From f0081cc693c81a0f5d2e0a7b82b9b4bf86598474 Mon Sep 17 00:00:00 2001
From: paul <paul@lazarus-ide.org>
Date: Thu, 20 Mar 2008 06:24:42 +0000
Subject: [PATCH] statusbar: draw themed statusbar if themes are enabled (from
 ThemeManager of Mike Lischke)

git-svn-id: trunk@14589 -
---
 lcl/interfaces/win32/win32callback.inc  | 18 ++++++-----
 lcl/interfaces/win32/win32wscomctrls.pp | 43 ++++++++++++++++++++++++-
 2 files changed, 52 insertions(+), 9 deletions(-)

diff --git a/lcl/interfaces/win32/win32callback.inc b/lcl/interfaces/win32/win32callback.inc
index 5e6c2e1e33..55ec9b990f 100644
--- a/lcl/interfaces/win32/win32callback.inc
+++ b/lcl/interfaces/win32/win32callback.inc
@@ -483,10 +483,10 @@ var
         PaintMsg.DC := DC;
       if not needParentPaint and not isNotebook then
       begin
-        // send through message to allow message override
-        //lWinControl.EraseBackground(PaintMsg.DC);
+        // send through message to allow message override, moreover use SendMessage
+        // to allow subclass window proc override this message too
         Include(TWinControlAccess(lWinControl).FWinControlFlags, wcfEraseBackground);
-        lWinControl.Perform(LM_ERASEBKGND, Windows.WPARAM(PaintMsg.DC), 0);
+        SendMessage(lWinControl.Handle, WM_ERASEBKGND, Windows.WPARAM(PaintMsg.DC), 0);
         Exclude(TWinControlAccess(lWinControl).FWinControlFlags, wcfEraseBackground);
       end;
       if ParentPaintWindow <> 0 then
@@ -1530,22 +1530,24 @@ begin
       end;
       if not GetNeedParentPaint(WindowInfo, lWinControl) or (eraseBkgndCommand = ecDoubleBufferNoRemove) then
       begin
-        if ThemeServices.ThemesEnabled and WindowInfo^.isGroupBox
-            and (lWinControl <> nil) then
+        if ThemeServices.ThemesEnabled and WindowInfo^.isGroupBox and (lWinControl <> nil) then
         begin
           // Groupbox (which is a button) doesn't erase it's background properly; force repaint
           lWinControl.EraseBackground(HDC(WParam));
           LMessage.Result := 1;
-        end else begin
+        end
+        else
+        begin
           LMessage.Msg := LM_ERASEBKGND;
           LMessage.WParam := WParam;
           LMessage.LParam := LParam;
         end;
-      end else begin
+      end else
+      begin
         SendPaintMessage(HDC(WParam));
         LMessage.Result := 1;
       end;
-      WinProcess := false;
+      WinProcess := False;
     end;
     WM_EXITMENULOOP:
       // is it a popup menu
diff --git a/lcl/interfaces/win32/win32wscomctrls.pp b/lcl/interfaces/win32/win32wscomctrls.pp
index 9fa814bfbb..966359cd25 100644
--- a/lcl/interfaces/win32/win32wscomctrls.pp
+++ b/lcl/interfaces/win32/win32wscomctrls.pp
@@ -30,7 +30,7 @@ uses
   // FCL
   CommCtrl, Windows, Classes, SysUtils, Win32Extra,
   // LCL
-  ComCtrls, LCLType, Controls, Graphics,
+  ComCtrls, LCLType, Controls, Graphics, Themes,
   ImgList, StdCtrls,
   LCLProc, InterfaceBase,
   // widgetset
@@ -328,6 +328,45 @@ begin
   end;
 end;
 
+function StatusBarWndProc(Window: HWnd; Msg: UInt; WParam: Windows.WParam;
+    LParam: Windows.LParam): LResult; stdcall;
+var
+  Info: PWindowInfo;
+  Control: TWinControl;
+  Details: TThemedElementDetails;
+begin
+  Info := GetWindowInfo(Window);
+  if (Info = nil) or (Info^.WinControl = nil) then
+  begin
+    Result := CallDefaultWindowProc(Window, Msg, WParam, LParam);
+    Exit;
+  end
+  else
+    Control := Info^.WinControl;
+
+  // Paul: next is a slightly modified code of TThemeManager.StatusBarWindowProc
+  // of Mike Lischke Theme manager library (Mike granted us permition to use his code)
+  
+  case Msg of
+    WM_NCCALCSIZE:
+      begin
+        // We need to override the window class' CS_HREDRAW and CS_VREDRAW styles but the following
+        // does the job very well too.
+        // Note: this may produce trouble with embedded controls (e.g. progress bars).
+        if WParam <> 0 then
+          Result := CallDefaultWindowProc(Window, Msg, WParam, LParam) or WVR_REDRAW;
+      end;
+    WM_ERASEBKGND:
+      begin
+        Details := ThemeServices.GetElementDetails(tsStatusRoot);
+        ThemeServices.DrawElement(HDC(WParam), Details, Control.ClientRect);
+        Result := 1;
+      end;
+    else
+      Result := WindowProc(Window, Msg, WParam, LParam);
+  end;
+end;
+
 { TWin32WSStatusBar }
 
 class function TWin32WSStatusBar.CreateHandle(const AWinControl: TWinControl;
@@ -342,6 +381,8 @@ begin
   begin
     pClassName := STATUSCLASSNAME;
     WindowTitle := StrCaption;
+    if ThemeServices.ThemesEnabled then
+      SubClassWndProc := @StatusBarWndProc;
   end;
   // create window
   FinishCreateWindow(AWinControl, Params, false);