Exclude formatting chars from text width approximation.

Fixes https://gitlab.com/kicad/code/kicad/issues/9080

common/string_utils.cpp

@@ -452,7 +452,7 @@ wxString EscapeHTML( const wxString& aString )
 {
     wxString converted;
 
-    for( wxUniChar c: aString )
+    for( wxUniChar c : aString )
     {
         if( c == '\"' )
             converted += """;
@@ -480,6 +480,90 @@ bool NoPrintableChars( const wxString& aString )
 }
 
 
+/**
+ * Return the number of printable (ie: non-formatting) chars.  Used to approximate rendered
+ * text size when speed is more important than accuracy.
+ */
+int PrintableCharCount( const wxString& aString )
+{
+    int char_count = 0;
+    int overbarDepth = -1;
+    int superSubDepth = -1;
+    int braceNesting = 0;
+
+    for( auto chIt = aString.begin(), end = aString.end(); chIt < end; ++chIt )
+    {
+        if( *chIt == '\t' )
+        {
+            // We don't format tabs in bitmap text (where this is currently used), so just
+            // drop them from the count.
+            continue;
+        }
+        else if( *chIt == '^' && superSubDepth == -1 )
+        {
+            auto lookahead = chIt;
+
+            if( ++lookahead != end && *lookahead == '{' )
+            {
+                chIt = lookahead;
+                superSubDepth = braceNesting;
+                braceNesting++;
+                continue;
+            }
+        }
+        else if( *chIt == '_' && superSubDepth == -1 )
+        {
+            auto lookahead = chIt;
+
+            if( ++lookahead != end && *lookahead == '{' )
+            {
+                chIt = lookahead;
+                superSubDepth = braceNesting;
+                braceNesting++;
+                continue;
+            }
+        }
+        else if( *chIt == '~' && overbarDepth == -1 )
+        {
+            auto lookahead = chIt;
+
+            if( ++lookahead != end && *lookahead == '{' )
+            {
+                chIt = lookahead;
+                overbarDepth = braceNesting;
+                braceNesting++;
+                continue;
+            }
+        }
+        else if( *chIt == '{' )
+        {
+            braceNesting++;
+        }
+        else if( *chIt == '}' )
+        {
+            if( braceNesting > 0 )
+                braceNesting--;
+
+            if( braceNesting == superSubDepth )
+            {
+                superSubDepth = -1;
+                continue;
+            }
+
+            if( braceNesting == overbarDepth )
+            {
+                overbarDepth = -1;
+                continue;
+            }
+        }
+
+        char_count++;
+    }
+
+    return char_count;
+}
+
+
 char* StrPurge( char* text )
 {
     static const char whitespace[] = " \t\n\r\f\v";

include/string_utils.h

@@ -133,6 +133,12 @@ char* GetLine( FILE* aFile, char* Line, int* LineNum = nullptr, int SizeLine = 2
  */
 bool NoPrintableChars( const wxString& aString );
 
+/**
+ * Return the number of printable (ie: non-formatting) chars.  Used to approximate rendered
+ * text size when speed is more important than accuracy.
+ */
+int PrintableCharCount( const wxString& aString );
+
 /**
  * Remove leading and training spaces, tabs and end of line chars in \a text
  *

pcbnew/pcb_painter.cpp

@@ -778,8 +778,8 @@ void PCB_PAINTER::draw( const PCB_VIA* aVia, int aLayer )
 
         wxString netname = UnescapeString( aVia->GetShortNetname() );
 
-        // calculate the size of net name text:
+        // approximate the size of net name text:
-        double tsize = 1.5 * size / netname.Length();
+        double tsize = 1.5 * size / PrintableCharCount( netname );
         tsize = std::min( tsize, size );
 
         // Use a smaller text size to handle interline, pen size..
@@ -960,8 +960,8 @@ void PCB_PAINTER::draw( const PAD* aPad, int aLayer )
             // position to display 2 lines
             if( displayNetname && m_pcbSettings.m_padNumbers )
             {
-                size = size / 2.0;
+                size = size / 2.5;
-                textpos.y = size / 2.0;
+                textpos.y = size / 1.7;
             }
 
             if( displayNetname )
@@ -974,11 +974,11 @@ void PCB_PAINTER::draw( const PAD* aPad, int aLayer )
                 else if( pinType == wxT( "free" ) && netname.StartsWith( wxT( "unconnected-(" ) ) )
                     netname = "*";
 
-                // calculate the size of net name text:
+                // approximate the size of net name text:
-                double tsize = 1.5 * padsize.x / netname.Length();
+                double tsize = 1.5 * padsize.x / PrintableCharCount( netname );
                 tsize = std::min( tsize, size );
 
-                // Use a smaller text size to handle interline, pen size..
+                // Use a smaller text size to handle interline, pen size...
                 tsize *= 0.7;
                 VECTOR2D namesize( tsize, tsize );
 
@@ -991,10 +991,12 @@ void PCB_PAINTER::draw( const PAD* aPad, int aLayer )
             {
                 const wxString& padNumber = aPad->GetNumber();
                 textpos.y = -textpos.y;
-                double tsize = 1.5 * padsize.x / padNumber.Length();
+
+                // approximate the size of the pad number text:
+                double tsize = 1.5 * padsize.x / PrintableCharCount( padNumber );
                 tsize = std::min( tsize, size );
 
-                // Use a smaller text size to handle interline, pen size..
+                // Use a smaller text size to handle interline, pen size...
                 tsize *= 0.7;
                 tsize = std::min( tsize, size );
                 VECTOR2D numsize( tsize, tsize );
@@ -1665,7 +1667,7 @@ void PCB_PAINTER::draw( const PCB_GROUP* aGroup, int aLayer )
         wxPoint textOffset = wxPoint( width.x / 2, - KiROUND( textSize * 0.5 ) );
         wxPoint titleHeight = wxPoint( 0, KiROUND( textSize * 2.0 ) );
 
-        if( !name.IsEmpty() && (int) aGroup->GetName().Length() * textSize < bbox.GetWidth() )
+        if( PrintableCharCount( name ) * textSize < bbox.GetWidth() )
         {
             m_gal->DrawLine( topLeft, topLeft - titleHeight );
             m_gal->DrawLine( topLeft - titleHeight, topLeft + width - titleHeight );