Deprecate and remove uses of AA_DisableHighDpiScaling

Change-Id: Ibadce68775858c524b998aacad310905ba2c2e8e
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

examples/widgets/gallery/main.cpp

@@ -54,16 +54,6 @@
 
 int main(int argc, char *argv[])
 {
-    bool useHighDpiScaling = true;
-
-    for (int i = 1; i < argc; ++i) {
-        if (qstrcmp(argv[i], "--no-scaling") == 0)
-            useHighDpiScaling = false;
-    }
-
-    if (!useHighDpiScaling)
-        QCoreApplication::setAttribute(Qt::AA_DisableHighDpiScaling);
-
     QApplication app(argc, argv);
     WidgetGallery gallery;
     gallery.show();

src/corelib/global/qnamespace.h

@@ -470,9 +470,13 @@ namespace Qt {
         AA_ShareOpenGLContexts = 18,
         AA_SetPalette = 19,
 #if QT_DEPRECATED_SINCE(6, 0)
-        AA_EnableHighDpiScaling Q_DECL_ENUMERATOR_DEPRECATED = 20,
+        AA_EnableHighDpiScaling Q_DECL_ENUMERATOR_DEPRECATED_X(
+            "High-DPI scaling is always enabled. " \
+            "This attribute no longer has any effect.") = 20,
+        AA_DisableHighDpiScaling Q_DECL_ENUMERATOR_DEPRECATED_X(
+            "High-DPI scaling is always enabled. " \
+            "This attribute no longer has any effect.") = 21,
 #endif
-        AA_DisableHighDpiScaling = 21,
         AA_UseStyleSheetPropagationInWidgetStyles = 22,
         AA_DontUseNativeDialogs = 23,
         AA_SynthesizeMouseForUnhandledTabletEvents = 24,

src/corelib/global/qnamespace.qdoc

@@ -208,15 +208,6 @@
     \value AA_SetPalette Indicates whether a palette was explicitly set on the
            QGuiApplication. This value was added in Qt 5.5.
 
-    \value AA_DisableHighDpiScaling Disables high-DPI scaling in Qt, exposing window
-           system coordinates. Note that the window system may do its own scaling,
-           so this does not guarantee that QPaintDevice::devicePixelRatio() will
-           be equal to 1. In addition, scale factors set by QT_SCALE_FACTOR will not
-           be affected. This corresponds to setting the
-           QT_AUTO_SCREEN\unicode{0x200b}_SCALE_FACTOR environment variable to 0.
-           This attribute must be set before QGuiApplication is constructed.
-           This value was added in Qt 5.6.
-
     \value AA_UseStyleSheetPropagationInWidgetStyles By default, Qt Style Sheets
            disable regular QWidget palette and font propagation. When this flag
            is enabled, font and palette changes propagate as though the user had
@@ -291,6 +282,7 @@
     \omitvalue AA_AttributeCount
     \omitvalue AA_EnableHighDpiScaling
     \omitvalue AA_UseHighDpiPixmaps
+    \omitvalue AA_DisableHighDpiScaling
 */
 
 /*!

src/corelib/kernel/qcoreapplication.cpp

@@ -951,7 +951,6 @@ void QCoreApplication::setAttribute(Qt::ApplicationAttribute attribute, bool on)
     if (Q_UNLIKELY(QCoreApplicationPrivate::is_app_running)) {
 #endif
         switch (attribute) {
-            case Qt::AA_DisableHighDpiScaling:
             case Qt::AA_PluginApplication:
             case Qt::AA_UseDesktopOpenGL:
             case Qt::AA_UseOpenGLES:

src/gui/kernel/qhighdpiscaling.cpp

@@ -208,10 +208,8 @@ static inline qreal initialGlobalScaleFactor()
         factor based on display density information. These platforms
         include X11, Windows, and Android.
 
