From b469289a6ed067be92eb24239c59f5cd1f5f7956 Mon Sep 17 00:00:00 2001
From: Michael Brasser <michael.brasser@nokia.com>
Date: Thu, 25 Feb 2010 17:07:16 +1000
Subject: Document and test resetting properties in a state change.

Task-number: QT-1817
---
 .../util/qdeclarativepropertychanges.cpp           | 29 +++++++++++++++++++++-
 .../declarative/qdeclarativestates/data/reset.qml  | 20 +++++++++++++++
 .../qdeclarativestates/tst_qdeclarativestates.cpp  | 21 ++++++++++++++++
 3 files changed, 69 insertions(+), 1 deletion(-)
 create mode 100644 tests/auto/declarative/qdeclarativestates/data/reset.qml

diff --git a/src/declarative/util/qdeclarativepropertychanges.cpp b/src/declarative/util/qdeclarativepropertychanges.cpp
index 6c2e256..454fb06 100644
--- a/src/declarative/util/qdeclarativepropertychanges.cpp
+++ b/src/declarative/util/qdeclarativepropertychanges.cpp
@@ -60,7 +60,7 @@ QT_BEGIN_NAMESPACE
 
 /*!
     \qmlclass PropertyChanges QDeclarativePropertyChanges
-  \since 4.7
+    \since 4.7
     \brief The PropertyChanges element describes new property values for a state.
 
     PropertyChanges provides a state change that modifies the properties of an item.
@@ -98,6 +98,33 @@ QT_BEGIN_NAMESPACE
     }
     \endqml
 
+    You can reset a property in a state change by assigning \c undefined. In the following
+    example we reset \c theText's width when we enter state1. This will give the text its
+    natural width (which is the whole string on one line).
+
+    \qml
+    import Qt 4.6
+
+    Rectangle {
+        width: 640
+        height: 480
+        Text {
+            id: theText
+            width: 50
+            wrap: true
+            text: "a text string that is longer than 50 pixels"
+        }
+
+        states: State {
+            name: "state1"
+            PropertyChanges {
+                target: theText
+                width: undefined
+            }
+        }
+    }
+    \endqml
+
     Changes to an Item's parent or anchors should be done using the associated change elements
     (ParentChange and AnchorChanges, respectively) rather than PropertyChanges.
 
diff --git a/tests/auto/declarative/qdeclarativestates/data/reset.qml b/tests/auto/declarative/qdeclarativestates/data/reset.qml
new file mode 100644
index 0000000..a0a2b8c
--- /dev/null
+++ b/tests/auto/declarative/qdeclarativestates/data/reset.qml
@@ -0,0 +1,20 @@
+import Qt 4.6
+
+Rectangle {
+    width: 640
+    height: 480
+    Text {
+        id: theText
+        width: 50
+        wrap: true
+        text: "a text string that is longer than 50 pixels"
+    }
+
+    states: State {
+        name: "state1"
+        PropertyChanges {
+            target: theText
+            width: undefined
+        }
+    }
+}
diff --git a/tests/auto/declarative/qdeclarativestates/tst_qdeclarativestates.cpp b/tests/auto/declarative/qdeclarativestates/tst_qdeclarativestates.cpp
index 44fb51f..5ffce11 100644
--- a/tests/auto/declarative/qdeclarativestates/tst_qdeclarativestates.cpp
+++ b/tests/auto/declarative/qdeclarativestates/tst_qdeclarativestates.cpp
@@ -43,6 +43,7 @@
 #include <QtDeclarative/qdeclarativecomponent.h>
 #include <private/qdeclarativeanchors_p_p.h>
 #include <private/qdeclarativerectangle_p.h>
+#include <private/qdeclarativetext_p.h>
 #include <private/qdeclarativepropertychanges_p.h>
 #include <private/qdeclarativestategroup_p.h>
 
@@ -81,6 +82,7 @@ private slots:
     void tempState();
     void illegalTempState();
     void nonExistantProperty();
+    void reset();
 };
 
 QByteArray tst_qdeclarativestates::fullDataPath(const QString &path)
@@ -912,6 +914,25 @@ void tst_qdeclarativestates::nonExistantProperty()
     QCOMPARE(rect->state(), QLatin1String("blue"));
 }
 
+void tst_qdeclarativestates::reset()
+{
+    QDeclarativeEngine engine;
+
+    QDeclarativeComponent c(&engine, SRCDIR "/data/reset.qml");
+    QDeclarativeRectangle *rect = qobject_cast<QDeclarativeRectangle*>(c.create());
+    QVERIFY(rect != 0);
+
+    QDeclarativeText *text = rect->findChild<QDeclarativeText*>();
+    QVERIFY(text != 0);
+    QCOMPARE(text->width(), qreal(50.));
+    QVERIFY(text->width() < text->height());
+
+    rect->setState("state1");
+
+    QVERIFY(text->width() > 51);
+    QVERIFY(text->width() > text->height());
+}
+
 QTEST_MAIN(tst_qdeclarativestates)
 
 #include "tst_qdeclarativestates.moc"
-- 
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