From 1c5e4034ddf536599e51febd485c9aba79d27e28 Mon Sep 17 00:00:00 2001
From: A4-Tacks <wdsjxhno1001@163.com>
Date: Wed, 9 Apr 2025 14:41:10 +0800
Subject: [PATCH] Add usage_column and usage_width

---
 src/lib.rs       | 56 +++++++++++++++++++++++++++++++++++---
 src/tests/mod.rs | 70 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 122 insertions(+), 4 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index f5c8e3cf..80d4cef8 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -142,6 +142,8 @@ pub struct Options {
     grps: Vec<OptGroup>,
     parsing_style: ParsingStyle,
     long_only: bool,
+    usage_column: usize,
+    usage_width: usize,
 }
 
 impl Default for Options {
@@ -157,6 +159,8 @@ impl Options {
             grps: Vec::new(),
             parsing_style: ParsingStyle::FloatingFrees,
             long_only: false,
+            usage_column: 24,
+            usage_width: 54,
         }
     }
 
@@ -618,7 +622,10 @@ impl Options {
 
     /// Derive usage items from a set of options.
     fn usage_items<'a>(&'a self) -> Box<dyn Iterator<Item = String> + 'a> {
-        let desc_sep = format!("\n{}", repeat(" ").take(24).collect::<String>());
+        let desc_sep = format!(
+            "\n{}",
+            repeat(" ").take(self.usage_column).collect::<String>()
+        );
 
         let any_short = self.grps.iter().any(|optref| !optref.short_name.is_empty());
 
@@ -678,15 +685,15 @@ impl Options {
             }
 
             let rowlen = row.width();
-            if rowlen < 24 {
-                for _ in 0..24 - rowlen {
+            if rowlen < self.usage_column {
+                for _ in 0..self.usage_column - rowlen {
                     row.push(' ');
                 }
             } else {
                 row.push_str(&desc_sep)
             }
 
-            let desc_rows = each_split_within(&desc, 54);
+            let desc_rows = each_split_within(&desc, self.usage_width);
             row.push_str(&desc_rows.join(&desc_sep));
 
             row
@@ -694,6 +701,47 @@ impl Options {
 
         Box::new(rows)
     }
+
+    /// Get the display column of usage, see [`Options::set_usage_column`] for details
+    pub fn usage_column(&self) -> usize {
+        self.usage_column.clone()
+    }
+
+    /// Set the display column of usage
+    ///
+    /// # Example
+    ///
+    /// ```text
+    /// Options:
+    ///     -h, --help          show help
+    /// |<-------------------->|
+    ///       usage_column
+    /// ```
+    pub fn set_usage_column(&mut self, column: usize) -> &mut Options {
+        self.usage_column = column;
+        self
+    }
+
+    /// Get the display width of usage, see [`Options::set_usage_width`] for details
+    pub fn usage_width(&self) -> usize {
+        self.usage_width.clone()
+    }
+
+    /// Set the display width of usage
+    ///
+    /// # Example
+    ///
+    /// ```text
+    /// Options:
+    ///     -h, --help          This description too long and will be split into new
+    ///                         line.
+    ///                         |<-------------------------------------------------->|
+    ///                                             usage_width
+    /// ```
+    pub fn set_usage_width(&mut self, width: usize) -> &mut Options {
+        self.usage_width = width;
+        self
+    }
 }
 
 fn validate_names(short_name: &str, long_name: &str) {
diff --git a/src/tests/mod.rs b/src/tests/mod.rs
index 17e689c4..054aaf63 100644
--- a/src/tests/mod.rs
+++ b/src/tests/mod.rs
@@ -919,6 +919,41 @@ Options:
     assert!(usage == expected)
 }
 
+#[test]
+#[cfg(feature = "unicode")]
+fn test_usage_description_newline_handling_custom_width() {
+    let mut opts = Options::new();
+    opts.set_usage_width(30);
+    opts.optflag(
+        "k",
+        "k\u{2013}w\u{2013}",
+        "The word kiwi is normally spelled with two i's",
+    );
+    opts.optflag(
+        "a",
+        "apple",
+        "This description forces a new line.\n Here is a premature\n\
+         newline",
+    );
+
+    let expected = "Usage: fruits
+
+Options:
+    -k, --k–w–          The word kiwi is normally
+                        spelled with two i's
+    -a, --apple         This description forces a new
+                        line.
+                        Here is a premature
+                        newline
+";
+
+    let usage = opts.usage("Usage: fruits");
+
+    debug!("expected: <<{}>>", expected);
+    debug!("generated: <<{}>>", usage);
+    assert!(usage == expected)
+}
+
 #[test]
 #[cfg(feature = "unicode")]
 fn test_usage_description_newline_handling() {
@@ -951,6 +986,41 @@ Options:
     assert!(usage == expected)
 }
 
+#[test]
+#[cfg(feature = "unicode")]
+fn test_usage_description_newline_handling_custom_column() {
+    let mut opts = Options::new();
+    opts.set_usage_column(10);
+    opts.optflag(
+        "k",
+        "k\u{2013}w\u{2013}",
+        "The word kiwi is normally spelled with two i's",
+    );
+    opts.optflag(
+        "a",
+        "apple",
+        "This description forces a new line.\n Here is a premature\n\
+         newline",
+    );
+
+    let expected = "Usage: fruits
+
+Options:
+    -k, --k–w–\u{0020}
+          The word kiwi is normally spelled with two i's
+    -a, --apple\u{0020}
+          This description forces a new line.
+          Here is a premature
+          newline
+";
+
+    let usage = opts.usage("Usage: fruits");
+
+    debug!("expected: <<{}>>", expected);
+    debug!("generated: <<{}>>", usage);
+    assert!(usage == expected)
+}
+
 #[test]
 #[cfg(feature = "unicode")]
 fn test_usage_multiwidth() {