performance(rendering): improve rendering performance (#1960)

* refactor(plugins): plugins now need to explicitly ask to be rendered

* performance(render): remove various needless renders

* performance(render): cache boundaries

* performance(render): adjust tests and cache cursor location/shape

* style(comment): remove outdated

* style(fmt): rustfmt

4 files changed, 102 insertions, 20 deletions

diff --git a/default-plugins/compact-bar/src/main.rs b/default-plugins/compact-bar/src/main.rs
index 505dc926d..c6ce9bbcd 100644
--- a/default-plugins/compact-bar/src/main.rs
+++ b/default-plugins/compact-bar/src/main.rs
@@ -22,7 +22,7 @@ struct State {
     active_tab_idx: usize,
     mode_info: ModeInfo,
     mouse_click_pos: usize,
-    should_render: bool,
+    should_change_tab: bool,
 }
 
 static ARROW_SEPARATOR: &str = "";
@@ -39,13 +39,23 @@ impl ZellijPlugin for State {
         ]);
     }
 
-    fn update(&mut self, event: Event) {
+    fn update(&mut self, event: Event) -> bool {
+        let mut should_render = false;
         match event {
-            Event::ModeUpdate(mode_info) => self.mode_info = mode_info,
+            Event::ModeUpdate(mode_info) => {
+                if self.mode_info != mode_info {
+                    should_render = true;
+                }
+                self.mode_info = mode_info
+            },
             Event::TabUpdate(tabs) => {
                 if let Some(active_tab_index) = tabs.iter().position(|t| t.active) {
                     // tabs are indexed starting from 1 so we need to add 1
-                    self.active_tab_idx = active_tab_index + 1;
+                    let active_tab_idx = active_tab_index + 1;
+                    if self.active_tab_idx != active_tab_idx || self.tabs != tabs {
+                        should_render = true;
+                    }
+                    self.active_tab_idx = active_tab_idx;
                     self.tabs = tabs;
                 } else {
                     eprintln!("Could not find active tab.");
@@ -53,13 +63,18 @@ impl ZellijPlugin for State {
             },
             Event::Mouse(me) => match me {
                 Mouse::LeftClick(_, col) => {
+                    if self.mouse_click_pos != col {
+                        should_render = true;
+                        self.should_change_tab = true;
+                    }
                     self.mouse_click_pos = col;
-                    self.should_render = true;
                 },
                 Mouse::ScrollUp(_) => {
+                    should_render = true;
                     switch_tab_to(min(self.active_tab_idx + 1, self.tabs.len()) as u32);
                 },
                 Mouse::ScrollDown(_) => {
+                    should_render = true;
                     switch_tab_to(max(self.active_tab_idx.saturating_sub(1), 1) as u32);
                 },
                 _ => {},
@@ -67,7 +82,8 @@ impl ZellijPlugin for State {
             _ => {
                 eprintln!("Got unrecognized event: {:?}", event);
             },
-        }
+        };
+        should_render
     }
 
     fn render(&mut self, _rows: usize, cols: usize) {
@@ -111,7 +127,7 @@ impl ZellijPlugin for State {
         for bar_part in tab_line {
             s = format!("{}{}", s, &bar_part.part);
 
-            if self.should_render
+            if self.should_change_tab
                 && self.mouse_click_pos >= len_cnt
                 && self.mouse_click_pos < len_cnt + bar_part.len
                 && bar_part.tab_index.is_some()
@@ -134,6 +150,6 @@ impl ZellijPlugin for State {
                 print!("{}\u{1b}[48;5;{}m\u{1b}[0K", s, color);
             },
         }
-        self.should_render = false;
+        self.should_change_tab = false;
     }
 }
diff --git a/default-plugins/status-bar/src/main.rs b/default-plugins/status-bar/src/main.rs
index 25e31d2f5..97f2bd2c6 100644
--- a/default-plugins/status-bar/src/main.rs
+++ b/default-plugins/status-bar/src/main.rs
@@ -182,26 +182,50 @@ impl ZellijPlugin for State {
         ]);
     }
 
-    fn update(&mut self, event: Event) {
+    fn update(&mut self, event: Event) -> bool {
+        let mut should_render = false;
         match event {
             Event::ModeUpdate(mode_info) => {
+                if self.mode_info != mode_info {
+                    should_render = true;
+                }
                 self.mode_info = mode_info;
             },
             Event::TabUpdate(tabs) => {
+                if self.tabs != tabs {
+                    should_render = true;
+                }
                 self.tabs = tabs;
             },
             Event::CopyToClipboard(copy_destination) => {
+                match self.text_copy_destination {
+                    Some(text_copy_destination) => {
+                        if text_copy_destination != copy_destination {
+                            should_render = true;
+                        }
+                    },
+                    None => {
+                        should_render = true;
+                    },
+                }
                 self.text_copy_destination = Some(copy_destination);
             },
             Event::SystemClipboardFailure => {
+                should_render = true;
                 self.display_system_clipboard_failure = true;
             },
             Event::InputReceived => {
+                if self.text_copy_destination.is_some()
+                    || self.display_system_clipboard_failure == true
+                {
+                    should_render = true;
+                }
                 self.text_copy_destination = None;
                 self.display_system_clipboard_failure = false;
             },
             _ => {},
-        }
+        };
+        should_render
     }
 
     fn render(&mut self, rows: usize, cols: usize) {
diff --git a/default-plugins/strider/src/main.rs b/default-plugins/strider/src/main.rs
index fcac6ec6a..6868c6706 100644
--- a/default-plugins/strider/src/main.rs
+++ b/default-plugins/strider/src/main.rs
@@ -13,7 +13,8 @@ impl ZellijPlugin for State {
         subscribe(&[EventType::Key, EventType::Mouse]);
     }
 
