Merge branch #1095

Because there was some overlap with branch #1095, these two PRs have
been added together and the config has been restructured to make use of
a `scrolling` section.

The default faux scrolling amount has also been changed to `3` because
this simplifies the code and falls in line with what most other terminal
emulators do.

There should be no additional test failures due to this.

6 files changed, 118 insertions, 91 deletions

diff --git a/alacritty.yml b/alacritty.yml
index 4dcdbb2b..d11e8a19 100644
--- a/alacritty.yml
+++ b/alacritty.yml
@@ -33,8 +33,24 @@ window:
   # Setting this to false will result in window without borders and title bar.
   decorations: true
 
-# How many lines of scrollback to keep
-scroll_history: 10000
+scrolling:
+  # How many lines of scrollback to keep,
+  # '0' will disable scrolling.
+  history: 10000
+
+  # Number of lines the viewport will move for every line
+  # scrolled when scrollback is enabled (history > 0).
+  multiplier: 1
+
+  # Faux Scrolling
+  #
+  # The `faux_multiplier` 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_multiplier` to 0.
+  faux_multiplier: 3
 
 # Display tabs using this many cells (changes require restart)
 tabspaces: 8
@@ -209,22 +225,6 @@ mouse:
   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
-
-  # Normal Scrolling
-  #
-  # Number of lines the viewport will move when scrolling in
-  # the terminal with scrollback enabled (>0).
-  normal_scrolling_lines: 3
-
 selection:
   semantic_escape_chars: ",│`|:\"' ()[]{}<>"
 
diff --git a/alacritty_macos.yml b/alacritty_macos.yml
index 08287c87..de8316af 100644
--- a/alacritty_macos.yml
+++ b/alacritty_macos.yml
@@ -31,8 +31,24 @@ window:
   # Setting this to false will result in window without borders and title bar.
   decorations: true
 
-# How many lines of scrollback to keep
-scroll_history: 10000
+scrolling:
+  # How many lines of scrollback to keep,
+  # '0' will disable scrolling.
+  history: 10000
+
+  # Number of lines the viewport will move for every line
+  # scrolled when scrollback is enabled (history > 0).
+  multiplier: 3
+
+  # Faux Scrolling
+  #
+  # The `faux_multiplier` 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_multiplier` to 0.
+  faux_multiplier: 3
 
 # Display tabs using this many cells (changes require restart)
 tabspaces: 8
@@ -190,22 +206,6 @@ mouse:
   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
-
-  # Normal Scrolling
-  #
-  # Number of lines the viewport will move when scrolling in
-  # the terminal with scrollback enabled (>0).
-  normal_scrolling_lines: 3
-
 selection:
   semantic_escape_chars: ",│`|:\"' ()[]{}<>"
 
diff --git a/src/config.rs b/src/config.rs
index d0741d9e..a7f3dbd6 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -82,47 +82,9 @@ pub struct Mouse {
     #[serde(default, deserialize_with = "failure_default")]
     pub triple_click: ClickHandler,
 
-    /// up/down arrows sent when scrolling in alt screen buffer
-    #[serde(deserialize_with = "deserialize_faux_scrollback_lines")]
-    #[serde(default="default_faux_scrollback_lines")]
-    pub faux_scrollback_lines: u8,
-
-    /// Number of lines scrolled in normal buffer with scrollback
-    #[serde(deserialize_with = "deserialize_normal_scrolling_lines")]
-    #[serde(default="default_normal_scrolling_lines")]
-    pub normal_scrolling_lines: u8,
-}
-
-fn default_faux_scrollback_lines() -> u8 {
-    1
-}
-
-fn default_normal_scrolling_lines() -> u8 {
-    3
-}
-
-fn deserialize_faux_scrollback_lines<'a, D>(deserializer: D) -> ::std::result::Result<u8, D::Error>
-    where D: de::Deserializer<'a>
-{
-    match u8::deserialize(deserializer) {
-        Ok(lines) => Ok(lines),
-        Err(err) => {
-            eprintln!("problem with config: {}; Using default value", err);
-            Ok(default_faux_scrollback_lines())
-        },
-    }
-}
-
-fn deserialize_normal_scrolling_lines<'a, D>(deserializer: D) -> ::std::result::Result<u8, D::Error>
-    where D: de::Deserializer<'a>
-{
-    match u8::deserialize(deserializer) {
-        Ok(lines) => Ok(lines),
-        Err(err) => {
-            eprintln!("problem with config: {}; Using default value", err);
-            Ok(default_normal_scrolling_lines())
-        },
-    }
+    // TODO: DEPRECATED
+    #[serde(default)]
+    pub faux_scrollback_lines: Option<usize>,
 }
 
