PDFlib how to calculate the size of box

[mediamind]

I'm trying to get a colored rectangle with text on top. (code at the bottom)

Height is set to 15 in the example, BUT i would like to get the height dynamicly set so that it adapts according to the amount of text that go's in the box.

How can i calculate the height?
+ the rectangle needs to be set first otherwise the text is under the colored rectangle and not visible! right?

PDF_setcolor($pdf, "both", "rgb", 0.666, 0.882, 0.980, 0);
PDF_rect($pdf, 340, 300, 75, 15);
PDF_fill_stroke($pdf);

PDF_setcolor($pdf, "fill", "rgb", 0, 0, 0, 0);
PDF_show_boxed($pdf, $text, 350, 300, 65, 15, "center");

[mediamind]

If i use this code i get the right result, BUT that means i have to print it to the screen twice !!
1st for measuring "texty"
2nd then make the rectangle with bgcolor
3rd print the final text again over the rectangle.

Isn't there a nicer way?

PDF_show_boxed($pdf, $ingredienten_1, 0, 0, 150, 400, "center");

$box_y = (PDF_get_value($pdf, "texty") - 400);

[Anon]

Use blind.

Such as:
while ((pdf_show_boxed($p, $text, $posx, $posy, $box_width, $text_height, left, blind)) > 0)
{
$text_height = $text_height + $font_size;
}

Blind will keep the text from actually showing up and $text_height will be the final height of your text in the given width.