multiplayer-canvas/lib/canvas-image.js

// lib/canvas-image.js
// Copyright (C) 2022 Rob Colbert @[email protected]
// License: Apache-2.0

'use strict';

import path, { dirname } from 'path';
import { fileURLToPath } from 'url';
import fs from 'fs';

const __dirname = dirname(fileURLToPath(import.meta.url)); // jshint ignore:line

import Jimp from 'jimp';

export default class CanvasImage {

  static async getImages (redis) {
    const images = [ ];

    for (const key of await redis.keys('mpcvs:images:*')) {
      const image = await redis.hgetall(key);
      image.width = parseInt(image.width, 10);
      image.height = parseInt(image.height, 10);

      const tokens = key.split(':');
      const id = tokens[tokens.length - 1];
      images.push({ id, ...image });
    }

    return images;
  }

  constructor (id, name) {
    this.id = id;
    this.name = name;
    this.idPrefix = this.id.slice(0, 4);
    this.imagePath = path.resolve(__dirname, '..', 'images', this.idPrefix);
    this._dirty = false;
  }

  get dirty ( ) { return this._dirty; }

  get key ( ) { return `mpcvs:images:${this.id}`; }

  get filename ( ) { return path.join(this.imagePath, `${this.id}.png`); }

  get width ( ) { return this.image.bitmap.width; }

  get height ( ) { return this.image.bitmap.height; }

  create (width, height) {
    this.image = new Jimp(width, height, 0xffffffff);
    this._dirty = false;
  }

  async load ( ) {
    try {
      this.image = await Jimp.read(this.filename);
    } catch (error) {
      throw error;
    } finally {
      this._dirty = false;
    }
  }

  async save ( ) {
    const filename = this.filename;
    console.log('writing image file', filename);

    await fs.promises.mkdir(this.imagePath, { recursive: true });
    await this.image
      .deflateLevel(9)
      .writeAsync(this.filename)
    ;
    this._dirty = false;
  }

  setPixel (pixel) {
    let idx = ((pixel.y * this.image.bitmap.width) + pixel.x) * 4;
    this.image.bitmap.data[idx++] = pixel.r;
    this.image.bitmap.data[idx++] = pixel.g;
    this.image.bitmap.data[idx++] = pixel.b;
    this._dirty = true;
  }
}