motif/SOURCES/0002-Xm-Display-Add-optional-Xinerama-support.patch

From 011e62e69fb87e78a128487a043cc13b042bb8b5 Mon Sep 17 00:00:00 2001
From: Olivier Fourdan <ofourdan@redhat.com>
Date: Wed, 20 Nov 2024 10:26:28 +0100
Subject: [PATCH 2/7] Xm/Display: Add optional Xinerama support

Xinerama support is disabled by default, unless the Xresource
"enableXinerama" is set in the X resources database, e.g.:

  *enableXinerama: True

This also provides an additional private Screen API to get the monitor
boundaries given a point on screen. This is meant to be used in the
following commits to implement Xinerama awareness in the relevant
widgets.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
---
 doc/man/man3/XmDisplay.3 |   2 +
 lib/Xm/Display.c         |  95 +++++++++++++++++++++++++++++
 lib/Xm/DisplayP.h        |  18 ++++++
 lib/Xm/Screen.c          | 128 +++++++++++++++++++++++++++++++++++++++
 lib/Xm/ScreenP.h         |   8 +++
 lib/Xm/xmstring.list.in  |   2 +
 6 files changed, 253 insertions(+)

diff --git a/doc/man/man3/XmDisplay.3 b/doc/man/man3/XmDisplay.3
index a57ea089..ec360c80 100644
--- a/doc/man/man3/XmDisplay.3
+++ b/doc/man/man3/XmDisplay.3
@@ -158,6 +158,8 @@ XmNnoRenditionCallbackXmCCallbackXtCallbackListNULLC
 _____
 XmNuserDataXmCUserDataXtPointerNULLCSG
 _____
+XmNenableXineramaXmCEnableXineramaBooleanFalseC
+_____
 .TE
 .IP "\fBXmNdefaultButtonEmphasis\fP" 10
 Specifies whether to change the look of the PushButton widget and
diff --git a/lib/Xm/Display.c b/lib/Xm/Display.c
index 55fe4cd3..3ab047f2 100644
--- a/lib/Xm/Display.c
+++ b/lib/Xm/Display.c
@@ -35,6 +35,9 @@ static char rcsid[] = "$TOG: Display.c /main/23 1997/06/18 17:36:59 samborn $"
 
 #include <X11/Intrinsic.h>
 #include <X11/extensions/shape.h>
+#ifdef HAVE_LIBXINERAMA
+#include <X11/extensions/Xinerama.h>
+#endif
 
 #include <X11/Xatom.h>
 #include <Xm/AtomMgr.h>
@@ -273,6 +276,13 @@ static XtResource resources[] = {
 	XtOffsetOf(WMShellRec, wm.wm_hints.icon_pixmap), 
 	XmRImmediate, NULL
     }, 
+    /* Xinerama support */
+    {
+	XmNenableXinerama, XmCEnableXinerama,
+	XmRBoolean, sizeof(Boolean),
+	Offset(display.enable_xinerama),
+	XmRImmediate, (XtPointer) False
+    },
 };
 
 #undef Offset
@@ -388,6 +398,45 @@ DisplayClassInitialize( void )
 		XmMakeCanonicalString("_MOTIF_DRAG_AND_DROP_MESSAGE");
 }    
 
