See the [build environment setup](https://docs.qmk.fm/#/getting_started_build_tools) and the [make instructions](https://docs.qmk.fm/#/getting_started_make_guide) for more information.
Brand new to QMK? Start with the [Complete Newbs Guide](https://docs.qmk.fm/#/newbs).
Check out the [keyboard build guides](https://docs.bastardkb.com) for the Charybdis and other ergonomic keyboards.
By default, the DPI is set to `400`. The Charybdis supports up to 16 different DPI values. By default, it cycles between `400` and `3400`, with a step of `200` (_ie._ `400`, `600`, `800`, …, `3400`).
Calling `charybdis_cycle_pointer_default_dpi(bool forward)` will cycle forward or backward the possible values.
Use `charybdis_cycle_pointer_default_dpi_noeeprom(bool forward)` to change the DPI value without persisting the change to EEPROM (_ie._ resetting the board will revert to the last saved value).
`charybdis_get_pointer_default_dpi()` returns the current DPI value.
This behavior can be further customized with the following defines:
```c
#define CHARYBDIS_MINIMUM_DEFAULT_DPI 400
#define CHARYBDIS_DEFAULT_DPI_CONFIG_STEP 200
```
### Drag-scroll
Drag-scroll enables scrolling with the trackball. When drag-scroll is enabled, the trackball's `x` and `y` movements are converted into `h` (horizontal) and `v` (vertical) movement, effectively sending scroll instructions to the host system.
Call `charybdis_set_pointer_dragscroll_enabled(bool enable)` to enable/disable drag-scroll.
To invert the horizontal scrolling direction, define `CHARYBDIS_DRAGSCROLL_REVERSE_X`:
```c
#define CHARYBDIS_DRAGSCROLL_REVERSE_X
```
To invert the vertical scrolling direction (_ie._ mimic macOS "natural" scroll direction), define `CHARYBDIS_DRAGSCROLL_REVERSE_Y`:
```c
#define CHARYBDIS_DRAGSCROLL_REVERSE_Y
```
This only affects the vertical scroll direction.
### Sniping mode
Sniping mode slows down the pointer for more precise gestures. It is useful when combined with a higher default DPI.
Call `charybdis_set_pointer_sniping_enabled(bool enable)` to enable/disable sniping mode.
`charybdis_get_pointer_sniping_enabled()` returns whether sniping mode is currently enabled.
Like the default pointer's DPI, the sniper mode DPI can be changed at runtime.
By default, sniping mode lowers the DPI to `200`. This can be changed at runtime: the Charybdis supports up to 4 different DPI values for sniping mode. By default, it cycles between `200`, `300`, `400` and `500`.
Calling `charybdis_cycle_pointer_sniping_dpi(bool forward)` will cycle forward or backward the possible values.
Use `charybdis_cycle_pointer_sniping_dpi_noeeprom(bool forward)` to change the sniping mode DPI value without persisting the change to EEPROM (_ie._ resetting the board will revert to the last saved value).
`charybdis_get_pointer_sniping_dpi()` returns the current sniping mode DPI value.
This behavior can be further customized with the following defines:
```c
#define CHARYBDIS_MINIMUM_SNIPING_DPI 200
#define CHARYBDIS_SNIPING_DPI_CONFIG_STEP 100
```
### Custom keycodes
The Charybdis firmware defines a number of keycodes to leverage its features, namely:
If you want/need to enable syncing of the charybdis config, such as to read the sniping or drag scroll modes on the other half (such as for displaying the status via rgb matrix, or added on screens, or what not), you can enabled this. To do so, add this to your `config.h`:
By default, the X and Y motion for the pointing device/mouse reports is -127 to 127. You can definitely hit the limit for that with the sensors. You can enable support for -32767 to 32767 by adding this to your `config.h`:
