LazMapViewer: Avoid drawing artefacts when the mapview is dragged. Patch by Ekkehard Domning.

git-svn-id: https://svn.code.sf.net/p/lazarus-ccr/svn@8830 8e941d3f-bd1b-0410-a28a-d453659cc2b4

components/lazmapviewer/examples/fulldemo/main.lfm

@@ -40,9 +40,9 @@ object MainForm: TMainForm
     Height = 640
     Top = 0
     Width = 275
-    ActivePage = PgData
+    ActivePage = PgConfig
     Align = alRight
-    TabIndex = 0
+    TabIndex = 1
     TabOrder = 1
     object PgData: TTabSheet
       Caption = 'Data'
@@ -834,6 +834,7 @@ object MainForm: TMainForm
         Width = 100
         BorderSpacing.Left = 6
         BorderSpacing.Top = 8
+        BorderSpacing.Right = 24
         Caption = 'Zoom to cursor'
         Checked = True
         OnChange = CbZoomToCursorChange
@@ -848,13 +849,28 @@ object MainForm: TMainForm
         Height = 19
         Top = 56
         Width = 77
-        BorderSpacing.Left = 24
         Caption = 'Cyclic view'
         Checked = True
         OnChange = cbCyclicViewChange
         State = cbChecked
         TabOrder = 8
       end
+      object ColorButton1: TColorButton
+        AnchorSideLeft.Control = cbCyclicView
+        AnchorSideTop.Control = CbUseThreads
+        AnchorSideTop.Side = asrCenter
+        Left = 130
+        Height = 25
+        Top = 78
+        Width = 105
+        BorderWidth = 2
+        ButtonColorAutoSize = False
+        ButtonColorSize = 15
+        ButtonColor = clWhite
+        Caption = 'Map backgr.'
+        Margin = 4
+        OnColorChanged = ColorButton1ColorChanged
+      end
     end
   end
   object GeoNames: TMVGeoNames
@@ -872,7 +888,7 @@ object MainForm: TMainForm
     MinFontSize = 0
     MaxFontSize = 0
     Left = 808
-    Top = 104
+    Top = 200
   end
   object POIImages: TImageList
     Height = 48

components/lazmapviewer/examples/fulldemo/main.pas

@@ -33,6 +33,7 @@ type
     cbPOITextBgColor: TColorBox;
     CbZoomToCursor: TCheckBox;
     cbCyclicView: TCheckBox;
+    ColorButton1: TColorButton;
     FontDialog: TFontDialog;
     GbCenterCoords: TGroupBox;
     GbScreenSize: TGroupBox;
@@ -86,6 +87,7 @@ type
     procedure CbUseThreadsChange(Sender: TObject);
     procedure CbDistanceUnitsChange(Sender: TObject);
     procedure CbZoomToCursorChange(Sender: TObject);
+    procedure ColorButton1ColorChanged(Sender: TObject);
     procedure FormCreate(Sender: TObject);
     procedure FormDestroy(Sender: TObject);
     procedure FormShow(Sender: TObject);
@@ -410,6 +412,11 @@ begin
   MapView.ZoomToCursor := CbZoomToCursor.Checked;
 end;
 
+procedure TMainForm.ColorButton1ColorChanged(Sender: TObject);
+begin
+  MapView.InactiveColor := ColorButton1.ButtonColor;
+end;
+
 procedure TMainForm.ClearFoundLocations;
 var
   i: Integer;
@@ -732,6 +739,7 @@ begin
     pt.Lon := StrToFloatDef(ini.ReadString('MapView', 'Center.Longitude', ''), 0.0, PointFormatSettings);
     pt.Lat := StrToFloatDef(ini.ReadString('MapView', 'Center.Latitude', ''), 0.0, PointFormatSettings);
     MapView.Center := pt;
+    MapView.InactiveColor := ini.ReadInteger('MapView', 'MapBkgrColor', MapView.InactiveColor);
 
     s := ini.ReadString('MapView', 'DistanceUnits', '');
     if s <> '' then begin
@@ -877,7 +885,7 @@ begin
     ini.WriteInteger('MapView', 'Zoom', MapView.Zoom);
     ini.WriteString('MapView', 'Center.Longitude', FloatToStr(MapView.Center.Lon, PointFormatSettings));
     ini.WriteString('MapView', 'Center.Latitude', FloatToStr(MapView.Center.Lat, PointFormatSettings));
-
+    ini.WriteInteger('MapView', 'MapBkgrColor', MapView.InactiveColor);
     ini.WriteString('MapView', 'DistanceUnits', DistanceUnit_Names[DistanceUnit]);
 
