Editing Overstrike

{{short description|Technique of printing two characters atop one another}}
{{about||the word processing mode where newly typed characters replace existing characters, also known as Overtype|Insert key|the typographical presentation of words with a line through the centre|Strikethrough|the term in coin hammering|Overstrike (numismatics)|the video game formerly titled Overstrike|Fuse (video game)}}
{{More Citations Needed|date=February 2024}}

In [[typography]], '''overstrike''' is a method of printing [[character (computing)|character]]s that are missing from the [[printer (computing)|printer]]'s [[character set]].<ref>{{cite conference |last1=Kuehn |first1=Jules |last2=Mould |first2=David |title=Algorithmic Typewriter Art: Can 1000 Words Paint a Picture? |date=2021 |pages=108–116 |doi=10.20380/GI2021.13 |url=https://graphicsinterface.org/proceedings/gi2021/gi2021-13/ |access-date=3 February 2024 |language=en-CA|conference=Graphics Interface 2021: Virtual Event, 28 - 29 May 2021}}</ref> The character is created by placing one character on another one – for example, overstriking ⟨L⟩ with ⟨-⟩ results in printing a ⟨Ł⟩ ([[L with stroke]]) character.<ref>{{cite journal |last1=Giese |first1=Ronald L. |last2=Lammert |first2=Richard A. |title=Software Review #2: Hebrew Word-Processing for the Macintosh |journal=Hebrew Studies |date=1989 |volume=30 |pages=203–211 |jstor=27909157 |url=https://www.jstor.org/stable/27909157 |access-date=3 February 2024 |issn=0146-4094}}</ref>

The [[ASCII]] code supports six different [[diacritics]]. These are: [[grave accent]], [[tilde]], [[acute accent]] (approximated by the [[apostrophe]]), [[Diaeresis (diacritic)|diaeresis]] (double quote), [[cedilla]] (comma), and [[circumflex accent]]. Each is typed by typing the preceding character, then backspace, and then the 'related character', which is ⟨`⟩, ⟨~⟩, ⟨'⟩, ⟨"⟩, or ⟨^⟩, respectively for the above-mentioned accents.

With the wide adoption of [[Unicode]] (especially [[UTF-8]], which supports a much larger number of characters in different [[writing system]]s), this technique is of little use today. However, [[combining character]]s such as [[diacritic]]s are still used to depict characters which cannot be shown otherwise.
[[File:Bold text using overstrike.svg|thumb|Left: letter A in regular font. Middle: Two letter A's superimposed, one of which is slightly offset to the side. Right: Resulting "fake bold" character]]
Many [[font]] renderers in [[computer programs]] invent missing [[Emphasis (typography)|bold]] characters by overstriking the normal character with itself, slightly horizontally offset.<ref>{{cite web |last1=Blake |first1=Irene A. |title=How to Configure the Overstrike in Word 2007 |url=https://smallbusiness.chron.com/configure-overstrike-word-2007-48809.html |website=Chron.com |access-date=3 February 2024}}</ref> The horizontal offset is essential since, unlike a [[typewriter]] where repeating a letter in exactly the same space will make it darker, most modern printers will not darken repeated "strikes" to the same space. Actual bold fonts are designed with some features thicker and others the same size as a regular font, so the use of this "fake bold" is considered undesirable from a typographic point of view.{{cn|date=February 2024}} Overstriking with an offset was also used to created "[[Blackboard bold]]" style characters used in mathematics.<ref>{{cite book |last1=Webb |first1=Stephen |title=Clash of Symbols: A ride through the riches of glyphs |date=2018 |publisher=Springer International Publishing |isbn=978-3-319-71350-2 |pages=181–223 |chapter-url=https://link.springer.com/chapter/10.1007/978-3-319-71350-2_5 |language=en |chapter=Meaningless marks on paper|doi=10.1007/978-3-319-71350-2_5 }}</ref>

The [[APL (codepage)|character set for the APL programming language]] includes several characters that were printed by overstriking other characters on printing terminals such as the [[IBM 2741]], for example the functions {{Key press|⌽}} and {{Key press|⊖}} may be used to reverse the elements of an array.<ref>{{cite journal |last1=Leong |first1=Warren W. |title=CRT Terminal Provides both APL and ASCII Operation |journal=Hewlett-Packard Journal |date=July 1977 |pages=25–28| url=https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=117ecc0a2d30a9ddd0e50900fcba94dff94ef978#page=25}} and {{cite journal |last1=Johnston |first1=Ronald L. |title=APLGOL: Structured Programming: Facilities for APL |journal=Hewlett-Packard Journal |date=July 1977 |pages=11–16|url=https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=117ecc0a2d30a9ddd0e50900fcba94dff94ef978#page=11}}</ref>

The [[WordPerfect]] word processor includes overstrike functionality.<ref>{{cite journal |last1=Kahrel |first1=Peter |title=Foreign languages in WordPerfect |journal=ASLIB Proceedings |date=1 January 1994 |volume=46 |issue=5 |pages=135–140 |doi=10.1108/eb051357 |url=https://www.emerald.com/insight/content/doi/10.1108/eb051357/full/html |access-date=3 February 2024 |issn=0001-253X|url-access=subscription }}</ref><ref>{{cite book |last1=Gosling |first1=Joanna |title=Easily into WordPerfect 5® |date=1990 |publisher=Macmillan Education UK |isbn=978-1-349-11017-9 |pages=66–87 |chapter-url=https://link.springer.com/chapter/10.1007/978-1-349-11017-9_8 |language=en |chapter=Enhancing Your Text|doi=10.1007/978-1-349-11017-9_8 }}</ref> [[Collabora Online]], [[LibreOffice]] and [[Microsoft Word]] do not; however Collabora Online and LibreOffice allow the use of the characters X and / (forward slash) to overstrike, using the [[strikethrough]] function.<ref>{{cite web |title=Tools for Linguistic Word Processing |url=https://pluto.huji.ac.il/~msyfalk/Tools.html |website=pluto.huji.ac.il |access-date=3 February 2024}}</ref>
No known [[Keyboard layout|keyboard arrangement]] includes a function key that allows any two characters to be superimposed.

==References==
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{{Typography}}
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[[Category:Typography]]