imagestring

(PHP 4, PHP 5, PHP 7, PHP 8)

imagestring — 文字列を水平に描画する

説明

imagestring(
    GdImage $image,
    GdFont|int $font,
    int $x,
    int $y,
    string $string,
    int $color
): bool

指定した座標に文字列 string を描画します。

パラメータ

image: imagecreatetruecolor()のような画像作成関数が返す GdImage オブジェクト。
font: latin2 エンコーディングの組み込みのフォントの場合は 1, 2, 3, 4, 5 のいずれか (数字が大きなほうが、より大きいフォントに対応します)、あるいは imageloadfont() が返した、GdFont クラスのインスタンスのいずれか。
x: 左上隅の x 座標。
y: 左上隅の y 座標。
string: 書き出す文字列。
color: imagecolorallocate() で作成された色識別子。

戻り値

成功した場合に true を、失敗した場合に false を返します。

変更履歴

バージョン	説明
8.1.0	引数 `font` は、GdFont クラスのインスタンスと数値を両方受け入れるようになりました。これより前のバージョンでは、数値のみを受け入れていました。
8.0.0	`image` は、 GdImage クラスのインスタンスを期待するようになりました。これより前のバージョンでは、有効な `gd` resource が期待されていました。

例

例1 imagestring() の例

<?php
// 100*30 の画像を生成します
$im = imagecreate(100, 30);

// 白色の背景と青色のテキスト
$bg = imagecolorallocate($im, 255, 255, 255);
$textcolor = imagecolorallocate($im, 0, 0, 255);

// 左上に文字列を描画します
imagestring($im, 5, 0, 0, "Hello world!", $textcolor);

// 画像を出力します
header("Content-type: image/png");

imagepng($im);
imagedestroy($im);
?>

上の例の出力は、たとえば以下のようになります。

参考

imagestringup() - 文字列を垂直に描画する
imageloadfont() - 新しいフォントを読み込む
imagettftext() - TrueType フォントを使用してテキストを画像に書き込む

add a note

User Contributed Notes 31 notes

down

keksnicoh at googlemail dot com ¶

16 years ago


Some fun with imagestring:

This function is a product of too much time..
It opens an image and create a new image with one letter instead of a pixel.

<?php
error_reporting(E_ALL);
/**
 * generates a image with chars instead of pixels
 *
 * @param string $url Filepath or url
 * @param string $chars The chars which should replace the pixels
 * @param int $shrpns Sharpness (2 = every second pixel, 1 = every pixel ... )
 * @param int $size 
 * @param int $weight font-weight/size
 * @return sesource
 * @author Nicolas 'KeksNicoh' Heimann <www.salamipla.net>
 * @date 02nov08
 */
function pixelfuck($url, $chars='ewk34543§G§$§$Tg34g4g', $shrpns=1, $size=4,$weight=2)
{
    list($w, $h, $type) = getimagesize($url);
    $resource = imagecreatefromstring(file_get_contents($url));
    $img = imagecreatetruecolor($w*$size,$h*$size);

    $cc = strlen($chars);
    for($y=0;$y <$h;$y+=$shrpns) 
        for($x=0;$x <$w;$x+=$shrpns)
            imagestring($img,$weight,$x*$size,$y*$size, $chars{@++$p%$cc}, imagecolorat($resource, $x, $y));
    return $img;
}

$url = 'http://upload.wikimedia.org/wikipedia/commons/b/be/Manga_Icon.png';
$text = 'I-dont-like-manga-...-Why-do-they-have-such-big-eyes? Strange-...-WHAT-WANT-YOU-DO?';

Header('Content-Type: image/png');
imagepng(pixelfuck($url, $text, 1, 6));
?>

Have fun  :)

down

Booteille ¶

9 years ago


Here is a function with similar declaration of imagestring() but who handles whitespaces (It creates new lines and 4 spaces instead of \n and \t) and image's size limits

