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

用户评论:

[#1] eikie [2008-05-05 09:32:30]

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);

[#2] eikie [2008-05-05 08:34:55]

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;
}

[#3] honza dot bartos at gmail dot com [2006-10-23 14:25:36]

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.

[#4] daniel at dantec dot NO_SPAM dot nl [2002-04-17 21:23:46]

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 ); ?>