Re: [Groff] offset scaling with .bd

[Daniel Senderowicz]

Hi Ralph,

>As Kernighan says, N's default unit is the `basic unit' as opposed to
>inches, points, etc.  The size of a basic unit differs between output
>devices.  There's 72000 basic units to the inch when talking about
>grops, so 3 won't go very far.  Presumably, 3 was sufficient for
>Kernighan's environment.

I always forget that those guys didn't have postscript when they
wrote troff. I need to refresh my few remaining brain cells more
often...

>And in the front reference pages lists it as `.bd S F N', which is
>wrong.

They show two different uses for .bd. One is the one I copied
before, and the other says:

 .bd S F N            "Embolden Special Font when current font is F."

so perhaps .bd looks at the number of arguments?

Thanks for your help. Regards,

Dan

>Hi Dan,
>
>> The original troff reference manual mumbles something like:
>> 
>>  .bd F N  "The characters in font F will be artificially
>>            emboldened by printing each one twice, separated by N-1
>>            basic units. A reasonable value for N is 3 when the charater
>>            size is in the vicinity of 10 points..."
>
>And in the front reference pages lists it as `.bd S F N', which is
>wrong.
>
>> However, unless I use values for N of the order of a few hundreds
>> (e.g.  600) the emboldening is negligible.  The gnu groff manual
>> mentions something about .bd that I don't understand if has any
>> relevance to this problem. Perhaps someone can educate me on how the
>> scaling of the offset in the .bd command works.
>
>As Kernighan says, N's default unit is the `basic unit' as opposed to
>inches, points, etc.  The size of a basic unit differs between output
>devices.  There's 72000 basic units to the inch when talking about
>grops, so 3 won't go very far.  Presumably, 3 was sufficient for
>Kernighan's environment.
>
>You can specify a unit, e.g. `.bd R 1p', so it's independent of the
>output device.  Or use something that returns a basic unit, e.g. `.bd R
>\w'x''.
>
>If I haven't made this clear, I've never used it, ask again and someone
>on the list will put me right.
>
>Cheers,
>
>
>Ralph.
>
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