<?php

/**
 * @author Booteille
 *
 * @param resource $image
 * @param int $font
 * @param int $x
 * @param int $y
 * @param string $string
 * @param int $color
 */
function whitespaces_imagestring($image, $font, $x, $y, $string, $color) {
    $font_height = imagefontheight($font);
    $font_width = imagefontwidth($font);
    $image_height = imagesy($image);
    $image_width = imagesx($image);
    $max_characters = (int) ($image_width - $x) / $font_width ;
    $next_offset_y = $y;

    for($i = 0, $exploded_string = explode("\n", $string), $i_count = count($exploded_string); $i < $i_count; $i++) {
        $exploded_wrapped_string = explode("\n", wordwrap(str_replace("\t", "    ", $exploded_string[$i]), $max_characters, "\n"));
        $j_count = count($exploded_wrapped_string);
        for($j = 0; $j < $j_count; $j++) {
            imagestring($image, $font, $x, $next_offset_y, $exploded_wrapped_string[$j], $color);
            $next_offset_y += $font_height;

            if($next_offset_y >= $image_height - $y) {
                return;
            }
        }
    }
}

?>

down

eviloverlord+php at gmail dot com ¶

16 years ago


Simple script to convert a string (such as an email addresses) to a transparent image.

Usage: 
<img src="stringtoimg.php?string=<?= urlencode(base64_encode($email)) ?>">

From a spambot's point of view, they see:
<img src="stringtoimg.php?string=ZpbXZG92ZXJsb3JkQGdtYWlsLmNvbQ%3D%3D">

Optional parameters:
    font_size: 1 to 5, with the default at 3
    R/G/B: the font color, in hex.

Usage:
<img src="stringtoimg.php?string=<?= urlencode(base64_encode($email)) ?>&font_size=4&R=FF&G=FF&B=00">

<?php
/*
Filename: stringtoimg.php

Parameters:
        string: the string to print
        font_size (optional): the size of the font from 1-5
        R/G/B (optional): the RGB colors of the font in hex       
*/

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

//Get string info
$font_size = isset($_GET['font_size']) ? $_GET['font_size'] : 3;
$string = urldecode(base64_decode($_GET['string']));

//Get the size of the string
$width = imagefontwidth($font_size) * strlen($string);
$height = imagefontheight($font_size);

//Create the image
$img = @imagecreatetruecolor($width, $height)
      or die("Cannot Initialize new GD image stream");

//Make it transparent
imagesavealpha($img, true);
$trans_colour = imagecolorallocatealpha($img, 0, 0, 0, 127);
imagefill($img, 0, 0, $trans_colour);

//Get the text color
$text_color = isset($_GET['R'], $_GET['G'], $_GET['B']) ?
        imagecolorallocate($img, hexdec($_GET['R']), hexdec($_GET['G']), hexdec($_GET['B'])) :
        imagecolorallocate($img, 0, 0, 0);

//Draw the string
imagestring($img, $font_size, 0, 0,  $string, $text_color);

//Output the image
imagepng($img);
imagedestroy($img);
?>

down

gannon (at) portablesofdoom (dot) org ¶

17 years ago


I like this better than "tjpoe at cableaz dot com"'s function for wrapping text to fit width (auto-adjusts height as needed) since it doesn't only do 1 word per line.

function make_wrapped_txt($txt, $color=000000, $space=4, $font=4, $w=300) {
  if (strlen($color) != 6) $color = 000000;
  $int = hexdec($color);
  $h = imagefontheight($font);
  $fw = imagefontwidth($font);
  $txt = explode("\n", wordwrap($txt, ($w / $fw), "\n"));
  $lines = count($txt);
  $im = imagecreate($w, (($h * $lines) + ($lines * $space)));
  $bg = imagecolorallocate($im, 255, 255, 255);
  $color = imagecolorallocate($im, 0xFF & ($int >> 0x10), 0xFF & ($int >> 0x8), 0xFF & $int);
  $y = 0;
  foreach ($txt as $text) {
    $x = (($w - ($fw * strlen($text))) / 2);
    imagestring($im, $font, $x, $y, $text, $color);
    $y += ($h + $space);
  }
  header('Content-type: image/jpeg');
  die(imagejpeg($im));
}

down

Piotr dot Sulecki at traxelektronik dot pl ¶

18 years ago


The built-in fonts used to be in latin-2 (iso8859-2) encoding. For some time, they are in latin-1 (iso8859-1) encoding. There is no way to change the encoding at all. If you need to use any other encoding, you have to use TrueType fonts.

