LazMapViewer: Add OnStartDrag and OnEndDrag events to TMarkerSelectAndDragPlugin

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@9694 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/lazmapviewer/source/addons/plugins/markers/mvmarkerplugins.pas

@@ -96,6 +96,8 @@ type
     ADrawingEngine: TMvCustomDrawingEngine; AGPSPoint: TGPSPoint;
     AScreenPoint: TPoint; AMarkerSize: Integer) of object;
 
+  TMarkerStartDragEvent = procedure (AMapView: TMapView; var CanDrag: Boolean) of object;
+
   TMarkerClickMode = (mcmAddPointToSelection, mcmAddShapeToSelection, mcmToggleSelectedPoint);
 
   TMarkerSelectAndDragPlugin = class(TMarkerClickPlugin)
@@ -108,6 +110,8 @@ type
     FOrigSelection: array of TRealPoint;  // Selection before dragging starts
     FOnDrawPoint: TMarkerDrawPointEvent;
     FOnSelectionChange: TNotifyEvent;
+    FOnStartDrag: TMarkerStartDragEvent;
+    FOnEndDrag: TNotifyEvent;
     procedure SetMultiSelect(AValue: Boolean);
   protected
     procedure AddToSelection(AMapView: TMapView; APoint: TGPSPoint);
@@ -121,7 +125,6 @@ type
     procedure DrawSelection(AMapView: TMapView);
     procedure FindContainerOfPoint(AMapView: TMapView; APoint: TGPSPoint; var AContainer: TGPSObj; var AIndex: Integer);
     procedure FindMapCollection(AMapView: TMapView; APoint: TGPSPoint; var ACollection: TMapCollectionBase; var AIndex: Integer);
-    procedure MoveSelectionBy(AMapView: TMapView; dx, dy: Integer);
     procedure ToggleSelected(AMapView: TMapView; APoint: TGPSPoint);
   protected
     procedure AfterDrawObjects(AMapView: TMapView; var {%H-}Handled: Boolean); override;
@@ -139,6 +142,8 @@ type
     function ConvertSelectedPointsToGPSTrack(AMapView: TMapView; ATrackID: Integer): TGPSTrack;
     function ConvertSelectedPointsToMapTrack(AMapView: TMapView; ALayer: TMapLayer): TMapTrack;
     procedure DeleteSelectedPoints(AMapView: TMapView);
+    procedure MoveSelectionBy(AMapView: TMapView; dx, dy: Double);
+    procedure MoveSelectionBy(AMapView: TMapView; dx, dy: Integer);
     procedure SelectAllPointsOfShape(AMapView: TMapView; APoint: TGPSPoint);
     property Selection: TGPSPointList read FSelection;
   published
@@ -146,7 +151,9 @@ type
     property DragCursor: TCursor read FDragCursor write FDragCursor default crSizeAll;
     property MultiSelect: Boolean read FMultiSelect write SetMultiSelect default false;
     property OnDrawPoint: TMarkerDrawPointEvent read FOnDrawPoint write FOnDrawPoint;
+    property OnEndDrag: TNotifyEvent read FOnEndDrag write FOnEndDrag;
     property OnSelectionChange: TNotifyEvent read FOnSelectionChange write FOnSelectionChange;
+    property OnStartDrag: TMarkerStartDragEvent read FOnStartDrag write FOnStartDrag;
   end;
 
 
@@ -568,7 +575,14 @@ end;
 procedure TMarkerSelectAndDragPlugin.DragStart(AMapView: TMapView);
 var
   i: Integer;
+  canDrag: Boolean;
 begin
+  if Assigned(FOnStartDrag) then
+  begin
+    canDrag := true;
+    FOnStartDrag(AMapView, canDrag);
+    if not canDrag then exit;
+  end;
   AMapView.Cursor := DragCursor;
   FDragging := true;
   // Save original selection point coordinates in case they must be restored later.
@@ -583,7 +597,6 @@ var
 begin
   if FDragging then
   begin
-  //  AMapView.Cursor := DragCursor;
     dX := X - FMousePoint.X;
     dY := Y - FMousePoint.Y;
     MoveSelectionBy(AMapView, dX, dY);
@@ -596,6 +609,8 @@ procedure TMarkerSelectAndDragPlugin.DragEnd(AMapView: TMapView);
 begin
   FDragging := false;
   AMapView.Cursor := FSavedCursor;
+  if Assigned(FOnEndDrag) then
+    FOnEndDrag(AMapView);
 end;
 
 { Draw the selection marker for the given point. The drawing engine already
@@ -651,6 +666,14 @@ begin
   end;
 end;
 
