Unl0kr
======

Disk unlocker for the initramfs based on [LVGL].

[[_TOC_]]

# About

Unl0kr is an [osk-sdl] clone written in [LVGL] and rendering directly to the Linux framebuffer. As a result, it doesn't depend on GPU hardware acceleration.

For some background on how unl0kr came to be, see postmarketOS/osk-sdl#121.

# Status

We are en route to v1 which aims at providing a useable, visually pleasant application including [osk-sdl]'s most essential features. For details about the current status, see the [v1 milestone]. You may also browse the full list of [open issues] to get an idea of what's planned beyond v1.

Here are a few highlights of what already works:

- Password-entry UI including on-screen keyboard on the framebuffer
- Input device discovery for keyboards, mice, trackpads and touch screens
- On-screen keyboard control via:
  - One or more mice / trackpads (including cursor)
  - One or more hardware keyboards (including support for different layouts using XKB)
  - Touchscreen (tested on PinePhone)
- Switching on-screen keyboard layout at runtime (currently supported layouts: de, es, fr, us)
- Toggling on-screen keyboard with slide in/out animation
- Switching between light and dark theme at runtime
- Disclosing and hiding entered password at runtime
- Shutting down the device via a soft button

For a growing collection of demo videos, see the [wiki]. Screenshots of the currently available themes may be found in the [screenshots] folder.

## Upstreaming

Over the course of implementing unl0kr, suitable fixes and features have been upstreamed to the [lvgl] and [lv_drivers] repositories. The benefit of this goes both ways. Downstream we can rely on the features being maintained in the future and upstream they can make the features available to the larger audience of [LVGL] users.

Below is a summary of contributions upstreamed thus far.

### lvgl

- [fix(examples) don't compile assets unless needed] (✅ merged)
- [feat(btnmatrix): add option to show popovers on button press] (✅ merged)
- [feat(msgbox): add function to get selected button index] (✅ merged)
- [feat(msgbox): omit title label unless needed] (✅ merged)
- [fix(btnmatrix): make ORed values work correctly with lv_btnmatrix_has_btn_ctrl] (✅ merged)

### lv_drivers

- [Add support for pointer devices to libinput driver] (✅ merged)
- [Add support for keypads to libinput driver] (✅ merged)
- [Add full keyboard support to libinput/evdev driver] (✅ merged)
- [Automatic device discovery via libinput] (✅ merged)
- [Make it possible to use multiple devices with the libinput and XKB drivers] (✅ merged)
- [Use LV_LOG instead of printf in fbdev driver] (✅ merged)

# Usage

A man page is planned to be added with #6. For the time being, you can get an overview of available command line options by running unl0kr with the `-h` or `--help` argument.

```
$ unl0kr --help
Usage: unl0kr [OPTION]

Mandatory arguments to long options are mandatory for short options too.
  -c, --config=PATH      Locaton of the main config file. Defaults to
                         /etc/unl0kr.conf.
  -C, --config-override  Location of the config override file. Values in
                         this file override values for the same keys in the
                         main config file. If specified multiple times, the
                         values from consecutive files will be merged in
                         order.
  -g, --geometry=NxM     Force a display size of N horizontal times M
                         vertical pixels
  -d  --dpi=N            Overrides the DPI
  -h, --help             Print this message and exit
  -v, --verbose          Enable more detailed logging output on STDERR
  -V, --version          Print the unl0kr version and exit
```

For an example configuration file, see [unl0kr.conf].

# Development

## Dependencies

- [inih]
- [lvgl] (git submodule / linked statically)
- [lv_drivers] (git submodule / linked statically)
- [squeek2lvgl] (git submodule / linked statically)
- [libinput]
- [libxkbcommon]
- [libdrm] (optional, required for the DRM backend)
- evdev kernel module

## Building & running

Some of unl0kr's dependencies are included as git submodules in this repository. You can clone the repository and initialise the submodules with

```
$ git clone https://gitlab.com/cherrypicker/unl0kr.git
$ cd unl0kr
$ git submodule init
$ git submodule update
```

When pulling changes from the remote later, either use `git pull --recurse-submodules` or manually run `git submodule update` as needed after pulling.

Once you have the sources, you can build the app and run it in a VT. Unless your user account has special privileges, `sudo` will be needed to access input device files.

```
$ meson _build
$ meson compile -C _build
$ sudo chvt 2
$ sudo ./_build/unl0kr
```

With meson <0\.55 use `ninja` instead of `meson compile`\.

### Optional features

If [libdrm] is installed, the DRM backend will be compiled automatically. It's possible to
change this behaviour using the `with-drm` meson feature. For example,

```
$ meson _build -Dwith-drm=disabled
```

will forcibly disable the DRM backend regardless if libdrm is installed or not.

## Backends

Unl0kr supports multiple lvgl display drivers, which are herein referred as "backends".

Currently supported backends:

- fbdev
- drm (optional)

The backend can be switched at runtime by modifying the `general.backend` configuration.

