zmk-input-zoom

A ZMK module that provides an input processor converting relative events into key-press events. This project was developed with the assistance of AI coding tools.

This processor watches for a configurable relative input event. When the delta is positive, it fires the zoom-in binding. When the delta is negative, it fires the zoom-out binding.

Usage

1. Define the processor node

#include <input/input_event_codes.h>

/ {
    zip_zoom_mapper: zip_zoom_mapper {
        compatible = "zmk,input-processor-zoom";
        #input-processor-cells = <0>;
        event-code = <INPUT_REL_MISC>;
        sensitivity = <1>;
        bindings = <&kp LG(MINUS)>, <&kp LG(EQUAL)>;
        track-remainders;
    };
};

Alternatively, use <&kp LC(MINUS)>, <&kp LC(EQUAL)> for the control key instead of command key.

Property	Required	Description
event-code	yes	Relative event code to match (e.g. INPUT_REL_MISC, INPUT_REL_WHEEL)
bindings	yes	Two behaviors: [zoom-out, zoom-in] fired on negative / positive delta
sensitivity	no	Delta units per zoom step (default 1)
track-remainders	no	Accumulate sub-threshold deltas across events (boolean flag; omit to disable)

2. Attach to an input processor

&my_trackpad {
  input-processors = <&zip_zoom_mapper>;
};

Or compose with other processors:

&my_trackpad {
  input-processors = <&zip_xy_scaler 2 1>, <&zip_zoom_mapper>;
};