     if HERE_AppID <> '' then

components/lazmapviewer/source/mvengine.pas

@@ -20,7 +20,7 @@ unit mvEngine;
 interface
 
 uses
-  Classes, SysUtils, IntfGraphics, Controls, Math,
+  Classes, SysUtils, IntfGraphics, Controls, Math, GraphType, FPImage,
   mvTypes, mvJobQueue, mvMapProvider, mvDownloadEngine, mvCache, mvDragObj;
 
 const
@@ -59,9 +59,11 @@ type
       DragObj : TDragObj;
       Cache : TPictureCache;
       FActive: boolean;
+      FBkColor: TFPColor;
       FCyclic: Boolean;
       FDownloadEngine: TMvCustomDownloadEngine;
       FDrawTitleInGuiThread: boolean;
+      FEmptyTileImg: TLazIntfImage;
       FOnCenterMove: TNotifyEvent;
       FOnChange: TNotifyEvent;
       FOnDrawTile: TDrawTileEvent;
@@ -81,6 +83,7 @@ type
       function IsValidTile(const aWin: TMapWindow; const aTile: TTIleId): boolean;
       procedure MoveMapCenter(Sender: TDragObj);
       procedure SetActive(AValue: boolean);
+      procedure SetBkColor(AValue: TFPColor);
       procedure SetCacheOnDisk(AValue: Boolean);
       procedure SetCachePath(AValue: String);
       procedure SetCenter(ACenter: TRealPoint);
@@ -104,6 +107,7 @@ type
       function IsCurrentWin(const aWin: TMapWindow) : boolean;
     protected
       procedure AdjustZoomCenter(var AWin: TMapWindow);
+      function CreateBlankImg: TLazIntfImage;
       procedure ConstraintZoom(var aWin: TMapWindow);
       function GetTileName(const Id: TTileId): String;
       procedure evDownload(Data: TObject; Job: TJob);
@@ -143,6 +147,7 @@ type
         WheelDelta: Integer; {%H-}MousePos: TPoint; var Handled: Boolean);
       procedure ZoomOnArea(const aArea: TRealArea);
 
+      property BkColor: TFPColor read FBkColor write SetBkColor;
       property Center: TRealPoint read GetCenter write SetCenter;
 
     published
@@ -377,6 +382,8 @@ begin
   DragObj.OnDrag := @DoDrag;
   Cache := TPictureCache.Create(self);
   lstProvider := TStringList.Create;
+  FBkColor := colWhite;
+  FEmptyTileImg := CreateBlankImg;
   RegisterProviders;
   Queue := TJobQueue.Create(8);
   Queue.OnIdle := @Cache.CheckCacheSize;
@@ -436,7 +443,7 @@ begin
   startY := -aWin.Y div TILE_SIZE;
   Result.Left := startX - 1;
   Result.Right := startX + MaxX;
-  Result.Top := startY;
+  Result.Top := startY - 1;
   Result.Bottom := startY + MaxY;
 end;
 
@@ -485,6 +492,22 @@ begin
   end;
 end;
 
+function TMapViewerEngine.CreateBlankImg: TLazIntfImage;
+var
+  rawImg: TRawImage;
+begin
+  rawImg.Init;
+  {$IFDEF DARWIN}
+  rawImg.Description.Init_BPP32_A8R8G8B8_BIO_TTB(TILE_SIZE, TILE_SIZE);
+  {$ELSE}
+  rawImg.Description.Init_BPP32_B8G8R8_BIO_TTB(TILE_SIZE, TILE_SIZE);
+  {$ENDIF}
+  rawImg.CreateData(True);
+
+  Result := TLazIntfImage.Create(rawImg, true);
+  Result.FillPixels(FBkColor);
+end;
+
 { Returns true when the visible window crosses the date line, i.e. the longitudes
   at the left of the window are > 0, and those at the right are < 0. }
 function TMapViewerEngine.CrossesDateline: Boolean;
@@ -1028,17 +1051,19 @@ begin
   Redraw(MapWin);
 end;
 
