What is GUI (Graphical User Interface)?

The Graphical User Interface (GUI) is a visual application interface that is provided using graphics like windows, text boxes, and buttons through which users can communicate with the software. GUI offers an interactive and easy-to-use platform as compared to the Command Line Interface (CLI) as users can use the mouse or other input devices such as a touchscreen, etc. without relying only on the keyboard.

Main Concepts of GUI Programming

A graphical user interface (GUI) involves designing windows, dialogs, buttons, etc which are all interactive user interface components. Then we control these widgets using event handlers like onClick, onHover, etc.

The main concepts of GUI Programming are:

Widgets

A graphical user interface (GUI) is made up of widgets. For example, these include buttons, textboxes, labels, etc. Properties and behaviors of each widget can be customized in accordance with the specific needs of an application. There are generally the following widgets in a GUI library:

1. Window: A top level window frame that host other widgets inside itself.
2. Button: A clickable button that have some event associated with its click.
3. Label: Simple read-only text
4. Checkbox: Box that provide the options to be on or off.
5. Radio Button: Box that provide the options to be on or off but we can only choose one radio button in a group.
6. Dropdown/Combo Box: Opens a dropdown menu when clicked. Only one item can be displayed in the non-opened form.
7. Textbox: Editable Text area.
8. Listbox: The box with multiple items and a scroll bar to go through all of them.
9. Slider: A navigation widget used to move around the application.
10. Menu: Shown at the top, menu provides different options to the application user.
11. Dialog Box: A box that is displayed on the top of a window. Sometimes to display the notification.
12. Grid: Used for the Layout Management of the UI.

Layout Management

The GUI applications must be optimised for various screens of different sizes, resolutions etc which seeks to keep an attractive but effective user interface with the various widgets organized onto the screen.

Event Handling

In GUI programming, the events like button clicks or key presses are critical. These events are handled by the app in order that it could follow the user actions. There are different events associated with different widgets. For example, for a clickable button, the associated events are:

1. Click Event
2. Mouse Move Event
3. Focus In Event
4. Focus Out Event

In C++, Graphical User Interface (GUI) programming is important in modern application development where users have nice graphics for them to work with. Although C++ is commonly linked with system programming and game writing, it can be an excellent alternative to GUI writing. In this article, we will discuss GUI programming in C++, some popular GUI libraries for C++, and how to create a basic GUI application in C++.

Prerequisites: Fundamentals of C++, C++ OOPs, Some GUI Library.