down

-2

deejay_world at yahoo dot com ¶

22 years ago


Width ImageString, the strings you draw are not automatically wrapped width the edge of the image. You may use this function to automatically wrap them:

function ImageStringWrap($image, $font, $x, $y, $text, $color, $maxwidth)
{
    $fontwidth = ImageFontWidth($font);
    $fontheight = ImageFontHeight($font);

    if ($maxwidth != NULL) {
        $maxcharsperline = floor($maxwidth / $fontwidth);
        $text = wordwrap($text, $maxcharsperline, "\n", 1);
      }

    $lines = explode("\n", $text);
    while (list($numl, $line) = each($lines)) {
        ImageString($image, $font, $x, $y, $line, $color);
        $y += $fontheight;
      }
}

So, in particular, if you want to wrap a text with the edge of the Image, you may do:
ImageStringWrap($img, $font, 0, $y, $text, $color, ImageSX($img) );

down

-2

sk89q ¶

16 years ago


Creates a box of text. Has horizontal and vertical alignment, box arguments, and custom leading. I submitted this to the manual in 2003 actually, but it disappeared after a year or so (not sure why). Here it is again.

<?php
define("ALIGN_LEFT", "left");
define("ALIGN_CENTER", "center");
define("ALIGN_RIGHT", "right");
define("VALIGN_TOP", "top");
define("VALIGN_MIDDLE", "middle");
define("VALIGN_BOTTOM", "bottom");

function imagestringbox(&$image, $font, $left, $top, $right, $bottom, $align, $valign, $leading, $text, $color)
{
   // Get size of box
   $height = $bottom - $top;
   $width = $right - $left;
  
   // Break the text into lines, and into an array
   $lines = wordwrap($text, floor($width / imagefontwidth($font)), "\n", true);
   $lines = explode("\n", $lines);
  
   // Other important numbers
   $line_height = imagefontheight($font) + $leading;
   $line_count = floor($height / $line_height);
   $line_count = ($line_count > count($lines)) ? (count($lines)) : ($line_count);
  
   // Loop through lines
   for ($i = 0; $i < $line_count; $i++)
   {
       // Vertical Align
       switch($valign)
       {
           case VALIGN_TOP: // Top
               $y = $top + ($i * $line_height);
               break;
           case VALIGN_MIDDLE: // Middle
               $y = $top + (($height - ($line_count * $line_height)) / 2) + ($i * $line_height);
               break;
           case VALIGN_BOTTOM: // Bottom
               $y = ($top + $height) - ($line_count * $line_height) + ($i * $line_height);
               break;
           default:
               return false;
       }
      
       // Horizontal Align
       $line_width = strlen($lines[$i]) * imagefontwidth($font);
       switch($align)
       {
           case ALIGN_LEFT: // Left
               $x = $left;
               break;
           case ALIGN_CENTER: // Center
               $x = $left + (($width - $line_width) / 2);
               break;
           case ALIGN_RIGHT: // Right
               $x = $left + ($width - $line_width);
               break;
           default:
               return false;
       }
      
       // Draw
       imagestring($image, $font, $x, $y, $lines[$i], $color);
   }
  
   return true;
}
?>

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-1

wheberson dot com dot br at gmail dot com ¶

5 years ago


// Convert e-mail to image (png)
function convertEmailToImg ($aValue, $aRed, $aGreen, $aBlue, $aAlphaF=0, $aAlphaB=127, $aFontSize=4)

