task(C2int): integrate pixi renderer as overlay with lazy import

frontend/src/components/CanvasArea.tsx

@@ -18,6 +18,7 @@ import { CADDocument } from '../kernel/document/CADDocument';
 import { YjsDocument } from '../crdt/YjsDocument';
 import { setActiveDocument, getActiveDocument } from '../kernel/document/documentService';
 import { V2_TOOLS_ENABLED } from '../kernel/featureFlags';
+import { PixiRenderer } from '../render/pixi/PixiRenderer';
 import { pluginRegistry } from '../plugins';
 
 const CanvasArea: React.FC<CanvasAreaProps> = ({
@@ -34,6 +35,10 @@ const CanvasArea: React.FC<CanvasAreaProps> = ({
   const renderEngineRef = useRef<RenderEngine | null>(null);
   const interactionRef = useRef<InteractionEngine | null>(null);
   const dispatcherRef = useRef<InteractionDispatcher | null>(null);
+  /** Task C2: PixiJS-Canvas-Ref für V2-Elemente-Overlay. */
+  const pixiCanvasRef = useRef<HTMLCanvasElement>(null);
+  /** Task C2: Aktiver PixiJS-Renderer (für Cleanup). */
+  const pixiRendererRef = useRef<PixiRenderer | null>(null);
   /** Bereits an onElementCreated gemeldete V2-Element-IDs (verhindert Doppelmeldung bei jedem onChanged-Frame). */
   const announcedV2Ids = useRef<Set<string>>(new Set());
   const spatialIndexRef = useRef<SpatialIndex | null>(null);
@@ -65,6 +70,60 @@ const CanvasArea: React.FC<CanvasAreaProps> = ({
       const v2Doc = new CADDocument(ydoc);
       // App-Level-Zugriffspunkt für HistoryPanel/Tastenkürzel (Task A4.11):
       setActiveDocument(v2Doc);
+
+      // ── Task C2: PixiJS-Renderer parallel schalten ──
+      // DEFENSIV: Ein Ausfall von Pixi (z.B. WebGL im Headless-Browser)
+      // darf NIEMALS den kompletten Editor-Mount brechen. Im Fehlerfall
+      // läuft weiter ohne Overlay.
+      let pixi: PixiRenderer | null = null;
+      const pixiCanvas = pixiCanvasRef.current;
+      if (pixiCanvas) {
+        try {
+          pixi = new PixiRenderer();
+          pixiRendererRef.current = pixi;
+          pixi.init(pixiCanvas);
+          pixi.waitForReady().catch((err) => {
+            logger.warn('Pixi init failed — V2-Overlay deaktiviert:', err);
+            pixi = null;
+            pixiRendererRef.current = null;
+          });
+        } catch (err) {
+          logger.warn('Pixi init exception — V2-Overlay deaktiviert:', err);
+          pixi = null;
+          pixiRendererRef.current = null;
+        }
+      }
+      /** Letztes bekanntes Elementobjekt je ID (Referenzdiff statt JSON). */
+      const lastKnownEl = new Map<string, CADElement>();
+      const syncPixi = (): void => {
+        if (!pixi) return;
+        void pixi.waitForReady().then(() => {
+          const all = v2Doc.getAllElements();
+          const visibleIds = new Set<string>();
+          for (const el of all) {
+            visibleIds.add(el.id);
+            // Nur neu zeichnen wenn sich die OBJEKTREFERENZ geändert hat:
+            if (lastKnownEl.get(el.id) !== el) {
+              lastKnownEl.set(el.id, el);
+              pixi!.drawElement(el, {
+                id: 'layer-0', name: 'Standard', visible: true, locked: false,
+                color: '#ffffff', lineType: 'solid', transparency: 0,
+                sortOrder: 0, parentId: null,
+              } as never, {
+                color: '#ffffff', lineType: 'solid', transparency: 0, visible: true,
+              });
+            }
+          }
+          // Gelöschte IDs aus dem Renderer entfernen:
+          for (const knownId of lastKnownEl.keys()) {
+            if (!visibleIds.has(knownId)) {
+              lastKnownEl.delete(knownId);
+              pixi!.removeElement(knownId);
+            }
+          }
+        });
+      };
+
       // Committete V2-Elemente fließen über den etablierten Kanal in UI/State:
       v2Doc.onChanged(() => {
         for (const el of v2Doc.getAllElements()) {
@@ -73,6 +132,7 @@ const CanvasArea: React.FC<CanvasAreaProps> = ({
             onElementCreated(el);
           }
         }
+        syncPixi();  // Task C2: V2-Elemente in den PixiJS-Overlay-Renderer spiegeln
       });
 
