PHPCon Poland 2024

imagefontwidth

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

imagefontwidth获取字体宽度

说明

imagefontwidth(GdFont|int $font): int

返回字体中字符的像素宽度。

参数

font

取值对于内建的 latin2 编码字体可以是:1、2、3、4、5(更高的数字对应更大的字体), 或是通过 imageloadfont() 返回的 GdFont 实例。

返回值

返回字体的像素宽度。

更新日志

版本 说明
8.1.0 font 参数现在接受 GdFont 实例和 int,之前仅接受 int

示例

示例 #1 在内置字体上使用 imagefontwidth()

<?php
echo 'Font width: ' . imagefontwidth(4);
?>

以上示例的输出类似于:

Font width: 8

示例 #2 将 imagefontwidth()imageloadfont() 一起使用

<?php
// Load a .gdf font
$font = imageloadfont('anonymous.gdf');

echo
'Font width: ' . imagefontwidth($font);
?>

以上示例的输出类似于:

Font width: 23

参见

add a note

User Contributed Notes 3 notes

up
-2
Anonymous
10 years ago
I've notice that with accented characters (so french !!)
like that:
strlen("câble" * imagefontwidth(FONTSIZE));
this command give a string length bigger than it is in reality
so you have to pass the chain in utf8 decode before

strlen(utf8_decode("câble") * imagefontwidth(FONTSIZE));

that's all (sorry for my english !)
up
-4
dev at numist dot net
19 years ago
This library function is very useful for variable-sized images that only contain text, like this function that I use to output error messages that accumulate and cause a fatal error in my thumbnailer:

<?php
function errimg($error) {
// $error is an array of error messages, each taking up one line
// initialization
$font_size = 2;
$text_width = imagefontwidth($font_size);
$text_height = imagefontheight($font_size);
$width = 0;
// the height of the image will be the number of items in $error
$height = count($error);

// this gets the length of the longest string, in characters to determine
// the width of the output image
for($x = 0; $x < count($error); $x++) {
if(
strlen($error[$x]) > $width) {
$width = strlen($error[$x]);
}
}

// next we turn the height and width into pixel values
$width = $width * $text_width;
$height = $height * $text_height;

// create image with dimensions to fit text, plus two extra rows and
// two extra columns for border
$im = imagecreatetruecolor($width + ( 2 * $text_width ),
$height + ( 2 * $text_height ) );
if(
$im) {
// image creation success
$text_color = imagecolorallocate($im, 233, 14, 91);
// this loop outputs the error message to the image
for($x = 0; $x < count($error); $x++) {
// imagestring(image, font, x, y, msg, color);
imagestring($im, $font_size, $text_width,
$text_height + $x * $text_height, $error[$x],
$text_color);
}
// now, render your image using your favorite image* function
// (imagejpeg, for instance)
out($im, array(), $error);
} else {
// image creation failed, so just dump the array along with extra error
$error[] = "Is GD Installed?";
die(
var_dump($error));
}
}
?>

The function expects an array of error messages to be passed in, and then outputs an image containing the contents of the array. This is especially useful if your code is contained in an html page that will display rexes if the images do not render correctly.

This function displays the array in image form with index 0 at the top, and the highest index at the bottom.

You have to write out() yourself though, see imagejpeg, imagepng, etc for good ideas on how to write a decent output function.
up
-4
puremango dot co dot uk at gmail dot com
18 years ago
a function that is faster than ImageFontWidth for certain uses:

<?
function ImageFontWidthByFilename($filename)
{
$handle = @fopen($font_locations[$i],"r");
$c_wid = @fread($handle,11);
@fclose($handle);
return(ord($c_wid{8})+ord($c_wid{9})+ord($c_wid{10})+ord($c_wid{11}));
}

echo "./font.gdf is ".ImageFontWidthByFilename("./font.gdf")." pixels wide";

?>

reading the widths of 5 different fonts, 500 times, ImageFontWidth took an average of ~0.004 seconds per 5 reads, my function takes ~0.0003 per 5.

The reason is that ImageFontWidth requires a call to ImageLoadFont, but if for some reason you won't need to load the font, just find out the width, this is the function for you :-)

more such wonders at http://puremango.co.uk
To Top