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

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

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.

用户评论:

[#1] Johan [2007-11-19 07:38:10]

For alignment i used this method:

if($align == "center" || $align == "right")
{
$verticaltxtspace = $backwidth - (2 * $posx);
$spacepositions = imagettfbbox($size, $angle, "fonts/verdanaz.ttf", " ");
$spacepx = $spacepositions[4] - $spacepositions[0];

// Split text in lines
$lines = split("[\r][\n]", $text);
for($count = 0; $count < count($lines); $count++)
{
$textpositions = imagettfbbox($size, $angle, "fonts/verdanaz.ttf", $lines[$count]);
$textpx = $textpositions[2] - $textpositions[0];

if($align == "right")
{
$spaces = ($verticaltxtspace - $textpx) / $spacepx;
}
else if($align == "center")
{
$spaces = (($verticaltxtspace - $textpx)/2) / $spacepx;
}

// Add spaces
$line = $lines[$count];
for($i = 0; $i < $spaces; $i++)
{
$line = " " . $line;
}
$lines[$count] = $line;
}

// Create new text of lines
$text = "";
for($count = 0; $count < count($lines); $count++)
{
$text .= $lines[$count] . "\r\n";
}
}

// Draw the shadow text on de shadow
imagettftext($background, $size, $angle, $posx, $posy, $textcolor, "fonts/verdanaz.ttf", $text);

[#2] theo v e -2 [2005-12-28 07:10:25]

ah... the problem between imageftbbox() and imagefttext() lies in the mirroring of the y-axes.
Below you see, for a font-size 16 the boudingboxes of "b", "p" and "bp":
< b: w=9 h=15
b(0,-1)
b(9,-1)
b(9,-16)
b(0,-16)
< p: w=9 h=16
p(0,4)
p(9,4)
p(9,-12)
p(0,-12)
< bp: w=20 h=20
bp(0,4)
bp(20,4)
bp(20,-16)
bp(0,-16)
If drawing "bp" using imagefttext() at y=0, the the top of "bp" indeed is at y=-16, and the bottom of "bp" at y=4. (Plus or minus a pixel here and there, because at y=0 there actually is a vissible pixel.)

[#3] fernando [2005-07-14 13:20:34]

imagettfbbox() 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.

[#4] groomed at users dot sf dot net [2004-05-27 12:38:25]

ImageFTBBox returns a bounding box, not metrics, as some (most?) of the notes above seem to assume. The 8 values it returns specify the 4 corners of this bounding box. So to properly determine the width and height of a string you need to do:

$bbox = ImageFTBBox(...);
$width = abs($bbox[0]) + abs($bbox[2]); // distance from left to right
$height = abs($bbox[1]) + abs($bbox[5]); // distance from top to bottom

[#5] sectionthirty1 at yahoo dot com [2004-04-22 02:50:43]

Here is a handy example I used to center "dynamic text" onto an image.

Ex. Say you want to center a clients IP Address onto a picture.

$ip=$_SERVER['REMOTE_ADDR'];

$details = imageftbbox($fontsize, 0, $font, $ip, array("linespacing" => 1));

$xcoord = ($imgwidth - $details[4]) / 2;  // this will return the x coordinate centered to your specific image.  Make sure  you set $imgwidth to the width of the image you are using.

imagettftext($image, $fontsize, 0, $xcoord, $ycoord, $fontcolor, $font, $ip);

[#6] Brian at PrintsMadeEasy dot com [2003-03-06 19:54:34]

I noticed that PHP's True Type functions do not allow you to create text blocks with multiple lines that automatically adjust for alignment. I wrote a function that will allow you to generate images with multiple lines, control the alignment, and handle rotation. I hope it helps someone.

There was too much code to paste on this message post so you can grab it off of my webserver. I also created an example page so that you can see the code in action.

Example Page:
http://www.PrintsMadeEasy.com/code_samples/php/text_generation.php

Download the Text file:
http://www.PrintsMadeEasy.com /code_samples/php/text_generation.txt

[#7] ta at NOSPAM dot magicsquare dot info [2002-09-06 09:37:18]

i've found a work around for this situation

it seems that height is directly proportional to line spacing so you just have to apply the same factor to image height

for example :

$spacing = 0.7;
$params = array("linespacing" => $spacing);

$box = imageftbbox ($size, 0, $font, $text, $params);
$tw=$box[4]-$box[0]; //image width
$th=($box[1]-$box[5])*$spacing; //image height

[#8] phpimageftbbox at juggernaut dot com dot au [2002-05-14 21:56:08]

This function can be used to generate right-aligned text. Just work out how wide the text image is and position it accordingly. Example:

$i_width  = 200;
$i_height = 40;

$string = "Hello World!";
$pointsize = 10;
$fontfile = "/usr/local/lib/ttf/Helve.ttf";

$im = imagecreate($i_width, $i_height);
$black = imagecolorallocate ($im, 0, 0, 0);
$white = imagecolorallocate ($im, 255, 255, 255);

$string_size = ImageFtBbox($pointsize, 0, $fontfile, $string, array("linespacing" => 1));
$s_width  = $string_size[4];
$s_height = $string_size[5];

ImageFtText($im, $pointsize, 0, $i_width - $s_width - 1,  0 - $s_height, $white, $fontfile, $string, array("linespacing" => 1));

Header ("Content-type: image/png");
ImagePNG ($im);
ImageDestroy ($im);