Difference between revisions of "Template:Italics correction/calc"

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(Add a few more Greek letter variants that are used as technical symbols, and one Latin (∂). Fill in Greek spacing.)
(Upon benchmarking, a large #switch turns out to be faster. And add ℓ.)
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{{#switch:0
+
{{#switch:{{{1}}}
|{{#expr:not{{#invoke:String|find|dijkrtvwxyzCDEFGHIJKMNUVWXYZγδζξϖπστΕΖΗΙΚΜΝΞΠΣΥϒΧΨ|{{{1}}}}}}}=0.1em
+
|d|i|j|k|ℓ|r|t|v|w|x|y|z|C|D|E|F|G|H|I|J|K|M|N|U|V|W|X|Y|Z|γ|δ|ζ|ξ|ϖ|π|σ|τ|Ε|Ζ|Η|Ι|Κ|Μ|Ν|Ξ|Π|Σ|Υ|ϒ|Χ|Ψ=0.1em
|{{#expr:not{{#invoke:String|find|cgsuBGOPQRSαβϑθκμνςυχψωΒΘΟΡΩ|{{{1}}}}}}}=0.05em
+
|c|g|s|u|B|G|O|P|Q|R|S|α|β|ϑ|θ|κ|μ|ν|ς|υ|χ|ψ|ω|Β|Θ|Ο|Ρ|Ω=0.05em
|{{#expr:not{{#invoke:String|find|ab∂ehmnopqALεϵηιλοϱρφϕΑΔΛΦ|{{{1}}}}}}}=0em
+
|a|b|∂|e|h|m|n|o|p|q|A|L|ε|ϵ|η|ι|λ|ο|ϱ|ρ|φ|ϕ|Α|Δ|Λ|Φ=0em
|{{#expr:not{{#invoke:String|find|flTΓΤ|{{{1}}}}}}}=0.15em
+
|f|l|T|Γ|Τ=0.15em
|0=0.1em
+
|0.1em
 
}}<noinclude><!--
 
}}<noinclude><!--
 +
Latin lower-case: abc∂defghijlℓmnopqrstuvwxyz
 +
Latin upper-case: ABCDEFGHIJLNOPQRSTUVWXYZ
 
Greek lower-case: αβγδεϵζηϑθικλμνξοϖπϱρςστυφϕχψω
 
Greek lower-case: αβγδεϵζηϑθικλμνξοϖπϱρςστυφϕχψω
 
Greek upper-case: ΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥϒΦΧΨΩ
 
Greek upper-case: ΑΒΓΔΕΖΗΘΙΚΛΜΝΞΟΠΡΣΤΥϒΦΧΨΩ
 +
When a letter has multiple forms, I'm listing the most common mathematical form last, and other variants (which may or may not be more common in ordinary text) before that.
 
-->{{documentation|content=
 
-->{{documentation|content=
 
This template takes one parameter, a single letter, and returns an amount of space (in units of "em", so something like "0.1em") that should be added after an italic version of that letter to prevent tall characters from colliding with its top-right corner.  It is large for letters like ''f'', ''l'' and ''T'', and zero for letters like ''o'', ''A'' and ''L'' which do not protrude to the top right.
 
This template takes one parameter, a single letter, and returns an amount of space (in units of "em", so something like "0.1em") that should be added after an italic version of that letter to prevent tall characters from colliding with its top-right corner.  It is large for letters like ''f'', ''l'' and ''T'', and zero for letters like ''o'', ''A'' and ''L'' which do not protrude to the top right.
Line 110: Line 113:
 
{{!}} {{mvar|τ′ Τ′}} {{!!}} {{mvar|1=τ<span style="padding-left:{{{{ARTICLEPAGENAME}}|τ}}">′</span> Τ<span style="padding-left:{{{{ARTICLEPAGENAME}}|Τ}}">′</span>}}
 
{{!}} {{mvar|τ′ Τ′}} {{!!}} {{mvar|1=τ<span style="padding-left:{{{{ARTICLEPAGENAME}}|τ}}">′</span> Τ<span style="padding-left:{{{{ARTICLEPAGENAME}}|Τ}}">′</span>}}
 
{{!}}-
 
{{!}}-
{{!}} ''l′ L′'' {{!!}} ''l<span style="padding-left:{{{{ARTICLEPAGENAME}}|l}}">′</span> L<span style="padding-left:{{{{ARTICLEPAGENAME}}|L}}">′</span>''
+
{{!}} ''l′ℓ′ L′'' {{!!}} ''l<span style="padding-left:{{{{ARTICLEPAGENAME}}|l}}">′</span>ℓ<span style="padding-left:{{{{ARTICLEPAGENAME}}|ℓ}}">′</span> L<span style="padding-left:{{{{ARTICLEPAGENAME}}|L}}">′</span>''
{{!}} {{mvar|l′ L′}} {{!!}} {{mvar|1=l<span style="padding-left:{{{{ARTICLEPAGENAME}}|l}}">′</span> L<span style="padding-left:{{{{ARTICLEPAGENAME}}|L}}">′</span>}}
+
{{!}} {{mvar|l′ℓ′ L′}} {{!!}} {{mvar|1=l<span style="padding-left:{{{{ARTICLEPAGENAME}}|l}}">′</span>ℓ<span style="padding-left:{{{{ARTICLEPAGENAME}}|ℓ}}">′</span> L<span style="padding-left:{{{{ARTICLEPAGENAME}}|L}}">′</span>}}
 
