Add (at this point faulty) text selection

src-tauri/assets/viewer-src/src/render-worker.ts

@@ -40,7 +40,7 @@
  */
 
 import type { PDFDocumentProxy } from "pdfjs-dist";
-import type { WorkerInbound, WorkerOutbound, PageDimensions } from "./types.js";
+import type { WorkerInbound, WorkerOutbound, PageDimensions, TextItem } from "./types.js";
 
 // pdf.min.js is prepended at build time and sets globalThis.pdfjsLib.
 declare const pdfjsLib: typeof import("pdfjs-dist");
@@ -189,11 +189,27 @@ async function handleRender(
     // OffscreenCanvasRenderingContext2D is assignable to the canvasContext
     // parameter of page.render(); the cast satisfies the type checker.
     const ctx = offscreen.getContext("2d") as unknown as CanvasRenderingContext2D;
-    await page.render({ canvasContext: ctx, viewport: vp }).promise;
+
+    // Run canvas rendering and text extraction in parallel — they are independent.
+    const [, textContent] = await Promise.all([
+      page.render({ canvasContext: ctx, viewport: vp }).promise,
+      page.getTextContent(),
+    ]);
 
     const bitmap = offscreen.transferToImageBitmap();
-    const out: WorkerOutbound = { type: "rendered", pageNum, gen, bitmap };
-    (self as unknown as Worker).postMessage(out, [bitmap]);
+    const renderedOut: WorkerOutbound = { type: "rendered", pageNum, gen, bitmap };
+    (self as unknown as Worker).postMessage(renderedOut, [bitmap]);
+
+    // Send text items for the selection overlay. Filter out TextMarkedContent
+    // entries (which lack a `str` field) — we only need actual text runs.
+    // eslint-disable-next-line @typescript-eslint/no-explicit-any
+    const items: TextItem[] = (textContent.items as any[])
+      .filter((item) => typeof item.str === "string")
+      .map(({ str, transform, width, height, hasEOL }: {
+        str: string; transform: number[]; width: number; height: number; hasEOL: boolean;
+      }) => ({ str, transform: Array.from(transform), width, height, hasEOL }));
+    const textOut: WorkerOutbound = { type: "textcontent", pageNum, gen, items };
+    self.postMessage(textOut);
   } catch (e) {
     if ((e as Error)?.name !== "RenderingCancelledException") {
       console.warn("[render-worker] render error page", pageNum, e);