Internals for changing the widths of panels (#921)

3 new internals:

* `set_panel_width`, taking as parameter the index of the panel and the desired width
* `move_panel_divider`, taking as parameter the index of the divider and the desired change
* `default_layout`, restores the default panel sizes

`ctrl-<` is bound by default to `:move_panel_divider 0 -1`

`ctrl->` is bound by default to `:move_panel_divider 0 1`

It's also possible to define the layout in conf, eg 

```
    layout_instructions: [
         { panel: 0, width: 18 }
     ]
```

CHANGELOG.md

@@ -3,6 +3,12 @@
 ctrl-s now triggers `:search_again` which either
 - brings back the last used search pattern, when no filtering pattern is active
 - does a "total search" if a filtering pattern is active and the search wasn't complete
+#### Major Feature: internals changing panel widths
+* `set_panel_width`, taking as parameter the index of the panel and the desired width
+* `move_panel_divider`, taking as parameter the index of the divider and the desired change
+`ctrl-<` is bound by default to `:move_panel_divider 0 -1`
+`ctrl->` is bound by default to `:move_panel_divider 0 1`
+See http://dystroy.org/broot/panels/#resize-panels
 #### Minor Changes:
 - when git file infos are shown, and git ignored files aren't hidden, those files are flagged with a 'I' - Fix #916
 - Remove .bak extension from content search exclusion list - Fix #915

src/app/app.rs

@@ -8,11 +8,7 @@ use {
             Sequence,
         },
         conf::Conf,
-        display::{
-            Areas,
-            Screen,
-            W,
-        },
+        display::*,
         errors::ProgramError,
         file_sum,
         git,
@@ -104,7 +100,7 @@ impl App {
         let panel = Panel::new(
             PanelId::from(0),
             browser_state,
-            Areas::create(&mut Vec::new(), 0, screen, false),
+            Areas::create(&mut Vec::new(), &con.layout_instructions, 0, screen, false),
             con,
         );
         let (tx_seqs, rx_seqs) = unbounded::<Sequence>();
@@ -191,6 +187,7 @@ impl App {
     fn close_panel(
         &mut self,
         panel_idx: usize,
+        con: &AppContext,
     ) -> bool {
         let active_panel_id = self.panels[self.active_panel_idx].id;
         if let Some(preview_id) = self.preview_panel {
@@ -214,6 +211,7 @@ impl App {
             }
             Areas::resize_all(
                 self.panels.as_mut_slice(),
+                &con.layout_instructions,
                 self.screen,
                 self.preview_panel.is_some(),
             );
@@ -233,9 +231,9 @@ impl App {
     /// Close the panel too if that was its only state.
     /// Close nothing and return false if there's not
     /// at least two states in the app.
-    fn remove_state(&mut self) -> bool {
+    fn remove_state(&mut self, con: &AppContext) -> bool {
         self.panels[self.active_panel_idx].remove_state()
-            || self.close_panel(self.active_panel_idx)
+            || self.close_panel(self.active_panel_idx, con)
     }
 
