Altium importer: Compensate field text for symbol orientation

When importing Altium schematics, text field properties (angle and
justification) for designators and parameters are stored in absolute
page coordinates. KiCad stores these relative to the parent symbol
and applies the symbol's transform at render time. Without
compensation, text appears with incorrect rotation and alignment
after the symbol orientation commit (090583a57e).

Add AdjustFieldForSymbolOrientation() to inverse-transform text angle
and horizontal justification based on the parent symbol's Altium
orientation. The compensation follows the same logic as
SCH_FIELD::Rotate() applied in the reverse direction for each of the
four orientation cases and mirror-Y.

Also add the missing SetTextPositioning() call in ParseLibDesignator()
to preserve text angle and justification for library-level designators.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/22907

eeschema/sch_io/altium/sch_io_altium.cpp

@@ -2032,6 +2032,65 @@ void SetTextPositioning( EDA_TEXT* text, ASCH_LABEL_JUSTIFICATION justification,
 }
 
 
+// Altium text orientation and justification are in absolute (page) coordinates. KiCad stores
+// field text properties relative to the parent symbol and applies the symbol's transform at
+// render time. This function adjusts the field's stored text angle and justification to
+// compensate for the symbol's orientation so that the final rendered appearance matches the
+// original Altium layout.
+//
+// The compensation follows the same logic as SCH_FIELD::Rotate() but applied in the
+// inverse direction to undo the symbol's rotation effect on text properties.
+void AdjustFieldForSymbolOrientation( SCH_FIELD* aField, const ASCH_SYMBOL& aSymbol )
+{
+    bool isHorizontal = aField->GetTextAngle().IsHorizontal();
+
+    // Altium orientation 0 (RIGHTWARDS) maps to KiCad SYM_ORIENT_90 (CCW). To compensate,
+    // apply CW 90-degree rotation to text properties. Per SCH_FIELD::Rotate(), CW rotation
+    // of horizontal text flips justification; CW rotation of vertical text does not.
+    if( aSymbol.orientation == 0 )
+    {
+        if( isHorizontal )
+        {
+            aField->SetHorizJustify(
+                    static_cast<GR_TEXT_H_ALIGN_T>( -aField->GetHorizJustify() ) );
+        }
+
+        aField->SetTextAngle( isHorizontal ? ANGLE_VERTICAL : ANGLE_HORIZONTAL );
+    }
+    // Altium orientation 1 (UPWARDS) maps to KiCad SYM_ORIENT_180 (two CCW rotations). The
+    // transform [-1,0,0,-1] negates both X and Y, flipping horizontal justification. Apply
+    // one correction for the full 180 degrees regardless of text angle.
+    else if( aSymbol.orientation == 1 )
+    {
+        aField->SetHorizJustify(
+                static_cast<GR_TEXT_H_ALIGN_T>( -aField->GetHorizJustify() ) );
+    }
+    // Altium orientation 2 (LEFTWARDS) maps to KiCad SYM_ORIENT_270 (CW). To compensate,
+    // apply CCW 90-degree rotation to text properties. Per SCH_FIELD::Rotate(), CCW rotation
+    // of vertical text flips justification; CCW rotation of horizontal text does not.
+    else if( aSymbol.orientation == 2 )
+    {
+        if( !isHorizontal )
+        {
+            aField->SetHorizJustify(
+                    static_cast<GR_TEXT_H_ALIGN_T>( -aField->GetHorizJustify() ) );
+        }
+
+        aField->SetTextAngle( isHorizontal ? ANGLE_VERTICAL : ANGLE_HORIZONTAL );
+    }
+    // Altium orientation 3 (DOWNWARDS) maps to KiCad SYM_ORIENT_0 (identity). No rotation
+    // compensation needed.
+
+    // Mirror-Y in KiCad negates the X component of the bounding box, which effectively
+    // flips horizontal justification. Compensate so the rendered text matches Altium.
+    if( aSymbol.isMirrored )
+    {
+        aField->SetHorizJustify(
+                static_cast<GR_TEXT_H_ALIGN_T>( -aField->GetHorizJustify() ) );
+    }
+}
+
+
 bool SCH_IO_ALTIUM::ShouldPutItemOnSheet( int aOwnerindex )
 {
     // No component assigned -> Put on sheet
@@ -4416,6 +4475,11 @@ void SCH_IO_ALTIUM::ParseDesignator( const std::map<wxString, wxString>& aProper
     field->SetVisible( visible );
     field->SetPosition( elem.location + m_sheetOffset );
     SetTextPositioning( field, elem.justification, elem.orientation );
+
+    const auto& altiumSymIt = m_altiumComponents.find( elem.ownerindex );
+
+    if( altiumSymIt != m_altiumComponents.end() )
+        AdjustFieldForSymbolOrientation( field, altiumSymIt->second );
 }
 
 
@@ -4437,6 +4501,7 @@ void SCH_IO_ALTIUM::ParseLibDesignator( const std::map<wxString, wxString>& aPro
             refField.SetText( elem.text.BeforeLast( '?' ) ); // remove the '?' at the end for KiCad-style
 
         refField.SetPosition( elem.location );
+        SetTextPositioning( &refField, elem.justification, elem.orientation );
 
         if( elem.fontId > 0 && elem.fontId <= static_cast<int>( aFontSizes.size() ) )
         {
@@ -4555,6 +4620,11 @@ void SCH_IO_ALTIUM::ParseParameter( const std::map<wxString, wxString>& aPropert
         field->SetVisible( !elem.isHidden );
         field->SetNameShown( elem.isShowName );
         SetTextPositioning( field, elem.justification, elem.orientation );
+
+        const auto& altiumSymIt = m_altiumComponents.find( elem.ownerindex );
+
+        if( altiumSymIt != m_altiumComponents.end() )
+            AdjustFieldForSymbolOrientation( field, altiumSymIt->second );
     }
 }