[mkupfer] 34325: - avoid clock flicker in timedate.cpl - TODO: limit repaint area to clock only (to avoid flicker of time adjusting control as well)

Author: mkupfer
Date: Sun Jul  6 07:05:17 2008
New Revision: 34325

URL: http://svn.reactos.org/svn/reactos?rev=34325&view=rev
Log:
- avoid clock flicker in timedate.cpl
- TODO: limit repaint area to clock only (to avoid flicker of time adjusting control as well)

Modified:
    trunk/reactos/dll/cpl/timedate/clock.c

Modified: trunk/reactos/dll/cpl/timedate/clock.c
URL: http://svn.reactos.org/svn/reactos/trunk/reactos/dll/cpl/timedate/clock.c?re...
==============================================================================
--- trunk/reactos/dll/cpl/timedate/clock.c [iso-8859-1] (original)
+++ trunk/reactos/dll/cpl/timedate/clock.c [iso-8859-1] Sun Jul  6 07:05:17 2008
@@ -141,7 +141,8 @@
              LPARAM lParam)
 {
     PCLOCKDATA pClockData;
-    HDC hdc;
+    HDC hdc, dcMem;
+    HBITMAP bmMem, bmOld;
     PAINTSTRUCT ps;

pClockData = (PCLOCKDATA)GetWindowLongPtrW(hwnd, GWLP_USERDATA);
@@ -168,15 +169,38 @@

case WM_TIMER:
             GetLocalTime(&pClockData->stCurrent);
-            InvalidateRect(hwnd, NULL, TRUE);
+            //InvalidateRect(hwnd, NULL, TRUE);
+            InvalidateRect(hwnd, NULL, FALSE);
             pClockData->stPrevious = pClockData->stCurrent;
             break;

case WM_PAINT:
             hdc = BeginPaint(hwnd, &ps);
-            SetIsotropic(hdc, pClockData);
-            DrawClock(hdc, pClockData);
-            DrawHands(hdc, &pClockData->stPrevious, TRUE);
+
+	    /* Use an offscreen dc to avoid flicker */
+
+	    dcMem = CreateCompatibleDC(hdc);
+	    bmMem = CreateCompatibleBitmap(hdc, ps.rcPaint.right - ps.rcPaint.left, ps.rcPaint.bottom - ps.rcPaint.top);
+
+	    bmOld = SelectObject(dcMem, bmMem);
+	    SetViewportOrgEx(dcMem, -ps.rcPaint.left, -ps.rcPaint.top, NULL);
+	    FillRect(dcMem, &ps.rcPaint, GetSysColorBrush(COLOR_BTNFACE));
+
+            SetIsotropic(dcMem, pClockData);
+            DrawClock(dcMem, pClockData);
+            DrawHands(dcMem, &pClockData->stPrevious, TRUE);
+            
+	    /* Blit the changes to the screen */
+	    BitBlt(hdc, 
+		ps.rcPaint.left, ps.rcPaint.top,
+		ps.rcPaint.right - ps.rcPaint.left, ps.rcPaint.bottom - ps.rcPaint.top,
+		dcMem,
+		ps.rcPaint.left, ps.rcPaint.top,
+		SRCCOPY);
+
+            SelectObject(dcMem, bmOld);
+	    DeleteObject(bmMem);
+	    DeleteObject(dcMem);
             EndPaint(hwnd, &ps);
             break;

@@ -202,7 +226,7 @@
             CopyMemory(&pClockData->stPrevious, (LPSYSTEMTIME)lParam, sizeof(SYSTEMTIME));

/* Redraw the clock */
-            InvalidateRect(hwnd, NULL, TRUE);
+            InvalidateRect(hwnd, NULL, FALSE);
             break;

default: