Add user documentation for scarce resource properties

Relates to commit 59ace5c5a666b1588560d2aeaa79a57da535e863.

Task-number: QMLNG-18
Reviewed-by: Aaron Kennedy
Change-Id: I216ced4c663ebab8003978999dc16ac809443a5f

1 files changed, 14 insertions, 1 deletions

diff --git a/doc/src/declarative/basictypes.qdoc b/doc/src/declarative/basictypes.qdoc
index 4792bba6ef..876ab0038a 100644
--- a/doc/src/declarative/basictypes.qdoc
+++ b/doc/src/declarative/basictypes.qdoc
@@ -439,7 +439,20 @@
     }
     \endqml
 
-    The \c variant type can also hold:
+    A \c variant type property can also hold an image or pixmap.
+    A \c variant which contains a QPixmap or QImage is known as a
+    "scarce resource" and the declarative engine will attempt to
+    automatically release such resources after evaluation of any JavaScript
+    expression which requires one to be copied has completed.
+
+    Clients may explicitly release such a scarce resource by calling the
+    "destroy" method on the \c variant property from within JavaScript.  They
+    may also explicitly preserve the scarce resource by calling the
+    "preserve" method on the \c variant property from within JavaScript.
+    For more information regarding the usage of a scarce resource, please
+    see \l{Scarce Resources in JavaScript}.
+
+    Finally, the \c variant type can also hold:
 
     \list
     \o An array of \l {QML Basic Types}{basic type} values