Select multiple TCL/TK text widgets at once - tcl

Question

I am trying to create a table using TCL/TK and am building it without using the Tktable widget.
I am using a canvas to build the table from ground up using the approach provided in:
simple Tktable
I have a whole bunch of customizations which (so far) I feel is easier if I build the table in a canvas and am hence using this approach instead of Tktable.
My table will be filled with read only text widgets, editable text widgets and some drop down menus.
Here is my question:
1) How can I allow a user to select multiple text widgets at the same time and retrieve the selection? Such as say, the user selects an entire row/col etc.
Please see the simplified code below:
package require Tk
proc makeWindow {} {
set toplevelWindow .gui
destroy $toplevelWindow
## Make the toplevel window
toplevel $toplevelWindow
wm title $toplevelWindow "Test case 1"
wm minsize $toplevelWindow 200 200
set pathName $toplevelWindow.testMultiSelection
## Create the canvas where I build the table
destroy $pathName
frame $pathName
set col 0
for {set i 0} {$i < 4} {incr i} {
set w "$pathName\_$i"
destroy $w
text $w -width 9 -height 1 -state normal
$w insert end $i
$w configure -state disabled
grid $w -row $i -column $col -sticky ew
}
grid config $toplevelWindow.testMultiSelection -column 0 -row 0 -sticky w
}
makeWindow
In the above example, I expect to select a few numbers (basically something like the ctrl+select) and somehow store the selection somewhere and retrieve them for later use.
Please let me know if the condensed test-case above is not clear.
EDIT 1
Forgot to add that I know how to retrieve single text widget selections using the selection get command.

Answer 1

Selections are restricted to a single widget at a time by default. If you turn off exporting of the selection at the widget level for each widget (configure -exportselection 0) then you can take over the management of that. However, some platforms also don't display the selection unless the widget has focus (due to platform GUI rules) so you might well also need to manage a text tag to apply the look of the selection. (The sel tag is the selection; it's managed specially, but you can copy its look fairly easily.)
Remember that you can embed widgets inside both canvases and text widgets (if the sub-widgets have names that make them child of the container). The window subcommand and/or item type is what you're looking for there if you're going that route.
The other big thing is managing the clipboard. You'll want to take that over explicitly. The usual command for that is clipboard, though the selection command can also be used (it gives access to the lower-level parts of the clipboard/selection mechanism; the clipboard is the CLIPBOARD selection).
Understand this, what you're doing is complicated and likely to take quite a bit of time and effort. Ask yourself whether your project is really justified in this level of complexity.

Answer 2

Gist of this idea is to use text tags to mark the selected text so you not only get the appearance of selected text you also mark that text as "selected". Then your copy operation merely iterates over all text widgets and gets the contents if it possesses the tag "selected". You can unselect selected text as you get the contents by removing the tag or as I have done below where the button command replaces itself with its own undo command.
So the flow is click on the column button, all text widgets in that column have their contents tagged as selected (selected text is white background & black foreground and so looks selected ) click on a popup menu or a menu button that accesses all selected items and performs operation on the contents then click on column button to unselect the column. all selected text widgets have the selected tag removed with restores the default look of the text.
Assuming you click the top of the column ( I assume its a button ) and you know the text widgets in that column you can tag the text in each text widget with a tag to indicate it is selected. Then to copy you can iterate over all text widgets and pull the content in each text widget that is tagged. To unselect iterate over all text widgets and untag the content. In the code below Im assuming that I have the following functions : getAllTextWindowPaths - gives me list of all textwidgets in the canvas, getAllTextPathsInColumn colnumber - gives me list of all textwidgets in canvas in column $colnumber.
# configure tags for all your text windows
foreach t [ getAllTextWindowPaths ] {
$t tag configure selected -background white -foreground black
}
# configure the column select button
button .canvas.button.column1 -text {1} -command [ list clickColumn .canvas.button.column1 1 ]
proc selectText { textpath { select 1 } } {
if { $select == 1 } {
$textpath tag add 1.0 end selected
} else {
$textpath tag remove 1.0 end selected
}
}
proc clickColumn { colpath colnum } {
# now call this click handler for for your column of textwidgets
# you can make same for a row
foreach t [getTextPathsInColumn $colnum ] {
selectText $t 1
}
$colpath configure -command [list unclickColumn $colpath $colnum ]
}
proc unclickColumn { colpath colnum } {
# now call this click handler for for your column of textwidgets
# you can make same for a row
foreach t [getTextPathsInColumn $colnum ] {
selectText $t 1
}
$colpath configure -command [list clickColumn $colpath $colnum ]
}
proc getSelectedContents { } {
# im adding to a list all the seleted contents but you can arrange
# it anyway you want
set retval {}
foreach t [getAllTextWindowPaths ] {
if { "selected" in [$t tag names 1.0 ] } {
lappend retval [ $t get 1.0 end ]
}
}
# optional call selectText $t 0 here foreach selected widget
# to clear selection or handle the column click handler again
return $retval
}