Warn when pdf.js can't load an OS font

src/core/font_substitutions.js

@@ -451,6 +451,7 @@ function getFontSubstitution(
       css: loadedName,
       guessFallback: true,
       loadedName,
+      baseFontName,
       src: `local(${baseFontName})`,
       style,
     };
@@ -470,6 +471,7 @@ function getFontSubstitution(
     css: `${loadedName},${ultimate}`,
     guessFallback: false,
     loadedName,
+    baseFontName,
     src: src.join(","),
     style,
   };

src/display/font_loader.js

@@ -97,17 +97,10 @@ class FontLoader {
         await fontFace.load();
         this.#systemFonts.add(loadedName);
       } catch {
-        if (info.guessFallback) {
+        warn(
-          // We're trying to load only one system font.
+          `Cannot load system font: ${info.baseFontName}, installing it could help to improve PDF rendering.`
-          const match = src.match(/^local\((.*)\)$/);
+        );
-          warn(
+
-            `Cannot load system font: ${match?.[1]}, installing it could help to improve PDF rendering.`
-          );
-        } else {
-          warn(
-            `Cannot load system font: ${loadedName} for style ${style.style} and weight ${style.weight}.`
-          );
-        }
         this.removeNativeFontFace(fontFace);
       }
       return;

test/unit/font_substitutions_spec.js

@@ -32,6 +32,7 @@ describe("getFontSubstitution", function () {
     expect(fontSubstitution).toEqual(
       jasmine.objectContaining({
         guessFallback: true,
+        baseFontName: "Foo",
         src: "local(Foo)",
         style: {
           style: "normal",
@@ -54,6 +55,7 @@ describe("getFontSubstitution", function () {
     expect(fontSubstitution).toEqual(
       jasmine.objectContaining({
         guessFallback: true,
+        baseFontName: "Foo-Bold",
         src: "local(Foo-Bold)",
         style: {
           style: "normal",
@@ -76,6 +78,7 @@ describe("getFontSubstitution", function () {
     expect(fontSubstitution).toEqual(
       jasmine.objectContaining({
         guessFallback: true,
+        baseFontName: "Foo-Italic",
         src: "local(Foo-Italic)",
         style: {
           style: "italic",
@@ -98,6 +101,7 @@ describe("getFontSubstitution", function () {
     expect(fontSubstitution).toEqual(
       jasmine.objectContaining({
         guessFallback: true,
+        baseFontName: "Foo-BoldItalic",
         src: "local(Foo-BoldItalic)",
         style: {
           style: "italic",
@@ -120,6 +124,7 @@ describe("getFontSubstitution", function () {
     expect(fontSubstitution).toEqual(
       jasmine.objectContaining({
         guessFallback: false,
+        baseFontName: "Foo",
         src:
           "local(Foo),local(Helvetica),local(Helvetica Neue)," +
           "local(Arial),local(Arial Nova),local(Liberation Sans)," +
@@ -150,6 +155,7 @@ describe("getFontSubstitution", function () {
     expect(fontSubstitution).toEqual(
       jasmine.objectContaining({
         guessFallback: false,
+        baseFontName: "Foo-Italic",
         src:
           "local(Foo-Italic),local(Helvetica Italic)," +
           "local(Helvetica Neue Italic),local(Arial Italic)," +
@@ -182,6 +188,7 @@ describe("getFontSubstitution", function () {
     expect(fontSubstitution).toEqual(
       jasmine.objectContaining({
         guessFallback: false,
+        baseFontName: "Foo-Bold",
         src:
           "local(Foo-Bold),local(Helvetica Bold),local(Helvetica Neue Bold)," +
           "local(Arial Bold),local(Arial Nova Bold)," +
@@ -213,6 +220,7 @@ describe("getFontSubstitution", function () {
     expect(fontSubstitution).toEqual(
       jasmine.objectContaining({
         guessFallback: false,
+        baseFontName: "Foo-BoldItalic",
         src:
           "local(Foo-BoldItalic),local(Helvetica Bold Italic)," +
           "local(Helvetica Neue Bold Italic),local(Arial Bold Italic)," +
@@ -247,6 +255,7 @@ describe("getFontSubstitution", function () {
     expect(fontSubstitution).toEqual(
       jasmine.objectContaining({
         guessFallback: false,
+        baseFontName: "Calibri",
         src:
           "local(Calibri),local(Carlito),local(Helvetica)," +
           "local(Helvetica Neue),local(Arial),local(Arial Nova)," +
@@ -277,6 +286,7 @@ describe("getFontSubstitution", function () {
     expect(fontSubstitution).toEqual(
       jasmine.objectContaining({
         guessFallback: false,
+        baseFontName: "Calibri-Bold",
         src:
           "local(Calibri Bold),local(Carlito Bold),local(Helvetica Bold)," +
           "local(Helvetica Neue Bold),local(Arial Bold)," +
@@ -309,6 +319,7 @@ describe("getFontSubstitution", function () {
     expect(fontSubstitution).toEqual(
       jasmine.objectContaining({
         guessFallback: false,
+        baseFontName: "ArialBlack",
         src:
           "local(Arial Black),local(Helvetica Bold)," +
           "local(Helvetica Neue Bold),local(Arial Bold)," +
@@ -341,6 +352,7 @@ describe("getFontSubstitution", function () {
     expect(fontSubstitution).toEqual(
       jasmine.objectContaining({
         guessFallback: false,
+        baseFontName: "ArialBlack-Bold",
         src:
           "local(Arial Black),local(Helvetica Bold)," +
           "local(Helvetica Neue Bold),local(Arial Bold)," +