persistentSelection3tk

Usage

Overview

Consider a Tk widget that sets its -exportselection option to boolean true, thereby exporting its selection. When the selection in the widget is canceled, by default Tk also cancels the PRIMARY selection. In this situation, an attempt to read the PRIMARY selection, e.g. by a <<PasteSelection>> event, will fail.

The persistentSelection package offers more convenient behavior. It will sustain as the PRIMARY selection the last non-empty value set by any Tk widget that it monitors, as long as the PRIMARY selection is not claimed by another process, or by a widget that it does not monitor.

The persistentSelection package works by binding to the <<Selection>> event on the widgets of interest, and using this binding to monitor any change of the selection in the widget. Its commands are confined to the namespace ::persistentSelection.

Commands

persistentSelection::fixText

Call this command once to resolve problems with text widgets that use the default Text bindtag (rather than Ntext). See Text widgets for an explanation.

The command adjusts some Text bindings to generate <<Selection>> events; and it re-orders calls to the text widget tag command in the private command ::tk::TextSelectTo, so that this command cooperates better with persistentSelection.

These adjustments are needed only to older versions of Tk. The command persistentSelection::fixText has no effect on sufficiently recent releases. It can safely be called for any version of Tk.

persistentSelection::getClassicPrimarySel ?displayOf? ?withOthers?

•

displayOf - a Tk window path on the display to be interrogated (optional, default {.})

•

withOthers - whether to return the PRIMARY selection if it is owned by another process or interpreter (optional, boolean, default false)

A command to return the classic (non-persistent) form of the PRIMARY selection. If the selection does not exist, or is sustained only by persistentSelection, the command returns the empty string.

persistentSelection::getPrimarySel ?displayOf?

•

displayOf - a Tk window on the display to be interrogated (optional, default {.})

A command to return the value of the PRIMARY selection. If the selection does not exist, the command returns the empty string. The usual Tk commands are perfectly valid, but they raise an error if the selection does not exist.

persistentSelection::report type pathName

•

type - (value text or entry) classification of the widget whose selection has changed

•

pathName - the Tk window path of the widget whose selection has changed

To make package persistentSelection monitor a widget, this command must be bound to the <<Selection>> event on that widget. The command records changes in the widget's selection, and uses the information to sustain a non-empty PRIMARY selection on each display.

Usage

To do

•

Test on a system with multiple displays.

Examples

Each example uses persistentSelection to retain the last non-empty value of the selection in certain widgets. Each example also includes the creation of sample widgets.

Monitor all entryPlus widgets.

package require widgetPlus
widgetPlus::entryPlus .ep
pack .ep
package require persistentSelection
bind EntryPlus <<Selection>> {::persistentSelection::report entry %W}

Monitor all text widgets that use the default Text bindings.

text .t
pack .t
package require persistentSelection
::persistentSelection::fixText
bind Text <<Selection>> {::persistentSelection::report text %W}

Monitor all text widgets that use the default Text bindings, and all entryPlus widgets.

text .t
pack .t
package require widgetPlus
widgetPlus::entryPlus .ep
pack .ep
package require persistentSelection
::persistentSelection::fixText
bind Text <<Selection>> {::persistentSelection::report text %W}
bind EntryPlus <<Selection>> {::persistentSelection::report entry %W}

Monitor all text widgets that use Ntext bindings.

text .t
pack .t
package require ntext
bindtags .t {.t Ntext . all}
package require persistentSelection
bind Ntext <<Selection>> {::persistentSelection::report text %W}

Monitor a single entryPlus widget .ep

package require widgetPlus
widgetPlus::entryPlus .ep
pack .ep
package require persistentSelection
bind .ep <<Selection>> {::persistentSelection::report entry %W}

Monitor a single text widget .t

text .t
pack .t
package require persistentSelection
bind .t <<Selection>> {::persistentSelection::report text %W}