For missing font, use a local font if it exists even if there's no st…

…andard substitution If the font foo is missing we just try lo load local(foo) and maybe we'll be lucky.
mozilla · May 13, 2023 · 864c1bb · 864c1bb
1 parent e738e15
commit 864c1bb
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Showing 4 changed files with 38 additions and 25 deletions.
diff --git a/src/core/evaluator.js b/src/core/evaluator.js
@@ -4197,15 +4197,15 @@ class PartialEvaluator {
         if (standardFontName) {
           file = await this.fetchStandardFontData(standardFontName);
           properties.isInternalFont = !!file;
-          if (!properties.isInternalFont && this.options.useSystemFonts) {
-            properties.systemFontInfo = getFontSubstitution(
-              this.systemFontCache,
-              this.idFactory,
-              this.options.standardFontDataUrl,
-              baseFontName,
-              standardFontName
-            );
-          }
+        }
+        if (!properties.isInternalFont && this.options.useSystemFonts) {
+          properties.systemFontInfo = getFontSubstitution(
+            this.systemFontCache,
+            this.idFactory,
+            this.options.standardFontDataUrl,
+            baseFontName,
+            standardFontName
+          );
         }
         return this.extractDataStructures(dict, dict, properties).then(
           newProperties => {
@@ -4310,15 +4310,15 @@ class PartialEvaluator {
       if (standardFontName) {
         fontFile = await this.fetchStandardFontData(standardFontName);
         isInternalFont = !!fontFile;
-        if (!isInternalFont && this.options.useSystemFonts) {
-          systemFontInfo = getFontSubstitution(
-            this.systemFontCache,
-            this.idFactory,
-            this.options.standardFontDataUrl,
-            fontName.name,
-            standardFontName
-          );
-        }
+      }
+      if (!isInternalFont && this.options.useSystemFonts) {
+        systemFontInfo = getFontSubstitution(
+          this.systemFontCache,
+          this.idFactory,
+          this.options.standardFontDataUrl,
+          fontName.name,
+          standardFontName
+        );
       }
     }
 

diff --git a/src/core/font_substitutions.js b/src/core/font_substitutions.js
@@ -378,8 +378,8 @@ function makeLocal(prepend, local) {
  * @param {Object} idFactory The ids factory.
  * @param {String} localFontPath Path to the fonts directory.
  * @param {String} baseFontName The font name to be substituted.
- * @param {String} standardFontName The standard font name to use if the base
- *   font is not available.
+ * @param {String|undefined} standardFontName The standard font name to use
+ *   if the base font is not available.
  * @returns an Object with the CSS, the loaded name, the src and the style.
  */
 function getFontSubstitution(
@@ -437,7 +437,8 @@ function getFontSubstitution(
       (italic && ITALIC) ||
       NORMAL;
     substitutionInfo = {
-      css: `${loadedName},sans-serif`,
+      css: loadedName,
+      mustGuessFallback: true,
       loadedName,
       src: `local(${baseFontName})`,
       style,

diff --git a/src/core/fonts.js b/src/core/fonts.js
@@ -986,6 +986,7 @@ class Font {
     let { type, subtype } = properties;
     this.type = type;
     this.subtype = subtype;
+    this.systemFontInfo = properties.systemFontInfo;
 
     const matches = name.match(/^InvalidPDFjsFont_(.*)_\d+$/);
     this.isInvalidPDFjsFont = !!matches;
@@ -999,7 +1000,10 @@ class Font {
       this.fallbackName = "sans-serif";
     }
 
-    this.systemFontInfo = properties.systemFontInfo;
+    if (this.systemFontInfo?.mustGuessFallback) {
+      this.systemFontInfo.css = `${this.systemFontInfo.css},${this.fallbackName}`;
+    }
+
     this.differences = properties.differences;
     this.widths = properties.widths;
     this.defaultWidth = properties.defaultWidth;

diff --git a/src/display/font_loader.js b/src/display/font_loader.js
@@ -97,9 +97,17 @@ class FontLoader {
         await fontFace.load();
         this.#systemFonts.add(loadedName);
       } catch {
-        warn(
-          `Cannot load system font: ${loadedName} for style ${style.style} and weight ${style.weight}.`
-        );
+        if (info.mustGuessFallback) {
+          // We're trying to load only one system font.
+          const match = src.match(/^local\((.*)\)$/);
+          warn(
+            `Cannot load system font: ${match[1]}, installing it could help to have a better PDF rendering.`
+          );
+        } else {
+          warn(
+            `Cannot load system font: ${loadedName} for style ${style.style} and weight ${style.weight}.`
+          );
+        }
         this.removeNativeFontFace(fontFace);
       }
       return;