Update DprGadadget

Display active environment variables. Reorder the
labels with device independent values to the left
and native values to the right. Display the Qt scale
factor.

Change-Id: If95c252b06eff5abd91a25847777246effe94be2
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

tests/manual/highdpi/dprgadget/CMakeLists.txt

@@ -14,6 +14,7 @@ qt_add_executable(dprgadget
 target_link_libraries(dprgadget PUBLIC
     Qt::Core
     Qt::Gui
+    Qt::GuiPrivate
     Qt::Widgets
 )
 

tests/manual/highdpi/dprgadget/main.cpp

@@ -26,8 +26,11 @@
  **
  ****************************************************************************/
 
-#include <QtWidgets/QtWidgets>
 #include <QtGui/qpa/qplatformscreen.h>
+#include <QtGui/qpa/qplatformwindow.h>
+#include <QtGui/private/qhighdpiscaling_p.h>
+#include <QtWidgets/QtWidgets>
+#include <iostream>
 
 /*
     DprGadget: The focused High-DPI settings debug utility
@@ -40,8 +43,12 @@
     an utility which displays all inputs.
 */
 
-bool g_qtUsePhysicalDpi = false;
 bool g_qtScaleFactor = false;
+bool g_qtUsePhysicalDpi = false;
+bool g_qtFontDpi = false;
+bool g_qtScaleFactorRoundingPolicy = false;
+bool g_displayEvents = false;
+
 
 class DprGadget : public QWidget
 {
@@ -49,10 +56,13 @@ public:
     std::function<void(void)> m_clearFn;
     std::function<void(void)> m_updateFn;
     qreal m_currentDpr = -1;
+    QString m_eventsText;
 
     DprGadget() {
-        setWindowTitle("DprGadget");
+        setWindowTitle(QString("DprGadget - Qt %1").arg(qVersion()));
 
+        QFont tinyFont;
+        tinyFont.setPointSize(8);
         QFont smallFont;
         smallFont.setPointSize(12);
         QFont bigFont;
@@ -68,71 +78,148 @@ public:
         dprValue->setFont(biggerFont);
         dprValue->setTextInteractionFlags(Qt::TextSelectableByMouse);
 
-        QLabel *dpiLabel = new QLabel("Logical DPI:");
+        QLabel *screenLabel = new QLabel("Current Screen:");
-        dpiLabel->setFont(smallFont);
+        screenLabel->setFont(smallFont);
-        dpiLabel->setTextInteractionFlags(Qt::TextSelectableByMouse);
 
         QLabel *sizeLabel = new QLabel("Window size:");
         sizeLabel->setFont(smallFont);
         sizeLabel->setTextInteractionFlags(Qt::TextSelectableByMouse);
 
+        QLabel *nativeSizeLabel = new QLabel("Native:");
+        nativeSizeLabel->setFont(smallFont);
+        nativeSizeLabel->setTextInteractionFlags(Qt::TextSelectableByMouse);
+
+        QLabel *dpiLabel = new QLabel("Logical DPI:");
+        dpiLabel->setFont(smallFont);
+        dpiLabel->setTextInteractionFlags(Qt::TextSelectableByMouse);
+
+        QLabel *windowDpiLabel = new QLabel("Window DPI:");
+        windowDpiLabel->setFont(smallFont);
+        windowDpiLabel->setTextInteractionFlags(Qt::TextSelectableByMouse);
+
         QLabel *platformDpiLabel = new QLabel("Native Device Pixel Ratio:");
-        QLabel *plarformDprLabel = new QLabel("Native Logical DPI:");
         platformDpiLabel->setFont(smallFont);
         platformDpiLabel->setTextInteractionFlags(Qt::TextSelectableByMouse);
+
+        QLabel *windowDprLabel = new QLabel("Window DPR:");
+        windowDprLabel->setFont(smallFont);
+        windowDprLabel->setTextInteractionFlags(Qt::TextSelectableByMouse);
+
+        QLabel *plarformDprLabel = new QLabel("Native DPI:");
         plarformDprLabel->setFont(smallFont);
         plarformDprLabel->setTextInteractionFlags(Qt::TextSelectableByMouse);
 
