win32u: Return -1 for NUMCOLORS with 8-bit display DCs.

According to tests, GetDeviceCaps(NUMCOLORS) returns -1 for display DCs when the current display mode is 8-bit on newer versions of Windows, which makes sense because lower bit depth display modes are actually emulated with 32-bit modes. Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=52679Signed-off-by: Zhiyi Zhang <zzhang@codeweavers.com> Signed-off-by: Huw Davies <huw@codeweavers.com> Signed-off-by: Alexandre Julliard <julliard@winehq.org>

win32u: Return -1 for NUMCOLORS with 8-bit display DCs.
a1dda8c3 · Zhiyi Zhang · Alexandre Julliard · bfed4330 · a1dda8c3 · a1dda8c3
Commit a1dda8c3 authored Apr 18, 2022 by Zhiyi Zhang Committed by Alexandre Julliard Apr 21, 2022
Show whitespace changes
Inline Side-by-side

Showing with 3 additions and 2 deletions

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

driver.c dlls/win32u/driver.c +2 -1

No files found.
--- a/dlls/user32/tests/monitor.c
+++ b/dlls/user32/tests/monitor.c
@@ -3,6 +3,7 @@
 *
 * Copyright 2005 Huw Davies
 * Copyright 2008 Dmitry Timoshkov
+ * Copyright 2019-2022 Zhiyi Zhang for CodeWeavers
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
@@ -2314,7 +2315,6 @@ static void test_display_dc(void)

            value = GetDeviceCaps(hdc, NUMCOLORS);
            if (bpps[i] > 8 || (bpps[i] == 8 && LOBYTE(LOWORD(GetVersion())) >= 6))
-                todo_wine_if(bpps[i] == 8 && LOBYTE(LOWORD(GetVersion())) >= 6)
                ok(value == -1, "Expected -1, got %d.\n", value);
            else if (bpps[i] == 8 && LOBYTE(LOWORD(GetVersion())) < 6)
                ok(value > 16 && value <= 256, "Got %d.\n", value);

--- a/dlls/win32u/driver.c
+++ b/dlls/win32u/driver.c
@@ -294,7 +294,8 @@ static INT CDECL nulldrv_GetDeviceCaps( PHYSDEV dev, INT cap )
    case LOGPIXELSY:      return get_system_dpi();
    case NUMCOLORS:
        bpp = NtGdiGetDeviceCaps( dev->hdc, BITSPIXEL );
-        return (bpp > 8) ? -1 : (1 << bpp);
+        /* Newer versions of Windows return -1 for 8-bit and higher */
+        return (bpp > 4) ? -1 : (1 << bpp);
    case COLORRES:
        /* The observed correspondence between BITSPIXEL and COLORRES is:
         * BITSPIXEL: 8  -> COLORRES: 18