Commit 2afee831 authored by Jon Turney's avatar Jon Turney

hw/xwin: Add an option to use alpha channel in multiwindow mode

Add an option to turn on the use of the X window's alpha channel in
multiwindow mode, i.e. this uses the X window's alpha channel for
compositing into the native desktop.

This works on W7/Vista (using DwmEnableBlurBehindWindow()), and Windows
10 (using the undocumented SetWindowCompositionAttribute()), but not on
Windows 8/8.1

-compositewm must be enabled for this to be useful, as we only have a
pixmap with an alpha channel for the X window in that case.  The
framebuffer/root window doesn't have one (unless perhaps you are using
the rootless extension, maybe...).

v2:
Update meson.build

Future work:

A window property to control use of alpha?
Option to turn off blur on W7/Vista
Implement _NET_WM_WINDOW_OPACITY
parent 2e1bc743
......@@ -62,7 +62,7 @@ TODO: Solaris.
TODO: *BSD.
Windows-dependent code assumes at least NT 5.1.
Windows-dependent code assumes at least NT 6.0.
OSX support is generally limited to the most recent version. Currently
that means 10.5.
......@@ -716,6 +716,8 @@ winUseMsg(void)
"\tthe updated region when num_boxes, or more, are in the\n"
"\tupdated region.\n");
ErrorF("-[no]compositealpha\n"
"\tX windows with per-pixel alpha are composited into the Windows desktop.\n");
ErrorF("-[no]compositewm\n"
"\tUse the Composite extension to keep a bitmap image of each top-level\n"
"\tX window, so window contents which are occluded show correctly in\n"
......@@ -803,7 +805,7 @@ winUseMsg(void)
"\tSpecify an optional refresh rate to use in fullscreen mode\n"
"\twith a DirectDraw engine.\n");
ErrorF("-resize=none|scrollbars|randr"
ErrorF("-resize=none|scrollbars|randr\n"
"\tIn windowed mode, [don't] allow resizing of the window. 'scrollbars'\n"
"\tmode gives the window scrollbars as needed, 'randr' mode uses the RANR\n"
"\textension to resize the X screen. 'randr' is the default.\n");
......
......@@ -27,7 +27,7 @@ SRCS_MULTIWINDOW = \
winmultiwindowwndproc.c \
propertystore.h \
winSetAppUserModelID.c
MULTIWINDOW_SYS_LIBS = -lshlwapi -lole32
MULTIWINDOW_SYS_LIBS = -lshlwapi -lole32 -ldwmapi
SRCS_RANDR = \
winrandr.c
......
......@@ -176,6 +176,15 @@ Use Composite extension redirection to maintain a bitmap image of each top-level
X window, so window contents which are occluded show correctly in task bar and
task switcher previews.
The default is enabled.
.TP 8
.B \-[no]compositealpha
X windows with per-pixel alpha are composited into the \fIWindows\fP desktop
(i.e. a \fIWindows\fP window can be seen through any transparency in an X window
placed over it).
This option has no effect on Windows 8 and 8.1.
This option has no effect if \fB-compositewm\fP is disabled.
The default is disabled.
.SH OPTIONS CONTROLLING WINDOWS INTEGRATION
.TP 8
......
......@@ -44,7 +44,7 @@ srcs_windows += [
'propertystore.h',
'winSetAppUserModelID.c',
]
xwin_sys_libs += ['-lshlwapi', '-lole32']
xwin_sys_libs += ['-lshlwapi', '-lole32', '-ldwmapi']
srcs_windows += [
'winrandr.c',
......
......@@ -59,6 +59,7 @@ HWND g_hDlgAbout = NULL;
const char *g_pszQueryHost = NULL;
Bool g_fXdmcpEnabled = FALSE;
Bool g_fAuthEnabled = FALSE;
Bool g_fCompositeAlpha = FALSE;
HICON g_hIconX = NULL;
HICON g_hSmallIconX = NULL;
......
......@@ -50,6 +50,7 @@ extern Bool g_fLogInited;
extern Bool g_fAuthEnabled;
extern Bool g_fXdmcpEnabled;
extern Bool g_fCompositeAlpha;
extern Bool g_fNoHelpMessageBox;
extern Bool g_fNativeGl;
......
......@@ -35,12 +35,18 @@
#ifdef HAVE_XWIN_CONFIG_H
#include <xwin-config.h>
#endif
#include "win.h"
#include "dixevents.h"
#include "winmultiwindowclass.h"
#include "winprefs.h"
#include "winmsg.h"
#include "inputstr.h"
#include <dwmapi.h>
#ifndef WM_DWMCOMPOSITIONCHANGED
#define WM_DWMCOMPOSITIONCHANGED 0x031e
#endif
extern void winUpdateWindowPosition(HWND hWnd, HWND * zstyle);
......@@ -294,6 +300,113 @@ winStartMousePolling(winPrivScreenPtr s_pScreenPriv)
MOUSE_POLLING_INTERVAL, NULL);
}
/* Undocumented */
typedef struct _ACCENTPOLICY
{
ULONG AccentState;
ULONG AccentFlags;
ULONG GradientColor;
ULONG AnimationId;
} ACCENTPOLICY;
#define ACCENT_ENABLE_BLURBEHIND 3
typedef struct _WINCOMPATTR
