From 0b23f54b345c7a6bae80345ff6908e8fd2ceb497 Mon Sep 17 00:00:00 2001
From: micha <micha@lazarus-ide.org>
Date: Wed, 7 Jan 2004 18:05:46 +0000
Subject: [PATCH] add TWinControl.DoubleBuffered property which is a hint for
 the interface to do double-buffering for this control

git-svn-id: trunk@5026 -
---
 lcl/controls.pp                        |  5 +++
 lcl/interfaces/win32/win32callback.inc | 49 ++++++++++++++++----------
 2 files changed, 36 insertions(+), 18 deletions(-)

diff --git a/lcl/controls.pp b/lcl/controls.pp
index bd99d3aad4..cc9e2e6d1c 100644
--- a/lcl/controls.pp
+++ b/lcl/controls.pp
@@ -975,6 +975,7 @@ type
     FControls: TList;
     FDefWndProc: Pointer;
     //FDockSite: Boolean;
+    FDoubleBuffered: Boolean;
     FClientWidth: Integer;
     FClientHeight: Integer;
     FDockManager: TDockManager;
@@ -1120,6 +1121,7 @@ type
     property DockClients[Index: Integer]: TControl read GetDockClients;
     property DockSite: Boolean read FDockSite write SetDockSite default False;
     property DockManager: TDockManager read FDockManager write FDockManager;
+    property DoubleBuffered: Boolean read FDoubleBuffered write FDoubleBuffered;
     property IsResizing: Boolean read GetIsResizing;
     property OnDockDrop: TDockDropEvent read FOnDockDrop write FOnDockDrop;
     property OnDockOver: TDockOverEvent read FOnDockOver write FOnDockOver;
@@ -1857,6 +1859,9 @@ end.
 { =============================================================================
 
   $Log$
+  Revision 1.167  2004/01/07 18:05:46  micha
+  add TWinControl.DoubleBuffered property which is a hint for the interface to do double-buffering for this control
+
   Revision 1.166  2004/01/03 23:14:59  mattias
   default font can now change height and fixed gtk crash
 
diff --git a/lcl/interfaces/win32/win32callback.inc b/lcl/interfaces/win32/win32callback.inc
index 273ab89cb9..479ce544b5 100644
--- a/lcl/interfaces/win32/win32callback.inc
+++ b/lcl/interfaces/win32/win32callback.inc
@@ -179,32 +179,42 @@ Var
 
     // create a paint message
     AWinControl := TWinControl(OwnerObject);
-    DC := Windows.GetDC(0);
-    GetWindowSize(Window, MemWidth, MemHeight);
-    MemBitmap := Windows.CreateCompatibleBitmap(DC, MemWidth, MemHeight);
-    Windows.ReleaseDC(0, DC);
-    MemDC := Windows.CreateCompatibleDC(0);
-    OldBitmap := Windows.SelectObject(MemDC, MemBitmap);
+    if AWinControl.DoubleBuffered then
+    begin
+      DC := Windows.GetDC(0);
+      GetWindowSize(Window, MemWidth, MemHeight);
+      MemBitmap := Windows.CreateCompatibleBitmap(DC, MemWidth, MemHeight);
+      Windows.ReleaseDC(0, DC);
+      MemDC := Windows.CreateCompatibleDC(0);
+      OldBitmap := Windows.SelectObject(MemDC, MemBitmap);
+      PaintMsg.DC := MemDC;
+    end;
     GetLclClientOriginOffset(AWinControl.Handle, LeftOffset, TopOffset);
     try
       DC := Windows.BeginPaint(Window, @PS);
-      AWinControl.EraseBackground(MemDC);
       PaintMsg.Msg := LM_PAINT;
-      PaintMsg.DC := MemDC;
       PaintMsg.PaintStruct := @PS;
-      MoveWindowOrgEx(MemDC, LeftOffset, TopOffset);
+      if not AWinControl.DoubleBuffered then
+        PaintMsg.DC := DC;
+      AWinControl.EraseBackground(PaintMsg.DC);
+      MoveWindowOrgEx(PaintMsg.DC, LeftOffset, TopOffset);
       DeliverMessage(OwnerObject, PaintMsg);
-      MoveWindowOrgEx(MemDC, -LeftOffset, -TopOffset);
-      Windows.BitBlt(DC, 0, 0, MemWidth, MemHeight, MemDC, 0, 0, SRCCOPY);
+      MoveWindowOrgEx(PaintMsg.DC, -LeftOffset, -TopOffset);
+      if AWinControl.DoubleBuffered then
+        Windows.BitBlt(DC, 0, 0, MemWidth, MemHeight, MemDC, 0, 0, SRCCOPY);
       Windows.EndPaint(Window, @PS);
     finally
-      SelectObject(MemDC, OldBitmap);
-      Windows.OpenClipboard(0);
-      Windows.EmptyClipboard;
-      Windows.SetClipboardData(CF_BITMAP, MemBitmap);
-      Windows.CloseClipboard;
-      DeleteDC(MemDC);
-      DeleteObject(MemBitmap);
+      if AWinControl.DoubleBuffered then
+      begin
+        SelectObject(MemDC, OldBitmap);
+//        for debugging purposes: copy rendered bitmap to clipboard
+//        Windows.OpenClipboard(0);
+//        Windows.EmptyClipboard;
+//        Windows.SetClipboardData(CF_BITMAP, MemBitmap);
+//        Windows.CloseClipboard;
+        DeleteDC(MemDC);
+        DeleteObject(MemBitmap);
+      end;
     end;
   end;
 
@@ -928,6 +938,9 @@ end;
 
 {
   $Log$
+  Revision 1.86  2004/01/07 18:05:46  micha
+  add TWinControl.DoubleBuffered property which is a hint for the interface to do double-buffering for this control
+
   Revision 1.85  2004/01/03 21:06:06  micha
   - fix win32/checklistbox
   - implement proper lcl to interface move/size notify via setwindowpos