-        There are two APIs for enabling or disabling this behavior:
+        There is one API 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
@@ -265,9 +263,6 @@ static inline bool usePixelDensity()
     // reported by the platform plugin. There are several enablers and several
     // disablers. A single disable may veto all other enablers.
 
-    // Check if there is an explicit disable
-    if (QCoreApplication::testAttribute(Qt::AA_DisableHighDpiScaling))
-        return false;
     bool screenEnvValueOk;
     const int screenEnvValue = qEnvironmentVariableIntValue(legacyAutoScreenEnvVar, &screenEnvValueOk);
     if (screenEnvValueOk && screenEnvValue < 1)
@@ -488,9 +483,6 @@ void QHighDpiScaling::initHighDpiScaling()
 
 void QHighDpiScaling::updateHighDpiScaling()
 {
-    if (QCoreApplication::testAttribute(Qt::AA_DisableHighDpiScaling))
-        return;
-
     m_usePixelDensity = usePixelDensity();
 
     if (m_usePixelDensity && !m_pixelDensityScalingActive) {

src/testlib/doc/src/qttestlib-manual.qdoc

@@ -129,8 +129,7 @@
 
     Finally, if the test class has a static public \c{void initMain()} method,
     it is called by the QTEST_MAIN macros before the QApplication object
-    is instantiated. For example, this allows for setting application
+    is instantiated. This was added in 5.14.
-    attributes like Qt::AA_DisableHighDpiScaling. This was added in 5.14.
 
     For more examples, refer to the \l{Qt Test Tutorial}.
 

src/testlib/qtest.h

@@ -465,7 +465,7 @@ bool compareSequence(ActualIterator actualIt, ActualIterator actualEnd,
 #if defined(TESTCASE_LOWDPI)
 void disableHighDpi()
 {
-    QCoreApplication::setAttribute(Qt::AA_DisableHighDpiScaling);
+    qputenv("QT_ENABLE_HIGHDPI_SCALING", "0");
 }
 Q_CONSTRUCTOR_FUNCTION(disableHighDpi);
 #endif

tests/auto/gui/kernel/noqteventloop/tst_noqteventloop.cpp

@@ -223,7 +223,8 @@ void tst_NoQtEventLoop::consumeMouseEvents()
     int argc = 1;
     char *argv[] = {const_cast<char*>("test")};
     // ensure scaling is off since the child window is positioned using QWindow API.
-    QCoreApplication::setAttribute(Qt::AA_DisableHighDpiScaling);
+    // FIXME: Position by taking the screen DPR into account instead
+    qputenv("QT_ENABLE_HIGHDPI_SCALING", "0");
     QGuiApplication app(argc, argv);
     QString clsName(QStringLiteral("tst_NoQtEventLoop_WINDOW"));
     const HINSTANCE appInstance = (HINSTANCE)GetModuleHandle(0);

tests/auto/widgets/styles/qstylesheetstyle/tst_qstylesheetstyle.cpp

@@ -72,8 +72,6 @@ class tst_QStyleSheetStyle : public QObject
 public:
     tst_QStyleSheetStyle();
 
-    static void initMain();
-
 private slots:
     void init();
     void cleanup();
@@ -173,12 +171,6 @@ private:
     QSize m_testSize;
 };
 
-// highdpiImages() tests HighDPI scaling; disable initially.
-void tst_QStyleSheetStyle::initMain()
-{
-    QCoreApplication::setAttribute(Qt::AA_DisableHighDpiScaling);
-}
-
 tst_QStyleSheetStyle::tst_QStyleSheetStyle()
 {
     const int testSize = qMax(200, m_availableGeometry.width() / 10);
@@ -2215,8 +2207,9 @@ void tst_QStyleSheetStyle::highdpiImages()
     w.setWindowTitle(QLatin1String(QTest::currentTestFunction()) + QLatin1String("::")
                      + QLatin1String(QTest::currentDataTag()));
     QScreen *screen = QGuiApplication::primaryScreen();
+    auto inverseDpr = 1 / screen->devicePixelRatio();
     w.move(screen->availableGeometry().topLeft());
-    QHighDpiScaling::setScreenFactor(screen, screenFactor);
+    QHighDpiScaling::setScreenFactor(screen, inverseDpr * screenFactor);
     w.setStyleSheet("QWidget { background-image: url(\":/images/testimage.png\"); }");
     w.show();
 

