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Diffstat (limited to 'src/gui/kernel/qhighdpiscaling.cpp')
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diff --git a/src/gui/kernel/qhighdpiscaling.cpp b/src/gui/kernel/qhighdpiscaling.cpp new file mode 100644 index 0000000000..b0ef2a284f --- /dev/null +++ b/src/gui/kernel/qhighdpiscaling.cpp @@ -0,0 +1,423 @@ +/**************************************************************************** +** +** Copyright (C) 2015 The Qt Company Ltd. +** Contact: http://www.qt.io/licensing/ +** +** This file is part of the QtGui module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL21$ +** 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 http://www.qt.io/terms-conditions. For further +** information use the contact form at http://www.qt.io/contact-us. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 or version 3 as published by the Free +** Software Foundation and appearing in the file LICENSE.LGPLv21 and +** LICENSE.LGPLv3 included in the packaging of this file. Please review the +** following information to ensure the GNU Lesser General Public License +** requirements will be met: https://www.gnu.org/licenses/lgpl.html and +** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** As a special exception, The Qt Company gives you certain additional +** rights. These rights are described in The Qt Company LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qhighdpiscaling_p.h" +#include "qguiapplication.h" +#include "qscreen.h" +#include "qplatformintegration.h" +#include "private/qscreen_p.h" + +#include <QtCore/qdebug.h> + +QT_BEGIN_NAMESPACE + +Q_LOGGING_CATEGORY(lcScaling, "qt.scaling"); + +#ifndef QT_NO_HIGHDPISCALING +static const char legacyDevicePixelEnvVar[] = "QT_DEVICE_PIXEL_RATIO"; +static const char scaleFactorEnvVar[] = "QT_SCALE_FACTOR"; +static const char autoScreenEnvVar[] = "QT_AUTO_SCREEN_SCALE_FACTOR"; +static const char screenFactorsEnvVar[] = "QT_SCREEN_SCALE_FACTORS"; + +static inline qreal initialGlobalScaleFactor() +{ + + qreal result = 1; + if (qEnvironmentVariableIsSet(scaleFactorEnvVar)) { + bool ok; + const qreal f = qgetenv(scaleFactorEnvVar).toDouble(&ok); + if (ok && f > 0) { + qCDebug(lcScaling) << "Apply " << scaleFactorEnvVar << f; + result = f; + } + } else { + if (qEnvironmentVariableIsSet(legacyDevicePixelEnvVar)) { + qWarning() << "Warning:" << legacyDevicePixelEnvVar << "is deprecated. Instead use:" << endl + << " " << autoScreenEnvVar << "to enable platform plugin controlled per-screen factors." << endl + << " " << screenFactorsEnvVar << "to set per-screen factors." << endl + << " " << scaleFactorEnvVar << "to set the application global scale factor."; + + int dpr = qEnvironmentVariableIntValue(legacyDevicePixelEnvVar); + if (dpr > 0) + result = dpr; + } + } + return result; +} + +/*! + \class QHighDpiScaling + \since 5.6 + \internal + \preliminary + \ingroup qpa + + \brief Collection of utility functions for UI scaling. + + QHighDpiScaling implements utility functions for high-dpi scaling for use + on operating systems that provide limited support for native scaling. In + addition this functionality can be used for simulation and testing purposes. + + The functions support scaling between the device independent coordinate + system used by Qt applications and the native coordinate system used by + the platform plugins. Intended usage locations are the low level / platform + plugin interfacing parts of QtGui, for example the QWindow, QScreen and + QWindowSystemInterface implementation. + + There are now up to three active coordinate systems in Qt: + + --------------------------------------------------- + | Application Device Independent Pixels | devicePixelRatio + | Qt Widgets | = + | Qt Gui | + |---------------------------------------------------| Qt Scale Factor + | Qt Gui QPlatform* Native Pixels | * + | Qt