Editing Diagrams/Dev/Migrate1.2 (section)

== Attributes using Measure ==

Many distances are now specified using values of type <code>Measure</code>. See the [http://projects.haskell.org/diagrams/doc/manual.html#measurement-units user manual] for full details.  The most noticeable effects of this change in porting diagrams code to 1.2 will be type errors on uses of attribute functions like <code>lw</code>, <code>dashing</code>, and <code>fontSize</code>.

* To simply retain the existing behavior, replace <code>lw</code> with <code>lwG</code>, <code>dashing</code> with <code>dashingG</code>, and <code>fontSize</code> with <code>fontSizeL</code>.
* In many cases, you can simply remove calls to <code>lw</code>, since the default behavior is much more sensible.  You can also use the named line weights provided in <code>Diagrams.TwoD.Attributes</code>: <code>none</code>, <code>ultraThin</code>, <code>veryThin</code>, <code>thin</code>, <code>medium</code>, <code>thick</code>, <code>veryThick</code>, or <code>ultraThick</code>.  For example, replace <code>lw 0</code> with <code>lw none</code>, and replace (say) <code>lw 0.2</code> with <code>lw veryThick</code> (though note that the relationship between the number used previously and the proper choice of line weight depends on the context, because the old semantics was not very sensible).
* While we think the new default line weight will work for more people more of the time, diagrams which used the old default will compile without error and may render quite differently.  You can express the old default as <code>lwG 0.01</code>, or add <code>lw</code> with the named line weights as necessary.