Address feedback

The config documentation has been changed to make it clear which part of
the documentation is related to which setting.

The faux scrollback part of the `scroll_terminal` method has been
cleaned up by making use of the fact that the `codepoint + 1` can be
used in the escape sequence which is used for scrolling.

alacritty.yml

@@ -197,20 +197,23 @@ background_opacity: 1.0
 mouse_bindings:
   - { mouse: Middle, action: PasteSelection }
 
-# Mouse settings
-#
-# The `faux_scrollback_lines` setting controls the number
-# of lines the terminal should scroll when the alternate
-# screen buffer is active. This is used to allow mouse
-# scrolling for applications like `man`.
-# To disable this completely, set `faux_scrollback_lines` to 0.
-#
-# The `double_click` and `triple_click` settings control the time
-# alacritty should wait for accepting multiple clicks as one double
-# or triple click.
 mouse:
+  # Click settings
+  #
+  # The `double_click` and `triple_click` settings control the time
+  # alacritty should wait for accepting multiple clicks as one double
+  # or triple click.
   double_click: { threshold: 300 }
   triple_click: { threshold: 300 }
+
+  # Faux Scrollback
+  #
+  # The `faux_scrollback_lines` setting controls the number
+  # of lines the terminal should scroll when the alternate
+  # screen buffer is active. This is used to allow mouse
+  # scrolling for applications like `man`.
+  #
+  # To disable this completely, set `faux_scrollback_lines` to 0.
   faux_scrollback_lines: 1
 
 selection:

alacritty_macos.yml

@@ -178,20 +178,23 @@ background_opacity: 1.0
 mouse_bindings:
   - { mouse: Middle, action: PasteSelection }
 
-# Mouse settings
-#
-# The `faux_scrollback_lines` setting controls the number
-# of lines the terminal should scroll when the alternate
-# screen buffer is active. This is used to allow mouse
-# scrolling for applications like `man`.
-# To disable this completely, set `faux_scrollback_lines` to 0.
-#
-# The `double_click` and `triple_click` settings control the time
-# alacritty should wait for accepting multiple clicks as one double
-# or triple click.
 mouse:
+  # Click settings
+  #
+  # The `double_click` and `triple_click` settings control the time
+  # alacritty should wait for accepting multiple clicks as one double
+  # or triple click.
   double_click: { threshold: 300 }
   triple_click: { threshold: 300 }
+
+  # Faux Scrollback
+  #
+  # The `faux_scrollback_lines` setting controls the number
+  # of lines the terminal should scroll when the alternate
+  # screen buffer is active. This is used to allow mouse
+  # scrolling for applications like `man`.
+  #
+  # To disable this completely, set `faux_scrollback_lines` to 0.
   faux_scrollback_lines: 1
 
 selection:

src/input.rs

@@ -424,26 +424,21 @@ impl<'a, A: ActionContext + 'a> Processor<'a, A> {
     }
 
     fn scroll_terminal(&mut self, mouse_modes: TermMode, code: u8) {
+        debug_assert!(code == 64 || code == 65);
+
         let faux_scrollback_lines = self.mouse_config.faux_scrollback_lines;
         if self.ctx.terminal_mode().intersects(mouse_modes) {
             self.normal_mouse_report(code);
         } else if faux_scrollback_lines > 0 {
             // Faux scrolling
-            if code == 64 {
-                // Scroll up by `faux_scrollback_lines`
-                let mut content = String::with_capacity(faux_scrollback_lines * 3);
-                for _ in 0..faux_scrollback_lines {
-                    content = content + "\x1bOA";
-                }
-                self.ctx.write_to_pty(content.into_bytes());
-            } else {
-                // Scroll down by `faux_scrollback_lines`
-                let mut content = String::with_capacity(faux_scrollback_lines * 3);
-                for _ in 0..faux_scrollback_lines {
-                    content = content + "\x1bOB";
-                }
-                self.ctx.write_to_pty(content.into_bytes());
+            let cmd = code + 1; // 64 + 1 = A, 65 + 1 = B
+            let mut content = Vec::with_capacity(faux_scrollback_lines * 3);
+            for _ in 0..faux_scrollback_lines {
+                content.push(0x1b);
+                content.push('O' as u8);
+                content.push(cmd);
             }
+            self.ctx.write_to_pty(content);
         }
     }