{
    $img= imagecreatetruecolor (imagefontwidth ($aFontSize) * strlen ($aValue), imagefontheight ($aFontSize));
    imagesavealpha ($img, true);
    imagefill ($img, 0, 0, imagecolorallocatealpha ($img, 0, 0, 0, $aAlphaB));
    imagestring ($img, $aFontSize, 0, 0, $aValue, imagecolorallocatealpha ($img, $aRed, $aGreen, $aBlue, $aAlphaF));
    ob_start ();
    imagepng ($img);
    imagedestroy ($img);
    return base64_encode (ob_get_clean ());
}

// Example
$imgString= convertEmailToImg ('contact@example.com', 0, 0, 255, 0, 127, 4);

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-1

mustafa at hafunny dot info ¶

16 years ago


If you have any problem with CentralEurope's words, for example : ľščťžýáíéúäňôď, I am try this problem by iconv() function.

<?php
// create example image
$im = imagecreate(200, 20);
$bg = imagecolorallocate($im, 255, 255, 255);
$textcolor = imagecolorallocate($im, 0, 0, 255);
$text = "ľščťžýáíéúäňôď...";

//simple convert string
$string = iconv("Windows-1250", "Latin2", $text);

// write converted string at the top left
imagestring($im, 4, 0, 0, $string, $textcolor);

// output the image
header("Content-type: image/png");
imagepng($im);
?>

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-2

jlamer ¶

17 years ago


//  Example of use...

//  This is a simple function to output text to an image
//  which is centered (as much as I want to do by eye)
//  and wrapped
//    Just remember that all the sizes are guessed
// doesn't cut on the space (only on number of characters)
//  or change color of text, but this isn't for that...
function imageCenterString( $imgw, $imgh,
   $image_text = '', $text_size=5 )
{
   $im = imagecreate( $imgw, $imgh );
    
   // white background and blue text
   $bg = imagecolorallocate($im, 255, 255, 255);
   $textcolor = imagecolorallocate($im, 0, 0, 0);
    
   $t_h = $t_w = $t_x = $t_y = 0;
   $base_w =9; $base_h = 16;
   $m = 0.88;
   switch ( $text_size )
   {
      case 1: $t_w = $base_w*pow(($m*.98),4);
         $t_h = $base_h*pow(($m*.98),4);
         break;
      case 2: $t_w = $base_w*pow($m,3);
         $t_h = $base_h*pow($m,3);
         break;
      case 3: $t_w = $base_w*pow($m,2);
         $t_h = $base_h*pow($m,2);
         break;
      case 4: $t_w = $base_w*$m;
         $t_h = $base_h*$m;
         break;
      case 5: $t_w = $base_w;
         $t_h = $base_h;
         break;
      default:
         if ( $text_size >= 5 ) // set to 5
         {   $t_w = $base_w; $t_h = $base_h; }
         if ( $text_size < 5 ) // set to 1
         {
            $t_w = $base_w*pow(($m*.98),4);
            $t_h = $base_h*pow(($m*.98),4);
         }
         break;
   }
    
   $text_array = array();
    
   $max = floor($imgw/$t_w);
    
   for( $i=0; strlen($image_text) > 0; $i += $max)
   {
      array_push($text_array, substr($image_text,0,$max));
      if ( strlen($image_text) >= $max )
      {   $image_text = substr($image_text,$max); }
      else
      {   $image_text = ''; }
   }
    
   $t_y = ($imgh/2) - ($t_h*count($text_array)/2);

   foreach ( $text_array as $text )
   {
      $t_x = ($imgw/2)-($t_w*strlen($text)/2);
      imagestring($im, $text_size, $t_x, $t_y,
         $text, $textcolor);
      $t_y += $t_h;
   }

   // output the image
   header("Content-type: image/gpeg");
   imagejpeg($im);
}

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-2

aly at slo-igre dot net ¶

19 years ago


There is an error in "tjpoe at cableaz dot com" 's function ImageStringWrap. Instead of 

    else
           $string = $text;

there should be

     else
           $string = array($text);

for function to work for strings with only one word. Otherwise it works like a charm, thanks.

