Laying It All Out, Part 1
 

The Motivation for a Layout System

One of the major complaints that any serious BeOS programmer would eventually make about the GUI classes in the Be API is the lack of easy font sensitivity. What this means is that if one designs a GUI using the system default fonts and then a user of your application changes their system fonts to be much smaller or larger than the default, the GUI will likely look bad (especially if the font size is larger.) Things that were previously aligned may not be, and likely text labels will run into other components or even disappear into the side of the window. This is especially true in fixed sized GUIs like dialog boxes and configuration panels. See Figure 1.

read more
 

http://www.haiku-os.org/documents/dev/laying_it_all_out_part_1