{
DWORD attribute;
PVOID pData;
ULONG dataSize;
} WINCOMPATTR;
#define WCA_ACCENT_POLICY 19
typedef WINBOOL WINAPI (*PFNSETWINDOWCOMPOSITIONATTRIBUTE)(HWND, WINCOMPATTR *);
static void
CheckForAlpha(HWND hWnd, WindowPtr pWin, winScreenInfo *pScreenInfo)
{
/* Check (once) which API we should use */
static Bool doOnce = TRUE;
static PFNSETWINDOWCOMPOSITIONATTRIBUTE pSetWindowCompositionAttribute = NULL;
static Bool useDwmEnableBlurBehindWindow = FALSE;
if (doOnce)
{
OSVERSIONINFOEX osvi = {0};
osvi.dwOSVersionInfoSize = sizeof(osvi);
GetVersionEx((LPOSVERSIONINFO)&osvi);
/* SetWindowCompositionAttribute() exists on Windows 7 and later,
but doesn't work for this purpose, so first check for Windows 10
or later */
if (osvi.dwMajorVersion >= 10)
{
HMODULE hUser32 = GetModuleHandle("user32");
if (hUser32)
pSetWindowCompositionAttribute = (PFNSETWINDOWCOMPOSITIONATTRIBUTE) GetProcAddress(hUser32, "SetWindowCompositionAttribute");
winDebug("SetWindowCompositionAttribute %s\n", pSetWindowCompositionAttribute ? "found" : "not found");
}
/* On Windows 7 and Windows Vista, use DwmEnableBlurBehindWindow() */
else if ((osvi.dwMajorVersion == 6) && (osvi.dwMinorVersion <= 1))
{
useDwmEnableBlurBehindWindow = TRUE;
}
/* On Windows 8 and Windows 8.1, using the alpha channel on those
seems near impossible, so we don't do anything. */
doOnce = FALSE;
}
/* alpha-channel use is wanted */
if (!g_fCompositeAlpha || !pScreenInfo->fCompositeWM)
return;
/* Image has alpha ... */
if (pWin->drawable.depth != 32)
return;
/* ... and we can do something useful with it? */
if (pSetWindowCompositionAttribute)
{
WINBOOL rc;
/* Use the (undocumented) SetWindowCompositionAttribute, if
available, to turn on alpha channel use on Windows 10. */
ACCENTPOLICY policy = { ACCENT_ENABLE_BLURBEHIND, 0, 0, 0 } ;
WINCOMPATTR data = { WCA_ACCENT_POLICY, &policy, sizeof(ACCENTPOLICY) };
/* This turns on DWM looking at the alpha-channel of this window */
winDebug("enabling alpha for XID %08x hWnd %p, using SetWindowCompositionAttribute()\n", (unsigned int)pWin->drawable.id, hWnd);
rc = pSetWindowCompositionAttribute(hWnd, &data);
if (!rc)
ErrorF("SetWindowCompositionAttribute failed: %d\n", (int)GetLastError());
}
else if (useDwmEnableBlurBehindWindow)
{
HRESULT rc;
WINBOOL enabled;
rc = DwmIsCompositionEnabled(&enabled);
if ((rc == S_OK) && enabled)
{
/* Use DwmEnableBlurBehindWindow, to turn on alpha channel
use on Windows Vista and Windows 7 */
DWM_BLURBEHIND bbh;
bbh.dwFlags = DWM_BB_ENABLE | DWM_BB_BLURREGION | DWM_BB_TRANSITIONONMAXIMIZED;
bbh.fEnable = TRUE;
bbh.hRgnBlur = NULL;
bbh.fTransitionOnMaximized = TRUE; /* What does this do ??? */
/* This terribly-named function actually controls if DWM
looks at the alpha channel of this window */
winDebug("enabling alpha for XID %08x hWnd %p, using DwmEnableBlurBehindWindow()\n", (unsigned int)pWin->drawable.id, hWnd);
rc = DwmEnableBlurBehindWindow(hWnd, &bbh);
if (rc != S_OK)
ErrorF("DwmEnableBlurBehindWindow failed: %x, %d\n", (int)rc, (int)GetLastError());
}
}
}
/*
* winTopLevelWindowProc - Window procedure for all top-level Windows windows.
*/
......@@ -416,6 +529,8 @@ winTopLevelWindowProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
SetWindowLongPtr(hwnd, GWLP_USERDATA, (LONG_PTR) XMING_SIGNATURE);
CheckForAlpha(hwnd, pWin, s_pScreenInfo);
return 0;
case WM_INIT_SYS_MENU:
......@@ -1114,6 +1229,12 @@ winTopLevelWindowProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
}
break;
case WM_DWMCOMPOSITIONCHANGED:
/* This message is only sent on Vista/W7 */
CheckForAlpha(hwnd, pWin, s_pScreenInfo);
return 0;
default:
break;
}
......
......@@ -591,6 +591,25 @@ ddxProcessArgument(int argc, char *argv[], int i)
return 1;
}
/*
* Look for the '-compositealpha' argument
*/
if (IS_OPTION("-compositealpha")) {
g_fCompositeAlpha = TRUE;
/* Indicate that we have processed this argument */
return 1;
}
/*
* Look for the '-nocompositealpha' argument
*/
if (IS_OPTION("-nocompositealpha")) {
g_fCompositeAlpha = FALSE;
/* Indicate that we have processed this argument */
return 1;
}
/*
* Look for the '-multiplemonitors' argument
*/
......
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment