user32: ScrollWindow should not use a cached DC, unlike ScrollWindowEx.

dlls/user32/painting.c

@@ -1367,17 +1367,8 @@ INT WINAPI ExcludeUpdateRgn( HDC hdc, HWND hwnd )
 }
 
 
-/*************************************************************************
- *		ScrollWindowEx (USER32.@)
- *
- * Note: contrary to what the doc says, pixels that are scrolled from the
- *      outside of clipRect to the inside are NOT painted.
- *
- */
-INT WINAPI ScrollWindowEx( HWND hwnd, INT dx, INT dy,
-                           const RECT *rect, const RECT *clipRect,
-                           HRGN hrgnUpdate, LPRECT rcUpdate,
-                           UINT flags )
+static INT scroll_window( HWND hwnd, INT dx, INT dy, const RECT *rect, const RECT *clipRect,
+                          HRGN hrgnUpdate, LPRECT rcUpdate, UINT flags, BOOL is_ex )
 {
     INT   retVal = NULLREGION;
     BOOL  bOwnRgn = TRUE;
@@ -1416,11 +1407,12 @@ INT WINAPI ScrollWindowEx( HWND hwnd, INT dx, INT dy,
     newCaretPos.x = newCaretPos.y = 0;
 
     if( !IsRectEmpty(&cliprc) && (dx || dy)) {
-        DWORD dcxflags = DCX_CACHE;
+        DWORD dcxflags = 0;
         DWORD style = GetWindowLongW( hwnd, GWL_STYLE );
 
         hwndCaret = fix_caret(hwnd, &rc, dx, dy, flags, &moveCaret, &newCaretPos);
 
+        if (is_ex) dcxflags |= DCX_CACHE;
         if( style & WS_CLIPSIBLINGS) dcxflags |= DCX_CLIPSIBLINGS;
         if( GetClassLongW( hwnd, GCL_STYLE ) & CS_PARENTDC)
             dcxflags |= DCX_PARENTCLIP;
@@ -1523,15 +1515,29 @@ INT WINAPI ScrollWindowEx( HWND hwnd, INT dx, INT dy,
 
 
 /*************************************************************************
+ *		ScrollWindowEx (USER32.@)
+ *
+ * Note: contrary to what the doc says, pixels that are scrolled from the
+ *      outside of clipRect to the inside are NOT painted.
+ *
+ */
+INT WINAPI ScrollWindowEx( HWND hwnd, INT dx, INT dy,
+                           const RECT *rect, const RECT *clipRect,
+                           HRGN hrgnUpdate, LPRECT rcUpdate,
+                           UINT flags )
+{
+    return scroll_window( hwnd, dx, dy, rect, clipRect, hrgnUpdate, rcUpdate, flags, TRUE );
+}
+
+/*************************************************************************
  *		ScrollWindow (USER32.@)
  *
  */
 BOOL WINAPI ScrollWindow( HWND hwnd, INT dx, INT dy,
                           const RECT *rect, const RECT *clipRect )
 {
-    return (ERROR != ScrollWindowEx( hwnd, dx, dy, rect, clipRect, 0, NULL,
-                                     (rect ? 0 : SW_SCROLLCHILDREN) |
-                                     SW_INVALIDATE | SW_ERASE ));
+    return scroll_window( hwnd, dx, dy, rect, clipRect, 0, NULL,
+                          SW_INVALIDATE | SW_ERASE | (rect ? 0 : SW_SCROLLCHILDREN), FALSE ) != ERROR;
 }
 
 

dlls/user32/tests/dce.c

@@ -406,6 +406,56 @@ static void test_begin_paint(void)
         "clip box should have been reset %d,%d-%d,%d\n", rect.left, rect.top, rect.right, rect.bottom );
 }
 
+/* test ScrollWindow with window DCs */
+static void test_scroll_window(void)
+{
+    PAINTSTRUCT ps;
+    HDC hdc;
+    RECT clip, rect;
+
+    /* ScrollWindow uses the window DC, ScrollWindowEx doesn't */
+
+    UpdateWindow( hwnd_owndc );
+    SetRect( &clip, 25, 25, 50, 50 );
+    ScrollWindow( hwnd_owndc, -5, -10, NULL, &clip );
+    hdc = BeginPaint( hwnd_owndc, &ps );
+    SetRectEmpty( &rect );
+    GetClipBox( hdc, &rect );
+    ok( rect.left >= 25 && rect.top >= 25 && rect.right <= 50 && rect.bottom <= 50,
+        "invalid clip box %d,%d-%d,%d\n", rect.left, rect.top, rect.right, rect.bottom );
+    EndPaint( hwnd_owndc, &ps );
+
+    SetViewportExtEx( hdc, 2, 3, NULL );
+    SetViewportOrgEx( hdc, 30, 20, NULL );
+
+    ScrollWindow( hwnd_owndc, -5, -10, NULL, &clip );
+    hdc = BeginPaint( hwnd_owndc, &ps );
+    SetRectEmpty( &rect );
+    GetClipBox( hdc, &rect );
+    ok( rect.left >= 25 && rect.top >= 25 && rect.right <= 50 && rect.bottom <= 50,
+        "invalid clip box %d,%d-%d,%d\n", rect.left, rect.top, rect.right, rect.bottom );
+    EndPaint( hwnd_owndc, &ps );
+
+    ScrollWindowEx( hwnd_owndc, -5, -10, NULL, &clip, 0, NULL, SW_INVALIDATE | SW_ERASE );
+    hdc = BeginPaint( hwnd_owndc, &ps );
+    SetRectEmpty( &rect );
+    GetClipBox( hdc, &rect );
+    ok( rect.left >= -5 && rect.top >= 5 && rect.right <= 20 && rect.bottom <= 30,
+        "invalid clip box %d,%d-%d,%d\n", rect.left, rect.top, rect.right, rect.bottom );
+    EndPaint( hwnd_owndc, &ps );
+
+    SetViewportExtEx( hdc, 1, 1, NULL );
+    SetViewportOrgEx( hdc, 0, 0, NULL );
+
+    ScrollWindowEx( hwnd_owndc, -5, -10, NULL, &clip, 0, NULL, SW_INVALIDATE | SW_ERASE );
+    hdc = BeginPaint( hwnd_owndc, &ps );
+    SetRectEmpty( &rect );
+    GetClipBox( hdc, &rect );
+    ok( rect.left >= 25 && rect.top >= 25 && rect.right <= 50 && rect.bottom <= 50,
+        "invalid clip box %d,%d-%d,%d\n", rect.left, rect.top, rect.right, rect.bottom );
+    EndPaint( hwnd_owndc, &ps );
+}
+
 static void test_invisible_create(void)
 {
     HWND hwnd_owndc = CreateWindowA("owndc_class", NULL, WS_OVERLAPPED,
@@ -559,6 +609,7 @@ START_TEST(dce)
     test_parameters();
     test_dc_visrgn();
     test_begin_paint();
+    test_scroll_window();
     test_invisible_create();
     test_dc_layout();