feat(layout): implement GridStack.js for resizable dashboards and fix p5.js resize stability

- Implemented GridStack.js as the core dashboard manager, enabling responsive dragging and resizing of the Radar, Video, and SpeedGraph panels.
- Replaced global windowResized events with debounced ResizeObserver instances attached to the specific panel containers.
- Fixed a massive memory leak in p5.js sketches by explicitly calling .remove() on old Graphics buffers before recreation.
- Optimized zoomSketch.js by removing destructive canvas teardown calls from radarSketch and using smoothed camera coordinates for tooltip bounding logic.
- Patched tooltip overflow bugs in drawUtils.js and speedGraphSketch.js to intelligently clamp within panel edges, even in narrow columns.
- Disabled native p5 windowResized triggers to prevent double-firing when moving the web app across multiple monitors.

steps/index.html

@@ -71,6 +71,9 @@
     })();
   </script>
   
+  <link href="https://cdnjs.cloudflare.com/ajax/libs/gridstack.js/10.1.2/gridstack.min.css" rel="stylesheet"/>
+  <script src="https://cdnjs.cloudflare.com/ajax/libs/gridstack.js/10.1.2/gridstack-all.js"></script>
+  
   <script>
     tailwind.config = {
       darkMode: "class",
@@ -473,49 +476,63 @@
   <!-- END: ADD THIS NEW SCRIM ELEMENT -->
 
