frontend/latex: reinstate explicit update_pdf calls, with debouncing, and manual PDF reload in output controls

Author: haraldschilly

src/packages/frontend/frame-editors/latex-editor/actions.ts

@@ -144,6 +144,9 @@ export class Actions extends BaseActions<LatexEditorState> {
   // PDF file watcher - watches directory for PDF file changes
   private pdf_watcher?: PDFWatcher;
 
+  // Debounced version - initialized in _init2()
+  update_pdf: (time: number, force: boolean) => void;
+
   // Auto-sync function for cursor position changes (forward sync: source → PDF)
   private async handle_cursor_sync_to_pdf(
     line: number,
@@ -179,6 +182,11 @@ export class Actions extends BaseActions<LatexEditorState> {
 
   _init2(): void {
     this.set_gutter = this.set_gutter.bind(this);
+    // Debounce update_pdf with 500ms delay, trailing only, has to work when PDF watcher fires during the build
+    this.update_pdf = debounce(this._update_pdf.bind(this), 500, {
+      leading: false,
+      trailing: true,
+    });
     if (!this.is_public) {
       this.init_bad_filename();
       this.init_ext_filename(); // safe to set before syncstring init
@@ -210,7 +218,10 @@ export class Actions extends BaseActions<LatexEditorState> {
     this.pdf_watcher = new PDFWatcher(
       this.project_id,
       pdfPath,
-      this.update_pdf.bind(this),
+      // We ignore the PDFs timestamp (mtime) and use last_save_time for consistency with build-triggered updates
+      (_mtime: number, force: boolean) => {
+        this.update_pdf(this.last_save_time(), force);
+      },
     );
     await this.pdf_watcher.init();
   }
@@ -882,22 +893,25 @@ export class Actions extends BaseActions<LatexEditorState> {
     if (this._has_frame_of_type("word_count")) {
       run_word_count = this.word_count(time, force);
     }
-    await this.run_latex(time, force);
+    // update_pdf=false, because it is deferred until the end
+    await this.run_latex(time, force, false);
     // ... and then patch the synctex file to align the source line numberings
     if (this.knitr) {
       await this.run_patch_synctex(time, force);
     }
 
     const s = this.store.unsafe_getIn(["build_logs", "latex", "stdout"]);
+    let update_pdf = true;
     if (typeof s == "string") {
       const is_sagetex = s.indexOf("sagetex.sty") != -1;
       const is_pythontex =
         s.indexOf("pythontex.sty") != -1 || s.indexOf("PythonTeX") != -1;
       if (is_sagetex || is_pythontex) {
         if (this.ensure_output_directory_disabled()) {
           // rebuild if build command changed
-          await this.run_latex(time, true);
+          await this.run_latex(time, true, false);
         }
+        update_pdf = false;
         if (is_sagetex) {
           await this.run_sagetex(time, force);
         }
@@ -908,6 +922,12 @@ export class Actions extends BaseActions<LatexEditorState> {
       }
     }
 
+    // we suppress a cycle of loading the PDF if sagetex or pythontex runs above
+    // because these two trigger a rebuild and update_pdf on their own at the end
+    if (update_pdf) {
+      this.update_pdf(time, force);
+    }
+
     if (run_word_count != null) {
       // and finally, wait for word count to finish -- to make clear the whole operation is done
       await run_word_count;
@@ -994,7 +1014,11 @@ export class Actions extends BaseActions<LatexEditorState> {
     }
   }
 
-  private async run_latex(time: number, force: boolean): Promise<void> {
+  private async run_latex(
+    time: number,
+    force: boolean,
+    update_pdf: boolean = true,
+  ): Promise<void> {
     if (this.is_stopping) return;
     let output: BuildLog;
     let build_command: string | string[];
@@ -1051,6 +1075,10 @@ export class Actions extends BaseActions<LatexEditorState> {
     this.check_for_fatal_error();
     this.update_gutters();
     this.update_gutters_soon();
+    // Explicit PDF reload after latex compilation
+    if (update_pdf) {
+      this.update_pdf(time, force);
+    }
   }
 
   // this *merges* errors from log into an eventually already existing this.parsed_output_log
@@ -1186,7 +1214,7 @@ export class Actions extends BaseActions<LatexEditorState> {
     });
   }
 
