add a scrollbar on help screen

2 files changed, 25 insertions, 47 deletions

diff --git a/src/screen_text.rs b/src/screen_text.rs
index 046e5bd..97d5d13 100644
--- a/src/screen_text.rs
+++ b/src/screen_text.rs
@@ -4,7 +4,7 @@
 //! broot are implemented.
 
 use regex::Regex;
-use std::io;
+use std::io::{self, Write};
 use termion::{color, style};
 
 use crate::screens::{Screen, ScreenArea};
@@ -54,8 +54,30 @@ impl Text {
     pub fn push(&mut self, line: String) {
         self.lines.push(line);
     }
+    // write the text in the area, taking into account the scrolled amount
+    // and drawing a vertical scrollbar at the right if needed
     pub fn write(&self, screen: &mut Screen, area: &ScreenArea) -> io::Result<()> {
-        screen.write_lines(area, &self.lines)
+        let scrollbar = area.scrollbar();
+        let mut i = area.scroll as usize;
+        for y in area.top..=area.bottom {
+            write!(
+                screen.stdout,
+                "{}{}",
+                termion::cursor::Goto(1, y),
+                termion::clear::CurrentLine,
+            )?;
+            if i < self.lines.len() {
+                write!(screen.stdout, "{}", &self.lines[i],)?;
+                i += 1;
+            }
+            if let Some((sctop, scbottom)) = scrollbar {
+                if sctop <= y && y <= scbottom {
+                    write!(screen.stdout, "{}▐", termion::cursor::Goto(screen.w, y),)?;
+                }
+            }
+        }
+        screen.stdout.flush()?;
+        Ok(())
     }
 }
 
diff --git a/src/screens.rs b/src/screens.rs
index 3965954..952cca2 100644
--- a/src/screens.rs
+++ b/src/screens.rs
@@ -1,5 +1,4 @@
 use std::io::{self, stdout, Write};
-use termion::color;
 use termion::raw::{IntoRawMode, RawTerminal};
 use termion::screen::AlternateScreen;
 
@@ -32,23 +31,6 @@ impl Screen {
         self.h = h;
         Ok(())
     }
-    pub fn write_lines(&mut self, area: &ScreenArea, lines: &[String]) -> io::Result<()> {
-        let mut i = area.scroll as usize;
-        for y in area.top..=area.bottom {
-            write!(
-                self.stdout,
-                "{}{}",
-                termion::cursor::Goto(1, y),
-                termion::clear::CurrentLine,
-            )?;
-            if i < lines.len() {
-                write!(self.stdout, "{}", &lines[i],)?;
-                i += 1;
-            }
-        }
-        self.stdout.flush()?;
-        Ok(())
-    }
 }
 
 impl Drop for Screen {
@@ -78,32 +60,6 @@ impl ScreenArea {
             self.scroll = self.content_length - 1;
         }
     }
-    // draw a scrollbar at the righ, above content.
-    // clears nothing before.
-    // (note that this may lead to flickering)
-    #[allow(dead_code)]
-    pub fn draw_scrollbar(&self, screen: &mut Screen) -> io::Result<()> {
-        let h = i32::from(self.bottom) - i32::from(self.top) + 1;
-        if self.content_length > h {
-            let sbh = h * h / self.content_length;
-            let sc = i32::from(self.top) + self.scroll * h / self.content_length;
-            write!(
-                screen.stdout,
-                "{}",
-                color::Fg(color::AnsiValue::grayscale(9)),
-            )?;
-            for y in 0..sbh {
-                write!(
-                    screen.stdout,
-                    "{}▐",
-                    termion::cursor::Goto(screen.w, ((y + sc) as u16).min(self.bottom - 1)),
-                )?;
-            }
-            write!(screen.stdout, "{}", color::Fg(color::Reset),)?;
-        }
-        Ok(())
-    }
-    // returns the top and bottom of the scrollbar, if any
     pub fn scrollbar(&self) -> Option<(u16, u16)> {
         let h = (self.bottom as i32) - (self.top as i32) + 1;
         if self.content_length <= h {
@@ -111,6 +67,6 @@ impl ScreenArea {
         }
         let sbh = h * h / self.content_length;
         let sc = i32::from(self.top) + self.scroll * h / self.content_length;
-        Some((sc as u16, (sc + sbh).min(i32::from(self.bottom) - 1) as u16))
+        Some((sc as u16, (sc + sbh - 1).min(i32::from(self.bottom)) as u16))
     }
 }