0031079: Visualization - embed minimal fallback font

Font_FTFont::FindAndCreate() now loads embedded fallback font within Font_StrictLevel_Any level.
Font_FontMgr::FindFont() - fixed misprint in message, and customized message for range fallback error.
Font_FontMgr - added one more fallback Korean font for Linux.

vfont command has been extended with options to clear Font Manager content.

dox/overview/overview.md

@@ -153,6 +153,9 @@ on this tool.
 **RapidJSON** is an Open Source JSON parser and generator for C++.
 RapidJSON is optionally used by OCCT for reading glTF files (https://rapidjson.org/).
 
+**DejaVu** fonts are a font family based on the Vera Fonts under a permissive license (MIT-like, https://dejavu-fonts.github.io/License.html).
+DejaVu Sans (basic Latin sub-set) is used by OCCT as fallback font when no system font is available.
+
 Adobe Systems, Inc. provides **Adobe Reader**, which can be used to view files in Portable Document Format (PDF). 
 
 @section OCCT_OVW_SECTION_3 Documentation

src/Font/FILES

@@ -18,3 +18,4 @@ Font_SystemFont.hxx
 Font_TextFormatter.hxx
 Font_TextFormatter.cxx
 Font_UnicodeSubset.hxx
+Font_DejavuSans_Latin_woff.pxx

src/Font/Font_FTFont.cxx

@@ -21,6 +21,8 @@
 #include <Message.hxx>
 #include <Message_Messenger.hxx>
 
+#include "Font_DejavuSans_Latin_woff.pxx"
+
 #include <algorithm>
 
 #include <ft2build.h>
@@ -156,9 +158,9 @@ Handle(Font_FTFont) Font_FTFont::FindAndCreate (const TCollection_AsciiString& t
 {
   Handle(Font_FontMgr) aFontMgr = Font_FontMgr::GetInstance();
   Font_FontAspect aFontAspect = theFontAspect;
+  Font_FTFontParams aParams = theParams;
   if (Handle(Font_SystemFont) aRequestedFont = aFontMgr->FindFont (theFontName, theStrictLevel, aFontAspect))
   {
-    Font_FTFontParams aParams = theParams;
     if (aRequestedFont->IsSingleStrokeFont())
     {
       aParams.IsSingleStrokeFont = true;
@@ -172,6 +174,31 @@ Handle(Font_FTFont) Font_FTFont::FindAndCreate (const TCollection_AsciiString& t
       return aFont;
     }
   }
+  else if (theStrictLevel == Font_StrictLevel_Any)
+  {
+    switch (theFontAspect)
+    {
+      case Font_FontAspect_UNDEFINED:
+      case Font_FontAspect_Regular:
+      case Font_FontAspect_Bold:
+        aFontAspect = Font_FontAspect_Regular;
+        break;
+      case Font_FontAspect_Italic:
+      case Font_FontAspect_BoldItalic:
+        aFontAspect = Font_FontAspect_Italic;
+        aParams.ToSynthesizeItalic = true;
+        break;
+    }
+    Handle(NCollection_Buffer) aBuffer = new NCollection_Buffer (Handle(NCollection_BaseAllocator)(),
+                                                                 Font_DejavuSans_Latin_woff_size,
+                                                                 const_cast<Standard_Byte*>(Font_DejavuSans_Latin_woff));
+    Handle(Font_FTFont) aFont = new Font_FTFont();
+    if (aFont->Init (aBuffer, "Embed Fallback Font", aParams))
+    {
+      aFont->myFontAspect = aFontAspect;
+      return aFont;
+    }
+  }
   return Handle(Font_FTFont)();
 }
 
@@ -197,6 +224,18 @@ bool Font_FTFont::FindAndInit (const TCollection_AsciiString& theFontName,
     const TCollection_AsciiString& aPath = aRequestedFont->FontPathAny (myFontAspect, aParams.ToSynthesizeItalic);
     return Init (aPath, aParams);
   }
+  else if (theStrictLevel == Font_StrictLevel_Any)
+  {
+    if (theFontAspect == Font_FontAspect_Italic
+     || theFontAspect == Font_FontAspect_BoldItalic)
+    {
+      aParams.ToSynthesizeItalic = true;
+    }
+    Handle(NCollection_Buffer) aBuffer = new NCollection_Buffer (Handle(NCollection_BaseAllocator)(),
+                                                                 Font_DejavuSans_Latin_woff_size,
+                                                                 const_cast<Standard_Byte*>(Font_DejavuSans_Latin_woff));
+    return Init (aBuffer, "Embed Fallback Font", aParams);
+  }
   Release();
   return false;
 }

