Ellipse fix, now using the radii and angle in JSON to draw directly.

.hintrc

@@ -0,0 +1,13 @@
+{
+  "extends": [
+    "development"
+  ],
+  "hints": {
+    "axe/forms": [
+      "default",
+      {
+        "label": "off"
+      }
+    ]
+  }
+}

steps/src/drawUtils.js

@@ -605,53 +605,14 @@ export function handleCloseUpDisplay(p, plotScales) {
 export function drawCovarianceEllipse(
   p,
   position,
-  covarianceP,
+  radii,
+  angle,
   plotScales,
   isStationary
 ) {
   // Only draw the ellipse for tracks that are not stationary.
   if (isStationary) return;
-
-  const pPos = [
-    [covarianceP[0][0], covarianceP[0][1]],
-    [covarianceP[1][0], covarianceP[1][1]],
-  ];
-
-  const a = pPos[0][0];
-  const b = pPos[0][1];
-  const d = pPos[1][1];
-  const trace = a + d;
-  const determinant = a * d - b * b;
-
-  //const lambda1 = trace / 2 + Math.sqrt(Math.pow(trace, 2) / 4 - determinant);
-  //const lambda2 = trace / 2 - Math.sqrt(Math.pow(trace, 2) / 4 - determinant);
-  // --- START: New robust calculation with logging ---
-  let sqrtTermVal = Math.pow(trace, 2) / 4 - determinant;
-
-  // Check for a negative value, which causes NaN errors
-  if (sqrtTermVal < 0) {
-    // Log a warning so we know it happened, as you suggested
-    console.warn(
-      `Clamping negative sqrtTermVal in frame ${appState.currentFrame} to prevent NaN. Original value: ${sqrtTermVal}`
-    );
-    // Clamp the value to 0. This allows drawing to continue instead of breaking.
-    sqrtTermVal = 0;
-  }
-
-  const sqrtTerm = Math.sqrt(sqrtTermVal);
-  const lambda1 = trace / 2 + sqrtTerm;
-  const lambda2 = trace / 2 - sqrtTerm;
-  // --- END: New robust calculation with logging ---
-  const chi2 = 5.991;
-  const majorAxis = Math.sqrt(chi2 * lambda1);
-  const minorAxis = Math.sqrt(chi2 * lambda2);
-
-  let eigenvector = [1, 0];
-  if (b !== 0) {
-    eigenvector = [lambda1 - d, b];
-  }
-  const angle = Math.atan2(eigenvector[1], eigenvector[0]);
-
+  const [radiusA, radiusB] = radii;  
   p.push();
   p.noFill();
   p.stroke(255, 0, 0, 150);
@@ -661,13 +622,53 @@ export function drawCovarianceEllipse(
     position[1] * plotScales.plotScaleY
   );
   p.rotate(angle);
-  p.ellipse(
-    0,
-    0,
-    majorAxis * 2 * plotScales.plotScaleX,
-    minorAxis * 2 * plotScales.plotScaleY
+  p.ellipse(0,0,
+    radiusA * 2 * plotScales.plotScaleX, // multiplied by 2 because ellipse function
+    radiusB * 2 * plotScales.plotScaleY //  in p5 library expect
   );
   p.pop();
+
+  //---old ellipse logic using covariance from data directly//
+  // const pPos = [
+  //   [covarianceP[0][0], covarianceP[0][1]],
+  //   [covarianceP[1][0], covarianceP[1][1]],
+  // ];
+
+  // const a = pPos[0][0];
+  // const b = pPos[0][1];
+  // const d = pPos[1][1];
+  // const trace = a + d;
+  // const determinant = a * d - b * b;
+
+  //const lambda1 = trace / 2 + Math.sqrt(Math.pow(trace, 2) / 4 - determinant);
+  //const lambda2 = trace / 2 - Math.sqrt(Math.pow(trace, 2) / 4 - determinant);
+  // --- START: New robust calculation with logging ---
+  // let sqrtTermVal = Math.pow(trace, 2) / 4 - determinant;
+
+  // Check for a negative value, which causes NaN errors
+  // if (sqrtTermVal < 0) {
+  //   // Log a warning so we know it happened, as you suggested
+  //   console.warn(
+  //     `Clamping negative sqrtTermVal in frame ${appState.currentFrame} to prevent NaN. Original value: ${sqrtTermVal}`
+  //   );
+  //   // Clamp the value to 0. This allows drawing to continue instead of breaking.
+  //   sqrtTermVal = 0;
+  // }
+
+  // const sqrtTerm = Math.sqrt(sqrtTermVal);
+  // const lambda1 = trace / 2 + sqrtTerm;
+  // const lambda2 = trace / 2 - sqrtTerm;
+  // // --- END: New robust calculation with logging ---
+  // const chi2 = 5.991;
+  // const majorAxis = Math.sqrt(chi2 * lambda1);
+  // const minorAxis = Math.sqrt(chi2 * lambda2);
+
+  // let eigenvector = [1, 0];
+  // if (b !== 0) {
+  //   eigenvector = [lambda1 - d, b];
+  // }
+  // const angle = Math.atan2(eigenvector[1], eigenvector[0]);
+  //---old ellipse logic using covariance from data directly//
 }
 
 // In src/drawUtils.js

steps/src/p5/radarSketch.js

@@ -125,16 +125,15 @@ export const radarSketch = function (p) {
         drawTrajectories(p, plotScales);
         if (toggleCovariance.checked) {
           for (const track of appState.vizData.tracks) {
-            const log = track.historyLog.find(
-              (log) => log.frameIdx === appState.currentFrame + 1
-            );
-            if (log && log.covarianceP) {
+            const log = track.historyLog.find((log) => log.frameIdx === appState.currentFrame + 1);
+            if (log && log.ellipseRadii && typeof log.ellipseAngle !== 'undefined') {
               const pos = log.predictedPosition;
               if (pos && pos[0] !== null) {
                 drawCovarianceEllipse(
                   p,
                   pos,
-                  log.covarianceP,
+                  log.ellipseRadii,
+                  log.ellipseAngle,
                   plotScales,
                   log.isStationary
                 );