Introduce parameters to OptimalFit

benches/linear.rs

@@ -31,7 +31,7 @@ pub fn benchmark(c: &mut Criterion) {
             #[cfg(feature = "unicode-linebreak")]
             {
                 let options = textwrap::Options::new(LINE_LENGTH)
-                    .wrap_algorithm(textwrap::wrap_algorithms::OptimalFit)
+                    .wrap_algorithm(textwrap::wrap_algorithms::OptimalFit::new())
                     .word_separator(textwrap::word_separators::UnicodeBreakProperties);
                 group.bench_with_input(
                     BenchmarkId::new("fill_optimal_fit_unicode", length),
@@ -43,7 +43,7 @@ pub fn benchmark(c: &mut Criterion) {
             }
 
             let options = textwrap::Options::new(LINE_LENGTH)
-                .wrap_algorithm(textwrap::wrap_algorithms::OptimalFit)
+                .wrap_algorithm(textwrap::wrap_algorithms::OptimalFit::new())
                 .word_separator(textwrap::word_separators::AsciiSpace);
             group.bench_with_input(
                 BenchmarkId::new("fill_optimal_fit_ascii", length),

examples/interactive.rs

@@ -109,12 +109,20 @@ mod unix_only {
 
         #[cfg(feature = "smawk")]
         {
+            // The OptimalFit struct formats itself with a ton of
+            // parameters. This removes the parameters, leaving only
+            // the struct name behind.
+            let wrap_algorithm_label = format!("{:?}", options.wrap_algorithm)
+                .split(' ')
+                .next()
+                .unwrap()
+                .to_string();
             write!(
                 stdout,
-                "{}- algorithm: {}{:?}{} (toggle with Ctrl-o)",
+                "{}- algorithm: {}{}{} (toggle with Ctrl-o)",
                 cursor::Goto(left_col, left_row),
                 style::Bold,
-                options.wrap_algorithm,
+                wrap_algorithm_label,
                 style::Reset,
             )?;
             left_row += 1;
@@ -233,9 +241,9 @@ mod unix_only {
 
     pub fn main() -> Result<(), io::Error> {
         let mut wrap_algorithms: Vec<Box<dyn wrap_algorithms::WrapAlgorithm>> =
-            vec![Box::new(wrap_algorithms::FirstFit)];
+            vec![Box::new(wrap_algorithms::FirstFit::new())];
         #[cfg(feature = "smawk")]
-        wrap_algorithms.push(Box::new(wrap_algorithms::OptimalFit));
+        wrap_algorithms.push(Box::new(wrap_algorithms::OptimalFit::new()));
 
         let mut word_splitters: Vec<Box<dyn word_splitters::WordSplitter>> = vec![
             Box::new(word_splitters::HyphenSplitter),

examples/wasm/src/lib.rs

@@ -5,7 +5,7 @@ use wasm_bindgen::JsCast;
 use textwrap::core;
 use textwrap::word_separators::{AsciiSpace, UnicodeBreakProperties, WordSeparator};
 use textwrap::word_splitters::{split_words, HyphenSplitter, NoHyphenation, WordSplitter};
-use textwrap::wrap_algorithms::{wrap_first_fit, wrap_optimal_fit};
+use textwrap::wrap_algorithms::{wrap_first_fit, wrap_optimal_fit, OptimalFit};
 
 #[wasm_bindgen]
 extern "C" {
@@ -248,6 +248,48 @@ pub enum WasmWrapAlgorithm {
     OptimalFit = "OptimalFit",
 }
 
