Tobias Pape uploaded a new version of TrueType to project The Trunk:
http://source.squeak.org/trunk/TrueType-topa.36.mcz

==================== Summary ====================

Name: TrueType-topa.36
Author: topa
Time: 3 April 2015, 7:50:06.323 pm
UUID: 9b5c4259-1944-4ee9-8ea0-0196c85240f4
Ancestors: TrueType-cmm.35

cope for the fact that typographicAscender and  typographicDescender may not be available and 0-height fonts are a bit useless

=============== Diff against TrueType-cmm.35 ===============

Item was changed:
  ----- Method: TTCFont>>lineGap (in category 'accessing') -----
  lineGap
  	"Answer the line gap from the ttf description"
+ 	^self pixelSize * ttcDescription typographicLineGap // ttcDescription typographicFontHeight!
- 	^self pixelSize * ttcDescription typographicLineGap // 
- 			(ttcDescription typographicAscender - ttcDescription typographicDescender)!

Item was added:
+ ----- Method: TTFileDescription>>typographicFontHeight (in category 'accessing') -----
+ typographicFontHeight
+ 	"cope for the fact that typographicAscender and 
+ 	typographicDescender may not be available and 
+ 	0-height fonts are a bit useless"
+ 	| tfh |
+ 	tfh := self typographicAscender - self typographicDescender.
+ 	^ tfh = 0 ifTrue: [self fontHeight] ifFalse: [tfh]!