diff options
Diffstat (limited to 'src/gui/kernel/qhighdpiscaling.cpp')
| -rw-r--r-- | src/gui/kernel/qhighdpiscaling.cpp | 355 |
1 files changed, 297 insertions, 58 deletions
diff --git a/src/gui/kernel/qhighdpiscaling.cpp b/src/gui/kernel/qhighdpiscaling.cpp index 8189eebedd..76548d5d86 100644 --- a/src/gui/kernel/qhighdpiscaling.cpp +++ b/src/gui/kernel/qhighdpiscaling.cpp @@ -46,6 +46,9 @@ #include <private/qguiapplication_p.h> #include <QtCore/qdebug.h> +#include <QtCore/qmetaobject.h> + +#include <algorithm> QT_BEGIN_NAMESPACE @@ -53,9 +56,29 @@ Q_LOGGING_CATEGORY(lcScaling, "qt.scaling"); #ifndef QT_NO_HIGHDPISCALING static const char legacyDevicePixelEnvVar[] = "QT_DEVICE_PIXEL_RATIO"; +static const char legacyAutoScreenEnvVar[] = "QT_AUTO_SCREEN_SCALE_FACTOR"; + +static const char enableHighDpiScalingEnvVar[] = "QT_ENABLE_HIGHDPI_SCALING"; 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 const char scaleFactorRoundingPolicyEnvVar[] = "QT_SCALE_FACTOR_ROUNDING_POLICY"; +static const char dpiAdjustmentPolicyEnvVar[] = "QT_DPI_ADJUSTMENT_POLICY"; +static const char usePhysicalDpiEnvVar[] = "QT_USE_PHYSICAL_DPI"; + +// Per-screen scale factors for named screens set with QT_SCREEN_SCALE_FACTORS +// are stored here. Use a global hash to keep the factor across screen +// disconnect/connect cycles where the screen object may be deleted. +typedef QHash<QString, qreal> QScreenScaleFactorHash; +Q_GLOBAL_STATIC(QScreenScaleFactorHash, qNamedScreenScaleFactors); + +// Reads and interprets the given environment variable as a bool, +// returns the default value if not set. +static bool qEnvironmentVariableAsBool(const char *name, bool defaultValue) +{ + bool ok = false; + int value = qEnvironmentVariableIntValue(name, &ok); + return ok ? value > 0 : defaultValue; +} static inline qreal initialGlobalScaleFactor() { @@ -63,23 +86,30 @@ static inline qreal initialGlobalScaleFactor() qreal result = 1; if (qEnvironmentVariableIsSet(scaleFactorEnvVar)) { bool ok; - const qreal f = qgetenv(scaleFactorEnvVar).toDouble(&ok); + const qreal f = qEnvironmentVariable(scaleFactorEnvVar).toDouble(&ok); if (ok && f > 0) { qCDebug(lcScaling) << "Apply " << scaleFactorEnvVar << f; result = f; } } else { + // Check for deprecated environment variables. if (qEnvironmentVariableIsSet(legacyDevicePixelEnvVar)) { qWarning("Warning: %s is deprecated. Instead use:\n" " %s to enable platform plugin controlled per-screen factors.\n" - " %s to set per-screen factors.\n" + " %s to set per-screen DPI.\n" " %s to set the application global scale factor.", - legacyDevicePixelEnvVar, autoScreenEnvVar, screenFactorsEnvVar, scaleFactorEnvVar); + legacyDevicePixelEnvVar, legacyAutoScreenEnvVar, screenFactorsEnvVar, scaleFactorEnvVar); int dpr = qEnvironmentVariableIntValue(legacyDevicePixelEnvVar); if (dpr > 0) result = dpr; } + + if (qEnvironmentVariableIsSet(legacyAutoScreenEnvVar)) { + qWarning("Warning: %s is deprecated. Instead use:\n" + " %s to enable platform plugin controlled per-screen factors.", + legacyAutoScreenEnvVar, enableHighDpiScalingEnvVar); + } } return result; } @@ -226,7 +256,6 @@ bool QHighDpiScaling::m_usePixelDensity = false; // use scale factor from platfo 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 @@ -238,16 +267,215 @@ 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. + + // First, check of there is an explicit disable. if (QCoreApplication::testAttribute(Qt::AA_DisableHighDpiScaling)) return false; bool screenEnvValueOk; - const int screenEnvValue = qEnvironmentVariableIntValue(autoScreenEnvVar, &screenEnvValueOk); + const int screenEnvValue = qEnvironmentVariableIntValue(legacyAutoScreenEnvVar, &screenEnvValueOk); if (screenEnvValueOk && screenEnvValue < 1) return false; + bool enableEnvValueOk; + const int enableEnvValue = qEnvironmentVariableIntValue(enableHighDpiScalingEnvVar, &enableEnvValueOk); + if (enableEnvValueOk && enableEnvValue < 1) + return false; + + // Then return if there was an enable. return QCoreApplication::testAttribute(Qt::AA_EnableHighDpiScaling) || (screenEnvValueOk && screenEnvValue > 0) - || (qEnvironmentVariableIsSet(legacyDevicePixelEnvVar) && - qgetenv(legacyDevicePixelEnvVar).compare("auto", Qt::CaseInsensitive) == 0); + || (enableEnvValueOk && enableEnvValue > 0) + || (qEnvironmentVariableIsSet(legacyDevicePixelEnvVar) + && qEnvironmentVariable(legacyDevicePixelEnvVar).compare(QLatin1String("auto"), Qt::CaseInsensitive) == 0); +} + +qreal QHighDpiScaling::rawScaleFactor(const QPlatformScreen *screen) +{ + // Determine if physical DPI should be used + static const bool usePhysicalDpi = qEnvironmentVariableAsBool(usePhysicalDpiEnvVar, false); + + // Calculate scale factor beased on platform screen DPI values + qreal factor; + QDpi platformBaseDpi = screen->logicalBaseDpi(); + if (usePhysicalDpi) { + qreal platformPhysicalDpi = screen->screen()->physicalDotsPerInch(); + factor = qreal(platformPhysicalDpi) / qreal(platformBaseDpi.first); + } else { + const QDpi platformLogicalDpi = QPlatformScreen::overrideDpi(screen->logicalDpi()); + factor = qreal(platformLogicalDpi.first) / qreal(platformBaseDpi.first); + } + + return factor; +} + +template <class EnumType> +struct EnumLookup +{ + const char *name; + EnumType value; +}; + +template <class EnumType> +static bool operator==(const EnumLookup<EnumType> &e1, const EnumLookup<EnumType> &e2) +{ + return qstricmp(e1.name, e2.name) == 0; +} + +template <class EnumType> +static QByteArray joinEnumValues(const EnumLookup<EnumType> *i1, const EnumLookup<EnumType> *i2) +{ + QByteArray result; + for (; i1 < i2; ++i1) { + if (!result.isEmpty()) + result += QByteArrayLiteral(", "); + result += i1->name; + } + return result; +} + +using ScaleFactorRoundingPolicyLookup = EnumLookup<Qt::HighDpiScaleFactorRoundingPolicy>; + +static const ScaleFactorRoundingPolicyLookup scaleFactorRoundingPolicyLookup[] = +{ + {"Round", Qt::HighDpiScaleFactorRoundingPolicy::Round}, + {"Ceil", Qt::HighDpiScaleFactorRoundingPolicy::Ceil}, + {"Floor", Qt::HighDpiScaleFactorRoundingPolicy::Floor}, + {"RoundPreferFloor", Qt::HighDpiScaleFactorRoundingPolicy::RoundPreferFloor}, + {"PassThrough", Qt::HighDpiScaleFactorRoundingPolicy::PassThrough} +}; + +static Qt::HighDpiScaleFactorRoundingPolicy + lookupScaleFactorRoundingPolicy(const QByteArray &v) +{ + auto end = std::end(scaleFactorRoundingPolicyLookup); + auto it = std::find(std::begin(scaleFactorRoundingPolicyLookup), end, + ScaleFactorRoundingPolicyLookup{v.constData(), Qt::HighDpiScaleFactorRoundingPolicy::Unset}); + return it != end ? it->value : Qt::HighDpiScaleFactorRoundingPolicy::Unset; +} + +using DpiAdjustmentPolicyLookup = EnumLookup<QHighDpiScaling::DpiAdjustmentPolicy>; + +static const DpiAdjustmentPolicyLookup dpiAdjustmentPolicyLookup[] = +{ + {"AdjustDpi", QHighDpiScaling::DpiAdjustmentPolicy::Enabled}, + {"DontAdjustDpi", QHighDpiScaling::DpiAdjustmentPolicy::Disabled}, + {"AdjustUpOnly", QHighDpiScaling::DpiAdjustmentPolicy::UpOnly} +}; + +static QHighDpiScaling::DpiAdjustmentPolicy + lookupDpiAdjustmentPolicy(const QByteArray &v) +{ + auto end = std::end(dpiAdjustmentPolicyLookup); + auto it = std::find(std::begin(dpiAdjustmentPolicyLookup), end, + DpiAdjustmentPolicyLookup{v.constData(), QHighDpiScaling::DpiAdjustmentPolicy::Unset}); + return it != end ? it->value : QHighDpiScaling::DpiAdjustmentPolicy::Unset; +} + +qreal QHighDpiScaling::roundScaleFactor(qreal rawFactor) +{ + // Apply scale factor rounding policy. Using mathematically correct rounding + // may not give the most desirable visual results, especially for + // critical fractions like .5. In general, rounding down results in visual + // sizes that are smaller than the ideal size, and opposite for rounding up. + // Rounding down is then preferable since "small UI" is a more acceptable + // high-DPI experience than "large UI". + static auto scaleFactorRoundingPolicy = Qt::HighDpiScaleFactorRoundingPolicy::Unset; + + // Determine rounding policy + if (scaleFactorRoundingPolicy == Qt::HighDpiScaleFactorRoundingPolicy::Unset) { + // Check environment + if (qEnvironmentVariableIsSet(scaleFactorRoundingPolicyEnvVar)) { + QByteArray policyText = qgetenv(scaleFactorRoundingPolicyEnvVar); + auto policyEnumValue = lookupScaleFactorRoundingPolicy(policyText); + if (policyEnumValue != Qt::HighDpiScaleFactorRoundingPolicy::Unset) { + scaleFactorRoundingPolicy = policyEnumValue; + } else { + auto values = joinEnumValues(std::begin(scaleFactorRoundingPolicyLookup), + std::end(scaleFactorRoundingPolicyLookup)); + qWarning("Unknown scale factor rounding policy: %s. Supported values are: %s.", + policyText.constData(), values.constData()); + } + } + + // Check application object if no environment value was set. + if (scaleFactorRoundingPolicy == Qt::HighDpiScaleFactorRoundingPolicy::Unset) { + scaleFactorRoundingPolicy = QGuiApplication::highDpiScaleFactorRoundingPolicy(); + } else { + // Make application setting reflect environment + QGuiApplication::setHighDpiScaleFactorRoundingPolicy(scaleFactorRoundingPolicy); + } + } + + // Apply rounding policy. + qreal roundedFactor = rawFactor; + switch (scaleFactorRoundingPolicy) { + case Qt::HighDpiScaleFactorRoundingPolicy::Round: + roundedFactor = qRound(rawFactor); + break; + case Qt::HighDpiScaleFactorRoundingPolicy::Ceil: + roundedFactor = qCeil(rawFactor); + break; + case Qt::HighDpiScaleFactorRoundingPolicy::Floor: + roundedFactor = qFloor(rawFactor); + break; + case Qt::HighDpiScaleFactorRoundingPolicy::RoundPreferFloor: + // Round up for .75 and higher. This favors "small UI" over "large UI". + roundedFactor = rawFactor - qFloor(rawFactor) < 0.75 + ? qFloor(rawFactor) : qCeil(rawFactor); + break; + case Qt::HighDpiScaleFactorRoundingPolicy::PassThrough: + case Qt::HighDpiScaleFactorRoundingPolicy::Unset: + break; + } + + // Don't round down to to zero; clamp the minimum (rounded) factor to 1. + // This is not a common case but can happen if a display reports a very + // low DPI. + if (scaleFactorRoundingPolicy != Qt::HighDpiScaleFactorRoundingPolicy::PassThrough) + roundedFactor = qMax(roundedFactor, qreal(1)); + + return roundedFactor; +} + +QDpi QHighDpiScaling::effectiveLogicalDpi(const QPlatformScreen *screen, qreal rawFactor, qreal roundedFactor) +{ + // Apply DPI adjustment policy, if needed. If enabled this will change the + // reported logical DPI to account for the difference between the rounded + // scale factor and the actual scale factor. The effect is that text size + // will be correct for the screen dpi, but may be (slightly) out of sync + // with the rest of the UI. The amount of out-of-synch-ness