   <!-- Main Content -->
-  <main class="flex-grow container mx-auto p-4 pt-8 flex flex-col lg:flex-row gap-6">
-    <div class="lg:w-1/2 flex flex-col gap-4">
-      <div class="relative">
-        <div id="canvas-container"
-          class="w-full h-[75vh] bg-white dark:bg-gray-700 border border-gray-200 dark:border-gray-600 rounded-lg shadow-inner flex items-center justify-center relative">
-          <p id="canvas-placeholder" class="hidden text-gray-500 dark:text-gray-400 text-lg">Load JSON data to start
-            visualization</p>
-          
-          <!-- Range Slider (Vertical) -->
-          <div class="absolute bottom-8 left-2 flex flex-col items-center gap-2 z-20 group">
-            <span id="range-value-display" class="bg-black bg-opacity-60 text-white text-[10px] px-1.5 py-0.5 rounded font-mono">80m</span>
-            <input type="range" id="range-slider" min="40" max="200" value="80" step="10"
-              class="h-32 cursor-pointer accent-blue-600" 
-              style="writing-mode: vertical-lr; direction: rtl; width: 8px;" />
-            <span class="text-[10px] font-bold text-gray-400 uppercase tracking-tighter" style="writing-mode: vertical-lr; transform: rotate(180deg);">Range</span>
+  <main class="flex-grow w-full max-w-[1920px] mx-auto p-4 pt-8">
+    <div class="grid-stack grid-stack-12">
+      <!-- Radar Panel -->
+      <div class="grid-stack-item shadow-md rounded-lg" gs-x="0" gs-y="0" gs-w="6" gs-h="12">
+        <div class="grid-stack-item-content bg-white dark:bg-gray-700 border border-gray-200 dark:border-gray-600 rounded-lg overflow-visible flex flex-col relative group">
+          <div class="absolute top-0 left-0 w-full h-4 cursor-grab active:cursor-grabbing bg-transparent hover:bg-gray-300/30 z-[60] transition-colors rounded-t-lg" title="Drag to move panel"></div>
+          
+          <div class="relative w-full h-full flex-grow">
+            <div id="canvas-container" class="w-full h-full flex items-center justify-center relative">
+              <p id="canvas-placeholder" class="hidden text-gray-500 dark:text-gray-400 text-lg">Load JSON data to start visualization</p>
+              
+              <!-- Range Slider (Vertical) -->
+              <div class="absolute bottom-8 left-2 flex flex-col items-center gap-2 z-20 group">
+                <span id="range-value-display" class="bg-black bg-opacity-60 text-white text-[10px] px-1.5 py-0.5 rounded font-mono">80m</span>
+                <input type="range" id="range-slider" min="40" max="200" value="80" step="10"
+                  class="h-32 cursor-pointer accent-blue-600" 
+                  style="writing-mode: vertical-lr; direction: rtl; width: 8px;" />
+                <span class="text-[10px] font-bold text-gray-400 uppercase tracking-tighter" style="writing-mode: vertical-lr; transform: rotate(180deg);">Range</span>
+              </div>
+            </div>
+            <div id="radar-info-overlay"
+              class="absolute top-4 left-0 right-0 z-10 bg-black bg-opacity-60 text-white font-mono text-xs p-2 rounded-md hidden pointer-events-none">
+            </div>
+            <div class="absolute bottom-2 left-1/2 -translate-x-1/2 flex items-center justify-center gap-4 z-20 pointer-events-none">
+              <div id="ego-speed-display"
+                class="bg-black bg-opacity-60 text-white text-sm px-3 py-1.5 rounded-md hidden font-mono"></div>
+              <div id="can-speed-display"
+                class="bg-black bg-opacity-60 text-white text-sm px-3 py-1.5 rounded-md hidden font-mono"></div>
+            </div>
           </div>
         </div>
-        <div id="radar-info-overlay"
-          class="absolute top-[-35px] left-0 right-0 z-10 bg-black bg-opacity-60 text-white font-mono text-xs p-2 rounded-md hidden">
-        </div>
-        <div class="absolute bottom left-1/2 -translate-x-1/2 flex items-center justify-center gap-4">
-          <div id="ego-speed-display"
-            class="bg-black bg-opacity-60 text-white text-sm px-3 py-1.5 rounded-md hidden font-mono"></div>
-          <div id="can-speed-display"
-            class="bg-black bg-opacity-60 text-white text-sm px-3 py-1.5 rounded-md hidden font-mono"></div>
-        </div>
       </div>
-    </div>
-    <div class="lg:w-1/2 flex flex-col gap-4">
-      <div class="w-full h-[50vh] bg-black rounded-lg shadow-inner flex items-center justify-center relative">
-        <video id="video-player" class="w-full h-full object-contain hidden" muted playsinline></video>
-        <p id="video-placeholder" class="hidden text-gray-500 dark:text-gray-400 text-lg">Load a video file</p>
-        <div id="video-info-overlay"
-          class="absolute top-1 left-2 z-10 bg-black bg-opacity-60 text-white font-mono text-xs p-2 rounded-md hidden">
+      
+      <!-- Video Panel -->
+      <div class="grid-stack-item shadow-md rounded-lg" gs-x="6" gs-y="0" gs-w="6" gs-h="8">
+        <div class="grid-stack-item-content bg-black rounded-lg overflow-hidden flex items-center justify-center relative group">
+          <div class="absolute top-0 left-0 w-full h-4 cursor-grab active:cursor-grabbing bg-transparent hover:bg-white/20 z-[60] transition-colors rounded-t-lg" title="Drag to move panel"></div>
+          
+          <video id="video-player" class="w-full h-full object-contain hidden" muted playsinline></video>
+          <p id="video-placeholder" class="hidden text-gray-500 text-lg">Load a video file</p>
+          <div id="video-info-overlay"
+            class="absolute top-4 left-2 z-[20] bg-black bg-opacity-60 text-white font-mono text-xs p-2 rounded-md hidden pointer-events-none">
+          </div>
+          <div id="debug-overlay"
+            class="absolute top-0 left-0 bg-black bg-opacity-60 text-white p-2 font-mono text-xs hidden w-full z-[20] pointer-events-none"></div>
         </div>
-        <div id="debug-overlay"
-          class="absolute top-0 left-0 bg-black bg-opacity-60 text-white p-2 font-mono text-xs hidden w-full"></div>
       </div>
-      <div id="speed-graph-container"
-        class="w-full h-[25vh] bg-white dark:bg-gray-700 border border-gray-200 dark:border-gray-600 rounded-lg shadow-inner flex items-center justify-center">
-        <p id="speed-graph-placeholder" class="text-gray-500 dark:text-gray-400 text-lg">Load JSON & Video to see speed
-          graph
-        </p>
+      
+      <!-- SpeedGraph Panel -->
+      <div class="grid-stack-item shadow-md rounded-lg" gs-x="6" gs-y="8" gs-w="6" gs-h="4">
+        <div class="grid-stack-item-content bg-white dark:bg-gray-700 border border-gray-200 dark:border-gray-600 rounded-lg overflow-hidden flex items-center justify-center relative group">
+          <div class="absolute top-0 left-0 w-full h-4 cursor-grab active:cursor-grabbing bg-transparent hover:bg-gray-300/30 z-[60] transition-colors rounded-t-lg" title="Drag to move panel"></div>
+          
+          <div id="speed-graph-container" class="w-full h-full flex items-center justify-center p-1 relative">
+            <p id="speed-graph-placeholder" class="text-gray-500 dark:text-gray-400 text-lg text-center absolute pointer-events-none">Load JSON & Video to see speed graph</p>
+          </div>
+        </div>
       </div>
     </div>
     <div id="data-explorer-panel"

