* Michael Walter <michael.walter@gmail.com> [2004-12-27 04:52]:
"Visibility testing" is more the generic case, "hit testing" is commonly referred to the special case when you check which object the cursor "hits" (for instance, in an editor).
Which is why I was talking about "hit" testing, since I was trying to look at the needs of an event router, and opposed to the renderer. Visibility testing is not necessary, or rather should not be necessary, for the an implementer of a form or grid renderer. The components within the form or grid are on the same z-axis. A dialog box might be obscuring the control, but that, "visibility testing", is done by a windowing system. Unlike a document renderer that implements CSS positioning, where there is an z-axis property, or a canvas renderer that renders a Visio diagram. An implementation of a form, or grid renderer depends on the windowing system for "visibility testing" and "hit testing" is made simply by dividing the drawing surface up aligned to the x and y axis. -- Alan Gutierrez - alan@engrm.com