imagechar()

(PHP 4, PHP 5, PHP 7)

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）。

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()。

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);
?>

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");
?>