src/Font/Font_FontMgr.cxx

@@ -303,6 +303,7 @@ Font_FontMgr::Font_FontMgr()
   aKorean->Append (Font_FontAlias ("nanummyeongjo")); // Linux
   aKorean->Append (Font_FontAlias ("noto serif cjk jp")); // Linux
   aKorean->Append (Font_FontAlias ("noto sans cjk jp")); // Linux
+  aKorean->Append (Font_FontAlias ("droid sans fallback")); // Linux
 
 #if defined(_WIN32)
   anArab->Append (Font_FontAlias ("times new roman"));
@@ -390,6 +391,15 @@ Standard_Boolean Font_FontMgr::RegisterFont (const Handle(Font_SystemFont)& theF
   return Standard_True;
 }
 
+// =======================================================================
+// function : ClearFontDataBase()
+// purpose  :
+// =======================================================================
+void Font_FontMgr::ClearFontDataBase()
+{
+  myFontMap.Clear();
+}
+
 // =======================================================================
 // function : InitFontDataBase
 // purpose  :
@@ -742,14 +752,27 @@ Handle(Font_SystemFont) Font_FontMgr::FindFallbackFont (Font_UnicodeSubset theSu
                                                         Font_FontAspect theFontAspect) const
 {
   Font_FontAspect aFontAspect = theFontAspect;
+  Handle(Font_SystemFont) aFont;
   switch (theSubset)
   {
-    case Font_UnicodeSubset_Western: return FindFont (Font_NOF_SANS_SERIF, Font_StrictLevel_Aliases, aFontAspect);
+    case Font_UnicodeSubset_Western: aFont = FindFont (Font_NOF_SANS_SERIF, Font_StrictLevel_Aliases, aFontAspect, false); break;
-    case Font_UnicodeSubset_Korean:  return FindFont (Font_NOF_KOREAN,     Font_StrictLevel_Aliases, aFontAspect);
+    case Font_UnicodeSubset_Korean:  aFont = FindFont (Font_NOF_KOREAN,     Font_StrictLevel_Aliases, aFontAspect, false); break;
-    case Font_UnicodeSubset_CJK:     return FindFont (Font_NOF_CJK,        Font_StrictLevel_Aliases, aFontAspect);
+    case Font_UnicodeSubset_CJK:     aFont = FindFont (Font_NOF_CJK,        Font_StrictLevel_Aliases, aFontAspect, false); break;
-    case Font_UnicodeSubset_Arabic:  return FindFont (Font_NOF_ARABIC,     Font_StrictLevel_Aliases, aFontAspect);
+    case Font_UnicodeSubset_Arabic:  aFont = FindFont (Font_NOF_ARABIC,     Font_StrictLevel_Aliases, aFontAspect, false); break;
   }
-  return Handle(Font_SystemFont)();
+  if (aFont.IsNull())
+  {
+    const char* aRange = "";
+    switch (theSubset)
+    {
+      case Font_UnicodeSubset_Western: aRange = "Western"; break;
+      case Font_UnicodeSubset_Korean:  aRange = "Korean";  break;
+      case Font_UnicodeSubset_CJK:     aRange = "CJK";     break;
+      case Font_UnicodeSubset_Arabic:  aRange = "Arabic";  break;
+    }
+    Message::DefaultMessenger()->Send (TCollection_AsciiString("Font_FontMgr, error: unable to find ") + aRange + " fallback font!", Message_Fail);
+  }
+  return aFont;
 }
 
 // =======================================================================
@@ -758,7 +781,8 @@ Handle(Font_SystemFont) Font_FontMgr::FindFallbackFont (Font_UnicodeSubset theSu
 // =======================================================================
 Handle(Font_SystemFont) Font_FontMgr::FindFont (const TCollection_AsciiString& theFontName,
                                                 Font_StrictLevel theStrictLevel,
-                                                Font_FontAspect& theFontAspect) const
+                                                Font_FontAspect& theFontAspect,
+                                                Standard_Boolean theDoFailMsg) const
 {
   TCollection_AsciiString aFontName (theFontName);
   aFontName.LowerCase();
@@ -844,7 +868,10 @@ Handle(Font_SystemFont) Font_FontMgr::FindFont (const TCollection_AsciiString& t
   }
   if (aFont.IsNull())
   {
-    Message::DefaultMessenger()->Send (TCollection_AsciiString("Font_FontMgr, error: unable to find any font!", Message_Fail));
+    if (theDoFailMsg)
+    {
+      Message::DefaultMessenger()->Send (TCollection_AsciiString("Font_FontMgr, error: unable to find any font!"), Message_Fail);
+    }
     return Handle(Font_SystemFont)();
   }
 

