# imageftbbox

(PHP 4 >= 4.0.7, PHP 5, PHP 7)

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

### 说明

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

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`

  Angle in degrees in which `text` will be measured.

`fontfile`

  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.

`text`

  The string to be measured.

`extrainfo`

  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.