task(D4): mtext tool - multiline text with line breaks, optional frame rect in same transaction (1 undo), fontSize option

frontend/src/plugins/builtin/core-annotate/index.ts

@@ -127,15 +127,81 @@ export const dimensionTool: ToolExtensionV2 = make2PointAnnotate('dimension', 'B
 export const leaderTool: ToolExtensionV2 = make2PointAnnotate('leader', 'Leader', '\u21b1', buildLeader);
 
 /** V2-Plugin: Beschriftung/Bemaßung (A4.4). */
+// ─────────────────────────────────────────────────────────────
+// Task D4: MTEXT — Mehrzeiliger Text mit optionalem Rahmen.
+// Klick platziert Text (Inhalt aus Options, Zeilenumbrüche erhalten),
+// frame-Option erzeugt ein rect in derselben Transaktion (1 Undo).
+// ─────────────────────────────────────────────────────────────
+
+export const mtextTool: ToolExtensionV2 = {
+  manifest: {
+    id: 'mtext',
+    label: 'Mehrzeilentext',
+    icon: '¶',
+    ribbonTab: 'format',
+    tags: ['basic'],
+    description: 'Mehrzeiligen Text platzieren (Rahmen optional, Task D4)',
+  },
+  optionsSchema: [
+    { key: 'text', label: 'Text', type: 'text' },
+    { key: 'fontSize', label: 'Größe', type: 'number', min: 6, max: 72 },
+    { key: 'frame', label: 'Rahmen', type: 'checkbox' },
+  ],
+  handlers: {
+    down(e, ctx) {
+      const c = ctx as FullToolContext;
+      if (!c.doc) return;
+      const layerId = (c.options.layerId as string | undefined) ?? 'layer-0';
+      const text = (c.options.text as string | undefined) ?? '';
+      const fontSize = (c.options.fontSize as number | undefined) ?? 12;
+      const frame = (c.options.frame as boolean | undefined) ?? false;
+      // Newline ohne Escape-Probleme: charCode 10
+      const NL = String.fromCharCode(10);
+      const lines = text.split(NL);
+      const lineCount = Math.max(1, lines.length);
+      const maxLen = lines.reduce((m, l) => Math.max(m, l.length), 0);
+      const textW = maxLen * fontSize * 0.6;
+      const textH = lineCount * fontSize * 1.4;
+      const els: CADElement[] = [{
+        id: uid('mtext'),
+        type: 'text',
+        layerId,
+        x: e.world.x,
+        y: e.world.y,
+        width: textW,
+        height: textH,
+        properties: { text, fontSize, mtext: true },
+      } as unknown as CADElement];
+      if (frame) {
+        const pad = fontSize * 0.4;
+        els.push({
+          id: uid('mtextframe'),
+          type: 'rect',
+          layerId,
+          x: e.world.x,
+          y: e.world.y,
+          width: textW + pad * 2,
+          height: textH + pad * 2,
+          properties: { stroke: '#9aa0a6', strokeWidth: 1, fill: 'none' },
+        } as unknown as CADElement);
+      }
+      c.doc.transact(() => {
+        for (const el of els) c.doc!.addElement(el);
+      });
+      ctx.setStatus(`Mehrzeilentext platziert (${lineCount} Zeile(n)${frame ? ', mit Rahmen' : ''})`);
+    },
+  },
+};
+
 export const coreAnnotatePlugin: PluginV2 = {
   manifest: {
     id: 'core-annotate',
     name: 'Beschriftung (Kern)',
-    version: '1.0.0',
+    version: '1.1.0',
     author: 'web-cad team',
     description: 'Text, Bemaßung, Leader (V2).',
     category: 'tools',
     enabledByDefault: true,
   },
-  tools: [textTool, dimensionTool, leaderTool],
+  tools: [textTool, dimensionTool, leaderTool, mtextTool],
 };