win32u: Create a dummy bitmap for display device contexts.

On Windows 7 and older versions of Windows, calling GetCurrentObject(hdc, OBJ_BITMAP) for a display device context will return a valid handle. However, this handle will fail for GetObject(). On newer versions of Windows, GetCurrentObject(hdc, OBJ_BITMAP) for display device contexts returns a bitmap of virtual screen size and its size changes after display mode changes. This behavior is tested in the _check_display_dc() function in user32/tests/monitor.c. The screen shot function of WeChat depends on GetObject() to either return failure or a valid size for the bitmap from display device contexts. Since Wine currently report Windows 7 as default and to save memory, the Windows 7 behavior is implemented. Signed-off-by: Zhiyi Zhang <zzhang@codeweavers.com>

win32u: Create a dummy bitmap for display device contexts.
546cbdc2 · Zhiyi Zhang · Alexandre Julliard · 18d4d5a5 · 546cbdc2 · 546cbdc2
Commit 546cbdc2 authored May 18, 2022 by Zhiyi Zhang Committed by Alexandre Julliard May 30, 2022
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Showing with 10 additions and 3 deletions

bitmap.c dlls/gdi32/tests/bitmap.c +0 -1

monitor.c dlls/user32/tests/monitor.c +0 -1

dc.c dlls/win32u/dc.c +10 -1

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--- a/dlls/gdi32/tests/bitmap.c
+++ b/dlls/gdi32/tests/bitmap.c
@@ -2789,7 +2789,6 @@ static void test_CreateBitmap(void)
       "0: %p, 1: %p, 4: %p, 5: %p, curObj1 %p, old1 %p\n",
       bm, bm1, bm4, bm5, curObj1, old1);
    ok(bm != bm2 && bm != bm3, "0: %p, 2: %p, 3: %p\n", bm, bm2, bm3);
-    todo_wine
    ok(bm != curObj2, "0: %p, curObj2 %p\n", bm, curObj2);
    ok(old2 == 0, "old2 %p\n", old2);


--- a/dlls/user32/tests/monitor.c
+++ b/dlls/user32/tests/monitor.c
@@ -2164,7 +2164,6 @@ static void _check_display_dc(INT line, HDC hdc, const DEVMODEA *dm, BOOL allow_
    ok_(__FILE__, line)(!!hbmp, "GetCurrentObject failed, error %#lx.\n", GetLastError());
    ret = GetObjectA(hbmp, sizeof(bitmap), &bitmap);
    /* GetObjectA fails on Win7 and older */
-    ok_(__FILE__, line)(ret || broken(!ret), "GetObjectA failed, error %ld.\n", GetLastError());
    if (ret)
    {
        ok_(__FILE__, line)(bitmap.bmType == 0, "Expected bmType %d, got %d.\n", 0, bitmap.bmType);

--- a/dlls/win32u/dc.c
+++ b/dlls/win32u/dc.c
@@ -274,7 +274,13 @@ void free_dc_ptr( DC *dc )
    GDI_dec_ref_count( dc->hPen );
    GDI_dec_ref_count( dc->hBrush );
    GDI_dec_ref_count( dc->hFont );
-    if (dc->hBitmap) GDI_dec_ref_count( dc->hBitmap );
+    if (dc->hBitmap)
+    {
+        if (dc->is_display)
+            NtGdiDeleteClientObj( dc->hBitmap );
+        else
+            GDI_dec_ref_count( dc->hBitmap );
+    }
    free_gdi_handle( dc->hSelf );
    free_dc_state( dc );
 }
@@ -724,6 +730,9 @@ HDC WINAPI NtGdiOpenDCW( UNICODE_STRING *device, const DEVMODEW *devmode, UNICOD
    if (!(dc = alloc_dc_ptr( NTGDI_OBJ_DC ))) return 0;
    hdc = dc->hSelf;

+    if (is_display)
+        dc->hBitmap = NtGdiCreateClientObj( NTGDI_OBJ_SURF );
+    else
        dc->hBitmap = GDI_inc_ref_count( GetStockObject( DEFAULT_BITMAP ));

    TRACE("(device=%s, output=%s): returning %p\n",