src/Font/Font_FontMgr.hxx

@@ -100,9 +100,11 @@ public:
   //! @param theStrictLevel [in]       search strict level for using aliases and fallback
   //! @param theFontAspect  [in] [out] font aspect to find (considered only if family name is not found);
   //!                                  can be modified if specified font alias refers to another style (compatibility with obsolete aliases)
+  //! @param theDoFailMsg   [in]       put error message on failure into default messenger
   Standard_EXPORT Handle(Font_SystemFont) FindFont (const TCollection_AsciiString& theFontName,
                                                     Font_StrictLevel theStrictLevel,
-                                                    Font_FontAspect& theFontAspect) const;
+                                                    Font_FontAspect& theFontAspect,
+                                                    Standard_Boolean theDoFailMsg = Standard_True) const;
 
   //! Tries to find font by given parameters.
   Handle(Font_SystemFont) FindFont (const TCollection_AsciiString& theFontName,
@@ -133,13 +135,16 @@ public:
   //! Can be disabled to avoid redundant messages with Message_Trace level.
   void SetTraceAliases (Standard_Boolean theToTrace) { myToTraceAliases = theToTrace; }
 
+  //! Collects available fonts paths.
+  Standard_EXPORT void InitFontDataBase();
+
+  //! Clear registry. Can be used for testing purposes.
+  Standard_EXPORT void ClearFontDataBase();
+
 private:
   
   //! Creates empty font manager object
   Standard_EXPORT Font_FontMgr();
-  
-  //! Collects available fonts paths.
-  Standard_EXPORT void InitFontDataBase();
 
 private:
 

src/ViewerTest/ViewerTest_ObjectCommands.cxx

@@ -5528,6 +5528,14 @@ static int VFont (Draw_Interpretor& theDI,
                                          theArgVec + anArgIter + 1,
                                          aStrictLevel);
     }
+    else if (anArgCase == "-clear")
+    {
+      aMgr->ClearFontDataBase();
+    }
+    else if (anArgCase == "-init")
+    {
+      aMgr->InitFontDataBase();
+    }
     else if (anArgIter + 1 < theArgNb
           && (anArgCase == "-find"
            || anArgCase == "find"))
@@ -6600,7 +6608,8 @@ void ViewerTest::ObjectCommands(Draw_Interpretor& theCommands)
   theCommands.Add ("vfont",
                             "vfont [-add pathToFont [fontName] [regular,bold,italic,boldItalic=undefined] [singleStroke]]"
                    "\n\t\t:        [-strict {any|aliases|strict}] [-find fontName [regular,bold,italic,boldItalic=undefined]] [-verbose {on|off}]"
-                   "\n\t\t:        [-unicodeFallback {on|off}]",
+                   "\n\t\t:        [-unicodeFallback {on|off}]"
+                   "\n\t\t:        [-clear] [-init]",
                    __FILE__, VFont, group);
 
   theCommands.Add ("vvertexmode",

tests/3rdparty/fonts/C3

@@ -0,0 +1,27 @@
+puts "================"
+puts "0031079: Visualization - embed minimal fallback font"
+puts "================"
+puts ""
+
+puts "REQUIRED All: Font_FontMgr, error: unable to find any font!"
+puts "REQUIRED All: Font_FontMgr, error: unable to find Western fallback font!"
+
+dtracelevel trace
+pload VISUALIZATION
+
+vfont -verbose 1
+vfont -clear
+# print empty list
+vfont
+
+vclear
+vinit View1
+vpoint p0 0 0 0
+vviewcube vc
+vdrawtext t "My Text, он мой!" -font "UNKNOWN" -aspect italic -pos 0 0 0 -2d -persPos -1 1 30
+text2brep b "My Text, он мой!" -font "UNKNOWN" -aspect italic
+vtop
+vdisplay -dispMode 1 b
+vfit
+
+vdump $imagedir/${casename}.png

tests/3rdparty/parse.rules

@@ -1 +0,0 @@
-SKIPPED /test skipped/ GL2PS is absent