-        QLabel *screenLabel = new QLabel("Current Screen:");
+        QLabel *qtScaleFactorLabel = new QLabel("Qt Internal Scale Factor:");
-        screenLabel->setFont(smallFont);
+        qtScaleFactorLabel->setFont(smallFont);
+
+        QLabel *eventsLabel = new QLabel(m_eventsText);
+        eventsLabel->setFont(tinyFont);
+        eventsLabel->setTextInteractionFlags(Qt::TextSelectableByMouse);
 
         QVBoxLayout *layout = new QVBoxLayout();
         layout->addWidget(dprLabel);
         layout->setAlignment(dprLabel, Qt::AlignHCenter);
         layout->addWidget(dprValue);
         layout->setAlignment(dprValue, Qt::AlignHCenter);
-        layout->addWidget(sizeLabel);
 
         bool displayLogicalDpi = false;
         if (displayLogicalDpi)
             layout->addWidget(dpiLabel);
 
-        if (g_qtScaleFactor) {
-            QString text = QString("QT_SCALE_FACTOR ") + qgetenv("QT_SCALE_FACTOR");
-            layout->addWidget(new QLabel(text));
-        }
-
         layout->addStretch();
-        layout->addWidget(screenLabel);
+
-        layout->addWidget(platformDpiLabel);
+        QHBoxLayout *screenLabelLayout = new QHBoxLayout();
-        layout->addWidget(plarformDprLabel);
+        screenLabelLayout->addStretch();
+        screenLabelLayout->addWidget(screenLabel);
+        screenLabelLayout->addStretch();
+        layout->addLayout(screenLabelLayout);
+
+        QHBoxLayout *windowSizeLayout = new QHBoxLayout();
+        windowSizeLayout->addWidget(sizeLabel);
+        windowSizeLayout->addStretch();
+        windowSizeLayout->addWidget(nativeSizeLabel);
+        layout->addLayout(windowSizeLayout);
+
+        QHBoxLayout *dpiLayout = new QHBoxLayout();
+        dpiLayout->addWidget(windowDpiLabel);
+        dpiLayout->addStretch();
+        dpiLayout->addWidget(platformDpiLabel);
+        layout->addLayout(dpiLayout);
+
+        QHBoxLayout *dprLayout = new QHBoxLayout();
+        dprLayout->addWidget(windowDprLabel);
+        dprLayout->addStretch();
+        dprLayout->addWidget(plarformDprLabel);
+        layout->addLayout(dprLayout);
+
+        QHBoxLayout *qtScaleFactorLabelLayout = new QHBoxLayout();
+        qtScaleFactorLabelLayout->addStretch();
+        qtScaleFactorLabelLayout->addWidget(qtScaleFactorLabel);
+        qtScaleFactorLabelLayout->addStretch();
+        layout->addLayout(qtScaleFactorLabelLayout);
+
+        if (g_displayEvents)
+            layout->addWidget(eventsLabel);
+
+        bool activeEnvironment = g_qtScaleFactor || g_qtUsePhysicalDpi || g_qtFontDpi || g_qtScaleFactorRoundingPolicy;
+        if (activeEnvironment) {
+            layout->addWidget(new QLabel("Active Environment:"));
+            if (g_qtScaleFactor) {
+                QString text = QString("QT_SCALE_FACTOR=") + qgetenv("QT_SCALE_FACTOR");
+                layout->addWidget(new QLabel(text));
+            }
+            if (g_qtUsePhysicalDpi) {
+                QString text = QString("QT_USE_PHYSICAL_DPI=") + qgetenv("QT_USE_PHYSICAL_DPI");
+                layout->addWidget(new QLabel(text));
+            }
+            if (g_qtFontDpi) {
+                QString text = QString("QT_FONT_DPI=") + qgetenv("QT_FONT_DPI");
+                layout->addWidget(new QLabel(text));
+            }
+            if (g_qtScaleFactorRoundingPolicy) {
+                QString text = QString("QT_SCALE_FACTOR_ROUNDING_POLICY=") + qgetenv("QT_SCALE_FACTOR_ROUNDING_POLICY");
+                layout->addWidget(new QLabel(text));
+            }
+
+        }
 
         auto updateValues = [=]() {
             dprValue->setText(QString("%1").arg(devicePixelRatioF()));
+            windowDpiLabel->setText(QString("QWindow DPI: %1").arg(logicalDpiX()));
             dpiLabel->setText(QString("Logical DPI: %1").arg(logicalDpiX()));
-            sizeLabel->setText(QString("Window size: %1 %2").arg(width()).arg(height()));
+            sizeLabel->setText(QString("QWindow size: %1 %2").arg(width()).arg(height()));
 
