Buffyboard

Buffyboard is a touch-enabled on-screen keyboard running on the Linux framebuffer. It's primarily intended for vampire hunting but you can also use it as a general purpose keyboard.

Buffyboard uses lvgl for input processing and rendering. Key events are forwarded directly to the kernel via a uinput device. Since the latter emulates a hardware keyboard, the terminal keymap must match with Buffyboard's layout or else on-screen keys might not produce the correct result.

Status

While partially usable, buffyboard currently still is a work in progress.

What works

On-screen keyboard control via mouse, trackpad or touchscreen
Multi-layer keyboard layout including lowercase letters, uppercase letters, numbers and selected symbols (based on top three layers of squeekboard's US terminal layout)
Key chords with one or more modifiers terminated by a single non-modifier (e.g. CTRL-c)
Highlighting of active modifiers

To do

Show keyboard at the bottom of the screen instead of at the top (just need to set the offset once lvgl/lv_drivers#164 is merged)
Resize VT screen size to not overlap with keyboard
Support different screen rotations
Eliminate libinput_multi.[ch] once support for multiple input devices has been upstreamed to lv_drivers (see lvgl/lv_drivers#151)
Add remaining layers from squeekboard's US terminal layout (symbols and actions)
Warn about mismatches between on-screen keyboard layout and terminal keyboard layout
Add squeekboard's FR terminal layout
And, and, and ...

Development

Dependencies

lvgl (git submodule / linked statically)
lv_drivers (git submodule / linked statically)
libinput
evdev kernel module
uinput kernel module

Building & running

For development and testing you can run the app in a VT. Usually sudo will be needed in order to access input device files.

$ make
$ sudo chvt 2
$ sudo ./buffyboard

Changing fonts

In order to work with lvgl, fonts need to be converted to C arrays. Buffyboard currently uses a combination of the Montserrat font for text and the FontAwesome font for pictograms. For both fonts only limited character ranges are included. To (re)generate the C file containing the combined font, run the following command

$ npx lv_font_conv --bpp 4 --size 32 --no-compress -o montserrat_extended_32.c --format lvgl \
    --font Montserrat-Regular.ttf \
      --range '0x0020-0x007F' \ # basic Latin
      --range '0x00A0-0x00FF' \ # Latin-1 supplement
      --range '0x0100-0x017F' \ # Latin extended A
      --range '0x2000-0x206F' \ # general punctuation
      --range '0x20A0-0x20CF' \ # currency symbols
    --font FontAwesome5-Solid+Brands+Regular.woff \
      --range '0xF001,0xF008,0xF00B,0xF00C,0xF00D,0xF011,0xF013,0xF015,0xF019,0xF01C,0xF021,0xF026,0xF027,0xF028,0xF03E,0xF0E0,0xF304,0xF043,0xF048,0xF04B,0xF04C,0xF04D,0xF051,0xF052,0xF053,0xF054,0xF067,0xF068,0xF06E,0xF070,0xF071,0xF074,0xF077,0xF078,0xF079,0xF07B,0xF093,0xF095,0xF0C4,0xF0C5,0xF0C7,0xF0C9,0xF0E7,0xF0EA,0xF0F3,0xF11C,0xF124,0xF158,0xF1EB,0xF240,0xF241,0xF242,0xF243,0xF244,0xF287,0xF293,0xF2ED,0xF55A,0xF7C2,0xF8A2' # Standard LV_SYMBOL_* glyphs

Changing layouts

Buffyboard uses squeekboard layouts converted to C via squeek2lvgl. To regenerate the layouts, run

$ ./regenerate-layouts.sh

from the root of the repository.

Acknowledgements

The lv_port_linux_frame_buffer project served as a starting point for the codebase.

The mouse cursor image was taken from lv_sim_emscripten.

Buffyboard was inspired by bakonyiferenc/fbkeyboard.

License

Buffyboard is licensed under the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

squeekboard and its keyboard layouts are licensed under the GNU General Public License version 3.0.

The Montserrat font is licensed under the Open Font License.

The FontAwesome font is licensed under the Open Font License version 1.1.

5.1 KiB Raw Blame History