platform plugin | + |---------------------------------------------------| OS Scale Factor + | Display Device Pixels | + | (Graphics Buffers) | + ----------------------------------------------------- + + This is an simplification and shows the main coordinate system. All layers + may work with device pixels in specific cases: OpenGL, creating the backing + store, and QPixmap management. The "Native Pixels" coordinate system is + internal to Qt and should not be exposed to Qt users: Seen from the outside + there are only two coordinate systems: device independent pixels and device + pixels. + + The devicePixelRatio seen by applications is the product of the Qt scale + factor and the OS scale factor. The value of the scale factors may be 1, + in which case two or more of the coordinate systems are equivalent. Platforms + that (may) have an OS scale factor include OS X, iOS and Wayland. + + Note that the functions in this file do not work with the OS scale factor + directly and are limited to converting between device independent and native + pixels. The OS scale factor is accunted for by QWindow::devicePixelRatio() + and similar functions. + + Configuration Examples: + + 'Classic': Device Independent Pixels = Native Pixels = Device Pixels + --------------------------------------------------- devicePixelRatio: 1 + | Application / Qt Gui 100 x 100 | + | | Qt Scale Factor: 1 + | Qt Platform / OS 100 x 100 | + | | OS Scale Factor: 1 + | Display 100 x 100 | + ----------------------------------------------------- + + 'Retina Device': Device Independent Pixels = Native Pixels + --------------------------------------------------- devicePixelRatio: 2 + | Application / Qt Gui 100 x 100 | + | | Qt Scale Factor: 1 + | Qt Platform / OS 100 x 100 | + |---------------------------------------------------| OS Scale Factor: 2 + | Display 200 x 200 | + ----------------------------------------------------- + + '2x Qt Scaling': Native Pixels = Device Pixels + --------------------------------------------------- devicePixelRatio: 2 + | Application / Qt Gui 100 x 100 | + |---------------------------------------------------| Qt Scale Factor: 2 + | Qt Platform / OS 200 x 200 | + | | OS Scale Factor: 1 + | Display 200 x 200 | + ----------------------------------------------------- + + The Qt Scale Factor is the product of two sub-scale factors, which + are independently either set or determined by the platform plugin. + Several APIs are offered for this, targeting both developers and + end users. All scale factors are of type qreal. + + 1) A global scale factor + The QT_SCALE_FACTOR environment variable can be used to set + a global scale factor for all windows in the processs. This + is useful for testing and debugging (you can simulate any + devicePixelRatio without needing access to sepcial hardware), + and perhaps also for targeting a specific application to + a specific display type (embedded use cases). + + 2) A per-screen scale factors + Some platform plugins support providing a per-screen scale + factor based on display density information. These platforms + include X11, Windows, and Android. + + There are two APIs for enabling or disabling this behavior: + - The QT_AUTO_SCREEN_SCALE_FACTOR environment variable. + - The AA_EnableHighDpiScaling and AA_DisableHighDpiScaling + application attributes + + Enabling either will make QHighDpiScaling call QPlatformScreen::pixelDensity() + and use the value provided as the scale factor for the screen in + question. Disabling is done on a 'veto' basis where either the + environment or the application source can disable. The intended use + cases are 'My system is not providing correct display density + information' and 'My application needs to work in display pixels', + respectively. + + The QT_SCREEN_SCALE_FACTORS environment variable can be used to set the screen + scale factors manually.Set