+function IsSamePoint(AItem: TGPSObj; APoint: TGPSPoint): Boolean;
+begin
+  Result := (AItem is TGPSPoint) and TGPSPoint(AItem).RealPoint.Equal(APoint.RealPoint);
+end;
+
+{ Tries to find the point in one of the gps-type lists.
+  If found, returns the found object and the index of the point in the list.
+  Otherwise, nil and -1 are returned, respectively. }
 procedure TMarkerSelectAndDragPlugin.FindContainerOfPoint(AMapView: TMapView;
   APoint: TGPSPoint; var AContainer: TGPSObj; var AIndex: Integer);
 var
@@ -658,12 +681,6 @@ var
   gpsLayer: TGPSObjectList;
   gpsPolyline: TGPSPolyLine;
   item: TGPSObj;
-
-  function IsSamePoint(AItem: TGPSObj): Boolean;
-  begin
-    Result := (AItem is TGPSPoint) and TGPSPoint(AItem).RealPoint.Equal(APoint.RealPoint);
-  end;
-
 begin
   // Iterate over the 10 layers of GPSItems
   for i := 0 to 9 do
@@ -672,7 +689,7 @@ begin
     for j := 0 to gpsLayer.Count-1 do
     begin
       item := gpsLayer[j];
-      if IsSamePoint(item) then
+      if IsSamePoint(item, APoint) then
       begin
         AContainer := gpsLayer;
         AIndex := j;
@@ -685,7 +702,7 @@ begin
         for k := 0 to gpsPolyLine.Points.Count-1 do
         begin
           item := gpsPolyLine.Points[k];
-          if IsSamePoint(item) then
+          if IsSamePoint(item, APoint) then
           begin
             AContainer := gpsPolyLine;
             AIndex := k;
@@ -712,12 +729,6 @@ var
   mapLayer: TMapLayer;
   mapTrack: TMapTrack;
   mapArea: TMapArea;
-
-  function IsSamePoint(AItem: TGPSObj): Boolean;
-  begin
-    Result := (AItem is TGPSPoint) and TGPSPoint(AItem).RealPoint.Equal(APoint.RealPoint);
-  end;
-
 begin
   // Iterate over all map-layers
   for i := 0 to AMapView.Layers.Count-1 do
@@ -727,7 +738,7 @@ begin
     for j := 0 to mapLayer.PointsOfInterest.Count-1 do
     begin
       p := mapLayer.PointsOfInterest[j];
-      if IsSamePoint(p.GPSObj) then
+      if IsSamePoint(p.GPSObj, APoint) then
       begin
         ACollection := mapLayer.PointsOfInterest;
         AIndex := j;
@@ -741,7 +752,7 @@ begin
       for k := 0 to mapTrack.Points.Count-1 do
       begin
         p := mapTrack.Points[k];
-        if IsSamePoint(p.GPSObj) then
+        if IsSamePoint(p.GPSObj, APoint) then
         begin
           ACollection := mapTrack.Points;
           AIndex := k;
@@ -756,7 +767,7 @@ begin
       for k := 0 to mapArea.Points.Count-1 do
       begin
         p := mapArea.Points[k];
-        if IsSamePoint(p.GPSObj) then
+        if IsSamePoint(p.GPSObj, APoint) then
         begin
           ACollection := mapArea.Points;
           AIndex := k;
@@ -770,6 +781,7 @@ begin
   AIndex := -1;
 end;
 
+{ Moves the selection by the given amound of pixels in x and y direction. }
 procedure TMarkerSelectAndDragPlugin.MoveSelectionBy(AMapView: TMapView; dx, dy: Integer);
 var
   i: Integer;
@@ -786,6 +798,28 @@ begin
   end;
 end;
 
+{ Moves the selection by the given amound of degrees in x and y direction }
+procedure TMarkerSelectAndDragPlugin.MoveSelectionBy(AMapView: TMapView; dx, dy: Double);
+var
+  i: Integer;
+  P: TPoint;
+  rPt: TRealPoint;
+begin
+  for i := 0 to FSelection.Count-1 do
+  begin
+    rPt := FSelection[i].RealPoint;
+    rPt.Lon := FSelection[i].Lon + dX;
+    rPt.Lat := FSelection[i].Lat + dY;
+    if rPt.Lat > 90 then
+      rPt.Lat := rPt.Lat - 180;
+    if rPt.Lon < -90 then
+      rPt.Lon := rPt.Lon + 180;
+    P := AMapView.LatLonToScreen(rPt);
+    rPt := AMapView.ScreenToLatLon(P);
+    FSelection[i].MoveTo(rPt.Lon, rPt.Lat);
+  end;
+end;
+
 procedure TMarkerSelectAndDragPlugin.MouseDown(AMapView: TMapView;
   {%H-}Button: TMouseButton; {%H-}AShift: TShiftState;
   X, Y: Integer; var Handled: Boolean);