2023 twenty-four merry days of Perl Feed

Who's That Clicking At The Window?

GUIDeFATE - 2023-12-08

Life at the Grotto has finally joined the modern age. Santa has got a new Laptop. The clacketty clack of his previous rather large steam powered workstation, a keyboard and a green phosphor terminal, replaced by a sleek portable device that could easily be carried on the sleigh. But some of the elves were mystified.

"Errr, what can you do with it?" asked Shinny Upatree, the aging elf.

"Look, " said Sugarplum eagerly,"Its looks so pretty, and you can move this arrow everywhere!",

Shinny was not convinced.

"I can even search for cute cat pictures",

Shinny knew all about gimmicks, "So what can you do that we NEED to do?",

"You can open up a terminal, and all our old software will work like before, I can even make the characters green", said Sugarplum desperately trying to make a case for new technology, "You can even use Notepad to write stuff"

Santa was passing by in a hurry, and overheard the conversation. "Of course, I have not got this new device just to still do things the old ways" he said, "I want a GUI", as he rushed by on his high performance electric scooter.

"Is that as messy as it sounds?" asked Shinny.

"Yes," groaned Sugarplum, "There are many GUI frameworks, it takes time to learn, and unlike terminal applications we are used to, a GUI application compiled for Santa's PC may not work on your Linux machines without significant effort."

"Alabaster Elf would know, but he is on leave!",

"Creating windows, positioning buttons, text entry widgets, drop down boxes, making menus, calling up dialog boxes, file selectors, callbacks,...oh how are we going to manage?"

Sugarplum had her head in her hands as Santa whizzed back again. "You can use Notepad?"

"That's about all I can do," she sniffled, "and Shinny can use vim on a terminal.",

"Then try GUIDeFATE", said Santa, "It stands for GUI Design From A Text Editor",

"Using GUIDeFATE, you simply draw the window and the widgets using ASCII characters in monospace fonts," he continued, "with a few easy-to-learn patterns to define widgets."

  • Ordinary text are "Static Text" items in the window

  • Buttons are enclosed in curly braces e.g. {Submit}

  • Inputs are in square braces e.g.[Default value]

  • Drop down boxes are in carets (not carrots) e.g.^ListName^

  • Images and Text Panels at drawn boxes with "I" ar or "T" in the top line

Half an hour later, after installing Tk and force installing GUIDeFATE Sugarplum Mary had already the following code:

#!/usr/bin/env perl
# A database for Santa

use strict;
use warnings;

my $window=<<END;
|T The Everybody Database |
| Making A List, Checking it twice |
| Gonna find out Who's naughty and nice |
| |
| {<} Person Index {>} [Name ]{?} |
| +T-----------------+ +I--------------+ |
| |Address | | Avatar.png | |
| | | | | |
| | | | | |
| +------------------+ +---------------+ |
| ^NiceOrNaughty ^ [Present ] |
| [Chimney Access Notes ] |
| {New}{Update}{Delete}{Read Letter} |
| Person 00000000001 of 8,342,124,422 |
| |



my $backend="tk"; # one of gtk, tk, gtk3, wx, win32 or html
my $assist="a"; # a for autogenerate, v for verbose, q for quiet
my $gui=GUIDeFATE->new($window,$backend,$assist); # Create the interface
my $frame=$gui->getFrame()||$gui; # $frame object now contains all the widgets
$gui->MainLoop(); # start the GUI

Executing this script yielded the following UIs with GTK, TK, HTML and Wx, effectively 17 "widgets" in less than 10 instructions.

But Santas laptop ran Windows. The solution was thankfully simple. Install Win32::GUI and Imager on Santas laptop, and change the $backend variable to "win32".

Making a UI was one thing, but tying actions to the widgets is quite another. How would you code the functions triggered by user interactions with the interface? Well passing "a" (for autogenerate) as the $assist parameter, makes GUIDeFATE to create a text file with all the detected widgets as well as the skeleton functions that represent the callbacks. This is only required once, and the assist can be switched off by reverting to "q", afterwards to prevent generating this file at every execution.

With the above UI it generates the following file:

#Static text 'Making A List, Checking it twice'  with id stattext0
#Static text 'Gonna find out Who's naughty and nice' with id stattext1
sub btn2 {#called using button with label <
# subroutine code goes here

sub btn3 {#called using button with label >
# subroutine code goes here

sub btn4 {#called using button with label ?
# subroutine code goes here

sub textctrl5 {#called using Text Control with default text ' Name '
# subroutine code goes here

#Static text 'Person Index' with id stattext6
#Static text '|' with id stattext7
#SubPanel 'T' Id 9 found position 3 height 5 width 18 at row 5 with content Address
#SubPanel 'I' Id 11 found position 25 height 5 width 15 at row 5 with content Avatar.png
#Static text '|' with id stattext12
sub combo13 {#called using combobox with data from @NiceOrNaughty
# subroutine code goes here

sub textctrl14 {#called using Text Control with default text ' Present '
# subroutine code goes here

sub textctrl15 {#called using Text Control with default text ' Chimney Access Notes '
# subroutine code goes here

sub btn16 {#called using button with label New
# subroutine code goes here

sub btn17 {#called using button with label Update
# subroutine code goes here

sub btn18 {#called using button with label Delete
# subroutine code goes here

sub btn19 {#called using button with label Read Letter
# subroutine code goes here

#Static text 'Person 00000000001 of 8,342,124,422' with id stattext20

Each item in the window can be accessed using the id. Each button click or input change triggers a subroutine. Static Texts can be changed by using their IDs.

More information can be found at GUIDEFATE's Github Pages

This was a quick and dirty solution to creating a general purpose intuitive UI; something that young Alabaster, the elf with advanced graphical interface powers could easily beautify once he returns from his well earned rest.

Gravatar Image This article contributed by: Saif <saiftynet@gmail.com>