这些函数允许您将字符串换行,以与比例字体(在本例中为 Arial,11px)的实际显示宽度进行比较。在某些情况下非常方便,因为 CSS3 尚未完全支持。100 个字符串 = ~5 毫秒
我以前的老式绵羊换行函数(发布在本文档的底部,有点过时了),而这个函数更快,更准确。
<?php
$fontwidth = 11;
$chargroup[0] = array(64);
$chargroup[1] = array(37,87,119);
$chargroup[2] = array(65,71,77,79,81,86,89,109);
$chargroup[3] = array(38,66,67,68,72,75,78,82,83,85,88,90);
$chargroup[4] = array(35,36,43,48,49,50,51,52,53,54,55,56,57,60,61,62,63, 69,70,76,80,84,95,97,98,99,100,101,103,104,110,111,112, 113,115,117,118,120,121,122,126);
$chargroup[5] = array(74,94,107);
$chargroup[6] = array(34,40,41,42,45,96,102,114,123,125);
$chargroup[7] = array(44,46,47,58,59,91,92,93,116);
$chargroup[8] = array(33,39,73,105,106,108,124);
$chargroup_relwidth[0] = 1; $chargroup_relwidth[1] = 0.909413854;
$chargroup_relwidth[2] = 0.728241563;
$chargroup_relwidth[3] = 0.637655417;
$chargroup_relwidth[4] = 0.547069272;
$chargroup_relwidth[5] = 0.456483126;
$chargroup_relwidth[6] = 0.36589698;
$chargroup_relwidth[7] = 0.275310835;
$chargroup_relwidth[8] = 0.184724689;
$char_relwidth = null;
for ($i=0;$i<count($chargroup);$i++){
for ($j=0;$j<count($chargroup[$i]);$j++){
$char_relwidth[$chargroup[$i][$j]] = $chargroup_relwidth[$i];
}
}
function get_str_width($str){
global $fontwidth,$char_relwidth;
$result = 0;
for ($i=0;$i<strlen($str);$i++){
$result += $char_relwidth[ord($str[$i])];
}
$result = $result * $fontwidth;
return $result;
}
function truncate_str_at_width($str, $width, $trunstr='...'){
global $fontwidth,$char_relwidth;
$trunstr_width = get_str_width($trunstr);
$width -= $trunstr_width;
$width = $width/$fontwidth;
$w = 0;
for ($i=0;$i<strlen($str);$i++){
$w += $char_relwidth[ord($str[$i])];
if ($w > $width)
break;
}
$result = substr($str,0,$i).$trunstr;
return $result;
}
?>