       dispatcherRef.current = new InteractionDispatcher(canvas, {
@@ -115,6 +175,8 @@ const CanvasArea: React.FC<CanvasAreaProps> = ({
       interaction.detach();
       dispatcherRef.current?.destroy();
       dispatcherRef.current = null;
+      pixiRendererRef.current?.destroy();   // Task C2: WebGL-Kontext freigeben
+      pixiRendererRef.current = null;
       setActiveDocument(null);
       zoomPanRef.current = null;
       renderEngineRef.current = null;
@@ -413,6 +475,22 @@ const CanvasArea: React.FC<CanvasAreaProps> = ({
         <span style={{ color: 'var(--color-text-faint)' }}>{unit}</span>
       </div>
 
+      {/* Task C2-Integration: PixiJS-Overlay für V2-Elemente — liegt ÜBER dem
+          Legacy-Canvas (z-index höher), rendert nur Elemente aus dem V2-Dokument.
+          Pointer-Events gehen durch (pointerEvents:none), damit Drag/Drop weiter
+          auf dem Legacy-Canvas funktioniert. */}
+      {V2_TOOLS_ENABLED && (
+        <canvas
+          ref={pixiCanvasRef}
+          style={{
+            position: 'absolute',
+            inset: 0,
+            pointerEvents: 'none',
+            zIndex: 5,
+          }}
+        />
+      )}
+
       <canvas
         ref={canvasRef}
         className="canvas-svg"

frontend/src/render/pixi/PixiRenderer.ts

@@ -1,15 +1,15 @@
 /**
  * PixiRenderer – WebGL-Implementierung des RenderAdapter (Task C2).
  *
- * - PixiJS v8: async Application.init(); danach synchron nutzbar
+ * - PixiJS v8 wird LAZY per dynamischem import() geladen — ein Ausfall des
- *   (Integration wartet auf waitForReady() vor dem ersten Frame)
+ *   Pixi-Moduls (z.B. fehlendes WebGL im Headless-Browser) beeinflusst damit
+ *   NICHT den Modul-Import der App (kein weißer Screen).
+ * - async Application.init(); danach synchron nutzbar über waitForReady()
  * - Inkrementell: gerenderte Container pro Element-ID gecacht;
  *   removeElement/clearElements halten Cache und Szene konsistent
  * - drawElement konsumiert die testbaren Shape-Primitives (elementDrawers)
- * - drawGrid nutzt Overlay-Layer für Linien; Ruler/Background/Selection
- *   folgen in Task C3
  */
-import { Application, Container, Graphics, Text } from 'pixi.js';
+import type { Application, Container, Graphics, Text } from 'pixi.js';
 import type {
   RenderAdapter,
   Viewport,
@@ -27,20 +27,23 @@ import { elementToPrimitives } from './elementDrawers';
 export class PixiRenderer implements RenderAdapter {
   private app: Application | null = null;
   private canvas: HTMLCanvasElement | null = null;
-  private root: Container | null = null;         // Weltkoordinaten-Container (skaliert)
+  private root: Container | null = null;
-  private overlayLayer: Container | null = null; // Grid/Ruler/Snaps — immer oben
+  private overlayLayer: Container | null = null;
   private graphicsCache = new Map<string, Container>();
   private viewport: Viewport = { x: 0, y: 0, scale: 1, width: 800, height: 600 };
   private readyResolve: (() => void) | null = null;
+  private readyReject: ((err: unknown) => void) | null = null;
   readonly ready: Promise<void>;
+  private pixiModule: typeof import('pixi.js') | null = null;
 
   constructor() {
-    this.ready = new Promise<void>((resolve) => {
+    this.ready = new Promise<void>((resolve, reject) => {
       this.readyResolve = resolve;
+      this.readyReject = reject;
     });
   }
 
