iptcembed -- Embed binary IPTC data into a JPEG image
iptcparse -- Parse a binary IPTC http://www.iptc.org/ block into single tags.
jpeg2wbmp -- Convert JPEG image file to WBMP image file
png2wbmp -- Convert PNG image file to WBMP image file
read_exif_data -- Alias of exif_read_data()

exif_imagetype

ob_iconv_handler

Last updated: Sat, 17 Jul 2004

add a note User Contributed Notes
Image Functions

dev at kingthief dot com
28-Mar-2008 09:20


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!

ph_corp at yahoo dot fr
23-Dec-2007 03:19


<?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 );

}



?>

shd at earthling dot net
28-Mar-2006 04:44


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 09:17


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 )



?>

peter dot hulstaert at gmail dot com
05-Jan-2006 05:18


While I was searching for a good way to draw a graph, I stumbled on skumar2k15's script.



I have taken the liberty to improve multiple aspects of it.



1. The array can grow and shrink in size, the graph will adjust accordingly.

2. All the values in the array are recalculated so they won't get bigger than the height of the graph.

3. I inserted the possibility to keep a percentage off the height away from the edge.

4. You can adjust the size of the grid.

5. Everything will adjust when you change the height of width.



<? 

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



// Define variables

$Values=array(50,90,30,155,50,40,320,50,40,86,240,128,650,540,320);

$imgWidth=500;

$imgHeight=200;

$grid=25;

$graphspacing=0.05;



//Creation of new array with hight adjusted values

while (list($key, $val) = each($Values)) 

    {if($val>$max){$max=$val;}}



for ($i=0; $i<count($Values); $i++){

$graphValues[$i] = $Values[$i] * (($imgHeight*(1-$graphspacing))/$max);

}

// Create image and define colors



$image=imagecreate($imgWidth, $imgHeight);

$colorWhite=imagecolorallocate($image, 255, 255, 255);

$colorGrey=imagecolorallocate($image, 192, 192, 192);

$colorBlue=imagecolorallocate($image, 0, 0, 255);



// Create border around image

imageline($image, 0, 0, 0, $imgHeight, $colorGrey);

imageline($image, 0, 0, $imgWidth, 0, $colorGrey);

imageline($image, $imgWidth-1, 0, $imgWidth-1, $imgHeight-1, $colorGrey);

imageline($image, 0, $imgHeight-1, $imgWidth-1, $imgHeight-1, $colorGrey);



// Create grid

for ($i=1; $i<($imgWidth/$grid); $i++)

    {imageline($image, $i*$grid, 0, $i*$grid, $imgHeight, $colorGrey);}

for ($i=1; $i<($imgHeight/$grid); $i++)

    {imageline($image, 0, $i*$grid, $imgWidth, $i*$grid, $colorGrey);}



// Create line graph

if($imgWidth/$grid>count($graphValues)){$space=$grid;}

else{$space = $imgWidth/(count($graphValues)-1);}



for ($i=0; $i<count($graphValues)-1; $i++)

    {imageline($image, $i*$space, ($imgHeight-$graphValues[$i]), ($i+1)*$space, ($imgHeight-$graphValues[$i+1]), $colorBlue);}



// Output graph and clear image from memory

imagepng($image);

imagedestroy($image);

?>

michal-ok at o2 dot pl
18-Oct-2005 02:29


The image sharpen function (by Alex R. Austin) provided below seems to be very resource hungry and I couldn't make it work on two different servers - trying to sharpen a 413 x 413 image I ended up with "Fatal error: Allowed memory size of 8388608 bytes exhausted" or "Internal Server Error" or the script terminated without notice. Because I had no priviliges to change the default memory limit on these servers I started looking for other sharpen functions. I have come across a php Unsharp Mask function which works like a charm on both of the servers I dealt with. It can be found at http://vikjavev.no/hovudsida/umtestside.php.

mslemko
09-Oct-2005 12:09


For fedora core 4 users that find that the gd library isn't installed, you can issue the command (as root)



# yum install php-gd



it should download and install the gd library. You will need to restart apache... phpinfo() should then tell you "GD Support     enabled".

timeshifting at gmail dot com
24-Aug-2005 03:39


To sharpen an image, rather than using the code below that produces a sharpening filter with php, use the built-in GD function "imageconvolution" which is designed for this purpose. Matrices can be used for sharpening, blurring, edge detection, etc, ala Photoshop.