     /// redraw the whole screen. All drawing
@@ -363,7 +361,7 @@ impl App {
                             .map(|p| p.to_string_lossy().to_string());
                     }
                 }
-                if self.close_panel(close_idx) {
+                if self.close_panel(close_idx, con) {
                     let screen = self.screen;
                     self.mut_state().refresh(screen, con);
                     if let Some(new_arg) = new_arg {
@@ -384,6 +382,15 @@ impl App {
                     self.quitting = true;
                 }
             }
+            ChangeLayout(instruction) => {
+                con.layout_instructions.push(instruction);
+                Areas::resize_all(
+                    self.panels.as_mut_slice(),
+                    &con.layout_instructions,
+                    self.screen,
+                    self.preview_panel.is_some(),
+                );
+            }
             DisplayError(txt) => {
                 error = Some(txt);
             }
@@ -404,7 +411,7 @@ impl App {
                             // we're here because the state wants us to either move to the panel
                             // to the left, or close the rightest one
                             if self.active_panel_idx == 0 {
-                                self.close_panel(self.panels.len().get() - 1);
+                                self.close_panel(self.panels.len().get() - 1, con);
                                 None
                             } else {
                                 Some(self.active_panel_idx - 1)
@@ -413,7 +420,7 @@ impl App {
                             // panel_right
                             // we either move to the right or close the leftest panel
                             if self.active_panel_idx + 1 == self.panels.len().get() {
-                                self.close_panel(0);
+                                self.close_panel(0, con);
                                 None
                             } else {
                                 Some(self.active_panel_idx + 1)
@@ -470,7 +477,7 @@ impl App {
                             if panels_count >= con.max_panels_count {
                                 for i in (0..panels_count).rev() {
                                     if self.panels[i].state().get_type() != PanelStateType::Tree {
-                                        self.close_panel(i);
+                                        self.close_panel(i, con);
                                         break;
                                     }
                                 }
@@ -502,7 +509,7 @@ impl App {
                                     if i == self.active_panel_idx {
                                         continue;
                                     }
-                                    self.close_panel(i);
+                                    self.close_panel(i, con);
                                     break;
                                 }
                             }
@@ -551,7 +558,7 @@ impl App {
                 if is_input_invocation {
                     self.mut_panel().clear_input();
                 }
-                if self.remove_state() {
+                if self.remove_state(con) {
                     self.mut_state().refresh(app_cmd_context.screen, con);
                     self.mut_panel()
                         .refresh_input_status(app_state, &app_cmd_context);
@@ -563,7 +570,7 @@ impl App {
                 if is_input_invocation {
                     self.mut_panel().clear_input();
                 }
-                if self.remove_state() {
+                if self.remove_state(con) {
                     let app_cmd_context = AppCmdContext {
                         panel_skin,
                         preview_panel: self.preview_panel,
@@ -681,6 +688,7 @@ impl App {
         let with_preview = purpose.is_preview() || self.preview_panel.is_some();
         let areas = Areas::create(
             self.panels.as_mut_slice(),
+            &con.layout_instructions,
             insertion_idx,
             self.screen,
             with_preview,
@@ -873,6 +881,7 @@ impl App {
                         self.screen.set_terminal_size(width, height, con);
                         Areas::resize_all(
                             self.panels.as_mut_slice(),
+                            &con.layout_instructions,
                             self.screen,
                             self.preview_panel.is_some(),
                         );

src/app/app_context.rs

@@ -5,6 +5,7 @@ use {
         cli::{Args, TriBool},
         conf::*,
         content_search,
+        display::LayoutInstructions,
         errors::*,
         file_sum,
         icon::*,
@@ -131,6 +132,9 @@ pub struct AppContext {
 
     /// The set of transformers called before previewing a file
     pub preview_transformers: PreviewTransformers,
+
+    /// layout modifiers, like divider moves
+    pub layout_instructions: LayoutInstructions,
 }
 
 impl AppContext {
@@ -200,8 +204,8 @@ impl AppContext {
             .unwrap_or(content_search::DEFAULT_MAX_FILE_SIZE);
 
         let terminal_title_pattern = config.terminal_title.clone();
-
         let preview_transformers = PreviewTransformers::new(&config.preview_transformers)?;
+        let layout_instructions = config.layout_instructions.clone().unwrap_or_default();
 
         Ok(Self {
             is_tty,
@@ -236,6 +240,7 @@ impl AppContext {
             lines_after_match_in_preview: config.lines_after_match_in_preview.unwrap_or(0),
             lines_before_match_in_preview: config.lines_before_match_in_preview.unwrap_or(0),
             preview_transformers,
+            layout_instructions,
         })
     }
     /// Return the --cmd argument, coming from the launch arguments (prefered)

src/app/cmd_result.rs

@@ -3,6 +3,7 @@ use {
     crate::{
         browser::BrowserState,
         command::Sequence,
+        display::LayoutInstruction,
         errors::TreeBuildError,
         launchable::Launchable,
         verb::Internal,
@@ -36,6 +37,7 @@ pub enum CmdResult {
         validate_purpose: bool,
         panel_ref: PanelReference,
     },
+    ChangeLayout(LayoutInstruction),
     DisplayError(String),
     ExecuteSequence {
         sequence: Sequence,
@@ -110,6 +112,7 @@ impl fmt::Debug for CmdResult {
             "{}",
             match self {
                 CmdResult::ApplyOnPanel { .. } => "ApplyOnPanel",
+                CmdResult::ChangeLayout(_) => "ChangeLayout",
                 CmdResult::ClosePanel {
                     validate_purpose: false, ..
                 } => "CancelPanel",