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-1

jordanslost at gmail ¶

15 years ago


Here is a small bit I made for writing to a image from right to left when you are limited to imagestring()

<?php

        $pageview_letters = preg_split('//', $string, -1 ); // Form are original array of letters.
        $minus = 6; // The letter spacing in pixels
        $first = true; // Whether or not we have started the string
        $x = 375; // X Location of imagestring
        $y = 23; // Y Location of imagestring
        $letters = array(); // Initiate the array o letters.

        foreach ( $pageview_letters as $letter ) {
        
            $letters[] = $letter;
            
        }
        
        $letters = array_reverse( $letters );
        
        foreach ( $letters as $letter ) {
        
            if ( $first ) {
            
                imagestring( $image, 2, $x, $y, $letter, $light_blue );
                $first = false;
                
            } else {
                
                $x = ( $x - $minus );
                imagestring( $image, 2, $x, $y, $letter, $light_blue );
                
            }
        
        }
?>

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-1

Epidemiah ¶

16 years ago


Its just an easy function to write an string in the middle of a picture.

<?php

function imageCenterString(&$img, $font, $text, $color)
{
    if($font < 0 || $font > 5){ $font = 0; }
    $num = array(array(4.6, 6),
                 array(4.6, 6),
                 array(5.6, 12),
                 array(6.5, 12),
                 array(7.6, 16),
                 array(8.5, 16));
    $width = ceil(strlen($text) * $num[$font][0]);
    $x     = imagesx($img) - $width - 8;
    $y     = Imagesy($img) - ($num[$font][1] + 2);
    imagestring($img, $font, $x/2, $y/2, $text, $color);
}

?>

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-1

cesargus at yahoo dot com ¶

20 years ago


//simple hello world

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

$img_handle = ImageCreate (200, 20) or die ("Cannot Create image");
$back_color = ImageColorAllocate ($img_handle, 0, 10, 10);
$txt_color = ImageColorAllocate ($img_handle, 235, 235, 51);
ImageString ($img_handle, 10, 25, 5,  "Hello world!", $txt_color);
ImagePng ($img_handle); 
?>

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-2

iibm at free dot fr ¶

17 years ago


I've made a little modification of the (quite usefull) imagestringcutted function (when align=center, it doesn't work well for me if x1!=0) so juste replace the last line with :

<?php
   [...]
   else imagestring($img,$font,$x1+($x2-$x1)/ 2 - strlen($text) * $fontwidth / 2,$y,$text,$color);
}
?>

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-2

webmaster at acdrifter dot com ¶

19 years ago


If you are looking to center the text, use the following function; I'm not promising perfection...

function imagecenteredstring ( &$img, $font, $xMin, $xMax, $y, $str, $col ) {
    $textWidth = imagefontwidth( $font ) * strlen( $str );
    $xLoc = ( $xMax - $xMin - $textWidth ) / 2 + $xMin + $font;
    imagestring( $img, $font, $xLoc, $y, $str, $col );
}

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-2

php dot net at mvoncken dot nl ¶

21 years ago


A simple example:
To make one line of text fit in the image.

<?php
header ("Content-type: image/png");
$string = "spam@mvoncken.nl";                                              
$font   = 4;
$width  = ImageFontWidth($font) * strlen($string);
$height = ImageFontHeight($font);

$im = @imagecreate ($width,$height);
$background_color = imagecolorallocate ($im, 255, 255, 255); //white background
$text_color = imagecolorallocate ($im, 0, 0,0);//black text
imagestring ($im, $font, 0, 0,  $string, $text_color);
imagepng ($im);
?>

I use something like this for spamprotection of my visitors (pass userid as an url-parameter for this php)

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-3

mike at mike-griffiths dot co dot uk ¶

15 years ago


I created an alternative using the function imagechar to create a string of an image.  The below function below was used to create an image the same height and width of the text string.  It is used on my website to mask users email addresses.



