src/Pure/General/graphics_file.scala

--- a/src/Pure/General/graphics_file.scala	Wed Nov 28 11:06:58 2018 +0100
+++ b/src/Pure/General/graphics_file.scala	Wed Nov 28 11:28:02 2018 +0100
@@ -45,7 +45,7 @@
   {
     val mapper = new DefaultFontMapper
     for {
-      font <- Isabelle_System.fonts()
+      font <- Isabelle_Fonts.files()
       name <- Library.try_unsuffix(".ttf", font.base_name)
     } {
       val parameters = new DefaultFontMapper.BaseFontParameters(File.platform_path(font))