{{!}} ''γ′ Γ′'' {{!!}} ''γ<span style="padding-left:{{{{ARTICLEPAGENAME}}|γ}}">′</span> Γ<span style="padding-left:{{{{ARTICLEPAGENAME}}|Γ}}">′</span>''
 
{{!}} ''γ′ Γ′'' {{!!}} ''γ<span style="padding-left:{{{{ARTICLEPAGENAME}}|γ}}">′</span> Γ<span style="padding-left:{{{{ARTICLEPAGENAME}}|Γ}}">′</span>''
 
{{!}} {{mvar|γ′ Γ′}} {{!!}} {{mvar|1=γ<span style="padding-left:{{{{ARTICLEPAGENAME}}|γ}}">′</span> Γ<span style="padding-left:{{{{ARTICLEPAGENAME}}|Γ}}">′</span>}}
 
{{!}} {{mvar|γ′ Γ′}} {{!!}} {{mvar|1=γ<span style="padding-left:{{{{ARTICLEPAGENAME}}|γ}}">′</span> Γ<span style="padding-left:{{{{ARTICLEPAGENAME}}|Γ}}">′</span>}}
Line 152: Line 155:
 
{{!)}}
 
{{!)}}
 
; Implementation
 
; Implementation
: The characters are grouped together based on the amount of space required.  Then, using the [[Help:Switch parser function|<code>#switch</code> parser function]], this steps through a number of [[Module:String|{{tlc|&#35;invoke:String|find}}]] instances which look up the single-letter parameter in each of the groups.
+
: It's just a big 109-way [[Help:Switch parser function|<code>#switch</code>]] statement.  For the sake of efficiency (this is likely to be used ''many'' times on a page), letters which take the same amount of space are grouped together, and the groups are sorted so the most common ones come first.
: Since {{tlc|&#35;invoke:String|find}} returns 0 if the argument is ''not'' found, and a non-zero string position if it is, the return value is inverted with {{tlc|&#35;expr:not}} and then compared to 0 to indicate a match.
+
: I tried
: For efficiency, the cases in the {{tlc|&#35;switch}} should be sorted in decreasing order of likelihood.
+
    <pre>{{#switch:0
: This ''could'' be written as one giant 108-way {{tlc|&#35;switch}}, branching on the passed-in character, but I'm guessing (''verify this!'') that {{tlc|&#35;invoke:String|find}} is faster than the general parser.
+
|{{#expr:not{{#invoke:String|find|dijkrtvwxyzCDEFGHIJKMNUVWXYZγδζξϖπστΕΖΗΙΚΜΝΞΠΣΥϒΧΨ|{{{1}}}}}}}=0.1em
 +
|{{#expr:not{{#invoke:String|find|cgsuBGOPQRSαβϑθκμνςυχψωΒΘΟΡΩ|{{{1}}}}}}}=0.05em
 +
|{{#expr:not{{#invoke:String|find|ab∂ehmnopqALεϵηιλοϱρφϕΑΔΛΦ|{{{1}}}}}}}=0em
 +
|{{#expr:not{{#invoke:String|find|flTΓΤ|{{{1}}}}}}}=0.15em
 +
|0=0.1em
 +
}}</pre>
 +
to reduce the number of cases in the <code>#switch</code>, but that was clearly slower. (The large table makes this documentation page a good benchmark!)
 
}}</noinclude>
 
}}</noinclude>

Revision as of 15:53, 17 November 2016

0.1em

Template documentation

This template takes one parameter, a single letter, and returns an amount of space (in units of "em", so something like "0.1em") that should be added after an italic version of that letter to prevent tall characters from colliding with its top-right corner. It is large for letters like f, l and T, and zero for letters like o, A and L which do not protrude to the top right.

Examples:

  • {{Template:Italics correction/calc|f}} = 0.15em
  • {{Template:Italics correction/calc|j}} = 0.1em
  • {{Template:Italics correction/calc|s}} = 0.05em
  • {{Template:Italics correction/calc|h}} = 0em

Because it does not know what font is in use on the user's browser, it is a much cruder approximation than TeX's "italic correction" macro \/, but it's still better than a fixed space.