<?PHP



// Set your string somehow

$string = 'your@example.com';



// Set font size

$font_size = 4;



// Create image width dependant on width of the string

$width  = imagefontwidth($font_size)*strlen($string);

// Set height to that of the font

$height = imagefontheight($font_size);

// Create the image pallette

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

// Grey background

$bg    = imagecolorallocate($img, 25, 25, 25);

// White font color

$color = imagecolorallocate($img, 255, 255, 255);

// Length of the string

$len = strlen($string);

// Y-coordinate of character, X changes, Y is static

$ypos = 0;

// Loop through the string

for($i=0;$i<$len;$i++){

    // Position of the character horizontally

    $xpos = $i * imagefontwidth($font_size);

    // Draw character

    imagechar($img, $font_size, $xpos, $ypos, $string, $color);

    // Remove character from string

    $string = substr($string, 1);    

    

}

// Return the image

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

imagegif($img);

// Remove image 

imagedestroy($img);



?>

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-2

god at in-heaven dot org ¶

18 years ago


Here's a simple function for creating an aligned string which is cutted to match the space between $x1 and $x2
<?php
function imagestringcutted($img,$font,$y,$x1,$x2,$text,$color,$align="center") {
    $fontwidth = imagefontwidth($font);
    $fullwidth = strlen($text) * $fontwidth;
    $maxwidth = $x2-$x1;
    $targetwidth = $fullwidth-(4*$fontwidth);
    if($fullwidth > $maxwidth) {
        for($i = 0; $i < strlen($text) AND ((strlen($text)-($i-4))*$fontwidth) > $targetwidth ;$i++) { }
        $text = substr($text,0,(strlen($text)-$i)-4)."...";
    }
    if($align == "left") imagestring($img,$font,$x1,$y,$text,$color);
    elseif($align == "right") imagestring($img,$font,$x2 - ((strlen($text) * $fontwidth)),$y,$text,$color);
    else imagestring($img,$font,($x2-$x1)/ 2 - strlen($text) * $fontwidth / 2,$y,$text,$color);
}
?>
Usage:
<?php
imagestringcutted($img,$font,$y,$x1,$x2,$text,$color,$align);
?>
Will create a string $text, which is cutted if it's too long to match between  $x1 and $2, on $img with font $font and color $color at height $y and with align to $align.
Hope it will help some people.
Sorry for my bad English.

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shadikka at gmail dot com ¶

19 years ago


My version of the centered string, it decreases the font number (since I've noticed smaller numbers are smaller fonts) until 1 if the string won't fit. Then it will give up.

<?php
function imagestringcentered ($img,$font,$cy,$text,$color) {
 while (strlen($text) * imagefontwidth($font) > imagesx($img)) {
  if ($font > 1) { $font--; }
  else { break; }
 }  
 imagestring($img,$font,imagesx($img) / 2 - strlen($text) * imagefontwidth($font) / 2,$cy,$text,$color);
}
?>

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bob dot brown at opus dot co dot nz ¶

22 years ago


If you find that you are getting two characters on the end of your imageString that look like a Y and an upside down L then they're probably representations of CR/LF.  Try trim()ing the string before outputting it.  (I was sooo sure this was a bug <g>)

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Abubaker dot shamlan at gmail dot com ¶

16 years ago


this is a function that is based on imagestring but it produces text in the center of an image i hope it helps :D



<?php

function ImageStringCenter($image_resource, $font_size, $line_number, $total_lines, $text, $color ) {



    $center_x = ceil( ( imagesx($image_resource) - ( ImageFontWidth($font_size) * strlen($text) ) ) / 2 );



    $center_y = ceil( ( ( imagesy($image_resource) - ( ImageFontHeight($font_size) * $total_lines ) ) / 2)  + ( ($line_number-1) * ImageFontHeight($font_size) ) );



