You can do it with a valueexpression, and only show a few characters, but that works best with text fields such as notes. It doesn't work great with URLs, since the browser only sees the partial URL which would be invalid when clicking on it.
What I like to do is to replace the URL string with text. Here is the code for that, just replace all instances of Design Doc URL with your custom field name.
case.0.comparison.icon=false
case.0.comparison.leftmethod=DE:Design Doc URL
case.0.comparison.lefttext=DE:Design Doc URL
case.0.comparison.operator=notblank
case.0.comparison.operatortype=string
case.0.comparison.righttext=
case.0.comparison.truetext=Design Doc URL
displayname=
link.isnewwindow=true
link.url=customDataLabelsAsString(Design Doc URL)
linkedname=direct
namekey=Design Doc URL
querysort=DE:Design Doc URL
styledef.case.0.comparison.icon=false
styledef.case.0.comparison.leftmethod=DE:Design Doc URL
styledef.case.0.comparison.lefttext=DE:Design Doc URL
styledef.case.0.comparison.operator=isblank
styledef.case.0.comparison.operatortype=string
styledef.case.0.comparison.righttext=
styledef.case.0.comparison.truetext=Design Doc URL
textmode=true
valuefield=Design Doc URL
valueformat=customDataLabelsAsString
The negative part of both valueexpression and replacing the text, is that you can't edit the URL, so if you need to, Katherine's option to usewidths is the best option.