-  /** Wartet bis Pixi initialisiert ist (vor dem ersten Frame aufrufen). */
+  /** Wartet auf Abschluss der Initialisierung; rejected bei Pixi-Fehler. */
   async waitForReady(): Promise<void> {
     await this.ready;
   }
@@ -48,11 +51,28 @@ export class PixiRenderer implements RenderAdapter {
   // ── Lifecycle ────────────────────────────────────────────
 
   init(canvas: HTMLCanvasElement): void {
-    const app = new Application();
-    this.app = app;
     this.canvas = canvas;
+    // LAZY-IMPORT: pixi.js wird erst jetzt geholt. Bei Fehler → ready rejected,
+    // CanvasArea deaktiviert das Overlay und die App läuft normal weiter.
+    void import('pixi.js')
+      .then((mod) => {
+        this.pixiModule = mod;
+        return this.setupApp(mod.Application, mod.Container, canvas);
+      })
+      .then(() => this.readyResolve?.())
+      .catch((err) => {
+        this.readyReject?.(err);
+      });
+  }
 
-    void app.init({
+  private setupApp(
+    ApplicationCtor: typeof Application,
+    ContainerCtor: typeof Container,
+    canvas: HTMLCanvasElement,
+  ): Promise<void> {
+    const app = new ApplicationCtor();
+    this.app = app;
+    return app.init({
       canvas,
       width: this.viewport.width,
       height: this.viewport.height,
@@ -61,12 +81,14 @@ export class PixiRenderer implements RenderAdapter {
       autoDensity: false,
       preference: 'webgl',
     }).then(() => {
-      this.root = new Container();
+      if (!this.app) return;
-      app.stage.addChild(this.root);
+      const root = new ContainerCtor();
-      this.overlayLayer = new Container();
+      this.root = root;
-      app.stage.addChild(this.overlayLayer);
+      this.app.stage.addChild(root);
+      const overlay = new ContainerCtor();
+      this.overlayLayer = overlay;
+      this.app.stage.addChild(overlay);
       this.applyViewportTransform();
-      this.readyResolve?.();
     });
   }
 
@@ -83,7 +105,11 @@ export class PixiRenderer implements RenderAdapter {
   }
 
   destroy(): void {
+    try {
       this.app?.destroy(true, { children: true });
+    } catch {
+      // Pixi darf im Teardown nichts mehr werfen
+    }
     this.app = null;
     this.root = null;
     this.overlayLayer = null;
@@ -94,13 +120,14 @@ export class PixiRenderer implements RenderAdapter {
   // ── Basis-Zeichenoperationen ────────────────────────────
 
   clear(_color: string): void {
-    // Hintergrundfarbe kommt vom Canvas-CSS/Stage-Hintergrund.
+    // Hintergrund kommt vom Canvas-CSS; Pixi leert Buffer beim render.
-    // Pixi's render()-Aufruf leert den Buffer selbst.
   }
 
   drawGrid(cfg: GridConfig): void {
     if (!cfg.enabled || !this.overlayLayer || !this.root) return;
-    const g = new Graphics();
+    const GraphicsCtor = this.pixiModule?.Graphics;
+    if (!GraphicsCtor) return;
+    const g = new GraphicsCtor();
     const vp = this.viewport;
     const worldLeft = vp.x;
     const worldTop = vp.y;
@@ -122,22 +149,22 @@ export class PixiRenderer implements RenderAdapter {
       g.moveTo(worldLeft, gy).lineTo(worldRight, gy)
         .stroke({ color: cfg.color, width: 0.5 / vp.scale });
     }
-    this.root.addChild(g); // skaliert mit, damit die Rasterlinien zur Welt passen
+    this.root.addChild(g);
   }
 
   drawBackground(_img: HTMLImageElement | null, _cfg: BackgroundDrawConfig): void {
-    // Sprite-/Texturintegration folgt in Task C3 (BUG-4-Korrelat in WebGL).
+    // Sprite-/Texturintegration folgt in Task C3.
   }
 
   drawRuler(_cfg: RulerConfig): void {
-    // Lineal-Rendering folgt in Task C3 (DOM-Layer oder Pixi-Text).
+    // Lineal-Rendering folgt in Task C3.
   }
 
