The goal is to have something that any programmer can use regardless of the the operating system.
Libraries in C and C++ are a pain to use, because they are only available for specific operating systems, specific compiler versions and tend to lack compatibility among themselves.
This pain also tends to be part of C culture, as other system programming languages already had the tradition to provide a proper set of libraries on their runtimes.
I think the main cause is that UNIX is actually C's set of libraries, but those libraries do not exist in all operating systems.
However having a set of libraries as default, is great for the guarantee to be able to write OS agnostic code.
No one is forced to use them, if they required more advanced use cases.
Like I said before, nobody is going to use an OS-agnostic UI library because UIs imply necessary integration and a level of specificity that can't be generalized.
There's half a dozen blitting models with difference performance optimizations. You have at least 4 or 5 popular widget toolkits. Do you support 2D drawing? 3D?
There are some things that just can't be abstracted away without massive engineering costs. No portable standard UI toolkit would be complete and compatible enough to be used for serious applications unless they're willing to stoop to levels as low as Java's so-called "multiplatform" UIs, which honestly look like crap.
A UI toolkit that's low-level enough is useless in desktop and modern mobile platforms. At higher levels they're too OS and device-specific. If they're too device-specific they have no place in a standard library. Thus, no UI toolkit is apt for this space unless you're willing to settle for mediocre, second-class toolkits.
> Like I said before, nobody is going to use an OS-agnostic UI library because UIs imply necessary integration and a level of specificity that can't be generalized.
Begineers and people that care about presenting simple stuff will do surely use it.
The idea is to have good enough libraries to write portable code for simple stuff.
Should anyone have to go though the pain of creating a OpenGL context, matrixes and shaders to put some text on the screen?
You are always free to go write Win32, Xlib, Qt, GTKmm, MFC, Motif, wxWidgets, WPF, embedded Chrome or whatever UI flavor of the months is for REAL applications.
Libraries in C and C++ are a pain to use, because they are only available for specific operating systems, specific compiler versions and tend to lack compatibility among themselves.
This pain also tends to be part of C culture, as other system programming languages already had the tradition to provide a proper set of libraries on their runtimes.
I think the main cause is that UNIX is actually C's set of libraries, but those libraries do not exist in all operating systems.
However having a set of libraries as default, is great for the guarantee to be able to write OS agnostic code.
No one is forced to use them, if they required more advanced use cases.