From bc6dea891ea3bff991cf6a080aed46baebdb0cf0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Morten=20S=C3=B8rvig?= <morten.sorvig@qt.io>
Date: Thu, 19 May 2022 22:23:36 +0200
Subject: [PATCH] High-dpi: Add test for setting the scale factor rounding
 policy
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Test setting both via QGuiApplication property and environment.

Change-Id: Iaccc920adb6294d610b02d4c844aa5b15eb7eecd
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
---
 .../auto/gui/kernel/qhighdpi/tst_qhighdpi.cpp | 56 +++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/tests/auto/gui/kernel/qhighdpi/tst_qhighdpi.cpp b/tests/auto/gui/kernel/qhighdpi/tst_qhighdpi.cpp
index 5f0d226124c..f221c9db909 100644
--- a/tests/auto/gui/kernel/qhighdpi/tst_qhighdpi.cpp
+++ b/tests/auto/gui/kernel/qhighdpi/tst_qhighdpi.cpp
@@ -39,6 +39,8 @@ private slots:
     void environment_QT_SCREEN_SCALE_FACTORS_data();
     void environment_QT_SCREEN_SCALE_FACTORS();
     void environment_QT_USE_PHYSICAL_DPI();
+    void environment_QT_SCALE_FACTOR_ROUNDING_POLICY();
+    void application_setScaleFactorRoundingPolicy();
     void screenAt_data();
     void screenAt();
     void screenGeometry_data();
@@ -187,6 +189,7 @@ void tst_QHighDpi::cleanup()
     qunsetenv("QT_SCALE_FACTOR");
     qunsetenv("QT_SCREEN_SCALE_FACTORS");
     qunsetenv("QT_USE_PHYSICAL_DPI");
+    qunsetenv("QT_SCALE_FACTOR_ROUNDING_POLICY");
 }
 
 void tst_QHighDpi::qhighdpiscaling_data()
@@ -351,6 +354,59 @@ void tst_QHighDpi::environment_QT_USE_PHYSICAL_DPI()
     }
 }
 
+void tst_QHighDpi::environment_QT_SCALE_FACTOR_ROUNDING_POLICY()
+{
+    QList<qreal> dpiValues { 96, 144, 192 };
+
+    qputenv("QT_SCALE_FACTOR_ROUNDING_POLICY", "PassThrough");
+    {
+        std::unique_ptr<QGuiApplication> app(createStandardOffscreenApp(dpiValues));
+        for (int i = 0; i < dpiValues.count(); ++i)
+            QCOMPARE(app->screens()[i]->devicePixelRatio(), dpiValues[i] / qreal(96));
+    }
+
+    qputenv("QT_SCALE_FACTOR_ROUNDING_POLICY", "Round");
+    {
+        std::unique_ptr<QGuiApplication> app(createStandardOffscreenApp(dpiValues));
+        for (int i = 0; i < dpiValues.count(); ++i)
+            QCOMPARE(app->screens()[i]->devicePixelRatio(), qRound(dpiValues[i] / qreal(96)));
+    }
+
+    qunsetenv("QT_SCALE_FACTOR_ROUNDING_POLICY");
+    {
+        std::unique_ptr<QGuiApplication> app(createStandardOffscreenApp(dpiValues));
+        for (int i = 0; i < dpiValues.count(); ++i)
+            QCOMPARE(app->screens()[i]->devicePixelRatio(), dpiValues[i] / qreal(96));
+    }
+}
+
+void tst_QHighDpi::application_setScaleFactorRoundingPolicy()
+{
+    QList<qreal> dpiValues { 96, 144, 192 };
+    QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::Round);
+    {
+        std::unique_ptr<QGuiApplication> app(createStandardOffscreenApp(dpiValues));
+        for (int i = 0; i < dpiValues.count(); ++i)
+            QCOMPARE(app->screens()[i]->devicePixelRatio(), qRound(dpiValues[i] / qreal(96)));
+    }
+
+    QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::PassThrough);
+    {
+        std::unique_ptr<QGuiApplication> app(createStandardOffscreenApp(dpiValues));
+        for (int i = 0; i < dpiValues.count(); ++i)
+            QCOMPARE(app->screens()[i]->devicePixelRatio(), dpiValues[i] / qreal(96));
+    }
+
+    // Verify that environment overrides app setting
+    QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::Round);
+    qputenv("QT_SCALE_FACTOR_ROUNDING_POLICY", "PassThrough");
+    {
+        std::unique_ptr<QGuiApplication> app(createStandardOffscreenApp(dpiValues));
+        for (int i = 0; i < dpiValues.count(); ++i)
+            QCOMPARE(app->screens()[i]->devicePixelRatio(), dpiValues[i] / qreal(96));
+    }
+}
+
 void tst_QHighDpi::minimumDpr()
 {
     QList<qreal> dpiValues { 40, 60, 95 };