ya-webadb/libraries/adb/src/commands/framebuffer.ts

import { BufferedReadableStream } from "@yume-chan/stream-extra";
import Struct from "@yume-chan/struct";

import type { Adb } from "../adb.js";

const Version = new Struct({ littleEndian: true }).uint32("version");

export const AdbFrameBufferV1 = new Struct({ littleEndian: true })
    .uint32("bpp")
    .uint32("size")
    .uint32("width")
    .uint32("height")
    .uint32("red_offset")
    .uint32("red_length")
    .uint32("blue_offset")
    .uint32("blue_length")
    .uint32("green_offset")
    .uint32("green_length")
    .uint32("alpha_offset")
    .uint32("alpha_length")
    .uint8Array("data", { lengthField: "size" });

export type AdbFrameBufferV1 = typeof AdbFrameBufferV1["TDeserializeResult"];

export const AdbFrameBufferV2 = new Struct({ littleEndian: true })
    .uint32("bpp")
    .uint32("colorSpace")
    .uint32("size")
    .uint32("width")
    .uint32("height")
    .uint32("red_offset")
    .uint32("red_length")
    .uint32("blue_offset")
    .uint32("blue_length")
    .uint32("green_offset")
    .uint32("green_length")
    .uint32("alpha_offset")
    .uint32("alpha_length")
    .uint8Array("data", { lengthField: "size" });

export type AdbFrameBufferV2 = typeof AdbFrameBufferV2["TDeserializeResult"];

/**
 * ADB uses 8 int32 fields to describe bit depths
 *
 * The only combination I have seen is RGBA8888, which is
 *
 *   red_offset:   0
 *   red_length:   8
 *   blue_offset:  16
 *   blue_length:  8
 *   green_offset: 8
 *   green_length: 8
 *   alpha_offset: 24
 *   alpha_length: 8
 *
 * But it doesn't mean that other combinations are not possible.
 */
export type AdbFrameBuffer = AdbFrameBufferV1 | AdbFrameBufferV2;

export async function framebuffer(adb: Adb): Promise<AdbFrameBuffer> {
    const socket = await adb.createSocket("framebuffer:");
    const stream = new BufferedReadableStream(socket.readable);
    const { version } = await Version.deserialize(stream);
    switch (version) {
        case 1:
            // TODO: AdbFrameBuffer: does all v1 responses uses the same color space? Add it so the command returns same format for all versions.
            return AdbFrameBufferV1.deserialize(stream);
        case 2:
            return AdbFrameBufferV2.deserialize(stream);
        default:
            throw new Error("Unsupported FrameBuffer version");
    }
}