Perl and GUI. Widgets

This article will continue the review of widgets of the Tk (tkx) graphics library.



We will consider:
Label
Button
Entry
CheckButton
RadioButton
ComboBox
Frame


ttk :: button The
widget is a regular button, when clicked, some command action is performed.

button is in the ttk namespace, so using the Tkx module, the constructor will look like this:
my $ button = $ parent-> new_ttk__button (% args);

The most commonly used arguments are:
-text - the inscription on the button
-command - the callback called when pressed (invoke).
-width - length (calculated in characters), usually there is no need to use
-state - state of the widget (it can be: normal, disabled)

Parameter values ​​can be changed during program execution using the configure method:
$ button-> configure (% args)

A small example:
Place two buttons on the form (first active, second inactive ), when you press one, the other is activated.

#! / usr / bin / perl
use strict;
use Tkx;
my $ mw = Tkx :: widget-> new ('.');
   $ mw-> g_wm_minsize (250,100);
my $ button_1 = $ mw-> new_ttk__button (-text => 'Button 1');
my $ button_2 = $ mw-> new_ttk__button (-text => 'Button 2', -state => 'disabled');
$ button_1-> configure (
    -command => sub {
        $ button_1-> configure (-state => 'disabled');
        $ button_2-> configure (-state => 'normal');
    },
);
$ button_2-> configure (
    -command => sub {
        $ button_2-> configure (-state => 'disabled');
        $ button_1-> configure (-state => 'normal');
    },
);
Tkx :: grid ($ button_1, -row => 0, -column => 0, -padx => 10, -pady => 10);
Tkx :: grid ($ button_2, -row => 0, -column => 1, -padx => 10, -pady => 10);
Tkx :: MainLoop ();

ttk :: label
Regular label, you can use different fonts.

Text can be specified in two ways, either through the -text option, or -textvariable (pointer to a variable).
my $ label = $ parent-> new_ttk__label (-text => 'Static text');
or
my $ textval = 'something';
my $ label = $ parent-> new_ttk__label (-textvariable => \ $ textval);

Options:
-text - text.
-textvariable - a variable that stores the text of the inscription
-font, -background, -foreground - font, background color and text.
-justify - text alignment, set like west-east, south-west (read more in Perl and Tkx. Widget packaging).
-relief - label relief (flat, groove, raised, ridge, solid, sunken)
-padding, -wraplength - set margins on the edges, and the maximum length of the line in pixels (followed by hyphenation);

Let's embellish our first example:


ttk :: entry
Text input field



Standard arguments:
-textvariable - variable in which the field value will be stored
-state - state (normal, disabled, readonly)
-justify - alignment (left, center, right)

- validate, -validatecommand, -invalidcommand - allow you to use validation of entered data.

When there are many such widgets, it is convenient for textvariable to use a hash (for example, -textvariable => \ $ UI {login}).

ttk :: checkbutton A
button that has several states. Status is written in -variable.
When pressed, like ttk :: button, a procedure can be called.



The arguments
-text, -textvariable - specify the label on the
-onvalue button , -offvalue - values ​​when the option is checked or not. By default, these are 1 and 0.
-variable is the variable in which the value is written.
-command - action performed when clicked.

my $ checkbutton = $ mw-> new_ttk__checkbutton (
    -text => 'enable bla-bla feature',
    -variable => \ $ UI {enable_blabla},
    -command => sub {
        # Update other widgets
    },
);

ttk :: radiobutton


The device is as follows: each radiobutton is assigned a unique value (value), which is written into a variable (variable)
When you need to combine, let's say two buttons in one group, we set the values ​​for each of them, and -variable will be common.

my $ radiobutton_1 = $ mw-> new_ttk__radiobutton (-text => 'Option 1', -value => 1, -variable => \ $ UI {radio});
my $ radiobutton_2 = $ mw-> new_ttk__radiobutton (-text => 'Option 2', -value => 2, -variable => \ $ UI {radio});

Options:
-text, -textvariable, -width, -underline, -style etc. For more details, see the Tcl / Tk

documentation ttk :: combobox
Input field with a drop-down list. When the state is readonly, it only works as a list.



Options:
-textvariable - the variable in which the value of the text field will be stored.
-state - state (normal, readonly, disabled)
-values ​​- anonymous array, list.
-postcommand - a command executed after selecting an item from the list.
-justify, -height, -width - widget geometry.

ttk :: frame
When there are a lot of objects on the form, it is convenient to group them using frames.
For example
my $ frame = $ mw-> new_ttk__frame ();
my $ button = $ frame-> new_ttk_button ();
...
One frame can be in another frame and so on ... The

arguments are:
-borderwidth, -relief - border thickness, relief flat, groove, raised, ridge, solid, sunken)
-width, -height - length, width
-padding - indent around the edges.

ttk :: labelframe
This is the same frame, only with the title (-text)



ttk :: progressbar
Progressbar, you can set the range of values ​​(default 0..100)



Options:
-orient - orientation (horizontal and vertical)
-length - length in pixels
-maximum - maximum value (100)
-value - current value
-variable - variable that stores the value.

Previous Posts:
Working with the menu Tkx
widget
packaging and streams

References:
Tcl8.5.7 / Tk8.5.7 Documentation