+static void
+DisplayInitializeXinerama( XmDisplay	xmDisplay )
+{
+#ifdef HAVE_LIBXINERAMA
+    Display     *display = XtDisplay(xmDisplay);
+    int		dummy1, dummy2;
+    Status      have_xinerama;
+
+    xmDisplay->display.monitors = NULL;
+    xmDisplay->display.n_monitors = 0;
+
+    /* Xinerama support is disabled by default, unless XmNenableXinerama is set */
+    if (!xmDisplay->display.enable_xinerama) {
+#ifdef DEBUG_XINERAMA
+      printf("XINERAMA support not enabled\n");
+#endif /* DEBUG_XINERAMA */
+      return;
+    }
+
+    if (!XineramaQueryExtension(display, &dummy1, &dummy2)) {
+#ifdef DEBUG_XINERAMA
+      printf("XINERAMA extension not available\n");
+#endif /* DEBUG_XINERAMA */
+      xmDisplay->display.enable_xinerama = False;
+      return;
+    }
+
+    if (!XineramaIsActive(display)) {
+#ifdef DEBUG_XINERAMA
+      printf("XINERAMA extension not activated\n");
+#endif /* DEBUG_XINERAMA */
+      xmDisplay->display.enable_xinerama = False;
+      return;
+    }
+
+    _XmDisplayUpdateXinerama(xmDisplay);
+#endif /* HAVE_LIBXINERAMA */
+}
+
 /*ARGSUSED*/
 static void 
 SetDragReceiverInfo(
@@ -553,6 +602,8 @@ DisplayInitialize(
 	  XmDRAG_PREFER_PREREGISTER;
     }
 
+    DisplayInitializeXinerama(xmDisplay);
+
     _XmVirtKeysInitialize (new_widget);
 
     _XmProcessLock();
@@ -672,6 +723,9 @@ DisplayDestroy(
 
     _XmVirtKeysDestroy (w);
 
+#ifdef HAVE_LIBXINERAMA
+    XFree(dd->display.monitors);
+#endif /* HAVE_LIBXINERAMA */
     XDeleteContext( XtDisplay( w), None, context) ;
 }
 
@@ -1225,3 +1279,44 @@ _XmSetThicknessDefault0(
 	value->addr = (XPointer)&thickness;
 
 }
+
+
+Boolean
+_XmDisplayUseXinerama(
+	XmDisplay xmDisplay )
+{
+    return xmDisplay && xmDisplay->display.enable_xinerama;
+}
+
+
+void
+_XmDisplayUpdateXinerama(
+	XmDisplay xmDisplay )
+{
+#ifdef HAVE_LIBXINERAMA
+#ifdef DEBUG_XINERAMA
+    int i;
+#endif /* DEBUG_XINERAMA */
+
+    if (!_XmDisplayUseXinerama(xmDisplay))
+      return;
+
+#ifdef DEBUG_XINERAMA
+    printf("Updating XINERAMA configuration\n");
+#endif /* DEBUG_XINERAMA */
+
+    if (xmDisplay->display.monitors)
+      XFree(xmDisplay->display.monitors);
+
+    xmDisplay->display.monitors =
+      XineramaQueryScreens (XtDisplay(xmDisplay), &xmDisplay->display.n_monitors);
+
+#ifdef DEBUG_XINERAMA
+    for (i = 0; i < xmDisplay->display.n_monitors; ++i) {
+      printf("XINERAMA Monitor %i: (%i,%i) [%ix%i]\n", i,
+              xmDisplay->display.monitors[i].x_org, xmDisplay->display.monitors[i].y_org,
+              xmDisplay->display.monitors[i].width, xmDisplay->display.monitors[i].height);
+    }
+#endif /* DEBUG_XINERAMA */
+#endif /* HAVE_LIBXINERAMA */
+}
diff --git a/lib/Xm/DisplayP.h b/lib/Xm/DisplayP.h
index 655c29b6..a2420f96 100644
--- a/lib/Xm/DisplayP.h
+++ b/lib/Xm/DisplayP.h
@@ -23,6 +23,14 @@
 #ifndef _XmDisplayP_h
 #define _XmDisplayP_h
 
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
+
+#ifdef HAVE_LIBXINERAMA
+#include <X11/extensions/Xinerama.h>
+#endif
+
 #include <Xm/DesktopP.h>
 #include <Xm/VendorSEP.h>
 #include <Xm/DropSMgr.h>
@@ -115,6 +123,11 @@ typedef struct {
     Boolean			enable_unselectable_drag;
     Boolean                     enable_thin_thickness;
     Boolean			enable_multi_key_bindings;
+    Boolean			enable_xinerama;
+#ifdef HAVE_LIBXINERAMA
+    XineramaScreenInfo          *monitors;
+    int                         n_monitors;
+#endif
 } XmDisplayPart, *XmDisplayPartPtr;
 
 typedef struct _XmDisplayInfo {
@@ -143,6 +156,11 @@ externalref XmDisplayClassRec 	xmDisplayClassRec;
 
 externalref String _Xm_MOTIF_DRAG_AND_DROP_MESSAGE ;
 
