Fake bold fakebold

Intro

Cuti simulates fake bold by utilizing the stroke attribute of text. This package is typically used on fonts that do not have a bold weight, such as "SimSun". This package uses 0.02857em as the parameter for stroke. In Microsoft Office software, enabling fake bold will apply a border of about 0.02857em to characters. This is where the value of 0.02857em is derived from. (In fact, the exact value may be 1/35.)

DEMO

Part 1: font: ("Times New Roman", "SimSun")

#set text(font: ("Times New Roman", "SimSun"))
#grid(
    columns: 2,
    column-gutter: 0.2em,
    row-gutter: 0.6em,
    [Regular:], [你说得对，但是《Cuti》是一个用于伪粗体和伪斜体的包。],
    [Bold(Font Only):], text(weight: "bold")[你说得对，但是《Cuti》是一个用于伪粗体和伪斜体的包。],
    [Bold(Fake Only):], fakebold[你说得对，但是《Cuti》是一个用于伪粗体和伪斜体的包。],
    [Bold(Fake+Font):], show-cn-fakebold(text(weight: "bold")[你说得对，但是《Cuti》是一个用于伪粗体和伪斜体的包。]),
)

Part 2: font: "Source Han Serif SC"

#set text(font: "Source Han Serif SC")
#grid(
    columns: 2,
    column-gutter: 0.2em,
    row-gutter: 0.6em,
    [Regular:], [前面忘了。同时，逐步发掘「Typst」的奥妙。],
    [Bold(Font Only):], text(weight: "bold")[前面忘了。同时，逐步发掘「Typst」的奥妙。],
    [Bold(Fake Only):], fakebold[前面忘了。同时，逐步发掘「Typst」的奥妙。],
    [Bold(Fake+Font):], show-cn-fakebold(text(weight: "bold")[前面忘了。同时，逐步发掘「Typst」的奥妙。])
)

fakebold

#fakebold[] with no parmerter will apply the fakebold effect to characters.

- Fakebold: #fakebold[#lorem(5)]
- Bold: #text(weight: "bold", lorem(5))
- Bold + Fakebold: #fakebold[#text(weight: "bold", lorem(5))]

#fakebold can accept the same parameters as #text.

• The stroke parameter, if specified, will be ignored.
• If the weight parameter is specified, it can be used to define which font weight to base the stroke on. The default is auto, and the options are auto, none, or an int/str representing font weight.
  • none - Stroke based on regular weight;
  • auto - Stroke based on current weight (may have side effects, see explanation below);
  • int/str - Please refer to the official documentation https://typst.app/docs/reference/text/text/#parameters-weight.

- Regular: #lorem(5)
- Regular + Fakebold: #fakebold[#lorem(5)]
- Bold: #text(weight: "bold")[#lorem(5)]
- Bold + Fakebold: #fakebold(weight: "bold")[#lorem(5)]
- Bold + Fakebold: #set text(weight: "bold"); #fakebold[#lorem(5)]

Compatibility Note

cuti:^0.3.0 (compatible with Typst 0.12.0) retains base-weight as an alias for weight for backward compatibility, and base-weight has higher priority than weight.

In cuti:^0.2.1 (compatible with Typst 0.11.x), the default value of weight is none, indicating stroke based on current weight.

If the text is set to a color, the fake bold stroke will also change to the corresponding color.

- Blue + Fakebold: #fakebold(fill: blue)[花生瓜子八宝粥，啤酒饮料矿泉水。#lorem(5)]
- Gradient + Fakebold: #set text(fill: gradient.conic(..color.map.rainbow)); #fakebold[花生瓜子八宝粥，啤酒饮料矿泉水。#lorem(5)]

regex-fakebold

The #regex-fakebold is designed to be used in multilingual and multi-font scenarios. It allows the use of a RegExp string as the reg-exp parameter to match characters that will have the fake bold effect applied. It can also accept the same parameters as #fakebold.

+ RegExp `[a-o]`: #regex-fakebold(reg-exp: "[a-o]")[#lorem(5)]
+ RegExp `\p{script=Han}`: #regex-fakebold(reg-exp: "\p{script=Han}")[衬衫的价格是9磅15便士。]
+ RegExp `\p{script=Han}`: #set text(weight: "bold"); #regex-fakebold(reg-exp: "\p{script=Han}")[衬衫的价格是9磅15便士。]

In Example 3, 9 and 15 are the real bold characters from the font file, while the other characters are simulated as "fake bold" based on the regular weight.

show-fakebold

In multilingual and multi-font scenarios, different languages often utilize their own fonts, but not all fonts contain the bold weight. It can be inconvenient to use #fakebold or #regex-fakebold each time we require strong or bold effects. Therefore, the #show-fakebold function is introduced for show rule.

show-fakebold and regex-fakebold share the same parameters. By default:

• show-fakebold uses "." as the regular expression, meaning all characters with bold or strong attributes will be fake-bolded;
• show-fakebold uses weight: none as the default base weight:
  • In cuti:^0.2.1 (compatible with Typst 0.11.x), it will apply fake bold based on the current font weight.
  • In cuti:^0.3.0 (compatible with Typst 0.12.0), it will apply fake bold based on the regular font weight.
  • However, in all current versions, using #strong[] or its syntactic sugar *strong* for bold text will result in a base font weight of bold, and this behavior cannot be modified at the moment. (Feel free to submit a PR or open an issue if you have a solution.)

#show: show-fakebold
- Regular: #lorem(10)
- Bold: #text(weight: "bold")[#lorem(10)]

Why the new version no longer defaults to boldening based on current weight

In Typst 0.11.x, boldening based on current weight generally didn't cause issues. However, in Typst 0.12.0, show rules might match already processed characters again, leading to infinite loops. Therefore, in cuti:0.3.0, cuti changed its default behavior.

Under normal circumstances, the combination of font-provided bold and fake bold is not the effect we want. Generally, we need to specify regular expressions to define the scope where fake bold should take effect.

#show: show-fakebold.with(reg-exp: "\p{script=Han}")
- Regular: 我正在使用 Typst 排版。
- Strong: *我正在使用 Typst 排版。*

cn-fakebold & show-cn-fakebold

cn-fakebold and show-cn-fakebold are encapsulations of the above regex-fakebold and show-fakebold, pre-configured for use with Chinese text. Please refer to the Chinese documentation for detailed usage instructions.

Known Issues

• When using strong for bold text, the base font weight is fixed at bold.

#show: show-cn-fakebold
- Regular: 滚滚长江东逝水，浪花淘尽英雄。 #lorem(5)
- Bold: #text(weight: "bold")[滚滚长江东逝水，浪花淘尽英雄。]
- Strong + Bug: *滚滚长江东逝水，浪花淘尽英雄。 #lorem(5)*

• text.tracking may not work properly.

#set text(tracking: 1em)
滚滚长江#text(weight: "bold")[东逝水，浪花。]淘尽英雄

Feel free to submit a PR or open an issue if you have a solution or workaround.