string - PHP: Get width in pixel of text including "normal" text and emoji's -

i want trim given text @ given number of pixels.

to achieve this, loop through length of text , each loop, add next character , measure string of method imagettfbbox. - works fine me on "normal text's" e.g. posting. ;)

but if add emoji's text, length shorter expected. think because emojis encoded more 1 byte. - that's why, i'm using mb_strwidth , mb_substr.

the method imagettfbbox expects font-file measure given string. font able display emoji's.

here's code

$line = "🏡 garden, 🕓 clock, other things"; $maxlength = 100; // pixel  // start looping through line, start 15 characters ( $len = 15; $len < mb_strwidth($line); $len++ ) {     // grep x chars line    $newline = mb_substr($line, 0, $len);     // measure string    $fontbox = imagettfbbox(12, 0, "fonts/opensansemoji.ttf", $newline);    $textwidth = $fontbox[2];     // compare measured string given max length    if ( $textwidth > $maxlength ) {       $line = mb_substr($line, 0, $len - 2) . "...";       break;    } }  $line = newline; 

expample lines

"🏡 garden, 🕓 clock, other things" "🏡🏡🏡🏡🏡🏡🏡🏡🏡🏡🏡🏡🏡🏡🏡🏡 gaaaaaaaaaaaardeeeeeeeeeeeeeeeeeen" "mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm" "iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii" "erufgbwuiergbvfuipwervbpiuwebvruiwbevuibwüeriuvbwieuörvböwieuvbr" 

result

as can see, more emoji's use, shorter line.

kind regards non native speaker. :)