tdf#50879 PDF export: ensure only built-in fonts are used for forms

Alternative would be to embed the whole font, which is unusual: PDF
typically just embeds the used subset.

(cherry picked from commit 6294ecd7b4da38de98b24ddfb9f201cef98c1f41)

[ Backport is missing the testcase, pdfium on this branch is too old. ]

Change-Id: Ic0b7e121b3ae38804c1a396ea36104ebcc0b9588
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/99070
Tested-by: Jenkins CollaboraOffice <jenkinscollaboraoffice@gmail.com>
Reviewed-by: Miklos Vajna <vmiklos@collabora.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/vcl/source/gdi/pdfwriter_impl.cxx b/vcl/source/gdi/pdfwriter_impl.cxx
index 60be24294217..e44edd1fe8a9 100644
--- a/vcl/source/gdi/pdfwriter_impl.cxx
+++ b/vcl/source/gdi/pdfwriter_impl.cxx
@@ -4066,6 +4066,13 @@ Font PDFWriterImpl::replaceFont( const vcl::Font& rControlFont, const vcl::Font&
 sal_Int32 PDFWriterImpl::getBestBuildinFont( const vcl::Font& rFont )
 {
     sal_Int32 nBest = 4; // default to Helvetica
+
+    if (rFont.GetFamilyType() == FAMILY_ROMAN)
+    {
+        // Serif: default to Times-Roman.
+        nBest = 8;
+    }
+
     OUString aFontName( rFont.GetFamilyName() );
     aFontName = aFontName.toAsciiLowerCase();
 
@@ -4212,14 +4219,14 @@ void PDFWriterImpl::createDefaultEditAppearance( PDFWidget& rEdit, const PDFWrit
 
     // prepare font to use, draw field border
     Font aFont = drawFieldBorder( rEdit, rWidget, rSettings );
-    sal_Int32 nBest = getSystemFont( aFont );
+    // Get the built-in font which is closest to aFont.
+    sal_Int32 nBest = getBestBuildinFont(aFont);
 
     // prepare DA string
     OStringBuffer aDA( 32 );
     appendNonStrokingColor( replaceColor( rWidget.TextColor, rSettings.GetFieldTextColor() ), aDA );
     aDA.append( ' ' );
-    aDA.append( "/F" );
-    aDA.append( nBest );
+    aDA.append(pdf::BuildinFontFace::Get(nBest).getNameObject());
 
     OStringBuffer aDR( 32 );
     aDR.append( "/Font " );