steps/src/drawUtils.js

@@ -956,12 +956,19 @@ export function handleCloseUpDisplay(p, plotScales, mouseX, mouseY) {
 
     const xOffset = 20;
     let boxX, lineAnchorX;
-    if (mouseX + xOffset + boxWidth > p.width) { // Use smoothed values
-      boxX = mouseX - boxWidth - xOffset;
-      lineAnchorX = boxX + boxWidth;
-    } else {
+    
+    // Strategy: Try placing on the right. If it overflows, try the left. If it still overflows, clamp it to screen edges.
+    if (mouseX + xOffset + boxWidth <= p.width) {
       boxX = mouseX + xOffset;
       lineAnchorX = boxX;
+    } else if (mouseX - xOffset - boxWidth >= 0) {
+      boxX = mouseX - xOffset - boxWidth;
+      lineAnchorX = boxX + boxWidth;
+    } else {
+      // Doesn't cleanly fit on either side. Clamp it to the canvas bounds.
+      boxX = Math.max(0, Math.min(mouseX + xOffset, p.width - boxWidth));
+      // Point the anchor to whichever side of the box is closer to the mouse
+      lineAnchorX = (boxX + boxWidth / 2 < mouseX) ? boxX + boxWidth : boxX;
     }
     let boxY = mouseY - boxHeight / 2;
     boxY = p.constrain(boxY, 0, p.height - boxHeight);

steps/src/p5/radarSketch.js

@@ -186,6 +186,20 @@ export const radarSketch = function (p) {
     }
     // --- END: Radar Range Slider Logic ---
 
+    // --- START: ResizeObserver for GridStack ---
+    let resizeDebounce = null;
+    const ro = new ResizeObserver(() => {
+      // Debounce to prevent massive memory/CPU spikes during fast dragging
+      if (resizeDebounce) clearTimeout(resizeDebounce);
+      resizeDebounce = setTimeout(() => {
+        if (canvasContainer && canvasContainer.offsetWidth > 0 && canvasContainer.offsetHeight > 0) {
+           if(typeof p.handleContainerResize === 'function') p.handleContainerResize();
+        }
+      }, 100);
+    });
+    ro.observe(canvasContainer);
+    // --- END: ResizeObserver for GridStack ---
+
     p.noLoop();
     // Disable continuous looping, redraw will be called manually
   };
@@ -588,27 +602,25 @@ export const radarSketch = function (p) {
 
 
 
-  p.windowResized = function () {
-    console.log("radarSketch: windowResized triggered!");
+  p.windowResized = function () {}; // Disable native p5 window event to prevent multi-monitor dragging double-fires
+
+  p.handleContainerResize = function () {
+    console.log("radarSketch: handleContainerResize triggered!");
 
