Add max page length to select

Author: justinbarclay

examples/select.rs

@@ -29,4 +29,14 @@ fn main() {
     } else {
         println!("You didn't select anything!");
     }
+
+    let selection = Select::with_theme(&ColorfulTheme::default())
+        .with_prompt("Optionally pick your flavor, hint it might be on the second page")
+        .default(0)
+        .max_length(2)
+        .items(&selections[..])
+        .interact()
+        .unwrap();
+
+    println!("Enjoy your {}!", selections[selection]);
 }

src/paging.rs

@@ -11,18 +11,23 @@ pub struct Paging<'a> {
     pub current_page: usize,
     pub capacity: usize,
     pub active: bool,
-
+    pub max_capacity: Option<usize>,
     term: &'a Term,
     current_term_size: (u16, u16),
     items_len: usize,
     activity_transition: bool,
 }
 
 impl<'a> Paging<'a> {
-    pub fn new(term: &'a Term, items_len: usize) -> Paging<'a> {
+    pub fn new(term: &'a Term, items_len: usize, max_capacity: Option<usize>) -> Paging<'a> {
         let term_size = term.size();
         // Subtract -2 because we need space to render the prompt, if paging is active
-        let capacity = term_size.0 as usize - 2;
+        let capacity = max_capacity
+            .unwrap_or(std::usize::MAX)
+            .min(term_size.0 as usize)
+            // Safeguard in case term_size or max_length is 2 or less. Guarantees no unwanted wrapping behavior.
+            .max(3)
+            - 2;
         let pages = (items_len as f64 / capacity as f64).ceil() as usize;
 
         Paging {
@@ -33,6 +38,7 @@ impl<'a> Paging<'a> {
             term,
             current_term_size: term_size,
             items_len,
+            max_capacity,
             // Set transition initially to true to trigger prompt rendering for inactive paging on start
             activity_transition: true,
         }
@@ -44,7 +50,12 @@ impl<'a> Paging<'a> {
 
         if self.current_term_size != new_term_size {
             self.current_term_size = new_term_size;
-            self.capacity = self.current_term_size.0 as usize - 2;
+            self.capacity = self
+                .max_capacity
+                .unwrap_or(std::usize::MAX)
+                .min(self.current_term_size.0 as usize)
+                .max(3)
+                - 2;
             self.pages = (self.items_len as f64 / self.capacity as f64).ceil() as usize;
         }
 

src/prompts/multi_select.rs

@@ -182,7 +182,7 @@ impl MultiSelect<'_> {
             ));
         }
 
-        let mut paging = Paging::new(term, self.items.len());
+        let mut paging = Paging::new(term, self.items.len(), None);
         let mut render = TermThemeRenderer::new(term, self.theme);
         let mut sel = 0;
 

src/prompts/select.rs

@@ -40,6 +40,7 @@ pub struct Select<'a> {
     prompt: Option<String>,
     clear: bool,
     theme: &'a dyn Theme,
+    max_length: Option<usize>,
 }
 
 impl Default for Select<'static> {
@@ -71,6 +72,17 @@ impl Select<'_> {
         self.default = val;
         self
     }
+    /// Sets an optional max length for a page.
+    ///
+    /// Max length is disabled by None
+    pub fn max_length(&mut self, val: usize) -> &mut Self {
+        // Paging subtracts two from the capacity, paging does this to
+        // make an offset for the page indicator. So to make sure that
+        // we can show the intended amount of items we need to add two
+        // to our value.
+        self.max_length = Some(val + 2);
+        self
+    }
 
     /// Add a single item to the selector.
     ///
@@ -220,7 +232,7 @@ impl Select<'_> {
             ));
         }
 
-        let mut paging = Paging::new(term, self.items.len());
+        let mut paging = Paging::new(term, self.items.len(), self.max_length);
         let mut render = TermThemeRenderer::new(term, self.theme);
         let mut sel = self.default;
 
@@ -347,6 +359,7 @@ impl<'a> Select<'a> {
             items: vec![],
             prompt: None,
             clear: true,
+            max_length: None,
             theme,
         }
     }

src/prompts/sort.rs

@@ -155,7 +155,7 @@ impl Sort<'_> {
             ));
         }
 
-        let mut paging = Paging::new(term, self.items.len());
+        let mut paging = Paging::new(term, self.items.len(), None);
         let mut render = TermThemeRenderer::new(term, self.theme);
         let mut sel = 0;