The primary application is mathematics, where italic letters are often followed by a close parenthesis, superscript, or prime symbol. Thus, the Latin and Greek alphabets are covered, but not the entire Unicode space. Some Hebrew and Cyrillic characters could be added as required.

Full list of characters
Italic text {{mvar}} Italic text {{mvar}} Italic text {{mvar}}
Bare +pad Bare +pad Bare +pad Bare +pad Bare +pad Bare +pad
a′ A′ a A Template:Mvar Template:Mvar r′ R′ r R Template:Mvar Template:Mvar ι′ Ι′ ι Ι Template:Mvar Template:Mvar
b′ B′ b B Template:Mvar Template:Mvar s′ S′ s S Template:Mvar Template:Mvar κ′ Κ′ κ Κ Template:Mvar Template:Mvar
c′ C′ c C Template:Mvar Template:Mvar t′ T′ t T Template:Mvar Template:Mvar λ′ Λ′ λ Λ Template:Mvar Template:Mvar
∂′d′ D′ d D Template:Mvar Template:Mvar u′ U′ u U Template:Mvar Template:Mvar μ′ Μ′ μ Μ Template:Mvar Template:Mvar
e′ E′ e E Template:Mvar Template:Mvar v′ V′ v V Template:Mvar Template:Mvar ν′ Ν′ ν Ν Template:Mvar Template:Mvar
f′ F′ f F Template:Mvar Template:Mvar w′ W′ w W Template:Mvar Template:Mvar ξ′ Ξ′ ξ Ξ Template:Mvar Template:Mvar
g′ G′ g G Template:Mvar Template:Mvar x′ X′ x X Template:Mvar Template:Mvar ο′ Ο′ ο Ο Template:Mvar Template:Mvar
h′ H′ h H Template:Mvar Template:Mvar y′ Y′ y Y Template:Mvar Template:Mvar ϖ′π′ Π′ ϖπ Π Template:Mvar Template:Mvar
i′ I′ i I Template:Mvar Template:Mvar z′ Z′ z Z Template:Mvar Template:Mvar ϱ′ρ′ Ρ′ ϱρ Ρ Template:Mvar Template:Mvar
j′ J′ j J Template:Mvar Template:Mvar α′ Α′ α Α Template:Mvar Template:Mvar ς′σ′ Σ′ ςσ Σ Template:Mvar Template:Mvar
k′ K′ k K Template:Mvar Template:Mvar β′ Β′ β Β Template:Mvar Template:Mvar τ′ Τ′ τ Τ Template:Mvar Template:Mvar
l′ℓ′ L′ l L Template:Mvar Template:Mvar γ′ Γ′ γ Γ Template:Mvar Template:Mvar υ′ Υ′ϒ′ υ Υϒ Template:Mvar Template:Mvar
m′ M′ m M Template:Mvar Template:Mvar δ′ Δ′ δ Δ Template:Mvar Template:Mvar φ′ϕ′ Φ′ φϕ Φ Template:Mvar Template:Mvar
n′ N′ n N Template:Mvar Template:Mvar ε′ϵ′ Ε′ εϵ Ε Template:Mvar Template:Mvar χ′ Χ′ χ Χ Template:Mvar Template:Mvar
o′ O′ o O Template:Mvar Template:Mvar ζ′ Ζ′ ζ Ζ Template:Mvar Template:Mvar ψ′ Ψ′ ψ Ψ Template:Mvar Template:Mvar
p′ P′ p P Template:Mvar Template:Mvar η′ Η′ η Η Template:Mvar Template:Mvar ω′ Ω′ ω Ω Template:Mvar Template:Mvar
q′ Q′ q Q Template:Mvar Template:Mvar ϑ′θ′ Θ′ ϑθ Θ Template:Mvar Template:Mvar
Implementation
It's just a big 109-way #switch statement. For the sake of efficiency (this is likely to be used many times on a page), letters which take the same amount of space are grouped together, and the groups are sorted so the most common ones come first.
I tried
{{#switch:0
|{{#expr:not{{#invoke:String|find|dijkrtvwxyzCDEFGHIJKMNUVWXYZγδζξϖπστΕΖΗΙΚΜΝΞΠΣΥϒΧΨ|{{{1}}}}}}}=0.1em
|{{#expr:not{{#invoke:String|find|cgsuBGOPQRSαβϑθκμνςυχψωΒΘΟΡΩ|{{{1}}}}}}}=0.05em
|{{#expr:not{{#invoke:String|find|ab∂ehmnopqALεϵηιλοϱρφϕΑΔΛΦ|{{{1}}}}}}}=0em
|{{#expr:not{{#invoke:String|find|flTΓΤ|{{{1}}}}}}}=0.15em
|0=0.1em
}}

to reduce the number of cases in the #switch, but that was clearly slower. (The large table makes this documentation page a good benchmark!)