xcb: support xrandr(1.5) monitor setup

More information about monitor in xrandr 1.5, see
https://keithp.com/blogs/MST-monitors/

Since this change, screen is logical instead of physical.

If xrandr 1.5 and later is installed, Qt screen info will get
from xrandr monitor object instead of xrandr output if only have
1.2 to 1.4.

Users can manipulate monitor as they want, for example, a
combination for two physical screens, half of one screen and etc.

Didn't have chance to access MST monitors, but it should work
if xrandr monitor object was created automatically.

[ChangeLog][xcb] Qt screen info will get from xrandr monitor
object if 1.5 is installed.

Fixes: QTBUG-65457
Change-Id: Iad339cc0d4293b2403b4ef6bf6eb770feb3e685f
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

5 files changed, 132 insertions, 0 deletions

diff --git a/tests/manual/CMakeLists.txt b/tests/manual/CMakeLists.txt
index f9eb23cd5f..6dee2e7448 100644
--- a/tests/manual/CMakeLists.txt
+++ b/tests/manual/CMakeLists.txt
@@ -39,6 +39,7 @@ endif()
 #special case end
 add_subdirectory(qstorageinfo)
 add_subdirectory(qscreen)
+add_subdirectory(qscreen_xrandr)
 add_subdirectory(qsslsocket)
 add_subdirectory(qsysinfo)
 add_subdirectory(qtabletevent)
diff --git a/tests/manual/manual.pro b/tests/manual/manual.pro
index 2ef802c8f3..8ad5882234 100644
--- a/tests/manual/manual.pro
+++ b/tests/manual/manual.pro
@@ -27,6 +27,7 @@ qnetworkaccessmanager/qget \
 qnetworkreply \
 qstorageinfo \
 qscreen \
+qscreen_xrandr \
 qssloptions \
 qsslsocket \
 qsysinfo \
diff --git a/tests/manual/qscreen_xrandr/CMakeLists.txt b/tests/manual/qscreen_xrandr/CMakeLists.txt
new file mode 100644
index 0000000000..095948b070
--- /dev/null
+++ b/tests/manual/qscreen_xrandr/CMakeLists.txt
@@ -0,0 +1,14 @@
+# Generated from qscreen_xrandr.pro.
+
+#####################################################################
+## tst_qscreen2 Test:
+#####################################################################
+
+qt_internal_add_test(tst_qscreen_xrandr
+    SOURCES
+        tst_qscreen_xrandr.cpp
+    PUBLIC_LIBRARIES
+        Qt::CorePrivate
+        Qt::Gui
+        Qt::GuiPrivate
+)
diff --git a/tests/manual/qscreen_xrandr/qscreen_xrandr.pro b/tests/manual/qscreen_xrandr/qscreen_xrandr.pro
new file mode 100644
index 0000000000..61132f63c2
--- /dev/null
+++ b/tests/manual/qscreen_xrandr/qscreen_xrandr.pro
@@ -0,0 +1,6 @@
+CONFIG += testcase
+TARGET = tst_qscreen_xrandr
+
+QT += core-private gui-private testlib
+
+SOURCES  += tst_qscreen_xrandr.cpp
diff --git a/tests/manual/qscreen_xrandr/tst_qscreen_xrandr.cpp b/tests/manual/qscreen_xrandr/tst_qscreen_xrandr.cpp
new file mode 100644
index 0000000000..f7611fc95a
--- /dev/null
+++ b/tests/manual/qscreen_xrandr/tst_qscreen_xrandr.cpp
@@ -0,0 +1,110 @@
+/****************************************************************************
+**
+** Copyright (C) 2020 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:GPL-EXCEPT$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <qpainter.h>
+#include <qrasterwindow.h>
+#include <qscreen.h>
+#include <qpa/qwindowsysteminterface.h>
+#include <QProcess>
+
+#include <QtTest/QtTest>
+
+class tst_QScreen_Xrandr: public QObject
+{
+    Q_OBJECT
+
+private slots:
+    void xrandr_15();
+};
+
+// this test requires an X11 desktop with at least two screens
+void tst_QScreen_Xrandr::xrandr_15()
+{
+    QStringList originalScreenNames;
+    QStringList mergedScreenNames;
+    {
+        QList<QScreen *> screens = QGuiApplication::screens();
+        QVERIFY(screens.size() >= 2);
+        qDebug() << "initial set of screens:" << screens.size();
+        for (QScreen *s : screens) {
+            qDebug() << "screen: " << s->name();
+            originalScreenNames << s->name();
+            if (mergedScreenNames.size() < 2)
+                mergedScreenNames << s->name();
+        }
+    }
+
+    QSignalSpy addedSpy(qApp, &QGuiApplication::screenAdded);
+    QSignalSpy removedSpy(qApp, &QGuiApplication::screenRemoved);
+
+    // combine the first two screens into one monitor
+    // e.g. "xrandr --setmonitor Qt-merged auto eDP,HDMI-0"
+    QString prog1 = "xrandr";
+    QStringList args1;
+    args1 << "--setmonitor" << "Qt-merged" << "auto" << mergedScreenNames.join(',');
+    qDebug() << prog1 << args1;
+    QProcess *myProcess1 = new QProcess(this);
+    myProcess1->start(prog1, args1);
+    QVERIFY(myProcess1->waitForFinished());
+
+    QTRY_COMPARE(removedSpy.count(), 2);
+    QVERIFY(QGuiApplication::screens().size() != originalScreenNames.size());
+    auto combinedScreens = QGuiApplication::screens();
+    qDebug() << "added" << addedSpy.count() << "removed" << removedSpy.count() << "combined screen(s):" << combinedScreens.size();
+    QScreen *merged = nullptr;
+    for (QScreen *s : combinedScreens) {
+        qDebug() << "screen: " << s->name();
+        if (s->name() == QLatin1String("Qt-merged"))
+            merged = s;
+    }
+    // the screen that we created must be in the list now
+    QVERIFY(merged);
+    QCOMPARE(QGuiApplication::screens().size(), originalScreenNames.size() - 1);
+    addedSpy.clear();
+    removedSpy.clear();
+
+    // "xrandr --delmonitor Qt-merged"
+    QString prog2 = "xrandr";
+    QStringList args2;
+    args2 << "--delmonitor" << "Qt-merged";
+    QProcess *myProcess2 = new QProcess(this);
+    myProcess2->start(prog2, args2);
+    QVERIFY(myProcess2->waitForFinished());
+
+    QTRY_COMPARE(removedSpy.count(), 1);
+    QVERIFY(QGuiApplication::screens().size() != combinedScreens.size());
+    auto separatedScreens = QGuiApplication::screens();
+    qDebug() << "added" << addedSpy.count() << "removed" << removedSpy.count() << "separated screen(s):" << separatedScreens.size();
+    for (QScreen *s : separatedScreens)
+        qDebug() << "screen: " << s->name();
+
+    QCOMPARE(QGuiApplication::screens().size(), originalScreenNames.size());
+}
+
+#include <tst_qscreen_xrandr.moc>
+QTEST_MAIN(tst_QScreen_Xrandr);