3 files changed, 19 insertions, 6 deletions
diff --git a/src/corelib/fpgfx.pas b/src/corelib/fpgfx.pas
index dd9a6d28..cb6c0092 100644
--- a/src/corelib/fpgfx.pas
+++ b/src/corelib/fpgfx.pas
@@ -311,8 +311,8 @@ function  CenterPoint(const Rect: TfpgRect): TPoint;
 function  fpgRect(ALeft, ATop, AWidth, AHeight: integer): TfpgRect;
 
 // Debug rountines
-procedure PrintRect(var Rect: TRect);
-procedure PrintRect(var Rect: TfpgRect);
+procedure PrintRect(const Rect: TRect);
+procedure PrintRect(const Rect: TfpgRect);
 procedure PrintCoord(const x, y: TfpgCoord);
 function  PrintCallTrace(const AClassName, AMethodName: string): IInterface;
 procedure PrintCallTraceDbgLn(const AMessage: string);
@@ -489,13 +489,13 @@ begin
   Result.SetRect(ALeft, ATop, AWidth, AHeight);
 end;
 
-procedure PrintRect(var Rect: TRect);
+procedure PrintRect(const Rect: TRect);
 begin
   writeln('Rect left=', Rect.Left, ' top=', Rect.Top, ' right=', Rect.Right,
       ' bottom=', Rect.Bottom);
 end;
 
-procedure PrintRect(var Rect: TfpgRect);
+procedure PrintRect(const Rect: TfpgRect);
 begin
   writeln('Rect left=', Rect.Left, ' top=', Rect.Top, ' right=', Rect.Right,
       ' bottom=', Rect.Bottom, ' width=', Rect.Width, ' height=', Rect.Height);
diff --git a/src/gui/gui_basegrid.pas b/src/gui/gui_basegrid.pas
index 90961d09..b18c7673 100644
--- a/src/gui/gui_basegrid.pas
+++ b/src/gui/gui_basegrid.pas
@@ -42,7 +42,7 @@ type
   TfpgFocusChangeNotify = procedure(Sender: TObject; ARow, ACol: integer) of object;
   TfpgRowChangeNotify = procedure(Sender: TObject; ARow: integer) of object;
   TfpgCanSelectCellEvent = procedure(Sender: TObject; const ARow, ACol: integer; var ACanSelect: boolean) of object;
-
+  TfpgDrawCellEvent = procedure(Sender: TObject; const ARow, ACol: integer; const ARect: TfpgRect; AFlags: integer; var ADefaultDrawing: boolean) of object;
 
   // Column 2 is special just for testing purposes. Descendant classes will
   // override that special behavior anyway.
@@ -50,6 +50,7 @@ type
   private
     FColResizing: boolean;
     FDragPos: integer;      // used for column resizing
+    FOnDrawCell: TfpgDrawCellEvent;
     FResizedCol: integer;   // used for column resizing
     FDefaultColWidth: integer;
     FDefaultRowHeight: integer;
@@ -100,6 +101,7 @@ type
     function    GetColumnCount: integer; virtual;
     function    GetRowCount: integer; virtual;
     function    CanSelectCell(const ARow, ACol: integer): boolean;
+    function    DoDrawCellEvent(ARow, ACol: integer; ARect: TfpgRect; AFlags: integer): boolean; virtual;
     procedure   DoCanSelectCell(const ARow, ACol: integer; var ACanSelect: boolean);
     procedure   DrawCell(ARow, ACol: integer; ARect: TfpgRect; AFlags: integer); virtual;
     procedure   DrawHeader(ACol: integer; ARect: TfpgRect; AFlags: integer); virtual;
@@ -131,6 +133,7 @@ type
 //    property    ColResizing: boolean read FColResizing write FColResizing;
     property    ColumnWidth[ACol: integer]: integer read GetColumnWidth write SetColumnWidth;
     property    TopRow: integer read FFirstRow write SetFirstRow;
+    property    OnDrawCell: TfpgDrawCellEvent read FOnDrawCell write FOnDrawCell;
     property    OnFocusChange: TfpgFocusChangeNotify read FOnFocusChange write FOnFocusChange;
     property    OnRowChange: TfpgRowChangeNotify read FOnRowChange write FOnRowChange;
     property    OnCanSelectCell: TfpgCanSelectCellEvent read FOnCanSelectCell write FOnCanSelectCell;
@@ -264,6 +267,14 @@ begin
     DoCanSelectCell(ARow, ACol, Result);
 end;
 
+function TfpgBaseGrid.DoDrawCellEvent(ARow, ACol: integer; ARect: TfpgRect;
+  AFlags: integer): boolean;
+begin
+  Result := True;
+  if Assigned(OnDrawCell) then
+    FOnDrawCell(self, ARow, ACol, ARect, AFlags, Result);
+end;
+
 procedure TfpgBaseGrid.DoCanSelectCell(const ARow, ACol: integer; var
   ACanSelect: boolean);
 begin
@@ -571,7 +582,8 @@ begin
         end;
         Canvas.AddClipRect(r);
         Canvas.FillRectangle(r);
-        DrawCell(row, col, r, 0);
+        if DoDrawCellEvent(row, col, r, 0) then
+          DrawCell(row, col, r, 0);
 
         // drawing grid lines
         if FShowGrid then
diff --git a/src/gui/gui_grid.pas b/src/gui/gui_grid.pas
index 0f1f0999..326789e3 100644
--- a/src/gui/gui_grid.pas
+++ b/src/gui/gui_grid.pas
@@ -160,6 +160,7 @@ type
     property    TabOrder;
     property    TopRow;
     property    OnCanSelectCell;
+    property    OnDrawCell;
     property    OnDoubleClick;
     property    OnFocusChange;
     property    OnKeyPress;