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
+    );
+  }
+}

apps/desktop/tests/electron-docx-media-capture.test.ts

@@ -0,0 +1,98 @@
+import { describe, expect, it, vi } from "vitest";
+import type { WebContents } from "electron";
+import {
+  createPagedDocumentPayload,
+  defaultExportConfig,
+  type DocxMediaCapturePlan
+} from "@md-to-pdf/core";
+import { captureDocxMediaWithElectronWebContents } from "../src/electron-docx-media-capture.js";
+
+const plan: DocxMediaCapturePlan = {
+  targets: [
+    {
+      id: "docx-media-1",
+      kind: "image",
+      ordinal: 1,
+      kindOrdinal: 1,
+      altText: "图片",
+      displayWidthPx: 200,
+      displayHeightPx: 100,
+      captureX: 12,
+      captureY: 24,
+      captureWidthPx: 200,
+      captureHeightPx: 100,
+      rasterScale: 3.125
+    }
+  ],
+  echartsErrors: [],
+  mermaidErrors: []
+};
+
+const request = {
+  payload: createPagedDocumentPayload({
+    document: {
+      rendererVersion: 1,
+      articleHtml: '<article id="write"></article>',
+      bodyHtml: "",
+      metadata: {
+        title: "",
+        author: "",
+        subject: "",
+        keywords: [],
+        language: "zh-CN"
+      },
+      features: [],
+      warnings: []
+    },
+    fileName: "test.md",
+    themeCss: "",
+    exportConfig: defaultExportConfig
+  }),
+  dimensions: {
+    contentWidthPx: 600,
+    contentHeightPx: 900
+  }
+};
+
+describe("Electron DOCX 媒体捕获", () => {
+  it("复用隐藏 Chromium 并在捕获后释放调试会话", async () => {
+    let attached = false;
+    const attach = vi.fn(() => {
+      attached = true;
+    });
+    const detach = vi.fn(() => {
+      attached = false;
+    });
+    const sendCommand = vi.fn(async () => ({
+      data: Buffer.from("png").toString("base64")
+    }));
+    const webContents = {
+      executeJavaScript: vi.fn(async () => plan),
+      debugger: {
+        isAttached: vi.fn(() => attached),
+        attach,
+        detach,
+        sendCommand
+      }
+    } as unknown as WebContents;
+
+    const result = await captureDocxMediaWithElectronWebContents(
+      webContents,
+      request
+    );
+
+    expect(result.captures[0]).toEqual({
+      id: "docx-media-1",
+      png: Buffer.from("png")
+    });
+    expect(attach).toHaveBeenCalledWith("1.3");
+    expect(sendCommand).toHaveBeenCalledWith(
+      "Page.captureScreenshot",
+      expect.objectContaining({
+        format: "png",
+        clip: expect.objectContaining({ scale: 3.125 })
+      })
+    );
+    expect(detach).toHaveBeenCalledOnce();
+  });
+});