tests/manual/embeddedintoforeignwindow/main.cpp

@@ -207,9 +207,6 @@ static inline bool isOptionSet(int argc, char *argv[], const char *option)
 
 int main(int argc, char *argv[])
 {
-    // Check for no scaling before QApplication is instantiated.
-    if (isOptionSet(argc, argv, "-s"))
-        QCoreApplication::setAttribute(Qt::AA_DisableHighDpiScaling);
     QCoreApplication::setApplicationVersion(QLatin1String(QT_VERSION_STR));
     QGuiApplication::setApplicationDisplayName("Foreign Window Embedding Tester");
 

tests/manual/foreignwindows/main.cpp

@@ -226,9 +226,6 @@ static inline bool isOptionSet(int argc, char *argv[], const char *option)
 
 int main(int argc, char *argv[])
 {
-    // Check for no scaling before QApplication is instantiated.
-    if (isOptionSet(argc, argv, "-s"))
-        QCoreApplication::setAttribute(Qt::AA_DisableHighDpiScaling);
     QCoreApplication::setApplicationVersion(QLatin1String(QT_VERSION_STR));
     QGuiApplication::setApplicationDisplayName("Foreign window tester");
 

tests/manual/highdpi/main.cpp

@@ -1424,19 +1424,8 @@ void MetricsTest::logScreenChangeSignal(const QObject *o, const char *name, cons
 
 int main(int argc, char **argv)
 {
-#define NOSCALINGOPTION "noscaling"
-
     qInfo("High DPI tester %s", QT_VERSION_STR);
 
-    int preAppOptionCount = 0;
-    for (int a = 1; a < argc; ++a) {
-        if (qstrcmp(argv[a], "--" NOSCALINGOPTION) == 0) {
-            QCoreApplication::setAttribute(Qt::AA_DisableHighDpiScaling);
-            preAppOptionCount++;
-            qInfo("AA_DisableHighDpiScaling");
-        }
-    }
-
     QApplication app(argc, argv);
     QCoreApplication::setApplicationVersion(QT_VERSION_STR);
 
@@ -1449,7 +1438,6 @@ int main(int argc, char **argv)
     parser.addVersionOption();
     QCommandLineOption controllerOption("interactive", "Show configuration window.");
     parser.addOption(controllerOption);
-    parser.addOption(QCommandLineOption(NOSCALINGOPTION, "Set AA_DisableHighDpiScaling"));
 
     DemoContainerList demoList;
     demoList << new DemoContainer<PixmapPainter>("pixmap", "Test pixmap painter");
@@ -1478,7 +1466,7 @@ int main(int argc, char **argv)
     //controller takes ownership of all demos
     DemoController controller(demoList, &parser);
 
-    if (parser.isSet(controllerOption) || (QCoreApplication::arguments().count() - preAppOptionCount) <= 1)
+    if (parser.isSet(controllerOption) || (QCoreApplication::arguments().count()) <= 1)
         controller.show();
 
     if (QApplication::topLevelWidgets().isEmpty())

tests/manual/qcursor/qcursorhighdpi/main.cpp

@@ -338,11 +338,6 @@ int main(int argc, char *argv[])
     QStringList arguments;
     std::copy(argv + 1, argv + argc, std::back_inserter(arguments));
 
-#if QT_VERSION > 0x050000
-    if (arguments.contains("-n"))
-        QCoreApplication::setAttribute(Qt::AA_DisableHighDpiScaling);
-#endif // Qt 5
-
     QApplication app(argc, argv);
 
     MainWindowPtrList windows;