     // Immediately resize the elements that we know are stable.
     p.resizeCanvas(canvasContainer.offsetWidth, canvasContainer.offsetHeight);
+    
+    // PREVENT MEMORY LEAK: Destroy old buffers to free memory
+    if (staticBackgroundBuffer) staticBackgroundBuffer.remove();
+    if (trackLegendBuffer) trackLegendBuffer.remove();
+    
     staticBackgroundBuffer = p.createGraphics(p.width, p.height);
     trackLegendBuffer = p.createGraphics(120, 120);
+    
     p.drawTrackLegendToBuffer();
     calculatePlotScales();
     drawStaticRegionsToBuffer(p, staticBackgroundBuffer, plotScales);
 
-    // Defer the call to destroy the zoom canvas.
-    if (appState.zoomSketchInstance && appState.isCloseUpMode) {
-      setTimeout(() => {
-        console.log(
-          "radarSketch: Executing deferred call to zoomSketch.handleResize()."
-        );
-        appState.zoomSketchInstance.handleResize();
-      }, 10); // A 10ms delay is slightly more robust than 0.
-    }
-
     if (appState.vizData) {
       p.redraw();
     }

steps/src/p5/speedGraphSketch.js

@@ -402,6 +402,21 @@ export const speedGraphSketch = function (p) {
     });
 
     staticBuffer = p.createGraphics(p.width, p.height);
+
+    // --- START: ResizeObserver for GridStack ---
+    let resizeDebounce = null;
+    const ro = new ResizeObserver(() => {
+      // Debounce to prevent massive memory/CPU spikes during fast dragging
+      if (resizeDebounce) clearTimeout(resizeDebounce);
+      resizeDebounce = setTimeout(() => {
+        if (speedGraphContainer && speedGraphContainer.offsetWidth > 0 && speedGraphContainer.offsetHeight > 0) {
+           if(typeof p.handleContainerResize === 'function') p.handleContainerResize();
+        }
+      }, 100);
+    });
+    ro.observe(speedGraphContainer);
+    // --- END: ResizeObserver for GridStack ---
+
     p.noLoop();
   };
 
@@ -479,6 +494,7 @@ export const speedGraphSketch = function (p) {
       // compute box position (avoid overflowing right edge)
       let boxX = hoverX + 12;
       if (boxX + boxW > p.width) boxX = hoverX - 12 - boxW;
+      boxX = Math.max(0, boxX); // avoid overflowing left edge
       const boxY = pad.top + 6;
 
       // Draw background box
@@ -527,9 +543,15 @@ export const speedGraphSketch = function (p) {
     }
   }
 
-  p.windowResized = function () {
+  p.windowResized = function () {}; // Disable native p5 window event
+
+  p.handleContainerResize = function () {
     p.resizeCanvas(speedGraphContainer.offsetWidth, speedGraphContainer.offsetHeight);
+    
+    // PREVENT MEMORY LEAK: Destroy old buffer before recreating
+    if (staticBuffer) staticBuffer.remove();
     staticBuffer = p.createGraphics(p.width, p.height);
+    
     hoverX = null; // reset hover on resize
     if (appState.vizData && videoDuration > 0) {
       p.drawStaticGraphToBuffer(appState.vizData);

steps/src/p5/zoomSketch.js

@@ -17,7 +17,7 @@ import {
   toggleCovariance,
 } from "../dom.js";
 
-function drawZoomTooltip(p, hoveredItems, mainMouseX, mainMouseY, smoothedAvgX, smoothedAvgY) {
+function drawZoomTooltip(p, hoveredItems, mainMouseX, mainMouseY, smoothedAvgX, smoothedAvgY, smoothedCamX, smoothedCamY) {
   if (!hoveredItems || hoveredItems.length === 0 || smoothedAvgX === null) return;
 
