Material: Add proper elevation support

- Added an ElevationEffect component based on elevation shadows from Angular Material
- Use it on Button, ToolBar, ComboBox, Drawer, Pane, Popup, Menu, and Switch
- Add an elevation property to the Material attached object
- Update the button colors based on the elevation property

Change-Id: I5152e1a56bdcb1016cc4f945a16ef510e0cdece6
Task-number: QTBUG-51276
Reviewed-by: Nikita Krupenko <krnekit@gmail.com>
Reviewed-by: J-P Nurmi <jpnurmi@qt.io>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/imports/controls/material/Pane.qml b/src/imports/controls/material/Pane.qml
index 43f9e34a..434c676c 100644
--- a/src/imports/controls/material/Pane.qml
+++ b/src/imports/controls/material/Pane.qml
@@ -37,6 +37,7 @@
 import QtQuick 2.6
 import QtQuick.Templates 2.0 as T
 import QtQuick.Controls.Material 2.0
+import QtQuick.Controls.Material.impl 2.0
 
 T.Pane {
     id: control
@@ -56,6 +57,11 @@ T.Pane {
     //! [background]
     background: Rectangle {
         color: control.Material.backgroundColor
+
+        layer.enabled: control.enabled && control.Material.elevation > 0
+        layer.effect: ElevationEffect {
+            elevation: control.Material.elevation
+        }
     }
     //! [background]
 }