+extern Boolean _XmDisplayUseXinerama(
+	XmDisplay xmDisplay ) ;
+
+extern void _XmDisplayUpdateXinerama(
+	XmDisplay xmDisplay ) ;
 
 #ifdef __cplusplus
 }  /* Close scope of 'extern "C"' declaration which encloses file. */
diff --git a/lib/Xm/Screen.c b/lib/Xm/Screen.c
index 10ba8d2b..44abcfb3 100644
--- a/lib/Xm/Screen.c
+++ b/lib/Xm/Screen.c
@@ -396,7 +396,67 @@ GetUnitFromFont(
     }
 
 }
+#ifdef HAVE_LIBXINERAMA
+/* ARGSUSED */
+static void
+StructureNotifyHandler(
+        Widget wid,
+        XtPointer data,
+        XEvent *event,
+        Boolean *cont )
+{
+    Display           *display = XtDisplay(wid);
+
+#ifdef DEBUG_XINERAMA
+    printf("Root event received\n");
+#endif /* DEBUG_XINERAMA */
 
+    if (event->type == ConfigureNotify)
+        _XmDisplayUpdateXinerama((XmDisplay) XmGetXmDisplay(display)) ;
+}
+
+/* ARGSUSED */
+static void
+InstallStructureNotifyHandler(
+        XmScreen     xmScreen)
+{
+    Display           *display = XtDisplay(xmScreen);
+    Window            rootwindow;
+    XWindowAttributes rootattributes;
+
+    if (!_XmDisplayUseXinerama((XmDisplay) XmGetXmDisplay(display)))
+        return;
+
+    rootwindow = RootWindowOfScreen(XtScreen(xmScreen));
+    XGetWindowAttributes(display, rootwindow, &rootattributes);
+    XSelectInput(display,
+		 rootwindow,
+		 StructureNotifyMask | rootattributes.your_event_mask);
+    XtRegisterDrawable(display, rootwindow, (Widget)xmScreen);
+    XtAddEventHandler((Widget)xmScreen,
+                         (EventMask) StructureNotifyMask, True,
+			 StructureNotifyHandler, (XtPointer) NULL);
+}
+
+/* ARGSUSED */
+static void
+UninstallStructureNotifyHandler(
+        XmScreen     xmScreen)
+{
+    Display           *display = XtDisplay(xmScreen);
+    Window            rootwindow;
+    XWindowAttributes rootattributes;
+
+    if (!_XmDisplayUseXinerama((XmDisplay) XmGetXmDisplay(display)))
+        return;
+
+    rootwindow = RootWindowOfScreen(XtScreen(xmScreen));
+    XtUnregisterDrawable(display, rootwindow);
+    XtRemoveEventHandler((Widget)xmScreen,
+                         (EventMask) StructureNotifyMask, True,
+			 StructureNotifyHandler, (XtPointer) NULL);
+}
+#endif /* HAVE_LIBXINERAMA */
 
 /************************************************************************
  *
@@ -413,6 +473,8 @@ Initialize(
 {
     XmScreen     xmScreen = (XmScreen)new_widget;
     Display      *display = XtDisplay(new_widget);
+    Window       rootwindow;
+    XWindowAttributes rootattributes;
 
     xmScreen->screen.screenInfo = NULL;
 
@@ -474,6 +536,9 @@ Initialize(
     }
 #endif
 
+#ifdef HAVE_LIBXINERAMA
+    InstallStructureNotifyHandler(xmScreen);
+#endif /* HAVE_LIBXINERAMA */
 }
 
 /************************************************************************
@@ -672,6 +737,10 @@ Destroy(
 
