From 29e5fe229921088667d0460004d6409dfdd73b9f Mon Sep 17 00:00:00 2001
From: Giannis Adamopoulos <gadamopoulos@reactos.org>
Date: Tue, 5 Jul 2011 10:15:09 +0000
Subject: [PATCH] [uxtheme] - Use double buffering when painting the caption

svn path=/branches/GSoC_2011/ThemesSupport/; revision=52544
---
 dll/win32/uxtheme/nonclient.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/dll/win32/uxtheme/nonclient.c b/dll/win32/uxtheme/nonclient.c
index 8e9947d7e0b..fc85c834652 100644
--- a/dll/win32/uxtheme/nonclient.c
+++ b/dll/win32/uxtheme/nonclient.c
@@ -26,6 +26,10 @@ typedef struct _DRAW_CONTEXT
     BOOL Active; /* wi.dwWindowStatus isn't correct for mdi child windows */
     HRGN hRgn;
     int CaptionHeight;
+
+    /* for double buffering */
+    HDC hDCScreen;
+    HBITMAP hbmpOld;
 } DRAW_CONTEXT, *PDRAW_CONTEXT;
 
 typedef enum 
@@ -59,6 +63,7 @@ typedef enum {
 
 #define BUTTON_GAP_SIZE 2
 
+#define MENU_BAR_ITEMS_SPACE (12)
 
 HFONT hMenuFont = NULL;
 HFONT hMenuFontBold = NULL;
@@ -234,6 +239,29 @@ ThemeCleanupDrawContext(PDRAW_CONTEXT pcontext)
     }
 }
 
+static void 
+ThemeStartBufferedPaint(PDRAW_CONTEXT pcontext, int cx, int cy)
+{
+    HBITMAP hbmp;
+
+    pcontext->hDCScreen = pcontext->hDC;
+    pcontext->hDC = CreateCompatibleDC(pcontext->hDCScreen);
+    hbmp = CreateCompatibleBitmap(pcontext->hDCScreen, cx, cy); 
+    pcontext->hbmpOld = (HBITMAP)SelectObject(pcontext->hDC, hbmp);
+}
+
+static void
+ThemeEndBufferedPaint(PDRAW_CONTEXT pcontext, int x, int y, int cx, int cy)
+{
+    HBITMAP hbmp;
+    BitBlt(pcontext->hDCScreen, 0, 0, cx, cy, pcontext->hDC, x, y, SRCCOPY);
+    hbmp = (HBITMAP) SelectObject(pcontext->hDC, pcontext->hbmpOld);
+    DeleteObject(pcontext->hDC);
+    DeleteObject(hbmp);
+
+    pcontext->hDC = pcontext->hDCScreen;
+}
+
 static void 
 ThemeDrawCaptionButton(PDRAW_CONTEXT pcontext, 
                        RECT* prcCurrent, 
@@ -663,7 +691,9 @@ ThemePaintWindow(PDRAW_CONTEXT pcontext, RECT* prcCurrent)
 
     if((pcontext->wi.dwStyle & WS_CAPTION)==WS_CAPTION)
     {
+        ThemeStartBufferedPaint(pcontext, prcCurrent->right, pcontext->CaptionHeight);
         ThemeDrawCaption(pcontext, prcCurrent);
+        ThemeEndBufferedPaint(pcontext, 0, 0, prcCurrent->right, pcontext->CaptionHeight);
         ThemeDrawBorders(pcontext, prcCurrent);
     }
     else