   // 1. Generate text content
@@ -153,10 +153,11 @@ function drawZoomTooltip(p, hoveredItems, mainMouseX, mainMouseY, smoothedAvgX,
   // Calculate the visible bounds in the current coordinate system (which is scaled and translated)
   const visibleW = p.width / zoomFactor;
   const visibleH = p.height / zoomFactor;
-  const minVisX = mainMouseX - visibleW / 2;
-  const maxVisX = mainMouseX + visibleW / 2;
-  const minVisY = mainMouseY - visibleH / 2;
-  const maxVisY = mainMouseY + visibleH / 2;
+  // Use camera center instead of raw mouse position to accurately represent the visible viewport
+  const minVisX = smoothedCamX - visibleW / 2;
+  const maxVisX = smoothedCamX + visibleW / 2;
+  const minVisY = smoothedCamY - visibleH / 2;
+  const maxVisY = smoothedCamY + visibleH / 2;
   const edgePad = 10 / zoomFactor;
 
   // Constrain X & Y to keep tooltip within the zoom view
@@ -229,6 +230,20 @@ export const zoomSketch = function (p) {
     p.frameRate(144);
     // We enable looping so the lerp smoothing can animate between frames
     p.loop();
+    
+    // --- START: ResizeObserver for ZoomSketch ---
+    let resizeDebounce = null;
+    const ro = new ResizeObserver(() => {
+      if (resizeDebounce) clearTimeout(resizeDebounce);
+      resizeDebounce = setTimeout(() => {
+        if (canvas) {
+           if(typeof p.handleContainerResize === 'function') p.handleContainerResize();
+        }
+      }, 100);
+    });
+    const container = document.getElementById(containerId);
+    if(container) ro.observe(container);
+    // --- END: ResizeObserver for ZoomSketch ---
   };
 
   p.updateAndDraw = function (mainMouseX, mainMouseY, hoveredItems, scales) {
@@ -251,14 +266,13 @@ export const zoomSketch = function (p) {
     // but it helps if updateAndDraw is called less frequently than the frame rate.
   };
 
-  p.handleResize = function () {
-    console.log("zoomSketch: handleResize triggered. Destroying old canvas.");
-    if (canvas) {
-      canvas.remove(); // p5.js function to properly remove the canvas from the DOM
-      canvas = null; // Set the internal reference to null
+  p.windowResized = function () {}; // Disable native p5 window resize
+  
+  p.handleContainerResize = function () {
+    const container = document.getElementById(containerId);
+    if (container && canvas) {
+      p.resizeCanvas(container.offsetWidth, container.offsetHeight);
     }
-    // The canvas will be recreated automatically the next time updateAndDraw() is called,
-    // at which point the container will have its correct, final dimensions.
   };
   p.draw = function () {
     if (!appState.vizData || !canvas) return;
@@ -393,7 +407,7 @@ export const zoomSketch = function (p) {
     p.pop(); // End radar transformations
 
     // --- Call the new, self-contained tooltip function with smoothed coords ---
-    drawZoomTooltip(p, hoveredItems, mainMouseX, mainMouseY, smoothedAvgX, smoothedAvgY);
+    drawZoomTooltip(p, hoveredItems, mainMouseX, mainMouseY, smoothedAvgX, smoothedAvgY, smoothedCamX, smoothedCamY);
 
     // --- START: Draw Purple Debug Circle ---
     // This circle represents the hover radius, drawn in the zoomed coordinate space.

steps/src/ui.js

@@ -119,6 +119,17 @@ function handleColorToggles(e) {
 }
 
 export function initUIEventListeners() {
+  // --- Initialize GridStack ---
+  if (typeof GridStack !== 'undefined') {
+    GridStack.init({
+      margin: 10,
+      cellHeight: '6vh', // Radar is 12h=72vh, Video is 8h=48vh, Graph is 4h=24vh
+      disableOneColumnMode: true,
+      animate: true,
+      handle: '.grid-stack-item-content > .cursor-grab', // use the specific drag handle we added
+    });
+  }
+
   // --- Shortcuts Modal ---
   shortcutsBtn.addEventListener("click", (e) => {
       e.preventDefault();