Per LuaTeX manual, \Umathradicalrule is equivalent to OpenType RadicalRuleThickness but the comment in page 111 doesn't seem right to me; RadicalRuleThickness, from its name, is the thickness radical rule and thus it should default to default_rule_thickness as TeX82 does and as recommended in OpenType MATH specification too. In short, \Umathradicalrule should be the same as, say, \Umathoverbarrule but it isn't: \the\Umathradicalrule\textstyle : \the\Umathoverbarrule\textstyle \bye Regards, Khaled -- Khaled Hosny Arabic localiser and member of Arabeyes.org team Free font developer
Hi Khaled, Khaled Hosny wrote:
Per LuaTeX manual, \Umathradicalrule is equivalent to OpenType RadicalRuleThickness but the comment in page 111 doesn't seem right to me; RadicalRuleThickness, from its name, is the thickness radical rule and thus it should default to default_rule_thickness as TeX82 does and
The comment is correct. TeX82 does not do what you think it does.
From the texbook, rule 11 in Appendix G:
"Note that the font designer specifies the thickness of the [radical] rule by making it the height of the radical character; the baseline of the character should be precisely at the bottom of the rule." Best wishes, Taco
On Wed, Jun 24, 2009 at 09:39:55AM +0200, Taco Hoekwater wrote:
Hi Khaled,
Khaled Hosny wrote:
Per LuaTeX manual, \Umathradicalrule is equivalent to OpenType RadicalRuleThickness but the comment in page 111 doesn't seem right to me; RadicalRuleThickness, from its name, is the thickness radical rule and thus it should default to default_rule_thickness as TeX82 does and
The comment is correct. TeX82 does not do what you think it does.
From the texbook, rule 11 in Appendix G:
"Note that the font designer specifies the thickness of the [radical] rule by making it the height of the radical character; the baseline of the character should be precisely at the bottom of the rule."
I read that part of TeXbook and I can hardly understand anything, so I'll not pretend that I understand anything and will trust you on this :) I'm just wondering whet \Umathradicalrule returns such so big value "16383.99998pt" compared to "0.39998pt" for \Umathoverbarrule, it can't be that big. There must be something wronge, either in the code or in my understanding of what this value does. Regards, Khaled -- Khaled Hosny Arabic localiser and member of Arabeyes.org team Free font developer
Khaled Hosny wrote:
I'm just wondering whet \Umathradicalrule returns such so big value "16383.99998pt" compared to "0.39998pt" for \Umathoverbarrule, it can't be that big. There must be something wronge, either in the code or in my understanding of what this value does.
Ah. That is the magical value for "parameter not set" (i.e.: use the tex82 radical char height instead of this explicit size), and that is indeed not documented. Best wishes, Taco
On Wed, Jun 24, 2009 at 05:53:45PM +0200, Taco Hoekwater wrote:
Khaled Hosny wrote:
I'm just wondering whet \Umathradicalrule returns such so big value "16383.99998pt" compared to "0.39998pt" for \Umathoverbarrule, it can't be that big. There must be something wronge, either in the code or in my understanding of what this value does.
Ah. That is the magical value for "parameter not set" (i.e.: use the tex82 radical char height instead of this explicit size), and that is indeed not documented.
That explains it, thanks. Regards, Khaled -- Khaled Hosny Arabic localiser and member of Arabeyes.org team Free font developer
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Khaled Hosny -
Taco Hoekwater