imagepsbbox

(PHP 4, PHP 5)

imagepsbbox — 给出一个使用 PostScript Type1 字体的文本方框

说明

array imagepsbbox ( string $text , resource $font , int $size )

array imagepsbbox ( string $text , resource $font , int $size , int $space , int $tightness , float $angle )

给出一个使用 PostScript Type1 字体的文本方框。

围绕文本范围的虚拟方框是用从字符度量学中的可用信息来计算的，不幸的是往往和实际上光栅生成的文本的结果有少许不同。如果角度为 0 度，（根据经验）文本在每个方向上都需要多 1 个像素。

参数

text: 要写入的文本。
font_index: imagepsloadfont() 所返回的字体资源。
size: size 以像素表示。
space: 可以用来改变字体中默认间距的值。此值将被加到通常的值上，可以为负值。以字符间距单元表示，1 个单元为 1 em-square 的一千分之一。
tightness: tightness 可以控制字符之间的间距。此值将被加到通常字符宽度上，可以为负值。以字符间距单元表示，1 个单元为 1 em-square 的一千分之一。
angle: angle 以角度表示。

返回值

本函数返回包含有下列单元的数组：

0	左下角的 X 坐标
1	左下角的 Y 坐标
2	右上角的 X 坐标
3	右上角的 Y 坐标

范例

Example #1 imagepsbbox() 用法


<?php
// 创建图像的句柄
$im = imagecreatetruecolor(200, 200);

// 分配颜色
$black = imagecolorallocate($im, 0, 0, 0);
$white = imagecolorallocate($im, 255, 255, 255);

// 载入 PostScript 字体
$font = imagepsloadfont('font.pfm');

// 设置文本方框
$bbox = imagepsbbox('Sample text is simple', $font, 12);

// 定义 X 和 Y 
$x = ($bbox[2] / 2) - 10;
$y = ($bbox[3] / 2) - 10;

// 字体写入图像
imagepstext($im, 'Sample text is simple', $font, 12, $black, $white, $x, $y);

// 输出并释放内存
header('Content-type: image/png');

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

注释

Note: 此函数仅在 PHP 编译时指定了 --with-t1lib[=DIR] 时可用。

参见

imagepstext() - 用 PostScript Type1 字体把文本字符串画在图像上

User Contributed Notes

eikie 05-May-2008 06:32


in my code below, there is an error! 



replace

$w += abs($bb[3])-abs($bb[1]); // accumulate width



with

$w += abs($bb[2])-abs($bb[0]); // accumulate width



also after

$bb = imagepsbbox($c, $font, $size); // calculate width



you can add this line because spaces make odd values...

if ($c == ' ' ) $bb = imagepsbbox('i', $font, $size);

eikie 05-May-2008 05:34


I have a given image width and need to render a long string on that image. By using the following function I'm, able to get an array of strings which each will fit into the images width. It might need a lot of CPU time, but it's cool:



// Function to return an Array of Strings 

// Arguments: String to be wrapped, maximum width in pixels of each line, font and fontsize

function imgwordwrap($s, $maxWidth, $font, $size) {

  // Make an empty ArrayList

  $a = array();

  $w = 0;    // Accumulate width of chars

  $i = 0;      // Count through chars

  $rememberSpace = 0; // Remember where the last space was

  // As long as we are not at the end of the String

  while ($i < strlen($s)) {

    // Current char

    $c = substr($s, $i, 1);

    $bb = imagepsbbox($c, $font, $size); // calculate width

    $w += abs($bb[3])-abs($bb[1]); // accumulate width

    if ($c == ' ') $rememberSpace = $i; // Are we a blank space?

    if ($w > $maxWidth) {  // Have we reached the end of a line?

      $sub = substr($s,0,$rememberSpace); // Make a substring

            // Chop off space at beginning

            if (substr($sub,0,1)==' ') $sub = substr($sub,1);

      // Add substring to the array

      $a[] = $sub;

      // Reset everything

      $s = substr($s,$rememberSpace);

      $i = 0;

      $w = 0;

    } 

    else {

      $i++;  // Keep going!

    }

  }

 

  // Take care of the last remaining line

  trim($s);

  if (substr($s,0,1)==' ') $s = substr($s,1);

  $a[] = $s;

 

  return $a;

}

honza dot bartos at gmail dot com 23-Oct-2006 11:25


When using imagepsbbox, keep in mind, that meaning of y-coordinates is slightly different here. Y-coordinates returned by this function are related to the baseline of the text starting at point [0,0]. Positive values represent points ABOVE the baseline, negative values represent points BELOW the baseline. That is why the lower left y-coordinate is always smaller here than the upper right y-coordinate (these two coordinates are actualy values of metrics.descent and metrics.ascent - see T1Lib docs).



So when you want to place some text using coordinates of the top left corner (for example [100,100]), use this:



<?php 



$x = 100;

$y = 100;

$text = "Dodge this";

$fontsize=18;

$font=imagepsloadfont("somefont.pfb");

list($lx,$ly,$rx,$ry) = imagepsbbox($text,$font,$fontsize);

imagepstext ($someimage, $text, $font, $fontsize, $somecolor, $somecolor, $x, $y + $ry);



?>



Hope it helps someone, I got stuck with this for a while.

daniel at dantec dot NO_SPAM dot nl 18-Apr-2002 06:23


When using imagepsbbox, you are probably trying to do something like creating a button with text, so that the button is large enough for the text...

Below is a very simple example of making a black button just big enough to display white text on it.



<?php 



//if text is no variable set sample text

if (!$text)

    $text = "This is a sample text";

    

// set the font size

$fontsize=14;



// load the font to use

$font=ImagePsLoadFont("/fonts/ariam___.pfb");



//get the left lower corner and the right upper

list($lx,$ly,$rx,$ry) = imagepsbbox($text,$font,$fontsize,0,0,0);



// calculate the size of the text

$textwidth = $rx - $lx;

$textheight = $ry - $ly;



// make an image 40 pixels wider and 20 pixels higher than the text

$imh = $textheight + 20;

$imw = $textwidth + 40;

$im = imageCreate( $imw, $imh );



//define colors, first color is used as background color!

$black  = ImageColorAllocate ($im, 0, 0, 0);

$white = ImageColorAllocate ($im, 255, 255, 255);



//create the text (with the same parameters as imagepsbbox!)

ImagePSText ($im, "$text", $font, $fontsize, $white, $white, 20, 20,'','','',4);



//send the header

header("Content-type: image/jpeg");



// create the image

ImageJPEG ($im,"",100);



//destroy the image & font to free memory

Imagepsfreefont ( $font );

ImageDestroy ( $im );



?>