ImageString($image_resource, $font_size, $center_x, $center_y, $text, $color );



}

?>

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tjpoe at cableaz dot com ¶

19 years ago


i modified the centering functions and created this which centers each word on it's own line. You can adjust the spacing with the $valign var. currently no implimentation if text is too large for image. strings are tokenized by space, but can obviously be changed. 

function ImageStringWrap($image, $font, $text, $color)
{
  $fontwidth = ImageFontWidth($font);
  $fontheight = ImageFontHeight($font);
  $words= str_word_count($text);
  if ($words > 1){
    $string=array(strtok($text,' '));
    for ($i = 1 ; $i <= $words ; $i++){
      $string=array_merge($string,array($i=>strtok(' ')));
    }
  }
  else
    $string=$text;
  $vspace=4;
  $y=((imagesy($image)-($fontheight*$words)-($words*$vspace))/2);
  foreach($string as $st){
    $x=((imagesx($image)-($fontwidth * strlen($st)))/2);
    ImageString($image,$font,$x,$y,$st,$color);
    $y+=($fontheight+$vspace);
  }
}
hope this is helpful

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brooks dot boyd at gmail dot com ¶

20 years ago


Drawing a string as an image is a handy way to disguise an eMail address so spam sniffers can't get it as easily. The only catch to creating a dynamic image with your eMail in it is the eMail to be displayed must be passed via the query string to enable static HTML to use it. So, the eMail must be encrypted slightly in order to not defeat the purpose of not typing your eMail address outright. I wrote the following script to do so:

Save the following as email.php
<?php
    if ($_GET['addr'] != "") {
        $msg = $_GET['addr'];
        $msg = preg_replace("/\[dot]/",".",$msg);
        $msg = preg_replace("/\[at]/","@",$msg);
        $final = "";
        for ($i=0; $i<=strlen($msg); $i++) {
            $final .= substr($msg, strlen($msg)-$i, 1);
        }
        $msg = $final;

        $char_width = 8;
        $char_height = 17;
        $padding = 3;
        $width = $padding*2+strlen($msg)*$char_width;
        $height = +$padding*2+$char_height;
        $im = imagecreatetruecolor($width,$height);
        imagealphablending($im, FALSE);
        imagesavealpha($im, TRUE);
        $bg = imagecolorallocatealpha($im, 255, 255, 0, 100);
        $text = imagecolorallocatealpha($im, 0, 0, 0, 0);
        imagefilledrectangle ($im, 0, 0, $width, $height, $bg); # Make transparent
        imagestring($im, 4, $padding, $padding, $msg, $text);
    } else {
        $im = imagecreatetruecolor(1,1);
        imagealphablending($im, FALSE);
        imagesavealpha($im, TRUE);
        $bg = imagecolorallocatealpha($im, 255, 0, 0, 125);
        imagefilledrectangle ($im, 0, 0, 1, 1, $bg); # Make transparent
    }
    header('Content-type: image/jpg');
    imagepng($im);
    imagedestroy($im);

?>

If the script is called without an eMail address, it outputs a 2x2 transparent image.

To call the script to generate the eMail "user@home.com", the HTML tag would be:

<img src="email.php?addr=moc[dot]emoh[at]resu">

To 'encrypt' the eMail address to pass to the script, write the address backwards and replace "." with "[dot]" and "@" with "[at]". It's not the most ironclad protection, but it thwarts most casual eMail sniffers.

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aholmes84 at hotmail dot com ¶

22 years ago


When setting the font, any integer less than 1 defaults to 1, and any integer greater than 5 defaults to 5.

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rush at 507magazine dot com ¶

18 years ago


hello, I noticed that if you put a rand(3,5) it will put random sizes of font to each character put on the image. this is very useful when programming captchas for anti-spam form verification.

