imageloadfont()

(PHP 4, PHP 5, PHP 7)

载入一新字体

说明

imageloadfont(string $file): int

imageloadfont()加载一个用户定义的位图字体并返回该字体的标识符（其值总是大于 5，因此不会和内置字体冲突）。在产生错误的情况下，该函数返回FALSE。

字体文件格式目前是二进制的且和平台有关。这意味着应该用和你运行 PHP 的机器相同类型 CPU 的机器生成字体。

使用 imageloadfont

<?php
header("Content-type: image/png");
$im = imagecreatetruecolor(50, 20);
$black = imagecolorallocate($im, 0, 0, 0);
$white = imagecolorallocate($im, 255, 255, 255);
imagefilledrectangle($im, 0, 0, 49, 19, $white);
$font = imageloadfont("04b.gdf");
imagestring($im, $font, 0, 0, "Hello", $black);
imagepng($im);
?>

参见imagefontwidth()和imagefontheight()。

Working under the assumption that the only 'architecture dependant' part of the font files is endianness, I wrote a quick and dirty Python script to convert between the two. It has only been tested on a single font on a single machine so don't bet your life on it working. All it does is swap the byte order of the first four ints.
#!/usr/bin/env python
f = open("myfont.gdf", "rb");
d = open("myconvertedfont.gdf", "wb");
for i in xrange(4):
    b = [f.read(1) for j in xrange(4)];
    b.reverse();
    d.write(''.join(b));
d.write(f.read());
I successfully used this script to convert anonymous.gdf, from one of the font links below, into something useable on Mac OS X.

You all should look at the GD image library site for information on extra fonts, it can be found at http://www.boutell.com/gd/

Confirmation code generation for preventing automated registrations on a website.
Function arguments are:
$code - the code that you shall random generate
$location - relative location of the image that shall be generated
$fonts_dir - relative location for the GDF fonts directory
This function will create an image with the code given by you and will save it in the directory specified with the name formed by MD5 hash of the code.
You may insert as many font types in the fonts directory as you wish, with random names.
<?php
function generate_image($code, $location, $fonts_dir)
{
   $image = imagecreate(150, 60);      
   imagecolorallocate($image, rand(0, 100), rand(100, 150), rand(150, 250));
   $fonts = scandir($fonts_dir);
   
   $max = count($fonts) - 2;
   
   $width = 10;
   for ($i = 0; $i <= strlen($code); $i++)
   {   
     $textcolor = imagecolorallocate($image, 255, 255, 255);
     $rand = rand(2, $max);
     $font = imageloadfont($fonts_dir."/".$fonts[$rand]);
     
     $fh = imagefontheight($font);
     $fw = imagefontwidth($font);
     imagechar($image, $font, $width, rand(10, 50 - $fh), $code[$i], $textcolor);   
     $width = $width + $fw;
    
   }
       
   imagejpeg($image, $location."/".md5($code).".jpg", 100);
   imagedestroy($image);    
  
   return $code;
   
}
?>

Remember - GD fonts aren't antialiased. If you're planning on using a pre-existing (TrueType) font, you may want to consider using imagettftext() instead of phillip's function.