this to a semicolon-separated + list of scale factors (matching the order of QGuiApplications::screens()), + or to a list of name=value pairs (where name matches QScreen::name()). + + Coordinate conversion functions must be used when writing code that passes + geometry across the Qt Gui / Platform plugin boundary. The main conversion + functions are: + T toNativePixels(T, QWindow *) + T fromNativePixels(T, QWindow*) + + The following classes in QtGui use native pixels, for the convenience of the + plataform plugins: + QPlatformWindow + QPlatformScreen + QWindowSystemInterface (API only - Events are in device independent pixels) + + As a special consideration platform plugin code should be careful about + calling QtGui geometry accessor functions: + QRect r = window->geometry(); + Here the returned geometry is in device independent pixels. Add a conversion call: + QRect r = QHighDpi::toNativePixels(window->geometry()); + (Avoiding calling QWindow and instead using the QPlatformWindow geometry + might be a better course of action in this case.) +*/ + +qreal QHighDpiScaling::m_factor = 1.0; +bool QHighDpiScaling::m_active = false; //"overall active" - is there any scale factor set. +bool QHighDpiScaling::m_usePixelDensity = false; // use scale factor from platform plugin +bool QHighDpiScaling::m_pixelDensityScalingActive = false; // pixel density scale factor > 1 +bool QHighDpiScaling::m_globalScalingActive = false; // global scale factor is active +bool QHighDpiScaling::m_screenFactorSet = false; // QHighDpiScaling::setScreenFactor has been used +QDpi QHighDpiScaling::m_logicalDpi = QDpi(-1,-1); // The scaled logical DPI of the primary screen + +/* + Initializes the QHighDpiScaling global variables. Called before the + platform plugin is created. +*/ + +static inline bool usePixelDensity() +{ + // Determine if we should set a scale factor based on the pixel density + // reported by the platform plugin. There are several enablers and several + // disablers. A single disable may veto all other enablers. + if (QCoreApplication::testAttribute(Qt::AA_DisableHighDpiScaling)) + return false; + bool screenEnvValueOk; + const int screenEnvValue = qEnvironmentVariableIntValue(autoScreenEnvVar, &screenEnvValueOk); + if (screenEnvValueOk && screenEnvValue < 1) + return false; + return QCoreApplication::testAttribute(Qt::AA_EnableHighDpiScaling) + || (screenEnvValueOk && screenEnvValue > 0) + || (qEnvironmentVariableIsSet(legacyDevicePixelEnvVar) && qgetenv(legacyDevicePixelEnvVar).toLower() == "auto"); +} + +void QHighDpiScaling::initHighDpiScaling() +{ + // Determine if there is a global scale factor set. + m_factor = initialGlobalScaleFactor(); + m_globalScalingActive = !qFuzzyCompare(m_factor, qreal(1)); + + m_usePixelDensity = usePixelDensity(); + + m_pixelDensityScalingActive = false; //set in updateHighDpiScaling below + + // we update m_active in updateHighDpiScaling, but while we create the + // screens, we have to assume that m_usePixelDensity implies scaling + m_active = m_globalScalingActive || m_usePixelDensity; +} + +void QHighDpiScaling::updateHighDpiScaling() +{ + if (QCoreApplication::testAttribute(Qt::AA_DisableHighDpiScaling)) + return; + + if (m_usePixelDensity && !m_pixelDensityScalingActive) { + Q_FOREACH (QScreen *screen, QGuiApplication::screens()) { + if (!qFuzzyCompare(screenSubfactor(screen->handle()), qreal(1))) { + m_pixelDensityScalingActive = true; + break; + } + } + } + if (qEnvironmentVariableIsSet(screenFactorsEnvVar)) { + int i = 0; + Q_FOREACH (const QByteArray &spec, qgetenv(screenFactorsEnvVar).split(';')) { + QScreen *screen = 0; + int equalsPos = spec.lastIndexOf('='); + double factor = 0; + if (equalsPos > 0) { + // support "name=factor" + QByteArray name = spec.mid(0, equalsPos); + QByteArray f = spec.mid(equalsPos + 1); + bool ok; + factor = f.toDouble(&ok); + if (ok) { + Q_FOREACH (QScreen *s, QGuiApplication::screens()) { + if (s->name() == QString::fromLocal8Bit(name)) { + screen = s; + break; + } + } + } + } else { + // listing screens in order + bool ok; + factor = spec.toDouble(&ok); + if (ok && i < QGuiApplication::screens().count()) + screen = QGuiApplication::screens().at(i); + } + if (screen) + setScreenFactor(screen, factor); + ++i; + } + } + m_active = m_globalScalingActive || m_screenFactorSet || m_pixelDensityScalingActive; + + QPlatformScreen *primaryScreen = QGuiApplication::primaryScreen()->handle(); + qreal sf = screenSubfactor(primaryScreen); + QDpi primaryDpi = primaryScreen->logicalDpi(); + m_logicalDpi = QDpi(primaryDpi.first / sf, primaryDpi.second / sf); +} + +/* + Sets the global scale factor which is applied to all windows. +*/ +void QHighDpiScaling::setGlobalFactor(qreal factor) +{ + if (qFuzzyCompare(factor, m_factor)) + return; + if (!QGuiApplication::allWindows().isEmpty()) + qWarning("QHighDpiScaling::setFactor: Should only be called when no windows exist."); + + m_globalScalingActive = !qFuzzyCompare(factor, qreal(1)); + m_factor = m_globalScalingActive ? factor : qreal(1); + m_active = m_globalScalingActive || m_screenFactorSet || m_pixelDensityScalingActive; + Q_FOREACH (QScreen *screen, QGuiApplication::screens()) + screen->d_func()->updateHighDpi(); +} + +static const char scaleFactorProperty[] = "_q_scaleFactor"; + +/* + Sets a per-screen scale factor. +*/ +void QHighDpiScaling::setScreenFactor(QScreen *screen, qreal factor) +{ + m_screenFactorSet = true; + m_active = true; + screen->setProperty(scaleFactorProperty, QVariant(factor)); + + // hack to force re-evaluation of screen geometry + if (screen->handle()) + screen->d_func()->setPlatformScreen(screen->handle()); // updates geometries based on scale factor +} + +QPoint QHighDpiScaling::mapPositionToNative(const QPoint &pos, const QPlatformScreen *platformScreen) +{ + if (!platformScreen) + return pos; + const qreal scaleFactor = factor(platformScreen); + const QPoint topLeft = platformScreen->geometry().topLeft(); + return (pos - topLeft) * scaleFactor + topLeft; +} + +QPoint QHighDpiScaling::mapPositionFromNative(const QPoint &pos, const QPlatformScreen *platformScreen) +{ + if (!platformScreen) + return pos; + const qreal scaleFactor = factor(platformScreen); + const QPoint topLeft = platformScreen->geometry().topLeft(); + return (pos - topLeft) / scaleFactor + topLeft; +} + +qreal QHighDpiScaling::screenSubfactor(const QPlatformScreen *screen) +{ + qreal factor = qreal(1.0); + if (screen) { + if (m_usePixelDensity) + factor *= screen->pixelDensity(); + if (m_screenFactorSet) { + QVariant screenFactor = screen->screen()->property(scaleFactorProperty); + if (screenFactor.isValid()) + factor *= screenFactor.toReal(); + } + } + return factor; +} + +QDpi QHighDpiScaling::logicalDpi() +{ + return m_logicalDpi; +} + +qreal QHighDpiScaling::factor(const QScreen *screen) +{ + // Fast path for when scaling in Qt is not used at all. + if (!m_active) + return qreal(1.0); + + // The effective factor for a given screen is the product of the + // screen and global sub-factors + qreal factor = m_factor; + if (screen) + factor *= screenSubfactor(screen->handle()); + return factor; +} + +qreal QHighDpiScaling::factor(const QPlatformScreen *platformScreen) +{ + if (!m_active) + return qreal(1.0); + + return m_factor * screenSubfactor(platformScreen); +} + +qreal QHighDpiScaling::factor(const QWindow *window) +{ + if (!m_active) + return qreal(1.0); + + return factor(window ? window->screen() : QGuiApplication::primaryScreen()); +} + +QPoint QHighDpiScaling::origin(const QScreen *screen) +{ + return screen->geometry().topLeft(); +} + +QPoint QHighDpiScaling::origin(const QPlatformScreen *platformScreen) +{ + return platformScreen->geometry().topLeft(); +} + +#endif //QT_NO_HIGHDPISCALING +QT_END_NAMESPACE |