Doc: Describe aligning and distributing items in Qt Quick Designer

Task-number: QDS-1307
Change-Id: I62d7e127ced887fec9dbfddb1a8607e74e846108
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

doc/src/qtquick/qtquick-components.qdoc

@@ -154,6 +154,7 @@
     \list
         \li \l{Setting Bindings}
         \li \l{Setting Anchors and Margins}
+        \li \l{Aligning and Distributing Items}
         \li \l{Using Positioners}
         \li \l{Using Layouts}
         \li \l{Organizing Items}
@@ -252,9 +253,9 @@
     Rectangle {
         id: rectangle2
         anchors.left: rectangle1.right
-        anchors.leftMargin: 15
+        anchors.leftMargin: 10
         anchors.bottom: parent.bottom
-        anchors.bottomMargin: 15
+        anchors.bottomMargin: 10
         //
     }
     \endqml
@@ -263,6 +264,60 @@
     item. Margins only have meaning for anchors. They do not take any effect
     when using layouts or absolute positioning.
 
+    \section2 Aligning and Distributing Items
+
+    When you're working with a group of items, you can select them to align
+    and distribute them evenly. As the positions of the items are fixed, you
+    cannot apply these functions to anchored items. For scalability, you can
+    anchor the aligned and distributed items when your design is ready.
+
+    \image qmldesigner-alignment.png "Aligning sibling items"
+
+    Select the buttons in the \uicontrol Align group to align the top/bottom
+    or left/right edges of the items in the group to the one farthest away from
+    the center of the group. For example, when left-aligning, the items are
+    aligned to the leftmost item. You can also align the horizontal/vertical
+    centers of items, or both, as in the image above.
+
+    In the \uicontrol {Align to} field, select whether to align the items in
+    respect to the selection, the root item, or a \e {key object} that you
+    select in the \uicontrol {Key object} field. The key object must be a part
+    of the selection.
+
+    You can distribute either \e objects or the \e spacing between them. If the
+    objects or spacing cannot be distributed to equal pixel values without
+    ending up with half pixels, you receive a notification. You can either allow
+    \QDS to distribute objects or spacing using the closest values possible or
+    tweak your design so that the objects and spacing can be distributed
+    perfectly.
+
+    When distributing objects, you can select whether the distance between
+    them is calculated from their top/bottom or left/right edges or their
+    horizontal/vertical center.
+
+    \image qmldesigner-distribute-objects.png "Distribute objects buttons"
+
+    You can distribute spacing either evenly within a target area or at
+    specified distances, calculated from a starting point.
+
+    You can select the orientation in which the objects are distributed evenly
+    within the target area: horizontally along the x axis or vertically along
+    the y axis.
+
+    \image qmldesigner-distribute-spacing-evenly.png "Distribute spacing evenly"
+
+    Alternatively, you can distribute spacing in pixels by selecting one of the
+    starting point buttons: left/right or top/bottom edge of the target area,
+    or its horizontal/vertical center. Note that some items might end up outside
+    the target area.
+
+    \image qmldesigner-distribute-spacing-pixels.png "Distribute spacing in pixels"
+
+    You can set the space between objects in pixels. You can
+    disable the distribution of spacing in pixels by clicking
+    the \inlineimage qmldesigner-distribute-spacing-x.png
+    button.
+
     \section2 Using Positioners
 
     \l{Important Concepts In Qt Quick - Positioning#positioners}