Re: pic doesn't center when i use a macro

[Holger Herrlich]

.PS

define label_for {[
    if $1 == 0 then { "Entête Ethernet"      } else {
    if $1 == 1 then { "Entête IP"            } else {
    if $1 == 2 then { "Entête TCP"           } else {
    if $1 == 3 then { "Donnees applicatives" } else {
    } } } }
]}

w = 3 ; h = 2; margin = .2 ; tr = 2 * margin
for layer = 0 to 3 do {
    s = layer * margin
    box width w height h with .sw at (s,s)
    box width w height margin with .nw at last box .nw dashed
    label_for(layer) at last box.c
    w = w - tr
    h = h - tr
}
.PE



On Mon, 1 Nov 2021 19:57:15 +0100
Marc Chantreux <eiro@phear.org> wrote:

> hello groffers,
> 
> I wrote the following code to illustrate the DOD model encapsulation.
> 
> sadly: the label of the layers are not centred. it seems to be
> relative to the fact i use a function as it works fine when i replace
> label_for(layer) by a simple string
> 
> like
> 
>     box width w height margin \
>         with .nw at last box .nw dashed \
>         "" label_for(layer) ""
> 
> by
> 
>     box width w height margin \
>         with .nw at last box .nw dashed \
>         "" "eat the road, jack" ""
> 
> I can do something more manual but i really would like to take
> advantage of the expressivity of pic. Any other comment is also
> warmly welcome.
> 
> regards,
> marc
> 
> # compiled with
> # scan.ps: scan.ms ${deps} ; groff -skp -ms -mfr $< > $@
> 
> .PS
> 
> define label_for {
>     if $1 == 0 then { "Entête Ethernet"      } else {
>     if $1 == 1 then { "Entête IP"            } else {
>     if $1 == 2 then { "Entête TCP"           } else {
>     if $1 == 3 then { "Donnees applicatives" } else {
>     } } } }
> }
> 
> w = 3 ; h = 2; margin = .2 ; tr = 2 * margin
> for layer = 0 to 3 do {
>     s = layer * margin
>     box width w height h with .sw at (s,s)
>     box width w height margin with .nw at last box .nw dashed ""
> label_for(layer) "" w = w - tr
>     h = h - tr
> }
> .PE
> 
>