Control placement of a button within a text widget

[Helmut Giese]

Hello out there,
I want to embed a button within a text widget - this is easy. However,
I also want it to be centered in the middle - this is hard (ok, hard
for me).
Here is what I have so far:
---
package require Tk
# just for re-sourcing this file
foreach w [pack slaves .] {destroy $w}

pack [text .t -width 12] -fill x
set s "This is line 1.
This is line 2.
This is line 3.
"
.t insert end $s
# this line helps a bit
#.t insert end " "
# now the button
.t window create end -align center -create \
[list button .t.btn -text Ok \
-command {puts "Click"}]
---
The button will appear flush left. I thought that '-align center'
would be the option I need, but this appears to not be the case.

If I uncomment the line marked by "# this line helps a bit" the button
will be pushed over to the right. I could experiment how many spaces
to fill in to have the button in the middle, but this is a kludge:
- If the text window is made wider, the button will stay at its place
and won't be centered any more.
- If the user changes the font, the button is likely to not be
centered any more.

Tcl (and Tk) being what it is, I am sure that there is a solution for
what I want. Any hints in this direction will be greatly appreciated.
Best regards
Helmut Giese

[sleb...@gmail.com]

You can with some trickery. Just create the window on a line that is
center justified (align refers to 'vertical' alignment). Sort of like:

This is line 1
This is line 2
This is line 3
blah[OK button]blah

if you make the text on that line space bars, then you have what you
want:

pack [text .t -width 12] -fill x

.t tag configure ctr -justify center

set s "This is line 1.
This is line 2.
This is line 3.
"
.t insert end $s
# this line helps a bit
#.t insert end " "
# now the button

.t insert end " " ctr

.t window create end -align center -create \
[list button .t.btn -text Ok \
-command {puts "Click"}]

.t insert end " " ctr
.t insert end "\n"

# Note how I surround the button with space bars to maintain
# correct center.

[Bryan Oakley]

sleb...@yahoo.com wrote:
> # Note how I surround the button with space bars to maintain
> # correct center.
>

Why do you add spaces "to maintain the correct center"? You can just add
the ctr tag to the created window after the fact with '.t tag add'.

[sleb...@gmail.com]

Ah, didn't realise I could tag a window. I tried:

.t window create end ..... tag

and it didn't work. Then when I read (quickly scanned) the docs I
couln't find a way to tag a window. Thanks. Then the solution is
simply:

pack [text .t -width 12] -fill x
.t tag configure ctr -justify center
set s "This is line 1.
This is line 2.
This is line 3.
"
.t insert end $s

.t window create end -align center -create \
[list button .t.btn -text Ok \
-command {puts "Click"}]

.t tag add ctr {end - 1 lines} end

[Helmut Giese]

Many thanks to both of you. Works like a charm.
... still so much to learn about the text widget and other GUI topics,
sigh.
Best regards
Helmut Giese