   // ── Elemente ─────────────────────────────────────────────
 
   drawElement(el: CADElement, layer: CADLayer, _style: LayerStyle): void {
     if (!this.root || !layer.visible || layer.locked) return;
-    this.removeElement(el.id);             // alter Zustand raus, neuer rein
+    this.removeElement(el.id);
     const container = this.buildGraphicsContainer(el);
     if (!container) return;
     this.graphicsCache.set(el.id, container);
@@ -147,36 +174,47 @@ export class PixiRenderer implements RenderAdapter {
   removeElement(id: string): void {
     const existing = this.graphicsCache.get(id);
     if (!existing) return;
+    try {
       existing.destroy({ children: true });
+    } catch {
+      // teardown-safe
+    }
     this.graphicsCache.delete(id);
   }
 
   clearElements(): void {
     for (const c of this.graphicsCache.values()) {
+      try {
         c.destroy({ children: true });
+      } catch {
+        // teardown-safe
+      }
     }
     this.graphicsCache.clear();
   }
 
   drawPreview(el: CADElement | null): void {
     if (!this.overlayLayer) return;
-    // Bestehende Preview-Container am Ende des Layers entfernen:
     for (const child of [...this.overlayLayer.children]) {
       if ((child as Container).label === '__preview__') {
+        try {
           child.destroy({ children: true });
+        } catch {
+          // teardown-safe
+        }
       }
     }
     if (!el) return;
     const g = this.buildGraphicsContainer(el);
     if (g) {
       g.label = '__preview__';
-      g.alpha = 0.6;                       // halbtransparent wie Legacy-Vorschau
+      g.alpha = 0.6;
       this.overlayLayer.addChild(g);
     }
   }
 
   setSelection(_sel: SelectionState): void {
-    // Selektionshandles in C3 (braucht BBox-Zugriff pro Element)
+    // Selektionshandles in C3
   }
 
   setSnapPoints(_pts: Array<{ x: number; y: number; type: string }>): void {
@@ -185,7 +223,10 @@ export class PixiRenderer implements RenderAdapter {
 
   overlay(draw: (g: OverlayPainter) => void): void {
     if (!this.overlayLayer) return;
-    const g = new Graphics();
+    const GraphicsCtor = this.pixiModule?.Graphics;
+    const TextCtor = this.pixiModule?.Text;
+    if (!GraphicsCtor || !TextCtor) return;
+    const g = new GraphicsCtor();
     const painter: OverlayPainter = {
       line: (a: Pt, b: Pt, color: string, width?: number) => {
         g.moveTo(a.x, a.y).lineTo(b.x, b.y).stroke({ color, width: width ?? 1 });
@@ -197,7 +238,7 @@ export class PixiRenderer implements RenderAdapter {
         g.circle(center.x, center.y, radius).stroke({ color: strokeColor });
       },
       text: (text: string, at: Pt, color: string, fontSize?: number) => {
-        const t = new Text({ text, style: { fontSize: fontSize ?? 12, fill: color } });
+        const t = new TextCtor({ text, style: { fontSize: fontSize ?? 12, fill: color } });
         t.position.set(at.x, at.y);
         g.addChild(t);
       },
@@ -207,7 +248,7 @@ export class PixiRenderer implements RenderAdapter {
   }
 
   hitTest(_world: Pt, _tolerancePx: number): CADElement | null {
-    // Delegation an SpatialIndex folgt in C3 (benötigt Elementliste).
+    // Delegation an SpatialIndex folgt in C3.
     return null;
   }
 
@@ -225,9 +266,13 @@ export class PixiRenderer implements RenderAdapter {
   private buildGraphicsContainer(el: CADElement): Container | null {
     const prims = elementToPrimitives(el);
     if (prims.length === 0) return null;
-    const container = new Container();
+    const GraphicsCtor = this.pixiModule?.Graphics;
+    const TextCtor = this.pixiModule?.Text;
+    if (!GraphicsCtor || !TextCtor) return null;
+    const ContainerCtor = this.pixiModule!.Container;
+    const container = new ContainerCtor();
     for (const prim of prims) {
-      const g = new Graphics();
+      const g = new GraphicsCtor();
       switch (prim.kind) {
         case 'line':
           g.moveTo(prim.from.x, prim.from.y)
@@ -262,7 +307,7 @@ export class PixiRenderer implements RenderAdapter {
           break;
         }
         case 'text': {
-          const t = new Text({ text: prim.text, style: { fontSize: prim.fontSize, fill: prim.color } });
+          const t = new TextCtor({ text: prim.text, style: { fontSize: prim.fontSize, fill: prim.color } });
           t.position.set(prim.at.x, prim.at.y);
           g.addChild(t);
           break;