## Fonts

In order to work with [LVGL], fonts need to be converted to bitmaps, stored as C arrays. Unl0kr currently uses a combination of the [OpenSans] font for text and the [FontAwesome] font for pictograms. For both fonts only limited character ranges are included to reduce the binary size. To (re)generate the C file containing the combined font, run the following command

```
$ ./regenerate-fonts.sh
```

Below is a short explanation of the different unicode ranges used above.

- [OpenSans]
  - Basic Latin (`0x0020-0x007F`)
  - Latin-1 supplement (`0x00A0-0x00FF`)
  - Latin extended A (`0x0100-0x017F`)
  - Greek and Coptic (`0x0370-0x03FF`)
  - General punctuation (`0x2000-0x206F`)
  - Currency symbols (`0x20A0-0x20CF`)
  - Mathematical operators (`0x2200-0x22FF`)
- [FontAwesome]
  - Standard `LV_SYMBOL_*` glyphs (`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`)
  - [adjust](https://fontawesome.com/v5/icons/adjust) (`0xF042`)
  - [arrow-alt-circle-up](https://fontawesome.com/v5/icons/arrow-alt-circle-up) (`0xF35B`)
  - [chevron-left](https://fontawesome.com/v5/icons/chevron-left) (`0xF053`)

## Keyboard layouts

Unl0kr uses [squeekboard layouts] converted to C via [squeek2lvgl]. To regenerate the layouts, ensure that you have pipenv installed (e.g. via `pip install --user pipenv`) and then run

```
$ ./regenerate-layouts.sh
```

from the root of the repository.

## Generating screenshots

To generate screenshots in a variety of common sizes, build unl0kr and then run

```
$ sudo ./regenerate-screenshots _build/unl0kr
```

where `_build/unl0kr` is the location of the unl0kr binary. Note that you may have to adapt some of the settings inside the script depending on the device you're using to generate the screenshots.

## Screen recording

For demonstration purposes you can record the framebuffer device, e.g. with ffmpeg:

```
$ sudo ffmpeg -f fbdev -i /dev/fb0 -r 24 -c:v libx264 -b:v 500k demo.avi
```

# 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].

# License

Unl0kr 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.

The [OpenSans] font is licensed under the Apache License 2.0.

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

[Add full keyboard support to libinput/evdev driver]: https://github.com/lvgl/lv_drivers/pull/156
[Add support for keypads to libinput driver]: https://github.com/lvgl/lv_drivers/pull/152
[Add support for pointer devices to libinput driver]: https://github.com/lvgl/lv_drivers/pull/150
[Automatic device discovery via libinput]: https://github.com/lvgl/lv_drivers/pull/157
[FontAwesome]: https://fontawesome.com
[LVGL]: https://lvgl.io
[Make it possible to use multiple devices with the libinput and XKB drivers]: https://github.com/lvgl/lv_drivers/pull/165
[OpenSans]: https://fonts.google.com/specimen/Open+Sans
[Use LV_LOG instead of printf in fbdev driver]: https://github.com/lvgl/lv_drivers/pull/167
[adjust]: https://fontawesome.com/v5.15/icons/adjust?style=solid
[arrow-alt-circle-up]: https://fontawesome.com/v5.15/icons/arrow-alt-circle-up?style=solid
[feat(btnmatrix): add option to show popovers on button press]: https://github.com/lvgl/lvgl/pull/2537
[feat(msgbox): add function to get selected button index]: https://github.com/lvgl/lvgl/pull/2538
[feat(msgbox): omit title label unless needed]: https://github.com/lvgl/lvgl/pull/2539
[fix(btnmatrix): make ORed values work correctly with lv_btnmatrix_has_btn_ctrl]: https://github.com/lvgl/lvgl/pull/2571
[fix(examples) don't compile assets unless needed]: https://github.com/lvgl/lvgl/pull/2523
[inih]: https://github.com/benhoyt/inih
[libinput]: https://gitlab.freedesktop.org/libinput/libinput
[libxkbcommon]: https://github.com/xkbcommon/libxkbcommon
[libdrm]: https://gitlab.freedesktop.org/mesa/drm
[lv_drivers]: https://github.com/lvgl/lv_drivers
[lv_port_linux_frame_buffer]: https://github.com/lvgl/lv_port_linux_frame_buffer
[lv_sim_emscripten]: https://github.com/lvgl/lv_sim_emscripten/blob/master/mouse_cursor_icon.c
[lvgl]: https://github.com/lvgl/lvgl
[online font converter]: https://lvgl.io/tools/fontconverter
[open issues]: https://gitlab.com/cherrypicker/unl0kr/-/issues
[osk-sdl]: https://gitlab.com/postmarketOS/osk-sdl
[screenshots]: ./screenshots
[squeek2lvgl]: https://gitlab.com/cherrypicker/squeek2lvgl
[squeekboard layouts]: https://gitlab.gnome.org/World/Phosh/squeekboard/-/tree/master/data/keyboards
[unl0kr.conf]: ./unl0kr.conf
[v1 milestone]: https://gitlab.com/cherrypicker/unl0kr/-/milestones/1
[wiki]: https://gitlab.com/cherrypicker/unl0kr/-/wikis/home
