From 35d4d400521d30d84c20cd1434626e131cbf9304 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 17 Sep 2016 02:00:36 +0300
Subject: [PATCH] Retain monitor positions when setting non-exclusive modes

Trying to rearrange the monitors was a stupid idea, as it can easily mess
up the user's configuration.
---
 source/graphics/x11/display.cpp | 72 +++++++--------------------------
 1 file changed, 15 insertions(+), 57 deletions(-)

diff --git a/source/graphics/x11/display.cpp b/source/graphics/x11/display.cpp
index ba8d253..972cc82 100644
--- a/source/graphics/x11/display.cpp
+++ b/source/graphics/x11/display.cpp
@@ -273,11 +273,17 @@ void Display::set_mode(const VideoMode &requested_mode, bool exclusive)
 		}
 	}
 
-	int x = 0;
-	int y = 0;
+	/* Due to the semantics of find_mode, the mode's monitor pointer must point
+	to one of the elements of the monitors list, which is non-const here. */
+	Monitor *monitor = const_cast<Monitor *>(mode->monitor);
 
 	if(exclusive)
 	{
+		monitor->current_settings.mode = mode;
+		monitor->current_settings.rotation = requested_rotation;
+		monitor->current_settings.x = 0;
+		monitor->current_settings.y = 0;
+
 		// Disable other outputs for exclusive mode
 		for(list<Monitor>::iterator i=monitors.begin(); i!=monitors.end(); ++i)
 			if(&*i!=mode->monitor)
@@ -295,63 +301,15 @@ void Display::set_mode(const VideoMode &requested_mode, bool exclusive)
 	}
 	else
 	{
-		const Monitor *left = mode->monitor->next_left;
-		while(left && !left->current_settings.mode)
-			left = left->next_left;
-
-		if(left)
-		{
-			const Monitor::Settings &cs = left->current_settings;
-			x = cs.x+mode_width(*cs.mode, cs.rotation);
-			y = cs.y;
-		}
+		monitor->current_settings.x = monitor->desktop_settings.x;
+		monitor->current_settings.y = monitor->desktop_settings.y;
 	}
 
-	XRRSetCrtcConfig(priv->display, res, crtc, CurrentTime, x, y, priv->modes[mode->index], rotation_to_sys(requested_rotation), &output, 1);
-
-	list<Monitor>::iterator i;
-	for(i=monitors.begin(); i!=monitors.end(); ++i)
-		if(&*i==mode->monitor)
-		{
-			i->current_settings.mode = mode;
-			i->current_settings.rotation = requested_rotation;
-			i->current_settings.x = x;
-			i->current_settings.y = y;
-
-			x += mode_width(*mode, requested_rotation);
-			++i;
-			break;
-		}
-
-	for(; i!=monitors.end(); ++i)
-		if(i->current_settings.mode)
-		{
-			XRROutputInfo *o = XRRGetOutputInfo(priv->display, res, priv->monitors[i->index]);
-			XRRSetCrtcConfig(priv->display, res, o->crtc, CurrentTime, x, y, priv->modes[i->current_settings.mode->index], rotation_to_sys(i->current_settings.rotation), &priv->monitors[i->index], 1);
-
-			XRRPanning panning;
-			panning.timestamp = CurrentTime;
-			panning.left = x;
-			panning.top = y;
-			panning.width = i->current_settings.mode->width;
-			panning.height = i->current_settings.mode->height;
-			panning.track_left = panning.left;
-			panning.track_top = panning.top;
-			panning.track_width = panning.width;
-			panning.track_height = panning.height;
-			panning.border_left = 0;
-			panning.border_top = 0;
-			panning.border_right = 0;
-			panning.border_bottom = 0;
-			XRRSetPanning(priv->display, res, o->crtc, &panning);
-
-			XRRFreeOutputInfo(o);
-
-			i->current_settings.x = x;
-			i->current_settings.y = y;
-
-			x += mode_width(*i->current_settings.mode, i->current_settings.rotation);
-		}
+	RRMode mode_id = priv->modes[mode->index];
+	int x = monitor->current_settings.x;
+	int y = monitor->current_settings.y;
+	Rotation sys_rot = rotation_to_sys(requested_rotation);
+	XRRSetCrtcConfig(priv->display, res, crtc, CurrentTime, x, y, mode_id, sys_rot, &output, 1);
 
 	XRRFreeOutputInfo(output_info);
 	XRRFreeCrtcInfo(crtc_info);
-- 
2.43.0