Use clearer styling of disabled entry fields on the materials page

Contributes to CURA-342

resources/qml/Preferences/ReadOnlyTextArea.qml

@@ -0,0 +1,46 @@
+// Copyright (c) 2016 Ultimaker B.V.
+// Uranium is released under the terms of the AGPLv3 or higher.
+
+import QtQuick 2.1
+import QtQuick.Controls 1.1
+import QtQuick.Dialogs 1.2
+
+Item
+{
+    id: base
+
+    property alias text: textArea.text
+    property alias wrapMode: textArea.wrapMode
+
+    signal editingFinished();
+
+    property bool readOnly: false
+
+    width: textArea.width
+    height: textArea.height
+
+    TextArea
+    {
+        id: textArea
+
+        enabled: !base.readOnly
+        opacity: base.readOnly ? 0.5 : 1.0
+
+        anchors.fill: parent
+
+        onEditingFinished: base.editingFinished()
+    }
+
+    Label
+    {
+        visible: base.readOnly
+        text: textArea.text
+
+        anchors.fill: parent
+        anchors.margins: textArea.__style ? textArea.__style.textMargin : 4
+
+        color: palette.buttonText
+    }
+
+    SystemPalette { id: palette }
+}