skip undefined mouse coords

lazpaint/lazpaintmainform.pas

@@ -1146,7 +1146,7 @@ procedure TFMain.FormMouseDown(Sender: TObject; Button: TMouseButton;
 begin
   if not Assigned(FImageView) then exit;
   ReleaseMouseButtons(Shift);
-  if not (Button in[mbLeft,mbRight,mbMiddle]) then exit;
+  if not (Button in[mbLeft,mbRight,mbMiddle]) or not FImageView.PictureCoordsDefined then exit;
   CanCompressOrUpdateStack := false;
   Image.OnImageChanged.DelayedStackUpdate := True;
 
@@ -1193,7 +1193,8 @@ begin
   FormMouseMovePos := Point(X,Y);
   if InFormMouseMove then exit;
   InFormMouseMove := True;
-  //Application.ProcessMessages; //empty message stack
+  if not FImageView.PictureCoordsDefined then
+    Application.ProcessMessages; //empty message stack
 
   BmpPos := FImageView.FormToBitmap(FormMouseMovePos);
   FCoordinatesCaption := IntToStr(round(BmpPos.X))+','+IntToStr(round(BmpPos.Y));
@@ -1236,7 +1237,9 @@ begin
   if (btnLeftDown and (Button = mbLeft)) or (btnRightDown and (Button=mbRight))
     or (btnMiddleDown and (Button = mbMiddle)) then
   begin
-    redraw := ToolManager.ToolMove(FImageView.FormToBitmap(X,Y),CurrentPressure);
+    if FImageView.PictureCoordsDefined then
+      redraw := ToolManager.ToolMove(FImageView.FormToBitmap(X,Y),CurrentPressure)
+      else redraw := false;
     if ToolManager.ToolUp then redraw := true;
     btnLeftDown := false;
     btnRightDown := false;
@@ -2358,7 +2361,7 @@ end;
 procedure TFMain.FormMouseWheel(Sender: TObject; Shift: TShiftState;
   WheelDelta: Integer; MousePos: TPoint; var Handled: Boolean);
 begin
-  if not Assigned(FImageView) then exit;
+  if not Assigned(FImageView) or not FImageView.PictureCoordsDefined then exit;
   Zoom.SetPosition(FImageView.FormToBitmap(MousePos.X,MousePos.Y), MousePos);
   if WheelDelta > 0 then Zoom.ZoomIn(ssCtrl in Shift) else
   if WheelDelta < 0 then Zoom.ZoomOut(ssCtrl in Shift);

lazpaint/uimageview.pas

@@ -49,6 +49,7 @@ type
     procedure PictureSelectionChanged({%H-}sender: TLazPaintImage; const ARect: TRect);
     procedure PaintVirtualScreenCursor({%H-}ACanvasOfs: TPoint; {%H-}AWorkArea: TRect; {%H-}AWinControlOfs: TPoint; {%H-}AWinControl: TWinControl);
     function GetRectToInvalidate(AInvalidateAll: boolean; AWorkArea: TRect): TRect;
+    function GetPictureCoordsDefined: boolean;
   public
     constructor Create(AInstance: TLazPaintCustomInstance; AZoom: TZoom; ACanvas: TCanvas);
     destructor Destroy; override;
@@ -71,6 +72,7 @@ type
     property FillSelectionHighlight: boolean read GetFillSelectionHighlight write SetFillSelectionHighlight;
     property ShowSelection: boolean read FShowSelection write SetShowSelection;
     property WorkspaceColor: TColor read GetWorkspaceColor;
+    property PictureCoordsDefined: boolean read GetPictureCoordsDefined;
   end;
 
 implementation
@@ -101,6 +103,11 @@ begin
   Image.ImageMayChangeCompletely;
 end;
 
+function TImageView.GetPictureCoordsDefined: boolean;
+begin
+  result := FLastPictureParameters.defined;
+end;
+
 function TImageView.GetImage: TLazPaintImage;
 begin
   result := FInstance.Image;