 impl Default for Mouse {
@@ -134,8 +96,7 @@ impl Default for Mouse {
             triple_click: ClickHandler {
                 threshold: Duration::from_millis(300),
             },
-            faux_scrollback_lines: default_faux_scrollback_lines(),
-            normal_scrolling_lines: default_normal_scrolling_lines(),
+            faux_scrollback_lines: None,
         }
     }
 }
@@ -420,12 +381,8 @@ pub struct Config {
     tabspaces: usize,
 
     /// How much scrolling history to keep
-    #[serde(default="default_scroll_history", deserialize_with="deserialize_scroll_history")]
-    scroll_history: u32,
-}
-
-fn default_scroll_history() -> u32 {
-    10_000
+    #[serde(default, deserialize_with="failure_default")]
+    scrolling: Scrolling,
 }
 
 fn deserialize_scroll_history<'a, D>(deserializer: D) -> ::std::result::Result<u32, D::Error>
@@ -521,6 +478,63 @@ impl Default for Config {
     }
 }
 
+/// Struct for scrolling related settings
+#[derive(Copy, Clone, Debug, Deserialize)]
+pub struct Scrolling {
+    #[serde(deserialize_with="deserialize_scrolling_history")]
+    #[serde(default="default_scrolling_history")]
+    pub history: u32,
+    #[serde(deserialize_with="deserialize_scrolling_multiplier")]
+    #[serde(default="default_scrolling_multiplier")]
+    pub multiplier: u8,
+    #[serde(deserialize_with="deserialize_scrolling_multiplier")]
+    #[serde(default="default_scrolling_multiplier")]
+    pub faux_multiplier: u8,
+}
+
+fn default_scrolling_history() -> u32 {
+    10_000
+}
+
+// Default for normal and faux scrolling
+fn default_scrolling_multiplier() -> u8 {
+    3
+}
+
+impl Default for Scrolling {
+    fn default() -> Self {
+        Self {
+            history: default_scrolling_history(),
+            multiplier: default_scrolling_multiplier(),
+            faux_multiplier: default_scrolling_multiplier(),
+        }
+    }
+}
+
+fn deserialize_scrolling_history<'a, D>(deserializer: D) -> ::std::result::Result<u32, D::Error>
+    where D: de::Deserializer<'a>
+{
+    match u32::deserialize(deserializer) {
+        Ok(lines) => Ok(lines),
+        Err(err) => {
+            eprintln!("problem with config: {}; Using default value", err);
+            Ok(default_scrolling_history())
+        },
+    }
+}
+
+fn deserialize_scrolling_multiplier<'a, D>(deserializer: D) -> ::std::result::Result<u8, D::Error>
+    where D: de::Deserializer<'a>
+{
+    match u8::deserialize(deserializer) {
+        Ok(lines) => Ok(lines),
+        Err(err) => {
+            eprintln!("problem with config: {}; Using default value", err);
+            Ok(default_scrolling_multiplier())
+        },
+    }
+}
+
 /// Newtype for implementing deserialize on glutin Mods
 ///
 /// Our deserialize impl wouldn't be covered by a derive(Deserialize); see the
@@ -1286,10 +1300,6 @@ impl Config {
             .map(|path| path.into())
     }
 
