Add IGUIElement::setRelativePosition(const core::position2di &) as requested...

Add IGUIElement::setRelativePosition(const core::position2di &) as requested on IRC.  Trivially tested with a modified example 05.  Also clarified a few comments.

git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@1776 dfc29bdd-3216-0410-991c-e03cc46cb475

include/IGUIElement.h

@@ -83,6 +83,7 @@ public:
 
 
 	//! Sets the relative rectangle of this element.
+	/** \param r	The absolute position to set */
 	void setRelativePosition(const core::rect<s32>& r)
 	{
 		if (Parent)
@@ -105,8 +106,20 @@ public:
 		updateAbsolutePosition();
 	}
 
+	//! Sets the relative rectangle of this element, maintaining its current width and height
+	/** \param position	The new relative position to set. Width and height will not be changed. */
+	void setRelativePosition(const core::position2di & position)
+	{
+		const core::dimension2di mySize = RelativeRect.getSize();
+		const core::rect<s32> rectangle(position.X, position.Y, 
+										position.X + mySize.Width, position.Y + mySize.Height);
+		setRelativePosition(rectangle);
+	}
 
-	//! Sets the relative rectangle of this element.
+
+
+	//! Sets the relative rectangle of this element as a proportion of its parent's area.
+	/** \param r  The rectangle to set, interpreted as a proportion of the parent's area */
 	void setRelativePosition(const core::rect<f32>& r)
 	{
 		if (!Parent)
@@ -125,8 +138,7 @@ public:
 		updateAbsolutePosition();
 	}
 
-
-	//! Returns the absolute rectangle of element.
+	//! Gets the absolute rectangle of this element
 	core::rect<s32> getAbsolutePosition() const
 	{
 		return AbsoluteRect;
@@ -141,6 +153,7 @@ public:
 
 
 	//! Sets whether the element will ignore its parent's clipping rectangle
+	/** \param noClip	If true, the element will not be clipped by its parent's clipping rectangle. */
 	void setNotClipped(bool noClip)
 	{
 		NoClip = noClip;
@@ -148,6 +161,7 @@ public:
 
 
 	//! Gets whether the element will ignore its parent's clipping rectangle
+	/** \return true if the element is not clipped by its parent's clipping rectangle. */
 	bool isNotClipped() const
 	{
 		return NoClip;