Initial Phoenix analyzer

www/views/static_layer.js

@@ -0,0 +1,24 @@
+export function createStaticLayerCanvas(width, height) {
+  const w = Math.max(1, width | 0);
+  const h = Math.max(1, height | 0);
+  if (typeof OffscreenCanvas !== 'undefined') return new OffscreenCanvas(w, h);
+  const c = document.createElement('canvas');
+  c.width = w;
+  c.height = h;
+  return c;
+}
+
+export function drawCachedStaticLayer(state, g, layerId, key, rect, build) {
+  if (!state || !rect || rect.w <= 0 || rect.h <= 0) return;
+  if (!state.staticLayers) state.staticLayers = new Map();
+  const fullKey = `${layerId}:${key}:${Math.max(0, rect.w | 0)}x${Math.max(0, rect.h | 0)}`;
+  let layer = state.staticLayers.get(fullKey);
+  if (!layer) {
+    const canvas = createStaticLayerCanvas(rect.w, rect.h);
+    const ctx = canvas.getContext('2d');
+    build(ctx, rect);
+    layer = { canvas };
+    state.staticLayers.set(fullKey, layer);
+  }
+  g.drawImage(layer.canvas, rect.x, rect.y);
+}