@lightningtv/renderer/src/core/renderers/canvas/CanvasTexture.ts

Lightning 3 Renderer

/*
 * If not stated otherwise in this file or this component's LICENSE file the
 * following copyright and licenses apply:
 *
 * Copyright 2023 Comcast Cable Communications Management, LLC.
 *
 * 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 type { Dimensions } from '../../../common/CommonTypes.js';
import { assertTruthy } from '../../../utils.js';
import { CoreContextTexture } from '../CoreContextTexture.js';
import { formatRgba, type IParsedColor } from './internal/ColorUtils.js';

export class CanvasTexture extends CoreContextTexture {
  protected image:
    | ImageBitmap
    | HTMLCanvasElement
    | HTMLImageElement
    | undefined;
  protected tintCache:
    | {
        key: string;
        image: HTMLCanvasElement;
      }
    | undefined;

  load(): void {
    this.textureSource.setState('loading');

    this.onLoadRequest()
      .then((size) => {
        this.textureSource.setState('loaded', size);
        this.textureSource.freeTextureData();
        this.updateMemSize();
      })
      .catch((err) => {
        this.textureSource.setState('failed', err as Error);
        this.textureSource.freeTextureData();
      });
  }

  free(): void {
    this.image = undefined;
    this.tintCache = undefined;
    this.textureSource.setState('freed');
    this.setTextureMemUse(0);
    this.textureSource.freeTextureData();
  }

  updateMemSize(): void {
    // Counting memory usage for:
    // - main image
    // - tinted image
    const mult = this.tintCache ? 8 : 4;
    if (this.textureSource.dimensions) {
      const { width, height } = this.textureSource.dimensions;
      this.setTextureMemUse(width * height * mult);
    }
  }

  hasImage(): boolean {
    return this.image !== undefined;
  }

  getImage(
    color: IParsedColor,
  ): ImageBitmap | HTMLCanvasElement | HTMLImageElement {
    const image = this.image;
    assertTruthy(image, 'Attempt to get unloaded image texture');

    if (color.isWhite) {
      if (this.tintCache) {
        this.tintCache = undefined;
        this.updateMemSize();
      }
      return image;
    }
    const key = formatRgba(color);
    if (this.tintCache?.key === key) {
      return this.tintCache.image;
    }

    const tintedImage = this.tintTexture(image, key);
    this.tintCache = {
      key,
      image: tintedImage,
    };
    this.updateMemSize();
    return tintedImage;
  }

  protected tintTexture(
    source: ImageBitmap | HTMLCanvasElement | HTMLImageElement,
    color: string,
  ) {
    const { width, height } = source;
    const canvas = document.createElement('canvas');
    canvas.width = width;
    canvas.height = height;
    const ctx = canvas.getContext('2d');
    if (ctx) {
      // fill with target color
      ctx.fillStyle = color;
      ctx.globalCompositeOperation = 'copy';
      ctx.fillRect(0, 0, width, height);

      // multiply with image, resulting in non-transparent tinted image
      ctx.globalCompositeOperation = 'multiply';
      ctx.drawImage(source, 0, 0, width, height, 0, 0, width, height);

      // apply original image alpha
      ctx.globalCompositeOperation = 'destination-in';
      ctx.drawImage(source, 0, 0, width, height, 0, 0, width, height);
    }
    return canvas;
  }

  private async onLoadRequest(): Promise<Dimensions> {
    assertTruthy(this.textureSource?.textureData?.data, 'Texture data is null');
    const { data } = this.textureSource.textureData;

    // TODO: canvas from text renderer should be able to provide the canvas directly
    // instead of having to re-draw it into a new canvas...
    if (data instanceof ImageData) {
      const canvas = document.createElement('canvas');
      canvas.width = data.width;
      canvas.height = data.height;
      const ctx = canvas.getContext('2d');
      if (ctx) ctx.putImageData(data, 0, 0);
      this.image = canvas;
      return { width: data.width, height: data.height };
    } else if (
      (typeof ImageBitmap !== 'undefined' && data instanceof ImageBitmap) ||
      data instanceof HTMLImageElement
    ) {
      this.image = data;
      return { width: data.width, height: data.height };
    }

    return { width: 0, height: 0 };
  }
}