Add screen dpi value to screen info source

analyzer/schematemplates/screens.schema

@@ -13,6 +13,10 @@
                 {
                     "name": "height",
                     "type": "int"
+                },
+                {
+                    "name": "dpi",
+                    "type": "int"
                 }
             ]
         }
@@ -22,6 +26,7 @@
         { "type": "xy", "elements": [
             { "type": "value", "schemaEntry": "screens", "schemaEntryElement": "width" },
             { "type": "value", "schemaEntry": "screens", "schemaEntryElement": "height" }
-        ] }
+        ] },
+        { "type": "numeric", "elements": [ { "type": "value", "schemaEntry": "screens", "schemaEntryElement": "dpi" } ] }
     ]
 }

provider/core/screeninfosource.cpp

@@ -38,6 +38,7 @@ QVariant ScreenInfoSource::data()
         QVariantMap m;
         m.insert(QStringLiteral("width"), screen->size().width());
         m.insert(QStringLiteral("height"), screen->size().height());
+        m.insert(QStringLiteral("dpi"), qRound(screen->physicalDotsPerInch()));
         l.push_back(m);
     }
 #endif

tests/auto/datasourcetest.cpp

@@ -80,6 +80,15 @@ private slots:
         QVERIFY(v.canConvert<QVariantList>());
         auto a = v.value<QVariantList>();
         QVERIFY(a.size() > 0);
+
+        for (int i = 0; i < a.size(); ++i) {
+            v = a.at(i);
+            QVERIFY(v.canConvert<QVariantMap>());
+            const auto scr = v.toMap();
+            QVERIFY(scr.contains(QLatin1String("height")));
+            QVERIFY(scr.contains(QLatin1String("width")));
+            QVERIFY(scr.contains(QLatin1String("dpi")));
+        }
     }
 
     void testPropertyRatioSource()