TIP:            147
Title:          Make Grid's Column/Row Configure Easier
Version:        $Revision: 1.5 $
Author:         Peter Spjuth <peter.spjuth@space.se>
State:          Final
Type:           Project
Vote:           Done
Created:        05-Aug-2003
Post-History:   
Tcl-Version:    8.5

~ Abstract

This TIP proposes to add an alternative way to state which
columns/rows in a grid are affected by an column/rowconfigure command.

~ Rationale

Usually when doing a grid layout I tend to think in terms of what I
want to do with a particular widget.  For example a canvas or a frame
that I want to expand within a resized window.  Currently I need to
translate that intention into a column and a row number to pass to
column/rowconfigure.  A more direct approach would be to pass the
widget name directly to column/rowconfigure.

Another situation is when all columns should be affected.  Here I
currently need to list them all {0 1 2 3 4 5}.  Allowing an "all"
keyword makes it easier and the code becomes more maintainable since
you can add/remove columns without updating the list.

What should be done when columnspan is greater than 1?

There are three obvious possibilities: affect all, affect the first
and affect the last.  Any of these may be wanted by a programmer at
one time or another so whatever is chosen, someone will be annoyed
with it.  Affecting all seems most logical.

See also
http://sf.net/tracker/?func=detail&aid=659218&group_id=12997&atid=362997

~ Specification

Anywhere ''column'' is used below, the same applies to ''row'' too.

In the ''index'' argument to ''grid columnconfigure'', widget names
and the keyword "all" is recognised besides the normal integers.

When a widget name is used, it must be currently managed by the given
''master''.  The columns currently occupied by the widget are affected
by the command.

When the keyword "all" is used, all columns currently occupied by
widgets in ''master'' are affected by the command.

''Note:'' "Currently occupied" means at the time of the invocation of
the ''grid columnconfigure'' command.  The grid does not try to trace
if a widget is moved in the grid or if more widgets are added.

~ Examples

|canvas .c
|scrollbar .sbx -orient horizontal
|scrollbar .sby -orient vertical
|grid .c .sby -sticky news
|grid .sbx    -sticky we
|grid columnconfigure . .c -weight 1
|grid rowconfigure    . .c -weight 1
|
|button .b1 -text a
|button .b2 -text b
|button .b3 -text example
|button .b4 -text xyzzy
|grid .b1 .b2 .b3 .b4 -sticky news
|grid columnconfigure . all -uniform a -weight 1

~ Other Possibilities

One possibility that is not proposed in this TIP is to also recognise
the end-style indexing that indices in Tcl support (through
''TclGetIntForIndex()''.)

Comment: "Personally, I think that end-index handling will be quite
tricky since it would require knowing what the *user* thinks is the
last column."

~ Reference Implementation

Not implemented yet.

~ Copyright

This document has been placed in the public domain.