Re: Are fractional font sizes OK?

Am 31.05.2026 um 12:49 schrieb Hans Hagen via ntg-context:
> On 5/31/2026 12:05 PM, Pablo Rodriguez via ntg-context wrote:
>> On 5/28/26 02:39, Jim via ntg-context wrote:
>>> Hi all,
>>> […]
>>> What do I learn from this?
>>> (a) Fractional point font sizes are not a thing, and I shouldn't do 
>>> that?
>>> (b) Fractional point font sizes may work, but are unreliable?
>>> (c) \switchtobodyfont[script] doesn't work with fractional point font 
>>> sizes?
>>> (d) Something else entirely?
>>
>> Hi Jim,
>>
>> just use the source: lines 654-662 from contain the explanation (or I
>> just found the fix reading those lines).
>>
>> If you use non-predefined font sizes (not just fractional, `50pt` gives
>> the same result), it seems that you have to setup the size.
>>
>> Your sample compiles fine, even with such an unorthodox approach such as:
>>
>>    \definebodyfontenvironment[10.5pt]
>>      [script=\cldcontext{10.5*(7/12)}pt]
>>    \setupbodyfont[10.5pt]
>>
>> I hope it helps,
> 
> In mkii times there we limnitation son the amount of fonts so we snapped 
> sizes to 2 digits. In mkiv times that was less needed but still we snap 
> in order not to get excessive definitions due to 'interesting usa 
> cases'. In lmtx we scale differently but still one needs to be careful 
> esp as bodyfont environments are expected to behave consistently.
> 
> In principle we could discard some compatibility here but that is always 
> tricky and as such some work from Wolfgang and me that we currently 
> happily delay. Of course there are sentimental reasons for such a delay 
> too.


An easy way to fix this problem is to limit the number of allowed 
keywords to small and big.

%%%% patch for font-ini.mklx
% macros=mkvi

\unprotect

\protected\def\font_basics_switchtobodyfont#specification%
   {\edef\m_font_step{\font_bodyfontvariable{#specification}}%
    \font_push_x_size % experiment
    \ifempty\m_font_step
      \font_helpers_set_font\zerocount{#specification}%
-  \else
+  \orelse\ifinset{#specification}{\v!small,\v!big}%
      \font_helpers_switch_bodyfont_step % so we have a fast [small] switch
    \fi
    \expand\everybodyfont
    \expand\everyswitchtobodyfont
    \expand\everyfont
    \expand\everyfontswitch
    \font_pop_x_size % experiment
    }

\protect

\starttext

text
\switchtobodyfont[script]
text
\switchtobodyfont[10.5pt]
\switchtobodyfont[script]
text
\switchtobodyfont[small]
text

\stoptext
%%%%

Wolfgang

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