+#[wasm_bindgen]
+#[derive(Copy, Clone, Debug, Default)]
+pub struct WasmOptimalFit {
+    pub nline_penalty: i32,
+    pub overflow_penalty: i32,
+    pub short_last_line_fraction: usize,
+    pub short_last_line_penalty: i32,
+    pub hyphen_penalty: i32,
+}
+
+#[wasm_bindgen]
+impl WasmOptimalFit {
+    #[wasm_bindgen(constructor)]
+    pub fn new(
+        nline_penalty: i32,
+        overflow_penalty: i32,
+        short_last_line_fraction: usize,
+        short_last_line_penalty: i32,
+        hyphen_penalty: i32,
+    ) -> WasmOptimalFit {
+        WasmOptimalFit {
+            nline_penalty,
+            overflow_penalty,
+            short_last_line_fraction,
+            short_last_line_penalty,
+            hyphen_penalty,
+        }
+    }
+}
+
+impl Into<OptimalFit> for WasmOptimalFit {
+    fn into(self) -> OptimalFit {
+        OptimalFit {
+            nline_penalty: self.nline_penalty,
+            overflow_penalty: self.overflow_penalty,
+            short_last_line_fraction: self.short_last_line_fraction,
+            short_last_line_penalty: self.short_last_line_penalty,
+            hyphen_penalty: self.hyphen_penalty,
+        }
+    }
+}
+
 #[wasm_bindgen]
 #[derive(Copy, Clone, Debug)]
 pub struct WasmOptions {
@@ -256,6 +298,7 @@ pub struct WasmOptions {
     pub word_separator: WasmWordSeparator,
     pub word_splitter: WasmWordSplitter,
     pub wrap_algorithm: WasmWrapAlgorithm,
+    pub optimal_fit: WasmOptimalFit,
 }
 
 #[wasm_bindgen]
@@ -267,13 +310,15 @@ impl WasmOptions {
         word_separator: WasmWordSeparator,
         word_splitter: WasmWordSplitter,
         wrap_algorithm: WasmWrapAlgorithm,
+        optimal_fit: WasmOptimalFit,
     ) -> WasmOptions {
         WasmOptions {
             width,
             break_words,
             word_separator,
             word_splitter,
             wrap_algorithm,
+            optimal_fit,
         }
     }
 }
@@ -325,7 +370,10 @@ pub fn draw_wrapped_text(
         let line_lengths = [options.width * PRECISION];
         let wrapped_words = match options.wrap_algorithm {
             WasmWrapAlgorithm::FirstFit => wrap_first_fit(&canvas_words, &line_lengths),
-            WasmWrapAlgorithm::OptimalFit => wrap_optimal_fit(&canvas_words, &line_lengths),
+            WasmWrapAlgorithm::OptimalFit => {
+                let penalties = options.optimal_fit.into();
+                wrap_optimal_fit(&canvas_words, &line_lengths, &penalties)
+            }
             _ => Err("WasmOptions has an invalid wrap_algorithm field")?,
         };
 

examples/wasm/www/index.html

@@ -80,15 +80,43 @@ <h1>Textwrap WebAssembly Demo</h1>
         </select>
       </div>
 
-      <!-- See https://github.com/mgeisler/textwrap/issues/326
       <div class="option">
         <label for="wrap-algorithm">Wrap algorithm:</label>
         <select id="wrap-algorithm">
           <option value="OptimalFit">Optimal-fit</option>
           <option value="FirstFit">First-fit</option>
-        </select>
+        </select>	
+      </div>
+
+      <div class="option">
+        <label for="nline-penalty">Nth line penalty:</label>
+        <input type="number" id="nline-penalty-text">
+        <input type="range" id="nline-penalty" min="0" max="10000" value="1000">
+      </div>
+
+      <div class="option">
+        <label for="overflow-penalty">Overflow penalty:</label>
+        <input type="number" id="overflow-penalty-text">
+        <input type="range" id="overflow-penalty" min="-1000" max="10000" value="7500">
+      </div>
+
+      <div class="option">
+        <label for="short-line-fraction">Short line fraction:</label>
+        <input type="number" id="short-line-fraction-text">
+        <input type="range" id="short-line-fraction" min="1" max="10" value="4">
+      </div>
+
+      <div class="option">
+        <label for="short-last-line-penalty">Short line penalty:</label>
+        <input type="number" id="short-last-line-penalty-text">
+        <input type="range" id="short-last-line-penalty" min="-2000" max="2000" value="100">
+      </div>
+
+      <div class="option">
+        <label for="hyphen-penalty">Hyphen penalty:</label>
+        <input type="number" id="hyphen-penalty-text">
+        <input type="range" id="hyphen-penalty" min="-2000" max="2000" value="100">
       </div>
-      -->
     </div>
 
