@vladmandic/face-api/src/draw/drawFaceExpressions.ts

FaceAPI: AI-powered Face Detection & Rotation Tracking, Face Description & Recognition, Age & Gender & Emotion Prediction for Browser and NodeJS using TensorFlow/JS

import { IPoint, Point } from '../classes/index';
import { FaceExpressions } from '../faceExpressionNet/index';
import { isWithFaceDetection } from '../factories/WithFaceDetection';
import { isWithFaceExpressions, WithFaceExpressions } from '../factories/WithFaceExpressions';
import { round } from '../utils/index';
import { DrawTextField } from './DrawTextField';

export type DrawFaceExpressionsInput = FaceExpressions | WithFaceExpressions<{}>

export function drawFaceExpressions(
  canvasArg: string | HTMLCanvasElement,
  faceExpressions: DrawFaceExpressionsInput | Array<DrawFaceExpressionsInput>,
  minConfidence = 0.1,
  textFieldAnchor?: IPoint,
) {
  const faceExpressionsArray = Array.isArray(faceExpressions) ? faceExpressions : [faceExpressions];

  faceExpressionsArray.forEach((e) => {
    // eslint-disable-next-line no-nested-ternary
    const expr = e instanceof FaceExpressions
      ? e
      : (isWithFaceExpressions(e) ? e.expressions : undefined);
    if (!expr) {
      throw new Error('drawFaceExpressions - expected faceExpressions to be FaceExpressions | WithFaceExpressions<{}> or array thereof');
    }

    const sorted = expr.asSortedArray();
    const resultsToDisplay = sorted.filter((exprLocal) => exprLocal.probability > minConfidence);

    const anchor = isWithFaceDetection(e)
      ? e.detection.box.bottomLeft
      : (textFieldAnchor || new Point(0, 0));

    const drawTextField = new DrawTextField(
      resultsToDisplay.map((exprLocal) => `${exprLocal.expression} (${round(exprLocal.probability)})`),
      anchor,
    );
    drawTextField.draw(canvasArg);
  });
}