feat: architectural grid editor fullPage + slash commands + doc info panel + AI title

memento-note/lib/client/excalidraw-export-image.ts

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+'use client'
+
+import type { ExcalidrawElement } from '@excalidraw/excalidraw/element/types'
+import type { BinaryFiles } from '@excalidraw/excalidraw/types'
+
+/**
+ * Parses canvas JSON from DB — either a bare elements array or { elements, files }.
+ * Returns null for PPTX placeholders or invalid JSON.
+ */
+export function parseExcalidrawSceneFromCanvasData(
+  dataStr: string
+): { elements: readonly ExcalidrawElement[]; files: BinaryFiles | null } | null {
+  if (!dataStr?.trim()) return null
+  try {
+    const parsed = JSON.parse(dataStr)
+    if (parsed && parsed.type === 'pptx') return null
+    if (Array.isArray(parsed)) {
+      return { elements: parsed as ExcalidrawElement[], files: null }
+    }
+    if (parsed?.elements && Array.isArray(parsed.elements)) {
+      const files =
+        parsed.files && typeof parsed.files === 'object' ? (parsed.files as BinaryFiles) : null
+      return { elements: parsed.elements as readonly ExcalidrawElement[], files }
+    }
+  } catch {
+    /* ignore */
+  }
+  return null
+}
+
+/**
+ * Renders Excali scene to PNG in the browser (uses Excalidraw export helpers).
+ */
+export async function exportExcalidrawSceneToPngBlob(dataStr: string): Promise<Blob | null> {
+  const scene = parseExcalidrawSceneFromCanvasData(dataStr)
+  if (!scene || scene.elements.length === 0) return null
+
+  const { exportToBlob, getNonDeletedElements, MIME_TYPES } = await import('@excalidraw/excalidraw')
+  const elements = getNonDeletedElements(scene.elements as ExcalidrawElement[])
+  if (!elements.length) return null
+
+  try {
+    return await exportToBlob({
+      elements,
+      files: scene.files,
+      mimeType: MIME_TYPES.png,
+      exportPadding: 24,
+      maxWidthOrHeight: 2400,
+      appState: {
+        exportBackground: true,
+        exportWithDarkMode: false,
+        viewBackgroundColor: '#ffffff',
+      },
+    })
+  } catch (e) {
+    console.error('[excalidraw-export-image] exportToBlob failed:', e)
+    return null
+  }
+}