-    pub fn scroll_history(&self) -> usize {
-        self.scroll_history as _
-    }
-
     pub fn write_defaults() -> io::Result<Cow<'static, Path>> {
         let path = ::xdg::BaseDirectories::with_prefix("alacritty")
             .map_err(|err| io::Error::new(io::ErrorKind::NotFound, ::std::error::Error::description(&err)))
@@ -1419,6 +1429,12 @@ impl Config {
         self.dynamic_title
     }
 
+    /// Scrolling settings
+    #[inline]
+    pub fn scrolling(&self) -> Scrolling {
+        self.scrolling
+    }
+
     pub fn load_from<P: Into<PathBuf>>(path: P) -> Result<Config> {
         let path = path.into();
         let raw = Config::read_file(path.as_path())?;
@@ -1451,6 +1467,11 @@ impl Config {
             eprintln!("{}", fmt::Yellow("Config `padding` is deprecated. \
                                         Please use `window.padding` instead."));
         }
+
+        if self.mouse.faux_scrollback_lines.is_some() {
+            println!("{}", fmt::Yellow("Config `mouse.faux_scrollback_lines` is deprecated. \
+                                        Please use `mouse.faux_scrolling_lines` instead."));
+        }
     }
 }
 
diff --git a/src/event.rs b/src/event.rs
index 04176963..af5053f4 100644
--- a/src/event.rs
+++ b/src/event.rs
@@ -191,6 +191,7 @@ pub struct Processor<N> {
     key_bindings: Vec<KeyBinding>,
     mouse_bindings: Vec<MouseBinding>,
     mouse_config: config::Mouse,
+    scrolling_config: config::Scrolling,
     print_events: bool,
     wait_for_event: bool,
     notifier: N,
@@ -232,6 +233,7 @@ impl<N: Notify> Processor<N> {
             key_bindings: config.key_bindings().to_vec(),
             mouse_bindings: config.mouse_bindings().to_vec(),
             mouse_config: config.mouse().to_owned(),
+            scrolling_config: config.scrolling(),
             print_events: options.print_events,
             wait_for_event: true,
             notifier,
@@ -395,6 +397,7 @@ impl<N: Notify> Processor<N> {
 
             processor = input::Processor {
                 ctx: context,
+                scrolling_config: &self.scrolling_config,
                 mouse_config: &self.mouse_config,
                 key_bindings: &self.key_bindings[..],
                 mouse_bindings: &self.mouse_bindings[..],
diff --git a/src/input.rs b/src/input.rs
index fabb3485..9b9aedc3 100644
--- a/src/input.rs
+++ b/src/input.rs
@@ -44,6 +44,7 @@ pub struct Processor<'a, A: 'a> {
     pub key_bindings: &'a [KeyBinding],
     pub mouse_bindings: &'a [MouseBinding],
     pub mouse_config: &'a config::Mouse,
+    pub scrolling_config: &'a config::Scrolling,
     pub ctx: A,
 }
 
@@ -711,8 +712,9 @@ mod tests {
                         triple_click: ClickHandler {
                             threshold: Duration::from_millis(1000),
                         },
-                        faux_scrollback_lines: 1,
+                        faux_scrollback_lines: None,
                     },
+                    scrolling_config: &config::Scrolling::default(),
                     key_bindings: &config.key_bindings()[..],
                     mouse_bindings: &config.mouse_bindings()[..],
                 };
diff --git a/src/term/mod.rs b/src/term/mod.rs
index 53bb3420..52d56ec8 100644
--- a/src/term/mod.rs
+++ b/src/term/mod.rs
@@ -847,7 +847,8 @@ impl Term {
         let num_cols = size.cols();
         let num_lines = size.lines();
 
-        let grid = Grid::new(num_lines, num_cols, config.scroll_history(), template);
+        let history_size = config.scrolling().history as usize;
+        let grid = Grid::new(num_lines, num_cols, history_size, template);
 
         let tabspaces = config.tabspaces();
         let tabs = IndexRange::from(Column(0)..grid.num_cols())