Struct KnuthPlass

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pub struct KnuthPlass<N> { /* private fields */ }

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Runs the Knuth-Plass line-breaking algorithm to calculate the optimal break points for a paragraph.

Implementations§

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impl<N: Num> KnuthPlass<N>

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pub fn new() -> Self

Creates a new KnuthPlass layout with default parameter values.

Examples found in repository ?

examples/readme.rs (line 60)

58fn layout_text() -> Result<String, fmt::Error> {
59    let text = "  Far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy lies a small unregarded yellow sun. Orbiting this at a distance of roughly ninety-two million miles is an utterly insignificant little blue-green planet whose ape-descended life forms are so amazingly primitive that they still think digital watches are a pretty neat idea.";
60    let knuth_plass = KnuthPlass::new().with_threshold(f32::INFINITY);
61    let lines = layout_paragraph(&text, &knuth_plass, 80);
62    let mut result = String::new();
63    writeln!(&mut result, "┏{}┓", "━".repeat(80))?;
64    for l in lines {
65        let pad = 80 - l.chars().count();
66        writeln!(&mut result, "┃{}{}┃", l, " ".repeat(pad))?;
67    }
68    writeln!(&mut result, "┗{}┛", "━".repeat(80))?;
69    Ok(result)
70}

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examples/fixed.rs (line 65)

63fn layout_text() -> Result<String, fmt::Error> {
64    let text = "  Far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy lies a small unregarded yellow sun. Orbiting this at a distance of roughly ninety-two million miles is an utterly insignificant little blue-green planet whose ape-descended life forms are so amazingly primitive that they still think digital watches are a pretty neat idea.";
65    let knuth_plass = KnuthPlass::new().with_threshold(F::MAX);
66    let lines = layout_paragraph(&text, &knuth_plass, F::from_num(80));
67    let mut result = String::new();
68    writeln!(&mut result, "┏{}┓", "━".repeat(80))?;
69    for l in lines {
70        let pad = 80 - l.chars().count();
71        writeln!(&mut result, "┃{}{}┃", l, " ".repeat(pad))?;
72    }
73    writeln!(&mut result, "┗{}┛", "━".repeat(80))?;
74    Ok(result)
75}

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pub fn with_flagged_demerit(self, flagged_demerit: N) -> Self

Sets the demerit for flagged penalties. Defaults to 100. Referred to as 𝛂 in Knuth-Plass ’81.

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pub fn with_fitness_demerit(self, fitness_demerit: N) -> Self

Sets the demerit for a line that belongs to a different fitness class than its predecessor. Defaults to 100. Referred to as 𝛄 in Knuth-Plass ’81.

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pub fn with_threshold(self, threshold: N) -> Self

Sets the adjustment ratio threshold. Lines will not be allowed to break at a given point if doing so would cause the line’s adjustment ratio to exceed this value. Defaults to 1. Referred to as 𝛒 in Knuth-Plass ’81.

Examples found in repository ?

examples/readme.rs (line 60)

58fn layout_text() -> Result<String, fmt::Error> {
59    let text = "  Far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy lies a small unregarded yellow sun. Orbiting this at a distance of roughly ninety-two million miles is an utterly insignificant little blue-green planet whose ape-descended life forms are so amazingly primitive that they still think digital watches are a pretty neat idea.";
60    let knuth_plass = KnuthPlass::new().with_threshold(f32::INFINITY);
61    let lines = layout_paragraph(&text, &knuth_plass, 80);
62    let mut result = String::new();
63    writeln!(&mut result, "┏{}┓", "━".repeat(80))?;
64    for l in lines {
65        let pad = 80 - l.chars().count();
66        writeln!(&mut result, "┃{}{}┃", l, " ".repeat(pad))?;
67    }
68    writeln!(&mut result, "┗{}┛", "━".repeat(80))?;
69    Ok(result)
70}

More examples

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examples/fixed.rs (line 65)

63fn layout_text() -> Result<String, fmt::Error> {
64    let text = "  Far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy lies a small unregarded yellow sun. Orbiting this at a distance of roughly ninety-two million miles is an utterly insignificant little blue-green planet whose ape-descended life forms are so amazingly primitive that they still think digital watches are a pretty neat idea.";
65    let knuth_plass = KnuthPlass::new().with_threshold(F::MAX);
66    let lines = layout_paragraph(&text, &knuth_plass, F::from_num(80));
67    let mut result = String::new();
68    writeln!(&mut result, "┏{}┓", "━".repeat(80))?;
69    for l in lines {
70        let pad = 80 - l.chars().count();
71        writeln!(&mut result, "┃{}{}┃", l, " ".repeat(pad))?;
72    }
73    writeln!(&mut result, "┗{}┛", "━".repeat(80))?;
74    Ok(result)
75}

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pub fn with_looseness(self, looseness: usize) -> Self

Sets the looseness parameter. The looseness is an integer 𝗾 such that the total number of lines produced for the paragraph is as close as possible to 𝗾 plus the optimum number, without violating the conditions of feasibility.