+            QPlatformWindow *platformWindow = windowHandle()->handle();
+            nativeSizeLabel->setText(QString("native size %1 %2").arg(platformWindow->geometry().width())
+                                                            .arg(platformWindow->geometry().height()));
             QPlatformScreen *pscreen = screen()->handle();
+            if (g_qtUsePhysicalDpi) {
+                int physicalDpi = qRound(pscreen->geometry().width() / pscreen->physicalSize().width() * qreal(25.4));
+                platformDpiLabel->setText(QString("Native Physical DPI: %1").arg(physicalDpi));
+            } else {
+                platformDpiLabel->setText(QString("native logical DPI: %1").arg(pscreen->logicalDpi().first));
+            }
 
-            if (g_qtUsePhysicalDpi)
+            windowDprLabel->setText(QString("QWindow DPR: %1").arg(windowHandle()->devicePixelRatio()));
-                platformDpiLabel->setText(QString("Native Physical DPI: TODO"));
+            plarformDprLabel->setText(QString("native DPR: %1").arg(pscreen->devicePixelRatio()));
-            else
-                platformDpiLabel->setText(QString("Native Logical DPI: %1").arg(pscreen->logicalDpi().first));
-
-            plarformDprLabel->setText(QString("Native Device Pixel Ratio: %1").arg(pscreen->devicePixelRatio()));
 
             screenLabel->setText(QString("Current Screen: %1").arg(screen()->name()));
+            qtScaleFactorLabel->setText(QString("Qt Internal Scale Factor: %1").arg(QHighDpiScaling::factor(windowHandle())));
+            eventsLabel->setText(QString(m_eventsText));
         };
         m_updateFn = updateValues;
 
         m_clearFn = [=]() {
             dprValue->setText(QString(""));
+            m_eventsText.clear();
         };
 
         create();
 
-        QObject::connect(this->windowHandle(), &QWindow::screenChanged, [updateValues](QScreen *screen){
+        QObject::connect(this->windowHandle(), &QWindow::screenChanged, [updateValues, this](QScreen *screen){
             Q_UNUSED(screen);
+            this->m_eventsText.prepend(QString("ScreenChange "));
+            this->m_eventsText.truncate(80);
             updateValues();
         });
 
@@ -142,6 +229,12 @@ public:
     }
 
     void paintEvent(QPaintEvent *) override  {
+
+        // Update the UI in the paint event - normally not good
+        // practice but it looks like we can get away with it here
+        this->m_eventsText.prepend(QString("Paint "));
+        this->m_eventsText.truncate(80);
+
         // Dpr change should trigger a repaint, update display values here
         if (m_currentDpr == devicePixelRatioF())
             return;
@@ -150,7 +243,10 @@ public:
         m_updateFn();
     }
 
-    void resizeEvent(QResizeEvent *) override {
+    void resizeEvent(QResizeEvent *event) override {
+        QSize size = event->size();
+        m_eventsText.prepend(QString("Resize(%1 %2) ").arg(size.width()).arg(size.height()));
+        m_eventsText.truncate(80);
         m_updateFn();
     }
 
@@ -168,18 +264,15 @@ int main(int argc, char **argv) {
     QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
     QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::PassThrough);
 
-    // react to (some) high-dpi eviornment variables.
+    // Display any set high-dpi eviornment variable.
-    g_qtUsePhysicalDpi = qgetenv("QT_USE_PHYSICAL_DPI") == QByteArray("1");
     g_qtScaleFactor = qEnvironmentVariableIsSet("QT_SCALE_FACTOR");
+    g_qtUsePhysicalDpi = qgetenv("QT_USE_PHYSICAL_DPI") == QByteArray("1");
+    g_qtFontDpi = qEnvironmentVariableIsSet("QT_FONT_DPI");
+    g_qtScaleFactorRoundingPolicy = qEnvironmentVariableIsSet("QT_SCALE_FACTOR_ROUNDING_POLICY");
 
     QApplication app(argc, argv);
 
     DprGadget dprGadget;
-
-    // Set initial size. We expect this size to be preserved across screen
-    // and DPI changes
-    dprGadget.resize(560, 380);
-
     dprGadget.show();
 
     return app.exec();