vtkit

Small C terminal control library that builds as a shared library for reuse in other projects.

Really its very very simple to use. Anywhere you can link c.

API

• vtk_clear() clear screen, cursor to 0,0
• vtk_goto(x, y) move cursor to column x, row y
• vtk_color(n) set foreground color (0..255)
• vtk_bg(n) set background color (0..255)
• vtk_reset() reset fg/bg to terminal defaults
• vtk_hide_cursor() hide cursor
• vtk_show_cursor() show cursor
• vtk_raw_mode() enable non-blocking single-char input
• vtk_restore_mode() restore normal terminal input mode
• vtk_getch() returns keycode int or -1 if no key pressed
• vtk_get_width() current terminal column count (fallback 80)
• vtk_get_height() current terminal row count (fallback 24)
• vtk_buffer_init(width, height) initialize a generic back/front buffer pair
• vtk_buffer_free() release buffer memory
• vtk_buffer_clear(ch, fg, bg) fill back buffer
• vtk_buffer_put(x, y, ch, fg, bg) write one cell in back buffer
• vtk_buffer_present() diff-render back buffer to terminal and update front buffer
• vtk_buffer_hline(x, y, len, ch, fg, bg) draw a horizontal run of cells
• vtk_buffer_vline(x, y, len, ch, fg, bg) draw a vertical run of cells
• vtk_buffer_text(x, y, text, fg, bg) write a string left-to-right
• vtk_buffer_rect(x, y, w, h, ch, fg, bg) fill a rectangle
• vtk_buffer_line(x, y, dx, dy, ch, fg, bg) draw a Bresenham line from (x,y) to (x+dx, y+dy)

Session helpers:

• vtk_begin() clear screen and hide cursor
• vtk_end() show cursor and reset attributes

Color constants are provided in enum vtk_color_code:

• VTK_BLACK, VTK_RED, VTK_GREEN, VTK_YELLOW
• VTK_BLUE, VTK_MAGENTA, VTK_CYAN, VTK_WHITE
• Bright variants are provided as macros: VTK_BRIGHT_BLACK through VTK_BRIGHT_WHITE
• Any explicit color index in 0..255 is accepted for both foreground and background

Build

cmake -S . -B build
cmake --build build

This produces:

• Linux/macOS: libvtkit.so or libvtkit.dylib
• Windows: term.dll (plus import library)

By default, a static library is also built:

• Linux/macOS: libvtk_static.a
• Windows: vtk_static.lib

Disable static library build if desired:

cmake -S . -B build -DVTK_BUILD_STATIC=OFF

Install

cmake --install build --prefix ./install

Installs headers and CMake package files so other projects can use find_package(term CONFIG REQUIRED).

Use from another CMake project

find_package(vtkit CONFIG REQUIRED)
target_link_libraries(my_app PRIVATE vtkit::vtkit)

To link the static variant (when built):

target_link_libraries(my_app PRIVATE term::vtk_static)

Demos

Build examples (default enabled):

cmake -S . -B build
cmake --build build

Run simple API demo:

./build/vtk_demo

Run lines/color demo (any key draws a new batch, Q to quit):

./build/vtk_lines

Run boxes/rectangles demo (any key draws a new batch, Q to quit):

./build/vtk_rect

Run animated Pong demo:

./build/vtk_pong

Controls for Pong demo:

• W / S: move left paddle up/down
• + / -: adjust speed while running
• Q: quit

Pong uses an internal key repeat controller for the player paddle, so initial hold delay and repeat interval can be tuned independently of your OS keyboard repeat settings.

The Pong renderer now uses the library's generic diff-rendered buffer and only redraws changed cells each frame to reduce flicker.