kwin/plugins/qpa/screen.cpp
Martin Flöser abedb464d5 [QPA] Implement Screen on top of internal Screens API
Summary:
The test DontCrashUseractionsMenu (Waylandonly) found an issue in our
screen handling implementation in the QPA. The code exposed a short time
frame between the dummy screen getting destroyed and the first screen
being added. This could result in a crash of KWin.

There is actually no need to implement Screen on top of Wayland screen.
KWin has all the knowledge, so we can also base this on top of the
Screens API.

Advantages:
 * no delays due to Wayland roundtrips
 * handle screen getting removed (was a TODO)
 * handle resolution changes (was a TODO)

The new implementation has a disadvantage that it destroys and readds
all screens whenever something around the screen changes. This shouldn't
be an issue in practice as it's only for the internal QPA and thus only
affects KWin internal windows which is placed in global coordinates
anyway. If it turns out to be a problem we need to track better the
screen changes - so far those were not tracked at all.

Test Plan: Run a few unit tests which change screens

Reviewers: #kwin, #plasma

Subscribers: plasma-devel, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D8345
2017-10-19 18:03:10 +02:00

80 lines
2 KiB
C++

/********************************************************************
KWin - the KDE window manager
This file is part of the KDE project.
Copyright (C) 2015 Martin Gräßlin <mgraesslin@kde.org>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*********************************************************************/
#include "screen.h"
#include "platformcursor.h"
#include "screens.h"
#include "wayland_server.h"
namespace KWin
{
namespace QPA
{
Screen::Screen(int screen)
: QPlatformScreen()
, m_screen(screen)
, m_cursor(new PlatformCursor)
{
}
Screen::~Screen() = default;
int Screen::depth() const
{
return 32;
}
QImage::Format Screen::format() const
{
return QImage::Format_ARGB32_Premultiplied;
}
QRect Screen::geometry() const
{
return m_screen != -1 ? screens()->geometry(m_screen) : QRect(0, 0, 1, 1);
}
QSizeF Screen::physicalSize() const
{
return m_screen != -1 ? screens()->physicalSize(m_screen) : QPlatformScreen::physicalSize();
}
QPlatformCursor *Screen::cursor() const
{
return m_cursor.data();
}
QDpi Screen::logicalDpi() const
{
static int force_dpi = qEnvironmentVariableIsSet("QT_WAYLAND_FORCE_DPI") ? qEnvironmentVariableIntValue("QT_WAYLAND_FORCE_DPI") : -1;
if (force_dpi > 0) {
return QDpi(force_dpi, force_dpi);
}
return QPlatformScreen::logicalDpi();
}
qreal Screen::devicePixelRatio() const
{
return m_screen != -1 ? screens()->scale(m_screen) : 1.0;
}
}
}