zmk/docs/docs/keymaps/input-processors/transformer.md

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Transformer Input Processor	Transformer

Overview

The transformer input processor is used to perform various transforms on the value of an input event that has a code matching the codes set on the transformer. Events with other codes will be ignored.

Available Transforms

The following transforms are available, by including the dt-bindings/zmk/input_transform.h header provided by ZMK near the top of your keymap/overlay:

#include <dt-bindings/zmk/input_transform.h>

• INPUT_TRANSFORM_XY_SWAP - When encountering a value with matching type, swap the type of the event to the other axis, e.g. change an event of type INPUT_REL_X to type INPUT_REL_Y.
• INPUT_TRANSFORM_X_INVERT - Invert the values of any events that match the configured x-codes of the processor, by multiplying by negative one.
• INPUT_TRANSFORM_Y_INVERT - Invert the values of any events that match the configured y-codes of the processor, by multiplying by negative one.

Usage

When used, a transformer takes one parameter, a combination of flags indicating which transforms to apply:

&zip_xy_transform (INPUT_TRANSFORM_X_INVERT | INPUT_TRANSFORM_Y_INVERT)

Pre-Defined Instances

Three pre-defined instance of the scaler input processor are available:

Reference	Description
&zip_xy_transform	Applies the given transforms to X/Y movement events
&zip_scroll_transform	Applies the given transforms to wheel/horizontal wheel events

User Defined Instances

Users can define new instances of the transform input processor if they want to target different codes.

Example

#include <zephyr/dt-bindings/input/input-event-codes.h>

/ {
    input_processors {
        my_rotation_event_transform: my_rotation_event_transform {
            compatible = "zmk,input-processor-transform";
            #input-processor-cells = <1>;
            type = <INPUT_EV_REL>;
            x-codes = <INPUT_REL_RX>;
            y-codes = <INPUT_REL_RY>;
        };
    };
}

Compatible

The transform input processor uses a compatible property of "zmk,input-processor-transform".

Standard Properties

• #input-processor-cells - required to be constant value of <1>.

User Properties

• type - The type of events to transform. Usually, this is INPUT_EV_REL for relative events.
• x-codes - The specific X codes within the given type to transform, e.g. relative event codes
• y-codes - The specific Y codes within the given type to transform, e.g. relative event codes