@openhps/core/dist/esm/three/extras/ImageUtils.js

Open Hybrid Positioning System - Core component

import { createElementNS } from '../utils.js';
import { SRGBToLinear } from '../math/ColorManagement.js';
let _canvas;

/**
 * A class containing utility functions for images.
 *
 * @hideconstructor
 */
class ImageUtils {
  /**
   * Returns a data URI containing a representation of the given image.
   *
   * @param {(HTMLImageElement|HTMLCanvasElement)} image - The image object.
   * @param {string} [type='image/png'] - Indicates the image format.
   * @return {string} The data URI.
   */
  static getDataURL(image, type = 'image/png') {
    if (/^data:/i.test(image.src)) {
      return image.src;
    }
    if (typeof HTMLCanvasElement === 'undefined') {
      return image.src;
    }
    let canvas;
    if (image instanceof HTMLCanvasElement) {
      canvas = image;
    } else {
      if (_canvas === undefined) _canvas = createElementNS('canvas');
      _canvas.width = image.width;
      _canvas.height = image.height;
      const context = _canvas.getContext('2d');
      if (image instanceof ImageData) {
        context.putImageData(image, 0, 0);
      } else {
        context.drawImage(image, 0, 0, image.width, image.height);
      }
      canvas = _canvas;
    }
    return canvas.toDataURL(type);
  }

  /**
   * Converts the given sRGB image data to linear color space.
   *
   * @param {(HTMLImageElement|HTMLCanvasElement|ImageBitmap|Object)} image - The image object.
   * @return {HTMLCanvasElement|Object} The converted image.
   */
  static sRGBToLinear(image) {
    if (typeof HTMLImageElement !== 'undefined' && image instanceof HTMLImageElement || typeof HTMLCanvasElement !== 'undefined' && image instanceof HTMLCanvasElement || typeof ImageBitmap !== 'undefined' && image instanceof ImageBitmap) {
      const canvas = createElementNS('canvas');
      canvas.width = image.width;
      canvas.height = image.height;
      const context = canvas.getContext('2d');
      context.drawImage(image, 0, 0, image.width, image.height);
      const imageData = context.getImageData(0, 0, image.width, image.height);
      const data = imageData.data;
      for (let i = 0; i < data.length; i++) {
        data[i] = SRGBToLinear(data[i] / 255) * 255;
      }
      context.putImageData(imageData, 0, 0);
      return canvas;
    } else if (image.data) {
      const data = image.data.slice(0);
      for (let i = 0; i < data.length; i++) {
        if (data instanceof Uint8Array || data instanceof Uint8ClampedArray) {
          data[i] = Math.floor(SRGBToLinear(data[i] / 255) * 255);
        } else {
          // assuming float

          data[i] = SRGBToLinear(data[i]);
        }
      }
      return {
        data: data,
        width: image.width,
        height: image.height
      };
    } else {
      console.warn('THREE.ImageUtils.sRGBToLinear(): Unsupported image type. No color space conversion applied.');
      return image;
    }
  }
}
export { ImageUtils };