imagepsbbox()

(PHP 4, PHP 5)

给出一个使用 PostScript Type1 字体的文本方框

说明

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

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

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：

范例

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

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;
}

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.

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 );
?>

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);