PHP:imageftbbox()的用法

imageftbbox

(PHP 4 >= 4.0.7, PHP 5)

imageftbbox — 给出一个使用 FreeType 2 字体的文本框

说明

array imageftbbox
( float $size
, float $angle
, string $fontfile
, string $text
[, array $extrainfo
] )

This function calculates and returns the bounding box in pixels for a FreeType text.

参数

size

字体的尺寸。根据 GD 的版本，为像素尺寸（GD1）或点（磅）尺寸（GD2）。

Angle in degrees in which text will be measured.

The name of the TrueType font file (can be a URL). Depending on which version of the GD library that PHP is using, it may attempt to search for files that do not begin with a leading '/' by appending '.ttf' to the filename and searching along a library-defined font path.

The string to be measured.

Possible array indexes for extrainfo Key Type Meaning linespacing float Defines drawing linespacing

返回值

imageftbbox() returns an array with 8 elements representing four points making the bounding box of the text: 0 lower left corner, X position 1 lower left corner, Y position 2 lower right corner, X position 3 lower right corner, Y position 4 upper right corner, X position 5 upper right corner, Y position 6 upper left corner, X position 7 upper left corner, Y position

The points are relative to the text regardless of the angle, so "upper left" means in the top left-hand corner seeing the text horizontally.

范例

Example #1 imageftbbox() example

<?php
// Create a 300x150 image
$im = imagecreatetruecolor(300, 150);
$black = imagecolorallocate($im, 0, 0, 0);
$white = imagecolorallocate($im, 255, 255, 255);

// Set the background to be white
imagefilledrectangle($im, 0, 0, 299, 299, $white);

// Path to our font file
$font = './arial.ttf';

// First we create our bounding box
$bbox = imageftbbox(10, 0, $font, 'The PHP Documentation Group');

// This is our cordinates for X and Y
$x = $bbox[0] + (imagesx($im) / 2) - ($bbox[4] / 2) - 5;
$y = $bbox[1] + (imagesy($im) / 2) - ($bbox[5] / 2) - 5;

imagefttext($im, 10, 0, $x, $y, $black, $font, 'The PHP Documentation Group');

// Output to browser
header('Content-Type: image/png');

imagepng($im);
imagedestroy($im);
?>

注释

Note: 此函数需要 GD 2.0.1 或更高版本(推荐 2.0.28 及更高版本)。

Note: 此函数仅在 PHP 编译时加入 freetype 支持时有效（--with-freetype-dir=DIR ）。

更新日志

版本 说明 4.3.5 extrainfo was made optional.