From 387f1214f0629fba2d2a7418bed63e0ba33bd85e Mon Sep 17 00:00:00 2001
From: Jeff Young <jeff@rokeby.ie>
Date: Sat, 26 Nov 2022 17:25:52 +0000
Subject: [PATCH] Add some heuristics to guess a better font overbar offset.

Fixes https://gitlab.com/kicad/code/kicad/issues/13010
---
 common/font/outline_font.cpp | 24 +++++++++++++++++++++---
 common/font/stroke_font.cpp  |  2 +-
 include/font/outline_font.h  |  4 ++--
 3 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/common/font/outline_font.cpp b/common/font/outline_font.cpp
index ac48618ae3..4ce2d4af52 100644
--- a/common/font/outline_font.cpp
+++ b/common/font/outline_font.cpp
@@ -297,6 +297,22 @@ VECTOR2I OUTLINE_FONT::GetTextAsGlyphs( BOX2I* aBBox, std::vector<std::unique_pt
 }
 
 
+double OUTLINE_FONT::getOverbarOffset( int ascender, int height, int thickness ) const
+{
+    double thicknessRatio = abs( (double) thickness ) / (double) height;
+    double ascenderRatio = (double) ascender / (double) height;
+
+    if( thicknessRatio < 0.05 )
+        return 0.04;
+    else if( ascenderRatio < 0.78 )
+        return 0.00;
+    else if( ascenderRatio < 0.80 )
+        return -0.03;
+    else
+        return -0.06;
+}
+
+
 VECTOR2I OUTLINE_FONT::getTextAsGlyphs( BOX2I* aBBox, std::vector<std::unique_ptr<GLYPH>>* aGlyphs,
                                         const wxString& aText, const VECTOR2I& aSize,
                                         const VECTOR2I& aPosition, const EDA_ANGLE& aAngle,
@@ -418,6 +434,7 @@ VECTOR2I OUTLINE_FONT::getTextAsGlyphs( BOX2I* aBBox, std::vector<std::unique_pt
     }
 
     int      ascender = abs( face->size->metrics.ascender * GLYPH_SIZE_SCALER );
+    int      height = abs( face->size->metrics.height * GLYPH_SIZE_SCALER );
     int      descender = abs( face->size->metrics.descender * GLYPH_SIZE_SCALER );
     VECTOR2I extents( cursor.x * scaleFactor.x, ( ascender + descender ) * abs( scaleFactor.y ) );
 
@@ -441,17 +458,18 @@ VECTOR2I OUTLINE_FONT::getTextAsGlyphs( BOX2I* aBBox, std::vector<std::unique_pt
 
         // Shorten the bar a little so its rounded ends don't make it over-long
         double barTrim = barThickness / 2.0;
+        double barOffset = getOverbarOffset( ascender, height, barThickness / scaleFactor.y );
 
         VECTOR2I topLeft( aPosition );
         VECTOR2I topRight( aPosition );
 
-        topLeft.y += ascender * scaleFactor.y * ( 1.0 + m_overbarOffsetRatio );
-        topRight.y += ascender * scaleFactor.y * ( 1.0 + m_overbarOffsetRatio );
+        topLeft.y += ascender * scaleFactor.y * ( 1.0 + barOffset );
+        topRight.y = topLeft.y;
 
         topLeft.x += barTrim;
         topRight.x += extents.x - barTrim;
 
-        extents.y *= ( 1.0 + m_overbarOffsetRatio + m_overbarOffsetRatio );
+        extents.y *= ( 1.0 + barOffset + barOffset );
         extents.x += barTrim;
 
         if( IsItalic() )
diff --git a/common/font/stroke_font.cpp b/common/font/stroke_font.cpp
index 568cadcf6b..b246825f83 100644
--- a/common/font/stroke_font.cpp
+++ b/common/font/stroke_font.cpp
@@ -44,7 +44,7 @@ using namespace KIFONT;
 
 
 ///< Factor that determines relative vertical position of the overbar.
-static constexpr double OVERBAR_POSITION_FACTOR = 1.33;
+static constexpr double OVERBAR_POSITION_FACTOR = 1.40;
 
 ///< Factor that determines relative vertical position of the underline.
 static constexpr double UNDERLINE_POSITION_FACTOR = -0.16;
diff --git a/include/font/outline_font.h b/include/font/outline_font.h
index e8f169eb3d..5096d700e8 100644
--- a/include/font/outline_font.h
+++ b/include/font/outline_font.h
@@ -114,6 +114,8 @@ public:
 protected:
     FT_Error loadFace( const wxString& aFontFileName );
 
+    double getOverbarOffset( int ascender, int height, int thickness ) const;
+
     BOX2I getBoundingBox( const std::vector<std::unique_ptr<GLYPH>>& aGlyphs ) const;
 
     VECTOR2I getTextAsGlyphs( BOX2I* aBoundingBox, std::vector<std::unique_ptr<GLYPH>>* aGlyphs,
@@ -165,8 +167,6 @@ private:
 
     static constexpr double m_subscriptVerticalOffset   = -0.25;
     static constexpr double m_superscriptVerticalOffset = 0.45;
-    static constexpr double m_overbarOffsetRatio        = -0.15;
-    static constexpr double m_overbarThicknessRatio     = 0.08;
 };
 
 } //namespace KIFONT