ya-webadb/libraries/scrcpy/src/1_25/impl/scroll-controller.ts

import { getInt16, setInt16 } from "@yume-chan/no-data-view";
import type { Field, StructInit } from "@yume-chan/struct";
import { bipedal, struct, u16, u32, u8 } from "@yume-chan/struct";

import type { ScrcpyScrollController } from "../../base/index.js";
import { ScrcpyControlMessageType } from "../../base/index.js";
import type { ScrcpyInjectScrollControlMessage } from "../../latest.js";
import { clamp } from "../../utils/index.js";

export const SignedFloat: Field<number, never, never> = {
    size: 2,
    serialize(value, { buffer, index, littleEndian }) {
        // https://github.com/Genymobile/scrcpy/blob/1f138aef41de651668043b32c4effc2d4adbfc44/app/src/util/binary.h#L51
        value = clamp(value, -1, 1);
        value = value === 1 ? 0x7fff : value * 0x8000;
        setInt16(buffer, index, value, littleEndian);
    },
    deserialize: bipedal(function* (then, { reader, littleEndian }) {
        const data = yield* then(reader.readExactly(2));
        const value = getInt16(data, 0, littleEndian);
        // https://github.com/Genymobile/scrcpy/blob/1f138aef41de651668043b32c4effc2d4adbfc44/server/src/main/java/com/genymobile/scrcpy/Binary.java#L34
        return value === 0x7fff ? 1 : value / 0x8000;
    }),
};

export const InjectScrollControlMessage = /* #__PURE__ */ (() =>
    struct(
        {
            type: u8(ScrcpyControlMessageType.InjectScroll),
            pointerX: u32,
            pointerY: u32,
            videoWidth: u16,
            videoHeight: u16,
            scrollX: SignedFloat,
            scrollY: SignedFloat,
            buttons: u32,
        },
        { littleEndian: false },
    ))();

export type InjectScrollControlMessage = StructInit<
    typeof InjectScrollControlMessage
>;

export class ScrollController implements ScrcpyScrollController {
    serializeScrollMessage(
        message: ScrcpyInjectScrollControlMessage,
    ): Uint8Array | undefined {
        return InjectScrollControlMessage.serialize(message);
    }
}

export function createScrollController(): ScrcpyScrollController {
    return new ScrollController();
}