#ptk overview

Ptk (parenthesized tk) is a library to ease the programming of tcltk-based gui’s. The main goal is to provide a progamming style that reflects the logical layout of the the gui, and hides/abstracts the technical details. - avoid the manipulation widget paths; - write things once; in particular creation and packing are not two different features.

Concretely, a gui consists in a recursive structure of horizontal and vertical frames containing basic widgets (leaves).

Containers

Each container has a kind that determines how nested items will be displayed and managed. Containers are created and finalized using begin and end. Every ptk items appearing within begin and end belongs to the container.

ptk::begin kind ?params? ?opts?
    ....
ptk::end ?kind?

• kind is the type of container; basic kinds are main (top-level), line, col etc.
• params is the list mandatory parameters (passed by position); their number and types depend on kind
• opts is a list of classical tk options -key value; valid options depends on kind.
• kind is optional for command end, but recommended to tract nesting errors.

Leaves

Each leaf has a kind that determines its layout and behavior. Ptk inherits classical tk widgets (label, button, checkbutton etc.), and provides some other meta-widgets (combobox, select_file, etc.). Leaves are created by the add command, whose arguments are similar to those of begin:

ptk::add kind ?params? ?opts?

Hello world

package require Ptk
namespace import ptk::*

begin main "My program"
    begin line 
        button -text "push me" -command {puts "Hello world!"}
    end line
end main

Customization and components

Ptk items are made of tk-widget that can be customized using -key values options. Each item has a main component, and possibly some others. When creating an item (with add or begin) options are directly passed to this main component. It is also possible to pass options just after the creation using the configure command. Note that this command is necessary to customize other component than the main one.

ptk::configure ?component? ?opts?

• configure applies implicitly to the last created item, and then must follow a add or begin command.
• component identifies the widget to customize inside the current item; valid components depend on item kind; if omitted, configure applies to the main component.

Note: it is possible to customize distant items (not the last created one) using the advanced store and reuse feature.

Basic items

Basic leaves

Basic leaves are just wrappers around basic tk widgets, and inherit their options:

ptk::label ?label-opts?
ptk::button ?buttons-opts?
ptk::checkbutton ?checkbutton-opts?
ptk::radiobutton ?radiobutton-opts?
ptk::scale ?scale-opts?
ptk::entry ?entry-opts?

Customization can be performed after add; valid options are the same than for add.

ptk::configure ?opts?

Packers

Line/column layout

Basic containers are packers. They allow to organize the layout as a structure of nested horizontal and vertical frames. * horizontal packers: sons are inserted from left to right; basic ones are line and hbar. * vertical packers: sons are inserted from top to bottom; basic ones col and vbar. Each container has a predefined packing policy that defines how the container behaves within its own container, and how it handles its content:

• line and col expand in both direction within their container, and expand their content if both direction too.
• hbar and vbar expand in one direction only (resp. x and y), and does not expand their content but stack them side by side (resp. left to right, top to bottom).

Example:

Here is a typical layout with a top hbar (e.g. to put menu entries), a left vbar (e.g. tool bar), and a central expandable zone to put the rest.

begin main "My program"
    begin hbar -text "Menu bar" 
        .....   
    end hbar
    begin line
        begin vbar -text "Tool bar" 
            .....   
        end vbar
        begin col -relief sunken
            .....
        end col
    end line
end main

Packers summary:

ptk::begin col|line|vbar|hbar ?opts?
...
ptk::end ?col|line|vbar|hbar?

• packers have no mandatory parameters
• valid options are any valid tk frame or labelframe options:
  • if -text <string> is specified, the packer is interpreted as a labelframe
  • otherwise as a simple frame

Customization can be performed after begin, valid options are tk-frame options.

ptk::configure ?opts?

Packing customization

Do not mix up with widget customization. The packreq command passes specific packing request from a item to its contained.

ptk::packreq ?pack-opts?

• pack-opts are packing option (cf. tk command pack configure)
• useful in particular to bypass the default packing policy, e.g.  -expand 1 inside a vbar/hbar or -expand 0 inside a line/col
• useful options are:
  • -anchor anchor
  • -expand boolean
  • -fill style
  • -ipadx amount
  • -ipady amount
  • -padx amount
  • -pady amount
• NEVER USE OTHER OPTIONS since they interfere with ptk algorithm and will lead to undefined behaviors.

Conditional display

TODO showif

Meta-containers

Switch and toggle

switch displays exactly one from its n sons one according to the value of an enumerate variable.

ptk::begin switch var values ?opts?
    <son 1>
    ...
    <son n>
ptk::end ?switch?

• values is a list of n string values (v1 … vn)
• var is a variable taking its value in values
• must contain exactly n sons, the ith son is displayed iff var holds value vi
• valid opts are tk-frame options

toggle is basically a switch commanded by a Boolean variable.

ptk::add toggle var ?opts?
    <son 1>
    <son 0>
ptk::add ?toggle?

• var is a variable containing Boolean values
• must contain exactly 2 sons, first son is displayed is var is true, second son if var is false.
• valid opts are tk-frame options

Customization: can be performed after begin:

ptk::configure ?opts?

Popup

popup displays a button which, when pressed opens a toplevel (independent) window displaying its content plus a predefined dissmis button.

ptk::begin popup title ?opts?
ptk::end ?popup?

• title is the name of the opened window; and the default text of the popup button.
• opts are tk-button options, in particular one can use -text to change button label.

Customization: popup has two configurable tk components, button (main one) and frame (main frame of the popup window):

ptk::configure ?button-opts?
ptk::configure button ?button-opts?
ptk::configure frame ?frame-opts?

Meta-leaves

Show var

{kind outer params components} {showvar packer {var} {labelframe label}}

Combobox

wrapper for Bryan Oakley’s combobox opts -> passed to combobox

{kind outer params components} {combobox packer {title var values} {combobox}}

Store and reuse

Principle

store

Reopen container

reopen reclose

Reconfigure

reconfigure

Appendix: Combobox (Bryan Oakley)

This section is extracted from Bryan Oakley’s Combobox manual.

Combobox options