src/app/panel_state.rs

@@ -2,12 +2,12 @@ use {
     super::*,
     crate::{
         command::*,
-        display::{Screen, W},
+        display::*,
         errors::ProgramError,
         flag::Flag,
         help::HelpState,
         pattern::*,
-        preview::{PreviewMode, PreviewState},
+        preview::*,
         print,
         stage::*,
         task_sync::Dam,
@@ -157,6 +157,25 @@ pub trait PanelState {
                 validate_purpose: false,
                 panel_ref: PanelReference::Active,
             },
+            Internal::move_panel_divider => {
+                let MoveDividerArgs { divider, dx } = get_arg(
+                    input_invocation,
+                    internal_exec,
+                    MoveDividerArgs { divider: 0, dx: 1 },
+                );
+                CmdResult::ChangeLayout(LayoutInstruction::MoveDivider { divider, dx })
+            }
+            Internal::default_layout => {
+                CmdResult::ChangeLayout(LayoutInstruction::Clear)
+            }
+            Internal::set_panel_width => {
+                let SetPanelWidthArgs { panel, width } = get_arg(
+                    input_invocation,
+                    internal_exec,
+                    SetPanelWidthArgs { panel: 0, width: 100 },
+                );
+                CmdResult::ChangeLayout(LayoutInstruction::SetPanelWidth { panel, width })
+            }
             #[cfg(feature = "trash")]
             Internal::purge_trash => {
                 let res = trash::os_limited::list()
@@ -1115,3 +1134,4 @@ pub fn get_arg<T: Copy + FromStr>(
         .unwrap_or(default)
 }
 
+

src/browser/browser_state.rs

@@ -2,7 +2,7 @@ use {
     crate::{
         app::*,
         command::*,
-        display::{DisplayableTree, Screen, W},
+        display::*,
         errors::{ProgramError, TreeBuildError},
         flag::Flag,
         git,

src/command/panel_input.rs

@@ -72,7 +72,7 @@ impl PanelInput {
     /// consume the event to
     /// - maybe change the input
     /// - build a command
-    /// then redraw the input field
+    ///   then redraw the input field
     #[allow(clippy::too_many_arguments)]
     pub fn on_event(
         &mut self,

src/command/sequence.rs

@@ -67,12 +67,15 @@ impl Sequence {
     }
 }
 
-/// an input may be made of two parts:
+/// Add commands to a sequence.
+///
+/// An input may be made of two parts:
 ///  - a search pattern
 ///  - a verb followed by its arguments
-/// we need to build a command for each part so
-/// that the search is effectively done before
-/// the verb invocation
+///
+/// We need to build a command for each part so
+///   that the search is effectively done before
+///   the verb invocation
 fn add_commands(
     input: &str,
     commands: &mut Vec<(String, Command)>,

src/conf/conf.rs

@@ -5,7 +5,7 @@ use {
     super::*,
     crate::{
         app::Mode,
-        display::ColsConf,
+        display::{ColsConf, LayoutInstructions},
         errors::{ConfError, ProgramError},
         kitty::TransmissionMedium,
         path::{
@@ -143,6 +143,9 @@ pub struct Conf {
     #[serde(default)]
     pub verbs: Vec<VerbConf>,
 
+    #[serde(alias="layout-instructions")]
+    pub layout_instructions: Option<LayoutInstructions>,
+
     // BEWARE: entries added here won't be usable unless also
     // added in read_file!
 }
@@ -232,6 +235,7 @@ impl Conf {
         overwrite!(self, kitty_graphics_transmission, conf);
         overwrite!(self, lines_after_match_in_preview, conf);
         overwrite!(self, lines_before_match_in_preview, conf);
+        overwrite!(self, layout_instructions, conf);
         self.verbs.append(&mut conf.verbs);
         // the following prefs are "additive": we can add entries from several
         // config files and they still make sense