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julien / at / theoconcept.com ¶

18 years ago


If you are looking for a way to generate a "CAPTCHA" image for a form verification (to verify it is not a robot), have a look at this : http://blog.theoconcept.com/static/distortion/

It gives an animated image with the parameter string, with distortion, here is an example :
http://blog.theoconcept.com/static/distortion/distortion.php

(*)  You'll need GD + Freetype support
(**) You'll need ImageMagick on the machine

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jurgen dot vanoosterwijck at pandora dot be ¶

19 years ago


Based on the previous example, here's how to center a string both horizontally and vertically...

<?php
function imagestringcentered ($img,$font,$text,$color) {
 while (strlen($text) * imagefontwidth($font) > imagesx($img)) {
  if ($font > 1) { $font--; }
  else { break; }
 } 
 $cy = (imagesy($img)/2) - (imagefontwidth($font)/2);
 imagestring($img,$font,imagesx($img) / 2 - strlen($text) * imagefontwidth($font) / 2,$cy,$text,$color);
}
?>

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eric dot brison at anakeen dot com ¶

15 years ago


Same function as above but it can display multi-line strings.
<?php
function sendimagetext($text) {
  // Set font size
  $font_size = 4;

  $ts=explode("\n",$text);
  $width=0;
  foreach ($ts as $k=>$string) { //compute width
    $width=max($width,strlen($string));
  }

  // Create image width dependant on width of the string
  $width  = imagefontwidth($font_size)*$width;
  // Set height to that of the font
  $height = imagefontheight($font_size)*count($ts);
  $el=imagefontheight($font_size);
  $em=imagefontwidth($font_size);
  // Create the image pallette
  $img = imagecreatetruecolor($width,$height);
  // Dark red background
  $bg = imagecolorallocate($img, 0xAA, 0x00, 0x00);
  imagefilledrectangle($img, 0, 0,$width ,$height , $bg);
  // White font color
  $color = imagecolorallocate($img, 255, 255, 255);

  foreach ($ts as $k=>$string) {
    // Length of the string
    $len = strlen($string);
    // Y-coordinate of character, X changes, Y is static
    $ypos = 0;
    // Loop through the string
    for($i=0;$i<$len;$i++){
      // Position of the character horizontally
      $xpos = $i * $em;
      $ypos = $k * $el;
      // Draw character
      imagechar($img, $font_size, $xpos, $ypos, $string, $color);
      // Remove character from string
      $string = substr($string, 1);      
    }
  }
  // Return the image
  header("Content-Type: image/png");
  imagepng($img);
  // Remove image
  imagedestroy($img);
}
?>

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bpgordon at gmail dot com ¶

19 years ago


This code produces a png image of the text within the query. It autofits to the length of the string. 
Usage: http://yoursite.com/text.php?abcdefg+hijk

Use + to produce a space in the image. The + can be excaped with a carat (^). Most other symbols work fine in the query string, like the ?.

<?php
header ("Content-type: image/png");
$string = $_ENV["QUERY_STRING"];
$md5 = md5($string); //just so we don't convert valid text into a +
$string = str_replace("^+", $md5, $string); //replaces ^+ with long, unnatural string
$string = str_replace("+", " ", $string); //replaces + with space
$string = str_replace($md5, "+", $string); //replaces the long, unnatural string with +
$width  = imagefontwidth($font) * strlen($string);
$height = imagefontheight($font);
$image = @imagecreate($width+2, $height+2);
$black = imagecolorallocate($image, 0, 0, 0); //background
$white = imagecolorallocate($image, 255, 255, 255);
imagestring($image, 2, 1, 1,  $string, $white);
imagepng($image);
imagedestroy($image);
?>

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m dot onderwater at esperantoxl dot nl ¶

18 years ago


There is a small error in the function for horizontal and vertical centering by "jurgen dot vanoosterwijck at pandora dot be"

the line 

 $cy = (imagesy($img)/2) - (imagefontwidth($font)/2);

should be

 $cy = (imagesy($img)/2) - (imagefontheight($font)/2);

add a note