avar table confuses rvrn GSUB lookup #521
Description
Running
for i in `seq 1 1000`; do echo $i; hb-shape --variations="FVTT=$i" avar_rvrn.ttf r; done
on the font in avar_rvrn.zip
which has a variation alternates glyph substitution with the following characteristics:
<SingleSubst index="0" Format="1">
<Substitution in="rvrn_base" out="rvrn_subst"/>
</SingleSubst>
<ConditionSet>
<!-- ConditionCount=1 -->
<ConditionTable index="0" Format="1">
<AxisIndex value="1"/>
<FilterRangeMinValue value="0.666667"/>
<FilterRangeMaxValue value="1.0"/>
</ConditionTable>
</ConditionSet>
and an FVTT axis as follows:
<Axis>
<AxisTag>FVTT</AxisTag>
<Flags>0x0</Flags>
<MinValue>0.0</MinValue>
<DefaultValue>0.0</DefaultValue>
<MaxValue>630.0</MaxValue>
<AxisNameID>259</AxisNameID>
</Axis>
And an avar entry as follows:
<segment axis="FVTT">
<mapping from="-1.0" to="-1.0"/>
<mapping from="0.0" to="0.0"/>
<mapping from="0.666667" to="0.5"/>
<mapping from="1.0" to="1.0"/>
</segment>
The above shell loop produces rvrn_subst output for more than one range, which it should not.
Abbreviated output below:
1
[rvrn_base=0+1529]
...
350
[rvrn_base=0+1529]
351
[rvrn_subst=0+1825]
...
419
[rvrn_subst=0+1825]
420
[rvrn_base=0+1529]
421
[rvrn_subst=0+1825]
...
526
[rvrn_base=0+1529]
...
629
[rvrn_base=0+1529]
630
[rvrn_subst=0+1825]
...
999
[rvrn_subst=0+1825]
1000
[rvrn_subst=0+1825]