Improve obscuring dialog algorithm to handle multiple dialogs.

Fixes https://gitlab.com/kicad/code/kicad/issues/8970

common/eda_draw_frame.cpp

@@ -836,15 +836,17 @@ void EDA_DRAW_FRAME::Zoom_Automatique( bool aWarpPointer )
 
 
 // Find the first child dialog.
-wxWindow* EDA_DRAW_FRAME::findDialog()
+std::vector<wxWindow*> EDA_DRAW_FRAME::findDialogs()
 {
+    std::vector<wxWindow*> dialogs;
+
     for( wxWindow* window : GetChildren() )
     {
         if( dynamic_cast<DIALOG_SHIM*>( window ) )
-            return window;
+            dialogs.push_back( window );
     }
 
-    return nullptr;
+    return dialogs;
 }
 
 
@@ -859,33 +861,25 @@ void EDA_DRAW_FRAME::FocusOnLocation( const wxPoint& aPos )
     if( !r.Contains( aPos ) )
         centerView = true;
 
-    // Center if we're behind an obscuring dialog, or within 10% of its edge
-    wxWindow* dialog = findDialog();
+    std::vector<BOX2D> dialogScreenRects;
 
-    if( dialog )
+    for( wxWindow* dialog : findDialogs() )
     {
-        wxRect dialogRect( GetCanvas()->ScreenToClient( dialog->GetScreenPosition() ),
-                           dialog->GetSize() );
-        dialogRect.Inflate( dialogRect.GetWidth() / 10 );
+        dialogScreenRects.emplace_back( GetCanvas()->ScreenToClient( dialog->GetScreenPosition() ),
+                                        dialog->GetSize() );
+    }
 
-        if( dialogRect.Contains( (wxPoint) GetCanvas()->GetView()->ToScreen( aPos ) ) )
+    // Center if we're behind an obscuring dialog, or within 10% of its edge
+    for( BOX2D rect : dialogScreenRects )
+    {
+        rect.Inflate( rect.GetWidth() / 10 );
+
+        if( rect.Contains( GetCanvas()->GetView()->ToScreen( aPos ) ) )
             centerView = true;
     }
 
     if( centerView )
-    {
-        // If a dialog partly obscures the window, then center on the uncovered area.
-        if( dialog )
-        {
-            BOX2D dialogRect( GetCanvas()->ScreenToClient( dialog->GetScreenPosition() ),
-                              dialog->GetSize() );
-            GetCanvas()->GetView()->SetCenter( aPos, dialogRect );
-        }
-        else
-        {
-            GetCanvas()->GetView()->SetCenter( aPos );
-        }
-    }
+        GetCanvas()->GetView()->SetCenter( aPos, dialogScreenRects );
 
     GetCanvas()->GetViewControls()->SetCrossHairCursorPosition( aPos );
 }

common/view/view.cpp

@@ -603,39 +603,35 @@ void VIEW::SetCenter( const VECTOR2D& aCenter )
 }
 
 
-void VIEW::SetCenter( const VECTOR2D& aCenter, const BOX2D& occultingScreenRect )
+void VIEW::SetCenter( const VECTOR2D& aCenter, const std::vector<BOX2D>& obscuringScreenRects )
 {
-    VECTOR2D center( aCenter );
-    BOX2D screenRect( VECTOR2D( 0, 0 ), m_gal->GetScreenPixelSize() );
+    if( obscuringScreenRects.empty() )
+        return SetCenter( aCenter );
 
-    if( !screenRect.Intersects( occultingScreenRect ) )
+    BOX2D          screenRect( { 0, 0 }, m_gal->GetScreenPixelSize() );
+    SHAPE_POLY_SET unobscuredPoly( screenRect );
+    VECTOR2D       unobscuredCenter = screenRect.Centre();
+
+    for( const BOX2D& obscuringScreenRect : obscuringScreenRects )
     {
-        SetCenter( aCenter );
-        return;
+        SHAPE_POLY_SET obscuringPoly( obscuringScreenRect );
+        unobscuredPoly.BooleanSubtract( obscuringPoly, SHAPE_POLY_SET::PM_FAST );
     }
 
