imagechar

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

imagechar — 水平地画一个字符

说明

imagechar ( resource $image , int $font , int $x , int $y , string $c , int $color ) : bool

imagechar() 将字符串 c 的第一个字符画在 image 指定的图像中，其左上角位于 x，y（图像左上角为 0, 0），颜色为 color。如果 font 是 1，2，3，4 或 5，则使用内置的字体（更大的数字对应于更大的字体）。

Example #1 imagechar() 例子


<?php

$im = imagecreate(100,100);

$string = 'PHP';

$bg = imagecolorallocate($im, 255, 255, 255);
$black = imagecolorallocate($im, 0, 0, 0);

// prints a black "P" in the top left corner
imagechar($im, 1, 0, 0, $string, $black);

header('Content-type: image/png');
imagepng($im);

?>

参见 imagecharup() 和 imageloadfont()。

User Contributed Notes

liam dot wiltshire at lineone dot net 29-Mar-2009 03:11


A quick function to automatically generate a multi line image from a string, with the image size automatically calculated from the string itself.





<?php





function multilineimage($string){





    // Probably not the best way of handling newlines, but bar OS9, doesn't really cause a problem


    $string = str_replace("\r","",$string);


    $string = explode("\n",$string);





    $maxlen = 0;


    foreach ($string as $str){


        if (strlen($str) > $maxlen){


            $maxlen = strlen($str);


        }


    }





    // Set font size


    $font_size = 4;





    // Create image width dependant on width of the string


    $width  = imagefontwidth($font_size)*$maxlen;


    // Set height to that of the font


    $height = imagefontheight($font_size) * count($string);


    // Create the image pallette


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


    // Grey background


    $bg    = imagecolorallocate($img, 205, 255, 255);


    // White font color


    $color = imagecolorallocate($img, 0, 0, 0);





    $ypos = 0;





    foreach ($string as $str){





        $len = strlen($str);


        for($i=0;$i<$len;$i++){


            // Position of the character horizontally


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


            // Draw character


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


            // Remove character from string


            $str = substr($str, 1);   


        }


        $ypos = $ypos + imagefontheight($font_size);   


    }





    // Return the image 


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


    imagegif($img);


    // Remove image


    imagedestroy($img);


}





multilineimage("This is an image


This is line 2\nLine 3


Line 4");





?>

sw at profilschmiede dot de 20-Jun-2005 08:35


For the sake of completeness, here is an example for imagechar. 

The base-image automatically adjusts to the size and the height of the given string. Using the rand()-function the y-position of each char is slightly varied with every loop-run. You can easily rewrite the script to use a randomly generated string - the one given here just serves as an example.



<?php



$string = '1 2 3 4 5 6 7 8 9 A B C D E F G';

$font_size = 5;

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

$height=imagefontheight($font_size)*2;

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

$bg = imagecolorallocate($img,225,225,225);

$black = imagecolorallocate($img,0,0,0);

$len=strlen($string);



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

{

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

    $ypos=rand(0,imagefontheight($font_size));

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

    $string = substr($string,1);    

    

}

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

imagegif($img); 

imagedestroy($img);

?>