When resolving font from /DR, copy it into resources

libqpdf/QPDFFormFieldObjectHelper.cc

@@ -963,11 +963,28 @@ QPDFFormFieldObjectHelper::generateTextAppearance(
         // See if the font is encoded with something we know about.
         QPDFObjectHandle resources = AS.getDict().getKey("/Resources");
         QPDFObjectHandle font = getFontFromResource(resources, font_name);
+        bool found_font_in_dr = false;
         if (! font.isInitialized())
         {
             QPDFObjectHandle dr = getDefaultResources();
             font = getFontFromResource(dr, font_name);
+            found_font_in_dr = (font.isInitialized() && font.isDictionary());
         }
+        if (found_font_in_dr && resources.isDictionary())
+        {
+            QTC::TC("qpdf", "QPDFFormFieldObjectHelper get font from /DR");
+            if (resources.isIndirect())
+            {
+                resources = resources.getOwningQPDF()->makeIndirectObject(
+                    resources.shallowCopy());
+                AS.getDict().replaceKey("/Resources", resources);
+            }
+            // Use mergeResources to force /Font to be local
+            resources.mergeResources(
+                QPDFObjectHandle::parse("<< /Font << >> >>"));
+            resources.getKey("/Font").replaceKey(font_name, font);
+        }
+
         if (font.isInitialized() &&
             font.isDictionary() &&
             font.getKey("/Encoding").isName())

qpdf/qpdf.testcov

@@ -583,3 +583,4 @@ qpdf pages keeping field from original 0
 qpdf no more fields in pages 0
 QPDFObjectHandle merge reuse 0
 QPDFObjectHandle merge generate 0
+QPDFFormFieldObjectHelper get font from /DR 0

qpdf/qtest/qpdf.test

@@ -385,7 +385,7 @@ $td->runtest("compare files",
 show_ntests();
 # ----------
 $td->notify("--- Appearance Streams ---");
-$n_tests += 8;
+$n_tests += 10;
 
 foreach my $f ('need-appearances',
                'need-appearances-more',
@@ -444,6 +444,17 @@ foreach my $i (@choice_values)
                  {$td->FILE => "appearances-$i.pdf"});
 }
 
+$td->runtest("Update resources from /DR",
+             {$td->COMMAND =>
+                      "qpdf --qdf --no-original-object-ids --static-id" .
+                      " --generate-appearances" .
+                      " resource-from-dr.pdf a.pdf"},
+             {$td->STRING => "", $td->EXIT_STATUS => 0},
+             $td->NORMALIZE_NEWLINES);
+$td->runtest("compare files",
+             {$td->FILE => "a.pdf"},
+             {$td->FILE => "resource-from-dr-out.pdf"});
+
 show_ntests();
 # ----------
 $td->notify("--- Form XObject, underlay, overlay ---");