Added bodySegmentation.getPartsId() (#219)

* Added `getPartsId()` & modified example

* Fixed styles & removed selfie segmentation constants

Author: alanvww

examples/bodySegmentation-select-body-parts/sketch.js

@@ -32,12 +32,11 @@ function draw() {
   background(255);
   image(video, 0, 0);
   if (segmentation) {
+    let parts = bodySegmentation.getPartsId();
     let gridSize = 10;
     for (let x = 0; x < video.width; x += gridSize) {
       for (let y = 0; y < video.height; y += gridSize) {
-        if (
-          segmentation.data[y * video.width + x] == bodySegmentation.TORSO_FRONT
-        ) {
+        if (segmentation.data[y * video.width + x] == parts.TORSO_FRONT) {
           fill(255, 0, 0);
           noStroke();
           circle(x, y, gridSize);

src/BodySegmentation/index.js

@@ -131,10 +131,14 @@ class BodySegmentation {
         "bodySegmentation"
       );
 
-      // add body part constants to the instance variable
-      for (let key in BODYPIX_PALETTE) {
-        this[key] = BODYPIX_PALETTE[key].id;
-      }
+      // Add function to return parts' key and id
+      this.getPartsId = () => {
+        let parts = {};
+        for (let key in BODYPIX_PALETTE) {
+          parts[key] = BODYPIX_PALETTE[key].id;
+        }
+        return parts;
+      };
     } else {
       pipeline = tfBodySegmentation.SupportedModels.MediaPipeSelfieSegmentation;
       modelConfig = handleOptions(
@@ -180,10 +184,6 @@ class BodySegmentation {
         },
         "bodySegmentation"
       );
-
-      // add constants to the instance variable
-      this.BACKGROUND = 0;
-      this.PERSON = 255;
     }
 
     await tf.ready();