Improve implicit size of Calendar on high DPI devices.

Task-number: QTBUG-39473
Change-Id: Ibfb1c040efd9744ba6c8bc56affcdf90a807b046
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>

examples/quick/controls/calendar/qml/main.qml

@@ -40,6 +40,7 @@
 
 import QtQuick 2.2
 import QtQuick.Controls 1.2
+import QtQuick.Controls.Private 1.0
 import QtQuick.Controls.Styles 1.1
 import org.qtproject.examples.calendar 1.0
 
@@ -53,6 +54,10 @@ ApplicationWindow {
 
     title: "Calendar Example"
 
+    SystemPalette {
+        id: systemPalette
+    }
+
     SqlEventModel {
         id: eventModel
     }
@@ -163,7 +168,7 @@ ApplicationWindow {
             style: CalendarStyle {
                 dayDelegate: Item {
                     readonly property color sameMonthDateTextColor: "#444"
-                    readonly property color selectedDateColor: Qt.platform.os === "osx" ? "#3778d0" : __syspal.highlight
+                    readonly property color selectedDateColor: Qt.platform.os === "osx" ? "#3778d0" : systemPalette.highlight
                     readonly property color selectedDateTextColor: "white"
                     readonly property color differentMonthDateTextColor: "#bbb"
                     readonly property color invalidDatecolor: "#dddddd"

src/controls/Styles/Base/CalendarStyle.qml

@@ -166,8 +166,8 @@ Style {
     */
     property Component background: Rectangle {
         color: "#fff"
-        implicitWidth: 250
-        implicitHeight: 250
+        implicitWidth: Math.max(250, Math.round(TextSingleton.implicitHeight * 14))
+        implicitHeight: Math.max(250, Math.round(TextSingleton.implicitHeight * 14))
     }
 
     /*!
@@ -183,7 +183,7 @@ Style {
         \endtable
     */
     property Component navigationBar: Rectangle {
-        height: 41
+        height: Math.round(TextSingleton.implicitHeight * 2.73)
         color: "#f9f9f9"
 
         Rectangle {
@@ -212,7 +212,7 @@ Style {
             text: styleData.title
             elide: Text.ElideRight
             horizontalAlignment: Text.AlignHCenter
-            font.pointSize: 14
+            font.pixelSize: TextSingleton.implicitHeight * 1.25
             anchors.verticalCenter: parent.verticalCenter
             anchors.left: previousMonth.right
             anchors.leftMargin: 2
@@ -313,7 +313,7 @@ Style {
     */
     property Component dayOfWeekDelegate: Rectangle {
         color: gridVisible ? "#fcfcfc" : "transparent"
-        implicitHeight: 40
+        implicitHeight: Math.round(TextSingleton.implicitHeight * 2.25)
         Label {
             text: control.__locale.dayName(styleData.dayOfWeek, control.dayOfWeekFormat)
             anchors.centerIn: parent
@@ -334,7 +334,7 @@ Style {
         \endtable
     */
     property Component weekNumberDelegate: Rectangle {
-        implicitWidth: 30
+        implicitWidth: Math.round(TextSingleton.implicitHeight * 2)
         Label {
             text: styleData.weekNumber
             anchors.centerIn: parent