     <div>

examples/wasm/www/index.js

@@ -1,4 +1,4 @@
-import { draw_wrapped_text, WasmOptions } from "textwrap-wasm-demo";
+import { draw_wrapped_text, WasmOptions, WasmOptimalFit } from "textwrap-wasm-demo";
 
 fetch("build-info.json").then(response => response.json()).then(buildInfo => {
     if (buildInfo.date && buildInfo.commit) {
@@ -25,24 +25,45 @@ function redraw(event) {
     let breakWords = document.getElementById("break-words").checked;
     let wordSeparator = document.getElementById("word-separator").value;
     let wordSplitter = document.getElementById("word-splitter").value;
-    // TODO: The optimal-fit algorithm does not work well for
-    // proportional fonts, so we always use FirstFit. See
-    // https://github.com/mgeisler/textwrap/issues/326.
-    let wrapAlgorithm = "FirstFit"; // document.getElementById("wrap-algorithm").value;
-    let options = new WasmOptions(lineWidth, breakWords, wordSeparator, wordSplitter, wrapAlgorithm);
-    draw_wrapped_text(ctx, options, text);
+    let wrapAlgorithm = document.getElementById("wrap-algorithm").value;
+    let optimalFit = new WasmOptimalFit(document.getElementById("nline-penalty").valueAsNumber,
+                                        document.getElementById("overflow-penalty").valueAsNumber,
+                                        document.getElementById("short-line-fraction").valueAsNumber,
+                                        document.getElementById("short-last-line-penalty").valueAsNumber,
+                                        document.getElementById("hyphen-penalty").valueAsNumber);
+    let options = new WasmOptions(lineWidth, breakWords, wordSeparator, wordSplitter, wrapAlgorithm, optimalFit);
+    draw_wrapped_text(ctx, options, text, optimalFit);
 }
 
-document.getElementById("line-width").addEventListener("input", (event) => {
-    let lineWidthText = document.getElementById("line-width-text");
-    lineWidthText.value = event.target.valueAsNumber;
+document.getElementById("wrap-algorithm").addEventListener("input", (event) => {
+    let disableOptimalFitParams = (event.target.value == "FirstFit");
+    let rangeInputIds = ["nline-penalty",
+               "overflow-penalty",
+               "short-line-fraction",
+               "short-last-line-penalty",
+               "hyphen-penalty"];
+    rangeInputIds.forEach((rangeInputId) => {
+        let rangeInput = document.getElementById(rangeInputId);
+        let textInput = document.getElementById(`${rangeInputId}-text`);
+        rangeInput.disabled = disableOptimalFitParams;
+        textInput.disabled = disableOptimalFitParams;
+    });
 });
 
-document.getElementById("line-width-text").addEventListener("input", (event) => {
-    let lineWidth = document.getElementById("line-width");
-    lineWidth.value = event.target.valueAsNumber;
-});
 
+document.querySelectorAll("input[type=range]").forEach((rangeInput) => {
+    let textInput = document.getElementById(`${rangeInput.id}-text`);
+    textInput.min = rangeInput.min;
+    textInput.max = rangeInput.max;
+    textInput.value = rangeInput.value;
+
+    rangeInput.addEventListener("input", (event) => {
+        textInput.value = rangeInput.valueAsNumber;
+    });
+    textInput.addEventListener("input", (event) => {
+        rangeInput.value = textInput.valueAsNumber;
+    });
+});
 
 document.querySelectorAll("textarea, select, input").forEach((elem) => {
     elem.addEventListener("input", redraw);

