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https://github.com/vvaltchev/tfblib

A Tiny Linux Framebuffer Library
https://github.com/vvaltchev/tfblib

c framebuffer library linux

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A Tiny Linux Framebuffer Library

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README 

        
# Tfblib (Tiny Framebuffer Library)



![Build](https://github.com/vvaltchev/tfblib/workflows/Linux/badge.svg)

[![Documentation](https://img.shields.io/badge/api-reference-blue.svg)](https://vvaltchev.github.io/tfblib/tfblib_8h.html)

[![License](https://img.shields.io/badge/License-BSD%202--Clause-orange.svg)](https://opensource.org/licenses/BSD-2-Clause)



`Tfblib` is a simple and low-level graphics library for drawing to the Linux

framebuffer. Currently, it is capable of drawing lines, rectangles and text.

It has support both for embedded (compiled-in) fonts in the library and

dynamically loaded `PSF` fonts at runtime. In addition to drawing functions,

`Tfblib` has a minimal support for keyboard input that allows simple

applications to put the TTY input in *raw mode* and read keystrokes. Both

blocking and non-blocking modes are supported.



![Drawing example](other/drawing.png)

![Drawing text example](other/text.png)



Building

---------



Building `Tfblib` as a static library is simple as executing (in project's root

directory):



```

$ mkdir build

$ cd build

$ cmake ..

$ make

```

The `make` command will build the library along with the programs in the

examples/ directory. In case a release build (with optimizations) is desired,

the `cmake` command has to be run this way (assuming the current working

directory is the build directory):



    cmake -DCMAKE_BUILD_TYPE=Release ..



Or:



    cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo ..



In case a release build with debug info is desired.



A "hello world" application

-----------------------------



Using `Tfblib` is extremely simple. Here below, there's an example about how

to initialize the library and draw a rectangle at the center of the screen.



```C

#include 

#include 

#include 



int main(int argc, char **argv)

{

   int rc;



   if ((rc = tfb_acquire_fb(0, NULL, NULL)) != TFB_SUCCESS) {

      fprintf(stderr, "tfb_acquire_fb() failed with error code: %d\n", rc);

      return 1;

   }



   uint32_t w = tfb_screen_width();

   uint32_t h = tfb_screen_height();

   uint32_t rect_w = w / 2;

   uint32_t rect_h = h / 2;



   /* Paint the whole screen in black */

   tfb_clear_screen(tfb_black);



   /* Draw some text on-screen */

   tfb_draw_string(10, 10, tfb_white, tfb_black, "Press ENTER to quit");



   /* Draw a red rectangle at the center of the screen */

   tfb_draw_rect(w / 2 - rect_w / 2,  /* x coordinate */

                 h / 2 - rect_h / 2,  /* y coordinate */

                 rect_w,              /* width */

                 rect_h,              /* height */

                 tfb_red              /* color */);



   getchar();

   tfb_release_fb();

   return 0;

}

```



Compatibility

--------------



`Tfblib` has been designed to work on the `Linux` kernel, on any hardware. It has

been tested on `x86` and on `ARM` machines (Raspberry Pi 3). It addition to that,

it works on [Tilck](https://github.com/vvaltchev/tilck), which is a small Linux

compatible kernel.



![Tetris on Tilck](other/tetris.png)



In order to compile `Tfblib` for `Tilck` is necessary to use a 32-bit x86

Linux `GCC` toolchian using `libmusl` and link everything statically. After

compiling this way, the examples will run both on Linux and on Tilck natively.

But, the **easiest way** to do that is just to use Tilck's build system.

Just drop a copy (or a symlink) of `Tfblib`'s main directory in the following

subdirectory of the `Tilck` project:



```

userapps/extra

```



Than just run:



```

$ ./scripts/cmake_run

```



And finally build Tilck with `make`. The `Tfblib` examples will be visible in

`/usr/bin/`, on Tilck.



Limitations

-------------



For the moment, the library supports only 32-bpp video modes.



Online API reference

----------------------



A pre-generated `doxygen` documentation is available at:

https://vvaltchev.github.io/tfblib/tfblib_8h.html



Generating the documentation locally

--------------------------------------



In order to generate the documentation locally, make sure you have `doxygen`

installed on your system and just run it in project's root directory.

The output html files will be placed in `/doxydocs/html`.

Just open `index.html` with your browser.