LazMapViewer: Improvements in GreatCircle plugin, by Ekkehard Domning.

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@9611 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/lazmapviewer/examples/plugin_demos/greatcirclepaint_demo/main.lfm

@@ -6,9 +6,9 @@ object MainForm: TMainForm
   Caption = 'Great Circle Plugin Demo'
   ClientHeight = 493
   ClientWidth = 872
-  LCLVersion = '4.99.0.0'
   OnActivate = FormActivate
   OnCreate = FormCreate
+  LCLVersion = '3.6.0.0'
   object ParamsPanel: TPanel
     Left = 8
     Height = 454
@@ -82,8 +82,8 @@ object MainForm: TMainForm
       Height = 25
       Top = 58
       Width = 108
-      Position = 0
       OnChange = tbSegmentLengthChange
+      Position = 0
       Anchors = [akTop, akLeft, akRight]
       BorderSpacing.Left = 8
       BorderSpacing.Top = 8
@@ -143,7 +143,7 @@ object MainForm: TMainForm
         Height = 25
         Top = 58
         Width = 164
-        Caption = 'Porto-PoS'
+        Caption = 'Porto-Port of Spain'
         TabOrder = 2
         OnClick = btnPresetPortoClick
       end
@@ -195,8 +195,8 @@ object MainForm: TMainForm
         'Mark Center'
         'Mark Destination'
       )
-      TabOrder = 3
       OnItemClick = cgOptionsItemClick
+      TabOrder = 3
       Data = {
         03000000020202
       }
@@ -244,9 +244,9 @@ object MainForm: TMainForm
         BorderSpacing.Bottom = 6
         MaxValue = 10
         MinValue = 1
+        OnChange = seOrthodromePenWidthChange
         TabOrder = 0
         Value = 3
-        OnChange = seOrthodromePenWidthChange
       end
       object clbOrthodromePenColor: TColorButton
         AnchorSideLeft.Control = seOrthodromePenWidth
@@ -309,9 +309,9 @@ object MainForm: TMainForm
         BorderSpacing.Bottom = 6
         MaxValue = 10
         MinValue = 1
+        OnChange = seGreatCirclePenWidthChange
         TabOrder = 0
         Value = 1
-        OnChange = seGreatCirclePenWidthChange
       end
       object clbGreatCirclePenColor: TColorButton
         AnchorSideLeft.Control = seGreatCirclePenWidth

components/lazmapviewer/source/addons/plugins/greatcircle/mvgreatcirclepainterplugin.pas

@@ -154,6 +154,7 @@ type
 
 implementation
 
+
 { TGreatCirclePoint }
 
 constructor TGreatCirclePoint.Create(const ARealPoint: TRealPoint; const ADistance : Double;
@@ -181,6 +182,7 @@ end;
 
 
 { TGreatCirclePainterPlugin }
+
 // Default SortCompare sortes the points along the longitude and on same
 // longitudes shorter distance from start first.
 function GreatCircleLinePointsListSortCompare(Item1, Item2: Pointer): Integer;
@@ -271,12 +273,11 @@ var
   i : Integer;
   lStart, lDest : TRealPoint;
   lWorldSize : Int64;
-  lGCP : TGreatCirclePoint;
+  lGCP0, lGCP1 : TGreatCirclePoint;
   ptKind : TGreatCirclePointKind;
   lon0, lon1 : Double;
   lLastRPt : TrealPoint;
   cnt : Integer;
-  lSuppressSort : Boolean = False;
   lFullSpan : Boolean;
   pt : TPoint;
   lDateBorderOnMap : Boolean;
@@ -442,9 +443,8 @@ begin
         // Sort all points along their distances from Start
         FGreatCircleLinePoints.Sort(@GreatCircleLinePolarPointsListSortCompare);
         // move the last point from the end to the beginning to draw a line from this pole prior to start
-        lGCP := TGreatCirclePoint(FGreatCircleLinePoints.Extract(FGreatCircleLinePoints.Items[FGreatCircleLinePoints.Count-1]));
+        lGCP0 := TGreatCirclePoint(FGreatCircleLinePoints.Extract(FGreatCircleLinePoints.Items[FGreatCircleLinePoints.Count-1]));
-        FGreatCircleLinePoints.Insert(0,lGCP);
+        FGreatCircleLinePoints.Insert(0,lGCP0);
-        lSuppressSort := True; // Points have been sorted here
         // The North-South straight line has been processed
         Exit;
       end;
@@ -521,7 +521,7 @@ begin
           if not lDateBorderOnMap then
           begin
             pt := MapView.LatLonToScreen(lScreenArea.TopLeft.Lat,-180.0);
-            if pt.X <= MapView.Engine.MapLeft then Continue;
+            if pt.X < MapView.Engine.MapLeft then Continue;
           end;
         end
         else
@@ -530,7 +530,7 @@ begin
           if not lDateBorderOnMap then
           begin
             pt := MapView.LatLonToScreen(lScreenArea.TopLeft.Lat,180.0);
-            if pt.X >= MapView.Engine.MapLeft+lWorldSize then Continue;
+            if pt.X > MapView.Engine.MapLeft+lWorldSize then Continue;
           end;
         end;
         LatFromLonAtGreatCircle(lStart.Lat, lStart.Lon, lDest.Lat, lDest.Lon,
@@ -539,14 +539,29 @@ begin
         ptKind := PointKindFromDist(d);
         FGreatCircleLinePoints.Add(TGreatCirclePoint.Create(rPt,d,ptKind));
       end;
-
+      // Finally the found points must be sorted, if not processed in a different way.
+      FGreatCircleLinePoints.Sort(@GreatCircleLinePointsListSortCompare);
+      // Check for duplicate items, if found remove them
+      cnt := FGreatCircleLinePoints.Count;
+      if cnt > 1 then
+      begin
+        for i := cnt-1 downto 1 do
+        begin
+          lGCP0 := TGreatCirclePoint(FGreatCircleLinePoints.Items[i]);
+          lGCP1 := TGreatCirclePoint(FGreatCircleLinePoints.Items[i-1]);
+          if (lGCP1.Distance = lGCP0.Distance) and
+             (lGCP1.FRealPoint.Lon = lGCP0.FRealPoint.Lon) and
+             (lGCP1.FRealPoint.Lat = lGCP0.FRealPoint.Lat) then
+          begin
+            FGreatCircleLinePoints.Extract(lGCP0);
+            FreeAndNil(lGCP0);
+          end;
+        end;
+      end;
     except
       // Keep silence on any computation errors
     end;
   finally
-    // Finally the found points must be sorted, if not processed in a different way.
-    if not lSuppressSort then
-      FGreatCircleLinePoints.Sort(@GreatCircleLinePointsListSortCompare);
     // Give the user a message, to update the information about the current great circle
     if Assigned(FOnChange) then
       FOnChange(Self);