-    BOX2D  occultedRect  = screenRect.Intersect( occultingScreenRect );
-    double topExposed    = occultedRect.GetTop() - screenRect.GetTop();
-    double bottomExposed = screenRect.GetBottom() - occultedRect.GetBottom();
-    double leftExposed   = occultedRect.GetLeft() - screenRect.GetLeft();
-    double rightExposed  = screenRect.GetRight() - occultedRect.GetRight();
+    /*
+     * Perform a step-wise deflate to find the center of the largest unobscured area
+     */
 
-    if( std::max( topExposed, bottomExposed ) > std::max( leftExposed, rightExposed ) )
-    {
-        if( topExposed > bottomExposed )
-            center.y += ToWorld( screenRect.GetHeight() / 2 - topExposed / 2 );
-        else
-            center.y -= ToWorld( screenRect.GetHeight() / 2 - bottomExposed / 2 );
-    }
-    else
+    BOX2I bbox = unobscuredPoly.BBox();
+    int   step = std::min( bbox.GetWidth(), bbox.GetHeight() ) / 10;
+
+    while( !unobscuredPoly.IsEmpty() )
     {
-        if( leftExposed > rightExposed )
-            center.x += ToWorld( screenRect.GetWidth() / 2 - leftExposed / 2 );
-        else
-            center.x -= ToWorld( screenRect.GetWidth() / 2 - rightExposed / 2 );
+        unobscuredCenter = (wxPoint) unobscuredPoly.BBox().Centre();
+        unobscuredPoly.Deflate( step, 4 );
     }
 
-    SetCenter( center );
+    SetCenter( aCenter - ToWorld( unobscuredCenter - screenRect.Centre(), false ) );
 }
 
 

include/eda_draw_frame.h

@@ -462,7 +462,7 @@ protected:
 
     void setupUnits( APP_SETTINGS_BASE* aCfg );
 
-    wxWindow* findDialog();
+    std::vector<wxWindow*> findDialogs();
 
     /**
      * Determines the Canvas type to load (with prompt if required) and initializes m_canvasType

include/view/view.h

@@ -318,13 +318,13 @@ public:
     void SetCenter( const VECTOR2D& aCenter );
 
     /**
-     * Set the center point of the VIEW, attempting to avoid \a occultingScreenRect (for
+     * Set the center point of the VIEW, attempting to avoid \a obscuringScreenRects (for
      * instance, the screen rect of a modeless dialog in front of the VIEW).
      *
      * @param aCenter: the new center point, in world space coordinates.
-     * @param occultingScreenRect: the occulting rect, in screen space coordinates.
+     * @param obscuringScreenRects: the obscuring rects, in screen space coordinates.
      */
-    void SetCenter( const VECTOR2D& aCenter, const BOX2D& occultingScreenRect );
+    void SetCenter( const VECTOR2D& aCenter, const std::vector<BOX2D>& obscuringScreenRects );
 
     /**
      * Return the center point of this VIEW (in world space coordinates).

pcbnew/pcb_base_frame.cpp

@@ -271,15 +271,14 @@ void PCB_BASE_FRAME::FocusOnItem( BOARD_ITEM* aItem, PCB_LAYER_ID aLayer )
         GetCanvas()->GetView()->Update( aItem );
         lastBrightenedItemID = aItem->m_Uuid;
 
-        // Focus on the object's location.  Prefer a visible part of the object to its anhcor
+        // Focus on the object's location.  Prefer a visible part of the object to its anchor
         // in order to keep from scrolling around.
 
         wxPoint        focusPt = aItem->GetFocusPosition();
         KIGFX::VIEW*   view = GetCanvas()->GetView();
         SHAPE_POLY_SET viewportPoly( view->GetViewport() );
-        wxWindow*      dialog = findDialog();
 
-        if( dialog )
+        for( wxWindow* dialog : findDialogs() )
         {
             wxPoint        dialogPos = GetCanvas()->ScreenToClient( dialog->GetScreenPosition() );
             SHAPE_POLY_SET dialogPoly( BOX2D( view->ToWorld( dialogPos, true ),
@@ -335,6 +334,10 @@ void PCB_BASE_FRAME::FocusOnItem( BOARD_ITEM* aItem, PCB_LAYER_ID aLayer )
         if( !clippedPoly.IsEmpty() )
             itemPoly = clippedPoly;
 
+        /*
+         * Perform a step-wise deflate to find the visual-center-of-mass
+         */
+
         BOX2I bbox = itemPoly.BBox();
         int   step = std::min( bbox.GetWidth(), bbox.GetHeight() ) / 10;