task(C2a): pure shape-primitive factory for all core drawing types

2026-08-27 08:49:18 +02:00
parent 98db99dc87
commit b412a65c33
4 changed files with 338 additions and 0 deletions
@@ -0,0 +1,136 @@
+/**
+ * elementDrawers – Reine Beschreibungs-Fabrik (Task C2).
+ *
+ * Wandelt CADElemente in eine Liste von Primitiven um (line/rect/circle/
+ * polyline/text/arc). Der PixiRenderer (C3) konsumiert diese Deskriptoren
+ * und überführt sie in konkrete Grafikobjekte.
+ *
+ * Vorteil dieser Zwischenschicht:
+ * - Vollständig unit-testbar OHNE WebGL/GPU
+ * - Backend-unabhängig (Pixi jetzt, Canvas2D oder andere später)
+ *
+ * Konventionen entsprechen dem Legacy RenderEngine.draw*:
+ * - rect: x/y = Zentrum der BBox
+ * - circle/arc: radius über properties.radius (Fallback width/2)
+ * - arc-Winkel in Grad, 0° = 3 Uhr, gegen den Uhrzeigersinn
+ */
+import type { CADElement } from '../../types/cad.types';
+import type { Pt } from '../../tools/modification/geometry';
+
+/** Zeichenprimitiv — kleinste darstellbare Einheit. */
+export type ShapePrimitive =
+  | { kind: 'line'; from: Pt; to: Pt; stroke: string; strokeWidth: number }
+  | { kind: 'rect'; x: number; y: number; w: number; h: number; fill: string | null; stroke: string; strokeWidth: number }
+  | { kind: 'circle'; center: Pt; radius: number; fill: string | null; stroke: string; strokeWidth: number }
+  | { kind: 'polyline'; points: Pt[]; close: boolean; stroke: string; strokeWidth: number }
+  | { kind: 'text'; at: Pt; text: string; fontSize: number; color: string }
+  | { kind: 'arc'; center: Pt; radius: number; startDeg: number; endDeg: number; stroke: string; strokeWidth: number };
+
+const FALLBACK_STROKE = '#e0e0e0';
+
+function asPoint(p: unknown): Pt {
+  const q = p as { x?: number; y?: number };
+  return { x: Number(q?.x ?? 0), y: Number(q?.y ?? 0) };
+}
+
+function fillOrNull(raw: unknown): string | null {
+  return typeof raw === 'string' && raw !== 'none' ? raw : null;
+}
+
+/**
+ * Wandelt ein CADElement in seine Zeichenprimitive um.
+ * Gibt ein leeres Array zurück für unbekannte Typen bzw. Elemente,
+ * die nichts Sichtbares beitragen (z.B. leerer Text).
+ */
+export function elementToPrimitives(el: CADElement): ShapePrimitive[] {
+  const props = (el.properties ?? {}) as Record<string, unknown>;
+  const stroke = (props.stroke as string | undefined) ?? FALLBACK_STROKE;
+  const sw = (props.strokeWidth as number | undefined) ?? 1;
+
+  switch (el.type) {
+    case 'line': {
+      if (
+        props.x1 === undefined || props.y1 === undefined ||
+        props.x2 === undefined || props.y2 === undefined
+      ) {
+        return [];
+      }
+      return [{
+        kind: 'line',
+        from: { x: props.x1 as number, y: props.y1 as number },
+        to: { x: props.x2 as number, y: props.y2 as number },
+        stroke,
+        strokeWidth: sw,
+      }];
+    }
+
+    case 'rect': {
+      // Legacy-BBox-Konvention: x/y ist das Zentrum des Rechtecks
+      return [{
+        kind: 'rect',
+        x: el.x - el.width / 2,
+        y: el.y - el.height / 2,
+        w: el.width,
+        h: el.height,
+        fill: fillOrNull(props.fill),
+        stroke,
+        strokeWidth: sw,
+      }];
+    }
+
+    case 'circle': {
+      const radius = (props.radius as number | undefined) ?? el.width / 2;
+      return [{
+        kind: 'circle',
+        center: { x: el.x, y: el.y },
+        radius,
+        fill: fillOrNull(props.fill),
+        stroke,
+        strokeWidth: sw,
+      }];
+    }
+
+    case 'arc': {
+      const radius = (props.radius as number | undefined) ?? el.width / 2;
+      return [{
+        kind: 'arc',
+        center: { x: el.x, y: el.y },
+        radius,
+        startDeg: (props.startAngle as number | undefined) ?? 0,
+        endDeg: (props.endAngle as number | undefined) ?? 360,
+        stroke,
+        strokeWidth: sw,
+      }];
+    }
+
+    case 'polyline':
+    case 'polygon': {
+      const pts = Array.isArray(props.points)
+        ? (props.points as unknown[]).map(asPoint)
+        : [];
+      if (pts.length < 2) return [];
+      return [{
+        kind: 'polyline',
+        points: pts,
+        close: el.type === 'polygon',
+        stroke,
+        strokeWidth: sw,
+      }];
+    }
+
+    case 'text': {
+      const txt = String(props.text ?? '');
+      if (!txt) return []; // leeren Platzhalter nicht rendern
+      return [{
+        kind: 'text',
+        at: { x: el.x, y: el.y },
+        text: txt,
+        fontSize: (props.fontSize as number | undefined) ?? 12,
+        color: (props.color as string | undefined) ?? stroke,
+      }];
+    }
+
+    default:
+      return [];
+  }
+}