Method getPixelIndex

packages/core/src/index.ts:550–605

* Returns the offset of a pixel in the bitmap buffer * @param x the x coordinate * @param y the y coordinate * @param edgeHandling (optional) define how to sum pixels from outside the border * @returns the index of the pixel or -1 if not found * @example * ```ts *

(x: number, y: number, edgeHandling?: Edge)

     * ```
     */
    getPixelIndex(x: number, y: number, edgeHandling?: Edge) {
      let xi;
      let yi;

      if (!edgeHandling) {
        edgeHandling = Edge.EXTEND;
      }

      if (typeof x !== "number" || typeof y !== "number") {
        throw new Error("x and y must be numbers");
      }

      // round input
      x = Math.round(x);
      y = Math.round(y);
      xi = x;
      yi = y;

      if (edgeHandling === Edge.EXTEND) {
        if (x < 0) xi = 0;
        if (x >= this.bitmap.width) xi = this.bitmap.width - 1;
        if (y < 0) yi = 0;
        if (y >= this.bitmap.height) yi = this.bitmap.height - 1;
      }

      if (edgeHandling === Edge.WRAP) {
        if (x < 0) {
          xi = this.bitmap.width + x;
        }

        if (x >= this.bitmap.width) {
          xi = x % this.bitmap.width;
        }

        if (y < 0) {
          yi = this.bitmap.height + y;
        }

        if (y >= this.bitmap.height) {
          yi = y % this.bitmap.height;
        }
      }

      let i = (this.bitmap.width * yi + xi) << 2;

      // if out of bounds index is -1
      if (xi < 0 || xi >= this.bitmap.width) {
        i = -1;
      }

      if (yi < 0 || yi >= this.bitmap.height) {
        i = -1;
      }

      return i;
    }

    /**