-procedure TMapViewerEngine.Redraw(const AWin: TmapWindow);
+procedure TMapViewerEngine.Redraw(const AWin: TMapWindow);
 var
   TilesVis: TArea;
   x, y : Integer; //int64;
   Tiles: TTileIdArray = nil;
   iTile: Integer;
   numTiles: Integer;
+  px, py: Integer;
 begin
   if not(Active) then
     Exit;
   Queue.CancelAllJob(self);
+
   TilesVis := CalculateVisibleTiles(AWin);
   SetLength(Tiles, (TilesVis.Bottom - TilesVis.Top + 1) * (TilesVis.Right - TilesVis.Left + 1));
   iTile := Low(Tiles);
@@ -1055,6 +1080,16 @@ begin
         Tiles[iTile].X := X;
       Tiles[iTile].Y := Y;
       Tiles[iTile].Z := AWin.Zoom;
+
+      // Avoid tiling artefacts when a tile does not exist (lowest zoom) or
+      // is not valid
+      if not Cache.InCache(AWin.MapProvider, Tiles[iTile]) then
+      begin
+        py := AWin.Y + Y * TILE_SIZE;
+        px := AWin.X + X * TILE_SIZE;
+        DrawTile(Tiles[iTile], px, py, FEmptyTileImg);
+      end;
+
       if IsValidTile(AWin, Tiles[iTile]) then
         inc(iTile);
     end;
@@ -1181,6 +1216,14 @@ begin
   end;
 end;
 
+procedure TMapViewerEngine.SetBkColor(AValue: TFPColor);
+begin
+  if FBkColor = AValue then Exit;
+  FBkColor := AValue;
+  FEmptyTileImg.FillPixels(FBkColor);
+  Redraw(MapWin);
+end;
+
 procedure TMapViewerEngine.SetCacheOnDisk(AValue: Boolean);
 begin
   if Cache.UseDisk = AValue then Exit;

components/lazmapviewer/source/mvmapviewer.pas

@@ -22,7 +22,7 @@ unit mvMapViewer;
 interface
 
 uses
-  Classes, SysUtils, Controls, Graphics, IntfGraphics, Forms, ImgList, LCLVersion,
+  Classes, SysUtils, Controls, Graphics, FPImage, IntfGraphics, Forms, ImgList, LCLVersion,
   MvTypes, MvGPSObj, MvEngine, MvMapProvider, MvDownloadEngine, MvDrawingEngine;
 
 Type
@@ -41,7 +41,6 @@ Type
       FDrawingEngine: TMvCustomDrawingEngine;
       FActive: boolean;
       FGPSItems: TGPSObjectList;
-      FInactiveColor: TColor;
       FPOIImage: TBitmap;
       FPOITextBgColor: TColor;
       FOnDrawGpsPoint: TDrawGpsPointEvent;
@@ -63,6 +62,7 @@ Type
       function GetCyclic: Boolean;
       function GetDownloadEngine: TMvCustomDownloadEngine;
       function GetDrawingEngine: TMvCustomDrawingEngine;
+      function GetInactiveColor: TColor;
       function GetMapProvider: String;
       function GetOnCenterMove: TNotifyEvent;
       function GetOnChange: TNotifyEvent;
@@ -150,7 +150,7 @@ Type
       property DrawingEngine: TMvCustomDrawingEngine read GetDrawingEngine write SetDrawingEngine;
       property Font: TFont read FFont write SetFont stored IsFontStored;
       property Height default 150;
-      property InactiveColor: TColor read FInactiveColor write SetInactiveColor default clWhite;
+      property InactiveColor: TColor read GetInactiveColor write SetInactiveColor default clWhite;
       property MapProvider: String read GetMapProvider write SetMapProvider;
       property POIImage: TBitmap read FPOIImage write SetPOIImage;
       property POIImages: TCustomImageList read FPOIImages write SetPOIImages;
@@ -343,6 +343,11 @@ begin
     Result := FDrawingEngine;
 end;
 
+function TMapView.GetInactiveColor: TColor;
+begin
+  Result := FPColorToTColor(Engine.BkColor);
+end;
+
 function TMapView.GetMapProvider: String;
 begin
   result := Engine.MapProvider;
@@ -457,9 +462,7 @@ end;
 
 procedure TMapView.SetInactiveColor(AValue: TColor);
 begin
-  if FInactiveColor = AValue then
+  Engine.BkColor := TColorToFPColor(AValue);
-    exit;
-  FInactiveColor := AValue;
   if not IsActive then
     Invalidate;
 end;
@@ -866,7 +869,6 @@ begin
   FActive := false;
   FDefaultTrackColor := clRed;
   FDefaultTrackWidth := 1;
-  FInactiveColor := clWhite;
 
   FGPSItems := TGPSObjectList.Create;
   FGPSItems.OnModified := @OnGPSItemsModified;
@@ -879,6 +881,7 @@ begin
   FBuiltinDownloadEngine.Name := 'BuiltInDLE';
 
   FEngine := TMapViewerEngine.Create(self);
+  FEngine.BkColor := colWhite;
   FEngine.CachePath := 'cache/';
   FEngine.CacheOnDisk := true;
   FEngine.OnDrawTile := @DoDrawTile;