Question

was just wondering, how are GUI libraries like GTK, wxWidget written ?? i mean what language or tools are used ...

Answer 1

Depends on the library. Most of them are written in C/C++ and they have what are called wrappers written for other languages.

Low Level graphics libraries are designed to abstract you away from alot of the platform specific architectures you would have to code for. Allowing for easier readability, maintainability, and portability.

If you are wondering how a programmer is able to write a library that tells the computer how to send a pixel to the screen. You have places in your memory/cache called I/O mappings.

Each pixel is typically a 16/32 bit int and has its own memory address.

When you define colors you may wonder why its in the format 255, 255, 255, 255 (RGBA)

Each of those numbers are actually a byte(currently at the max a byte can hold). Which when assigned to the address that your GPU knows belongs to a pixel it reads the 32 bit int thats store in that address and converts the color to whatever you set it as.

Thats kinda a simple way to put it, but thats the gist of the idea.