feat: 实现 DOCX 媒体预处理与跨端 PNG 捕获

apps/desktop/src/electron-docx-media-capture.ts

@@ -0,0 +1,79 @@
+import type { WebContents } from "electron";
+import type {
+  DocxMediaCaptureAdapter,
+  DocxMediaCaptureRequest
+} from "@md-to-pdf/application";
+import type { DocxMediaCapturePlan } from "@md-to-pdf/core";
+
+interface CaptureScreenshotResult {
+  data: string;
+}
+
+function createRenderScript(request: DocxMediaCaptureRequest) {
+  const serialized = JSON.stringify(request);
+  return `(async () => {
+    const request = ${serialized};
+    const renderer = window.__mdToPdfRenderDocxMedia;
+    if (!renderer) {
+      throw new Error("DOCX 媒体渲染运行时不可用");
+    }
+    return renderer(request.payload, request.dimensions);
+  })()`;
+}
+
+export async function captureDocxMediaWithElectronWebContents(
+  webContents: WebContents,
+  request: DocxMediaCaptureRequest
+) {
+  const plan = (await webContents.executeJavaScript(
+    createRenderScript(request),
+    true
+  )) as DocxMediaCapturePlan;
+  const ownsDebugger = !webContents.debugger.isAttached();
+  if (ownsDebugger) {
+    webContents.debugger.attach("1.3");
+  }
+
+  try {
+    const captures = [];
+    for (const target of plan.targets) {
+      const result = (await webContents.debugger.sendCommand(
+        "Page.captureScreenshot",
+        {
+          format: "png",
+          fromSurface: true,
+          captureBeyondViewport: true,
+          clip: {
+            x: target.captureX,
+            y: target.captureY,
+            width: target.captureWidthPx,
+            height: target.captureHeightPx,
+            scale: target.rasterScale
+          }
+        }
+      )) as CaptureScreenshotResult;
+      captures.push({
+        id: target.id,
+        png: Buffer.from(result.data, "base64")
+      });
+    }
+    return { plan, captures };
+  } finally {
+    if (ownsDebugger && webContents.debugger.isAttached()) {
+      webContents.debugger.detach();
+    }
+  }
+}
+
+export class ElectronDocxMediaCaptureAdapter
+  implements DocxMediaCaptureAdapter
+{
+  constructor(private readonly webContents: WebContents) {}
+
+  capture(request: DocxMediaCaptureRequest) {
+    return captureDocxMediaWithElectronWebContents(
+      this.webContents,
+      request
+    );
+  }
+}