depends on how + // well user code handles a non-standard DPI values, but since the + // adjustment is small (typically +/- 48 max) this might be OK. + static auto dpiAdjustmentPolicy = DpiAdjustmentPolicy::Unset; + + // Determine adjustment policy. + if (dpiAdjustmentPolicy == DpiAdjustmentPolicy::Unset) { + if (qEnvironmentVariableIsSet(dpiAdjustmentPolicyEnvVar)) { + QByteArray policyText = qgetenv(dpiAdjustmentPolicyEnvVar); + auto policyEnumValue = lookupDpiAdjustmentPolicy(policyText); + if (policyEnumValue != DpiAdjustmentPolicy::Unset) { + dpiAdjustmentPolicy = policyEnumValue; + } else { + auto values = joinEnumValues(std::begin(dpiAdjustmentPolicyLookup), + std::end(dpiAdjustmentPolicyLookup)); + qWarning("Unknown DPI adjustment policy: %s. Supported values are: %s.", + policyText.constData(), values.constData()); + } + } + if (dpiAdjustmentPolicy == DpiAdjustmentPolicy::Unset) + dpiAdjustmentPolicy = DpiAdjustmentPolicy::UpOnly; + } + + // Apply adjustment policy. + const QDpi baseDpi = screen->logicalBaseDpi(); + const qreal dpiAdjustmentFactor = rawFactor / roundedFactor; + + // Return the base DPI for cases where there is no adjustment + if (dpiAdjustmentPolicy == DpiAdjustmentPolicy::Disabled) + return baseDpi; + if (dpiAdjustmentPolicy == DpiAdjustmentPolicy::UpOnly && dpiAdjustmentFactor < 1) + return baseDpi; + + return QDpi(baseDpi.first * dpiAdjustmentFactor, baseDpi.second * dpiAdjustmentFactor); } void QHighDpiScaling::initHighDpiScaling() @@ -260,8 +488,6 @@ void QHighDpiScaling::initHighDpiScaling() 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; } @@ -281,22 +507,21 @@ void QHighDpiScaling::updateHighDpiScaling() } if (qEnvironmentVariableIsSet(screenFactorsEnvVar)) { int i = 0; - const auto specs = qgetenv(screenFactorsEnvVar).split(';'); - for (const QByteArray &spec : specs) { - QScreen *screen = 0; - int equalsPos = spec.lastIndexOf('='); - double factor = 0; + const QString spec = qEnvironmentVariable(screenFactorsEnvVar); + const auto specs = spec.splitRef(QLatin1Char(';')); + for (const QStringRef &spec : specs) { + int equalsPos = spec.lastIndexOf(QLatin1Char('=')); + qreal 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) { + const auto name = spec.left(equalsPos); + factor = spec.mid(equalsPos + 1).toDouble(&ok); + if (ok && factor > 0 ) { const auto screens = QGuiApplication::screens(); for (QScreen *s : screens) { - if (s->name() == QString::fromLocal8Bit(name)) { - screen = s; + if (s->name() == name) { + setScreenFactor(s, factor); break; } } @@ -305,23 +530,15 @@ void QHighDpiScaling::updateHighDpiScaling() // listing screens in order bool ok; factor = spec.toDouble(&ok); - if (ok && i < QGuiApplication::screens().count()) - screen = QGuiApplication::screens().at(i); + if (ok && factor > 0 && i < QGuiApplication::screens().count()) { + QScreen *screen = QGuiApplication::screens().at(i); + setScreenFactor(screen, factor); + } } - if (screen) - setScreenFactor(screen, factor); ++i; } } - m_active = m_globalScalingActive || m_screenFactorSet || m_pixelDensityScalingActive; - - QScreen *primaryScreen = QGuiApplication::primaryScreen(); - if (!primaryScreen) - return; - QPlatformScreen *platformScreen = primaryScreen->handle(); - qreal sf = screenSubfactor(platformScreen); - QDpi primaryDpi = platformScreen->logicalDpi(); - m_logicalDpi = QDpi(primaryDpi.first / sf, primaryDpi.second / sf); + m_active = m_globalScalingActive || m_screenFactorSet || m_usePixelDensity; } /* @@ -353,7 +570,14 @@ void QHighDpiScaling::setScreenFactor(QScreen *screen, qreal factor) m_screenFactorSet = true; m_active = true; } - screen->setProperty(scaleFactorProperty, QVariant(factor)); + + // Prefer associating the factor with screen name over the object + // since the screen object may be deleted on screen disconnects. + const QString name = screen->name(); + if (name.isEmpty()) + screen->setProperty(scaleFactorProperty, QVariant(factor)); + else + qNamedScreenScaleFactors()->insert(name, factor); // hack to force re-evaluation of screen geometry if (screen->handle()) @@ -421,35 +645,50 @@ QPoint QHighDpiScaling::mapPositionFromGlobal(const QPoint &pos, const QPoint &w qreal QHighDpiScaling::screenSubfactor(const QPlatformScreen *screen) { qreal factor = qreal(1.0); - if (screen) { - if (m_usePixelDensity) { - qreal pixelDensity = screen->pixelDensity(); - - // Pixel density reported by the screen is sometimes not precise enough, - // so recalculate it: divide px (physical pixels) by dp (device-independent pixels) - // for both width and height, and then use the average if it is different from - // the one initially reported by the screen - QRect screenGeometry = screen->geometry(); - qreal wFactor = qreal(screenGeometry.width()) / qRound(screenGeometry.width() / pixelDensity); - qreal hFactor = qreal(screenGeometry.height()) / qRound(screenGeometry.height() / pixelDensity); - qreal averageDensity = (wFactor + hFactor) / 2; - if (!qFuzzyCompare(pixelDensity, averageDensity)) - pixelDensity = averageDensity; - - factor *= pixelDensity; - } - if (m_screenFactorSet) { - QVariant screenFactor = screen->screen()->property(scaleFactorProperty); - if (screenFactor.isValid()) - factor *= screenFactor.toReal(); + if (!screen) + return factor; + + // Unlike the other code where factors are combined by multiplication, + // factors from QT_SCREEN_SCALE_FACTORS takes precedence over the factor + // computed from platform plugin DPI. The rationale is that the user is + // setting the factor to override erroneous DPI values. + bool screenPropertyUsed = false; + if (m_screenFactorSet) { + // Check if there is a factor set on the screen object or associated + // with the screen name. These are mutually exclusive, so checking + // order is not significant. + QVariant byIndex = screen->screen()->property(scaleFactorProperty); + auto byNameIt = qNamedScreenScaleFactors()->constFind(screen->name()); + if (byIndex.isValid()) { + screenPropertyUsed = true; + factor = byIndex.toReal(); + } else if (byNameIt != qNamedScreenScaleFactors()->cend()) { + screenPropertyUsed = true; + factor = *byNameIt; } } + + if (!screenPropertyUsed && m_usePixelDensity) + factor = roundScaleFactor(rawScaleFactor(screen)); + return factor; } -QDpi QHighDpiScaling::logicalDpi() +QDpi QHighDpiScaling::logicalDpi(const QScreen *screen) { - return m_logicalDpi; + // (Note: m_active test is performed at call site.) + if (!screen || !screen->handle()) + return QDpi(96, 96); + + if (!m_usePixelDensity) { + const qreal screenScaleFactor = screenSubfactor(screen->handle()); + const QDpi dpi = QPlatformScreen::overrideDpi(screen->handle()->logicalDpi()); + return QDpi{ dpi.first / screenScaleFactor, dpi.second / screenScaleFactor }; + } + + const qreal scaleFactor = rawScaleFactor(screen->handle()); + const qreal roundedScaleFactor = roundScaleFactor(scaleFactor); + return effectiveLogicalDpi(screen->handle(), scaleFactor, roundedScaleFactor); } QHighDpiScaling::ScaleAndOrigin QHighDpiScaling::scaleAndOrigin(const QPlatformScreen *platformScreen, QPoint *nativePosition) |