World: r3wp

what I did at first was just to use the font size. that doesn't work, 
because it does not take the baseline into account.

then I used Graham's method and it does practically the same thing 
(I forgot to test for letters like "g"), but you can successfully 
calculate the bbox for a text string this way, if you need it.

Combining Graham's method with getting the height from the entire 
alphabet instead of the single word would eliminate the varying height 
problem you mention. But the baseline problem turns up again.

The bbox information for the entire font is stored in each font metric 
file as a [llx, lly, urx, ury] coordinate set, so I shouldn't need 
to calculate it. This information is crucial in order to get one 
line of vertically centered text. I already got everything in place 
except that particular number. :-)

the source you are reading contains Graham's method

Isn't this centered?

PageSize A4
page [
	font [Times 40] linewidth 0
	at 0x421 "Centered text" center 595
]

well, that's hardcoded :-)

Yes, that's what I think, you should do. Build a dialect with keywords 
as top, middle, bottom etc. and make that dialect know the size of 
the paper and correctly calculate the positions. That's the way to 
do it, I think. I would do it like that.

as mentioned before, that won't work, because the font information 
is not obtainable from inside REBOL. it has to be done inside postscript. 
I've already tried that method a year ago and it failed. :-)

Remember what kind of language, PS is.

There is no information about font (other than Times 40) in my example.

The 0x421 and 595 comes from the papersize, which is 595x842 when 
using A4.

ok, tell me then the algorithm for calculating the font height inside 
REBOL. :-) you cannot possibly know without reading and parsing the 
.PFM files yourself.

and as mentioned at first, I already tried the font size... doesn't 
work.

Why would I need the font height? I didn't need that in my example 
to center the text.

no, because you probably were eyeballing it.

No, I didn't! :)

center the text
 ... are you talking about _horizontally_ centered text?

When you do things like:
at 100x200 "some text"

the character origin of the first character in the text is at position 
100x200.

No, horiz and vert!

where did you get 0x421 from?

0 is left side of paper. 421 is height of paper divided by 2. 842 
/ 2 = 421.

Then it's centered.

if that's the case, let me test the theory

what?...

why doesn't that work for smaller cells?

PageSize A4
page [
	font [Times 18]
	at 60x421 "abcdefg"
	font [Times 36]
	at 130x421 "abcdefg"
	font [Times 96]
	at 260x421 "abcdefg"
]

In my example, the baseline of all the text is vertical centered 
on the page.

now I'm reallly confused. it would mean the height of the paper is 
somehow misleading. I tried your method in the table cells and get 
top-aligned text as I expected.

sorry

not top-aligned text, but text where the baseline is the center.

Ok, if it does, what you need. :-)

Do you have the psrefman.pdf document for PS second edition? Seciton 
5.4 has a drawing of font positioning.

I. Need. Vertically. Centered. Text. :-) Is that so hard to understand? 
:-)

LOL :)

Your method produces this:

http://hmkdesign.dk/rebol/postscript/testsheet.ps

That is _not_ vertically centered text. That is text that is vertically 
centered around the baseline.

Eh, the baseline is centered in each cell, right? And you're asking 
each word to be centered within its cell with equal space above and 
below the text?

... yes :-)

Because if you want that, then it'll look strange, because each line 
in the table will have text jumping up and down, depending on whether 
you have letters like 'g' and 't' or you just have letters like 'a'. 
And that will look less nice to me.

sigh... I've already said 4 times that I use the alphabet to prevent 
this! :-)

But you're right, that if you really want that, then you need to 
get info from each letter in the font.

yes! now you get it

:) In REBOL/View, there is things like offsets to position text within 
field and so. Couldn't you go with something like that? Just subtract 
a little from each vertical position to get the text a little down, 
if you want?

then I have to do that for each single individual case. with the 
deadline I have to produce this table, that may be my option for 
now, but that is definitely not optimal.

If you have different fontsizes in your tables, you could do something 
like:
y-pos: y-pos - (fontsize / 10)

Then adjust the 10 factor, until you're satisfied. And that should 
then work for all fontsizes.

well, possibly. I'll see if that works for now.

Sorry, that I find it hard to understand, what you mean from time 
to time, my fault. I get you now. I would put things like margins, 
linespace, vertical position within tables, etc. in a dialect above 
the postscript dialect level. Doing it that way, the same postscript 
dialect can be used for all sorts of layout engines, because it has 
little restriction.

for the syntax and input yes, but if you need accuracy, you need 
to get the information via postscript.