A sharpening example:



<?php



$sharpenMatrix = array(-1,-1,-1,-1,16,-1,-1,-1,-1);

$divisor = 8;

$offset = 0;



imageconvolution($myImage, $sharpenMatrix, $divisor, $offset);



?>



Below is some information on building different kinds of matrices. (If you have photoshop (or PSP, GIMP) you can test out your matrices before applying them in PHP)



http://loriweb.pair.com/8udf-basics.html (covers blurs)

http://loriweb.pair.com/8udf-sharpen.html

http://loriweb.pair.com/8udf-edges.html

http://loriweb.pair.com/8udf-emboss.html

jeff at lushmedia dot com
04-Nov-2003 08:52


I wrote an online overview of the image functions that people might find useful. In addition to a general overview of the various function categories and code samples, I have included many interactive examples of the functions, allowing viewers to experiment with the parameters, and seeing the results in real time. The presentation is located at New York PHP

http://www.nyphp.org/content/presentations/GDintro/

sellout at NoSpAm dot dharmadevil dot com
16-Apr-2003 10:06


A fun little function to output UPC-A 11-digit barcodes.

Thanks to barcodeisland.com for the specs.



<?php



function UPCAbarcode($code) {

  $lw = 2; $hi = 100;

  $Lencode = array('0001101','0011001','0010011','0111101','0100011',

                   '0110001','0101111','0111011','0110111','0001011');

  $Rencode = array('1110010','1100110','1101100','1000010','1011100',

                   '1001110','1010000','1000100','1001000','1110100');

  $ends = '101'; $center = '01010';

  /* UPC-A Must be 11 digits, we compute the checksum. */

  if ( strlen($code) != 11 ) { die("UPC-A Must be 11 digits."); }

  /* Compute the EAN-13 Checksum digit */

  $ncode = '0'.$code;

  $even = 0; $odd = 0;

  for ($x=0;$x<12;$x++) {

    if ($x % 2) { $odd += $ncode[$x]; } else { $even += $ncode[$x]; }

  }

  $code.=(10 - (($odd * 3 + $even) % 10)) % 10;

  /* Create the bar encoding using a binary string */

  $bars=$ends;

  $bars.=$Lencode[$code[0]];

  for($x=1;$x<6;$x++) {

    $bars.=$Lencode[$code[$x]];

  }

  $bars.=$center;

  for($x=6;$x<12;$x++) {

    $bars.=$Rencode[$code[$x]];

  }

  $bars.=$ends;

  /* Generate the Barcode Image */

  $img = ImageCreate($lw*95+30,$hi+30);

  $fg = ImageColorAllocate($img, 0, 0, 0);

  $bg = ImageColorAllocate($img, 255, 255, 255);

  ImageFilledRectangle($img, 0, 0, $lw*95+30, $hi+30, $bg);

  $shift=10;

  for ($x=0;$x<strlen($bars);$x++) {

    if (($x<10) || ($x>=45 && $x<50) || ($x >=85)) { $sh=10; } else { $sh=0; }

    if ($bars[$x] == '1') { $color = $fg; } else { $color = $bg; }

    ImageFilledRectangle($img, ($x*$lw)+15,5,($x+1)*$lw+14,$hi+5+$sh,$color);

  }

  /* Add the Human Readable Label */

  ImageString($img,4,5,$hi-5,$code[0],$fg);

  for ($x=0;$x<5;$x++) {

    ImageString($img,5,$lw*(13+$x*6)+15,$hi+5,$code[$x+1],$fg);

    ImageString($img,5,$lw*(53+$x*6)+15,$hi+5,$code[$x+6],$fg);

  }

  ImageString($img,4,$lw*95+17,$hi-5,$code[11],$fg);

  /* Output the Header and Content. */

  header("Content-Type: image/png");

  ImagePNG($img);

}



UPCAbarcode('12345678901');



?>

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Last updated: Sat, 17 Jul 2004