     /* need to remove pixmap and GC related to this screen */
     _XmCleanPixmapCache (XtScreen(widget), NULL);
+
+#ifdef HAVE_LIBXINERAMA
+    UninstallStructureNotifyHandler(xmScreen);
+#endif /* HAVE_LIBXINERAMA */
 }
 
 static void 
@@ -1447,3 +1516,62 @@ XmGetXmScreen(
 	_XmAppUnlock(app);
 	return widget;
 }
+
+void
+_XmScreenGetBoundariesAtpoint(
+        Screen *screen,
+	Position pt_x,
+	Position pt_y,
+	Position *ret_x,
+	Position *ret_y,
+	Position *ret_max_x,
+	Position *ret_max_y )
+{
+    XmDisplay	xmDisplay;
+    Position screen_x, screen_y;
+    Position screen_max_x, screen_max_y;
+#ifdef HAVE_LIBXINERAMA
+    Position tmp_x, tmp_y;
+    Position tmp_max_x, tmp_max_y;
+    int i;
+#endif /* HAVE_LIBXINERAMA */
+
+    xmDisplay = (XmDisplay) XmGetXmDisplay(DisplayOfScreen(screen));
+    screen_x = 0;
+    screen_y = 0;
+    screen_max_x = WidthOfScreen(screen);
+    screen_max_y = HeightOfScreen(screen);
+
+    if (!_XmDisplayUseXinerama(xmDisplay))
+      goto out;
+
+#ifdef HAVE_LIBXINERAMA
+    for (i = 0; i < xmDisplay->display.n_monitors; ++i) {
+      tmp_x = xmDisplay->display.monitors[i].x_org;
+      tmp_y = xmDisplay->display.monitors[i].y_org;
+      tmp_max_x = tmp_x + xmDisplay->display.monitors[i].width;
+      tmp_max_y = tmp_y + xmDisplay->display.monitors[i].height;
+
+      if (pt_x >= tmp_x && pt_x < tmp_max_x && pt_y >= tmp_y && pt_y < tmp_max_y) {
+	screen_x = tmp_x;
+	screen_y = tmp_y;
+	screen_max_x = tmp_max_x;
+	screen_max_y = tmp_max_y;
+        break; /* We have a match */
+      }
+    }
+#endif /* HAVE_LIBXINERAMA */
+out:
+#ifdef DEBUG_XINERAMA
+    printf("Point (%i,%i) constrained within (%i,%i) and (%i,%i)\n",
+           pt_x, pt_y, screen_x, screen_y, screen_max_x, screen_max_y);
+#endif /* DEBUG_XINERAMA */
+    if (ret_x)
+      *ret_x = screen_x;
+    if (ret_y)
+      *ret_y = screen_y;
+    if (ret_max_x)
+      *ret_max_x = screen_max_x;
+    if (ret_max_y)
+      *ret_max_y = screen_max_y;
+}
diff --git a/lib/Xm/ScreenP.h b/lib/Xm/ScreenP.h
index c870c19e..b4b95a6f 100644
--- a/lib/Xm/ScreenP.h
+++ b/lib/Xm/ScreenP.h
@@ -134,6 +134,14 @@ typedef struct _XmScreenRec {
     XmScreenPart		screen;
 } XmScreenRec;
 
+extern void _XmScreenGetBoundariesAtpoint(
+        Screen *screen,
+	Position pt_x,
+	Position pt_y,
+	Position *ret_x,
+	Position *ret_y,
+	Position *ret_max_x,
+	Position *ret_max_y ) ;
 
 #ifdef __cplusplus
 }  /* Close scope of 'extern "C"' declaration which encloses file. */
diff --git a/lib/Xm/xmstring.list.in b/lib/Xm/xmstring.list.in
index 8c0c4f9a..5887e7ad 100644
--- a/lib/Xm/xmstring.list.in
+++ b/lib/Xm/xmstring.list.in
@@ -1692,6 +1692,8 @@ CFontEncoding
 NxftFont
 CXftFont
 SUTF8_STRING
+NenableXinerama
+CEnableXinerama
 
 #file XmStrDefsI.h
 #table _XmStringsI
-- 
2.47.1