ui/src/frontend/track.ts

// Copyright (C) 2018 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import {TrackState} from '../common/state';

import {TimeScale} from './time_scale';
import {VirtualCanvasContext} from './virtual_canvas_context';

/**
 * This interface forces track implementations to have some static properties.
 * Typescript does not have abstract static members, which is why this needs to
 * be in a seperate interface.
 */
export interface TrackCreator {
  // Store the kind explicitly as a string as opposed to using class.kind in
  // case we ever minify our code.
  readonly kind: string;

  // We need the |create| method because the stored value in the registry is an
  // abstract class, and we cannot call 'new' on an abstract class.
  create(TrackState: TrackState): Track;
}

/**
 * The abstract class that needs to be implemented by all tracks.
 */
export abstract class Track {
  // TODO: Typecheck that arg of consumeData and published data for a Track has
  // the same type.
  /**
   * Receive data published by the TrackController of this track.
   */
  abstract consumeData(trackData: {}): void;
  constructor(protected trackState: TrackState) {}
  abstract renderCanvas(
      vCtx: VirtualCanvasContext, width: number, timeScale: TimeScale,
      visibleWindowMs: {start: number, end: number}, data?: {}): void;
}