imagechar

(PHP 4, PHP 5, PHP 7)

imagechar — 水平地画一个字符

说明

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

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 30-Mar-2009 12:11
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 05:35
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);
?>