GTK install --

sudo apt install libgtk-3-dev

CURL install --

sudo apt-get install libcurl4-openssl-dev

JSON install --

sudo apt-get install libjson-c-dev

GTK (GIMP Toolkit) is a free and open-source cross-platform toolkit for creating graphical user interfaces (GUIs). It is widely used for developing applications on Linux and supports other platforms like Windows and macOS. Here's an overview of GTK: Key Features

Cross-Platform:
    Applications built with GTK can run on multiple operating systems with little or no modification.

Object-Oriented Design:
    GTK uses GObject, an object-oriented system in C, 
    enabling features like inheritance and polymorphism in C-based code.

Rich Set of Widgets:
    Provides standard GUI elements like buttons, text entries, 
    labels, sliders, and advanced widgets like tree views and tables.

Theming and Customization:
    Supports themes, allowing developers and users to change the look and feel of applications.

High-Performance Rendering:
    Uses Cairo for rendering, providing anti-aliased graphics and modern drawing capabilities.

Language Bindings:
    Supports multiple programming languages, including C, Python, C++, JavaScript, and more.

Core Concepts

Widgets:
    The building blocks of GTK applications (e.g., GtkButton, GtkLabel, GtkEntry).
    Organized in a hierarchy to form the GUI layout.

Signals:
    GTK uses an event-driven programming model.
    Signals are emitted when user actions or programmatic events occur 
    (e.g., a button click emits a "clicked" signal).

Containers:
    Widgets are arranged using container widgets like GtkBox, GtkGrid, and GtkFixed.
    Containers manage the size and position of child widgets.

Drawing:
    The GtkDrawingArea widget allows custom rendering using the Cairo graphics library.

GTK Workflow

Initialization:
    Start by calling gtk_init() or gtk_application_new() to set up the toolkit.

Widget Creation:
    Create widgets like windows, buttons, or text inputs.

Layout:
    Arrange widgets in containers to define the interface structure.

Signal Handling:
    Connect signals to callback functions to handle user interactions.

Main Loop:
    Use gtk_main() or g_application_run() to start the main event loop.

Advantages

Modern Look: GTK applications look polished and integrate well with desktop environments like GNOME.
Community Support: Active development and a large community.
Flexible Licensing: Licensed under LGPL, making it suitable for open-source and proprietary projects.