-  update_pdf(time: number, force: boolean): void {
+  private _update_pdf(time: number, force: boolean): void {
     const timestamp = this.make_timestamp(time, force);
     // forget currently cached pdf
     this._forget_pdf_document();
@@ -1230,11 +1258,13 @@ export class Actions extends BaseActions<LatexEditorState> {
           this.get_output_directory(),
         );
         if (hash === this._last_sagetex_hash) {
-          // no change - nothing to do
+          // no change - nothing to do except updating the pdf preview
+          this.update_pdf(time, force);
           return;
         }
       } catch (err) {
         this.set_error(err);
+        this.update_pdf(time, force);
         return;
       } finally {
         this.set_status("");
@@ -1264,6 +1294,7 @@ export class Actions extends BaseActions<LatexEditorState> {
       await this.run_latex(time + 1, force);
     } catch (err) {
       this.set_error(err);
+      this.update_pdf(time, force);
     } finally {
       this._last_sagetex_hash = hash;
       this.set_status("");
@@ -1303,6 +1334,7 @@ export class Actions extends BaseActions<LatexEditorState> {
     } catch (err) {
       this.set_error(err);
       // this.setState({ pythontex_error: true });
+      this.update_pdf(time, force);
       return;
     } finally {
       this.set_status("");
@@ -1469,15 +1501,15 @@ export class Actions extends BaseActions<LatexEditorState> {
 
   _get_most_recent_output_panel(): string | undefined {
     let result = this._get_most_recent_active_frame_id_of_type("output");
-    console.log(
-      "LaTeX: _get_most_recent_output_panel() via active history returning",
-      result,
-    );
+    // console.log(
+    //   "LaTeX: _get_most_recent_output_panel() via active history returning",
+    //   result,
+    // );
 
     // If no recently active output panel found, look for any output panel
     if (!result) {
       result = this._get_any_frame_id_of_type("output");
-      console.log("LaTeX: _get_any_frame_id_of_type() returning", result);
+      //console.log("LaTeX: _get_any_frame_id_of_type() returning", result);
     }
 
     return result;

src/packages/frontend/frame-editors/latex-editor/output-control-build.tsx

@@ -22,6 +22,7 @@ import {
   BUILD_ON_SAVE_ICON_ENABLED,
   BUILD_ON_SAVE_LABEL,
 } from "@cocalc/frontend/frame-editors/frame-tree/commands/generic-commands";
+import { server_time } from "@cocalc/frontend/frame-editors/generic/client";
 import { editor, IntlMessage } from "@cocalc/frontend/i18n";
 import { DARK_MODE_ICON } from "@cocalc/util/consts/ui";
 
@@ -67,6 +68,10 @@ export function BuildControls({ actions, id, narrow }: BuildControlsProps) {
     set_account_table({ editor_settings: { build_on_save: !buildOnSave } });
   };
 
+  const handleReloadPdf = () => {
+    actions.update_pdf(server_time().valueOf(), true);
+  };
+
   const buildMenuItems: MenuProps["items"] = [
     {
       key: "force-build",
@@ -83,6 +88,12 @@ export function BuildControls({ actions, id, narrow }: BuildControlsProps) {
     {
       type: "divider",
     },
+    {
+      key: "reload-pdf",
+      label: "Reload PDF",
+      icon: <Icon name="refresh" />,
+      onClick: handleReloadPdf,
+    },
     {
       key: "download-pdf",
       label: intl.formatMessage(COMMANDS.download_pdf.label as IntlMessage),

src/packages/frontend/frame-editors/latex-editor/pdf-watcher.ts

@@ -50,10 +50,11 @@ export class PDFWatcher {
 
       // Listen for directory changes
       this.directory_listings.on("change", async (paths: string[]) => {
+        if (this.directory_listings == null) return;
         if (paths.includes(this.watch_dir)) {
           try {
             const updatedFiles: DirectoryListingEntry[] | undefined =
-              await this.directory_listings!.get(this.watch_dir);
+              await this.directory_listings.get(this.watch_dir);
             const updatedPdfFile = updatedFiles?.find(
               (f) => f.name === this.pdf_filename,
             );