src/lib.rs

@@ -317,9 +317,9 @@ impl<'a>
     ///     #[cfg(not(feature = "unicode-linebreak"))]
     ///     word_separator: textwrap::word_separators::AsciiSpace,
     ///     #[cfg(feature = "smawk")]
-    ///     wrap_algorithm: textwrap::wrap_algorithms::OptimalFit,
+    ///     wrap_algorithm: textwrap::wrap_algorithms::OptimalFit::new(),
     ///     #[cfg(not(feature = "smawk"))]
-    ///     wrap_algorithm: textwrap::wrap_algorithms::FirstFit,
+    ///     wrap_algorithm: textwrap::wrap_algorithms::FirstFit::new(),
     ///     word_splitter: textwrap::word_splitters::HyphenSplitter,
     /// }
     /// # ;
@@ -429,9 +429,9 @@ impl<'a, WordSplit> Options<'a, DefaultWrapAlgorithm!(), DefaultWordSeparator!()
     ///     #[cfg(not(feature = "unicode-linebreak"))]
     ///     word_separator: textwrap::word_separators::AsciiSpace,
     ///     #[cfg(feature = "smawk")]
-    ///     wrap_algorithm: textwrap::wrap_algorithms::OptimalFit,
+    ///     wrap_algorithm: textwrap::wrap_algorithms::OptimalFit::new(),
     ///     #[cfg(not(feature = "smawk"))]
-    ///     wrap_algorithm: textwrap::wrap_algorithms::FirstFit,
+    ///     wrap_algorithm: textwrap::wrap_algorithms::FirstFit::new(),
     ///     word_splitter: word_splitter,
     /// }
     /// # ;
@@ -492,7 +492,7 @@ impl<'a, WordSplit> Options<'a, DefaultWrapAlgorithm!(), DefaultWordSeparator!()
             subsequent_indent: "",
             break_words: true,
             word_separator: DefaultWordSeparator!(),
-            wrap_algorithm: DefaultWrapAlgorithm!(),
+            wrap_algorithm: <DefaultWrapAlgorithm!()>::new(),
             word_splitter: word_splitter,
         }
     }
@@ -993,7 +993,7 @@ where
 /// # use textwrap::wrap_algorithms::OptimalFit;
 /// #
 /// # let lines = wrap("To be, or not to be: that is the question",
-/// #                  Options::new(10).wrap_algorithm(OptimalFit));
+/// #                  Options::new(10).wrap_algorithm(OptimalFit::new()));
 /// # assert_eq!(lines.join("\n") + "\n", "\
 /// To be,
 /// or not to

src/wrap_algorithms.rs

@@ -74,9 +74,22 @@ impl WrapAlgorithm for Box<dyn WrapAlgorithm> {
 /// This algorithm uses no look-ahead when finding line breaks.
 /// Implemented by [`wrap_first_fit`], please see that function for
 /// details and examples.
-#[derive(Clone, Copy, Debug, Default)]
+#[derive(Clone, Copy, Debug)]
 pub struct FirstFit;
 
+impl FirstFit {
+    /// Create a new empty struct.
+    pub const fn new() -> Self {
+        FirstFit
+    }
+}
+
+impl Default for FirstFit {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl WrapAlgorithm for FirstFit {
     #[inline]
     fn wrap<'a, 'b>(&self, words: &'b [Word<'a>], line_widths: &'b [usize]) -> Vec<&'b [Word<'a>]> {
@@ -107,7 +120,7 @@ impl WrapAlgorithm for FirstFit {
 ///
 /// ```
 /// use textwrap::core::Word;
-/// use textwrap::wrap_algorithms;
+/// use textwrap::wrap_algorithms::wrap_first_fit;
 /// use textwrap::word_separators::{AsciiSpace, WordSeparator};
 ///
 /// // Helper to convert wrapped lines to a Vec<String>.
@@ -119,7 +132,7 @@ impl WrapAlgorithm for FirstFit {
 ///
 /// let text = "These few words will unfortunately not wrap nicely.";
 /// let words = AsciiSpace.find_words(text).collect::<Vec<_>>();
-/// assert_eq!(lines_to_strings(wrap_algorithms::wrap_first_fit(&words, &[15])),
+/// assert_eq!(lines_to_strings(wrap_first_fit(&words, &[15])),
 ///            vec!["These few words",
 ///                 "will",  // <-- short line
 ///                 "unfortunately",
@@ -128,7 +141,9 @@ impl WrapAlgorithm for FirstFit {
 ///
 /// // We can avoid the short line if we look ahead:
 /// #[cfg(feature = "smawk")]
-/// assert_eq!(lines_to_strings(wrap_algorithms::wrap_optimal_fit(&words, &[15])),
+/// use textwrap::wrap_algorithms::{wrap_optimal_fit, OptimalFit};
+/// #[cfg(feature = "smawk")]
+/// assert_eq!(lines_to_strings(wrap_optimal_fit(&words, &[15], &OptimalFit::new())),
 ///            vec!["These few",
 ///                 "words will",
 ///                 "unfortunately",