-    fn update(&mut self, event: Event) {
+    fn update(&mut self, event: Event) -> bool {
+        let mut should_render = false;
         let prev_event = if self.ev_history.len() == 2 {
             self.ev_history.pop_front()
         } else {
@@ -23,13 +24,22 @@ impl ZellijPlugin for State {
         match event {
             Event::Key(key) => match key {
                 Key::Up | Key::Char('k') => {
+                    let currently_selected = self.selected();
                     *self.selected_mut() = self.selected().saturating_sub(1);
+                    if currently_selected != self.selected() {
+                        should_render = true;
+                    }
                 },
                 Key::Down | Key::Char('j') => {
+                    let currently_selected = self.selected();
                     let next = self.selected().saturating_add(1);
                     *self.selected_mut() = min(self.files.len().saturating_sub(1), next);
+                    if currently_selected != self.selected() {
+                        should_render = true;
+                    }
                 },
                 Key::Right | Key::Char('\n') | Key::Char('l') if !self.files.is_empty() => {
+                    should_render = true;
                     self.traverse_dir_or_open_file();
                     self.ev_history.clear();
                 },
@@ -39,11 +49,13 @@ impl ZellijPlugin for State {
                         // the reason this is a hard-coded number (2) and not "== ROOT"
                         // or some such is that there are certain cases in which self.path
                         // is empty and this will work then too
+                        should_render = true;
                         self.path.pop();
                         refresh_directory(self);
                     }
                 },
                 Key::Char('.') => {
+                    should_render = true;
                     self.toggle_hidden_files();
                     refresh_directory(self);
                 },
@@ -52,15 +64,23 @@ impl ZellijPlugin for State {
             },
             Event::Mouse(mouse_event) => match mouse_event {
                 Mouse::ScrollDown(_) => {
+                    let currently_selected = self.selected();
                     let next = self.selected().saturating_add(1);
                     *self.selected_mut() = min(self.files.len().saturating_sub(1), next);
+                    if currently_selected != self.selected() {
+                        should_render = true;
+                    }
                 },
                 Mouse::ScrollUp(_) => {
+                    let currently_selected = self.selected();
                     *self.selected_mut() = self.selected().saturating_sub(1);
+                    if currently_selected != self.selected() {
+                        should_render = true;
+                    }
                 },
                 Mouse::Release(line, _) => {
                     if line < 0 {
-                        return;
+                        return should_render;
                     }
                     let mut should_select = true;
                     if let Some((Event::Mouse(Mouse::Release(prev_line, _)), t)) = prev_event {
@@ -70,10 +90,15 @@ impl ZellijPlugin for State {
                             self.traverse_dir_or_open_file();
                             self.ev_history.clear();
                             should_select = false;
+                            should_render = true;
                         }
                     }
                     if should_select && self.scroll() + (line as usize) < self.files.len() {
+                        let currently_selected = self.selected();
                         *self.selected_mut() = self.scroll() + (line as usize);
+                        if currently_selected != self.selected() {
+                            should_render = true;
+                        }
                     }
                 },
                 _ => {},
@@ -81,7 +106,8 @@ impl ZellijPlugin for State {
             _ => {
                 dbg!("Unknown event {:?}", event);
             },
-        }
+        };
+        should_render
     }
 
     fn render(&mut self, rows: usize, cols: usize) {
diff --git a/default-plugins/tab-bar/src/main.rs b/default-plugins/tab-bar/src/main.rs
index f03102610..6f0456a8f 100644
--- a/default-plugins/tab-bar/src/main.rs
+++ b/default-plugins/tab-bar/src/main.rs
@@ -22,7 +22,7 @@ struct State {
     active_tab_idx: usize,
     mode_info: ModeInfo,
     mouse_click_pos: usize,
-    should_render: bool,
+    should_change_tab: bool,
 }
 
 static ARROW_SEPARATOR: &str = "";
@@ -39,13 +39,23 @@ impl ZellijPlugin for State {
         ]);
     }
 
-    fn update(&mut self, event: Event) {
+    fn update(&mut self, event: Event) -> bool {
+        let mut should_render = false;
         match event {
-            Event::ModeUpdate(mode_info) => self.mode_info = mode_info,
+            Event::ModeUpdate(mode_info) => {
+                if self.mode_info != mode_info {
+                    should_render = true;
+                }
+                self.mode_info = mode_info;
+            },
             Event::TabUpdate(tabs) => {
                 if let Some(active_tab_index) = tabs.iter().position(|t| t.active) {
                     // tabs are indexed starting from 1 so we need to add 1
-                    self.active_tab_idx = active_tab_index + 1;
+                    let active_tab_idx = active_tab_index + 1;
+                    if self.active_tab_idx != active_tab_idx || self.tabs != tabs {
+                        should_render = true;
+                    }
+                    self.active_tab_idx = active_tab_idx;
                     self.tabs = tabs;
                 } else {
                     eprintln!("Could not find active tab.");
@@ -53,13 +63,18 @@ impl ZellijPlugin for State {
             },
             Event::Mouse(me) => match me {
                 Mouse::LeftClick(_, col) => {
+                    if self.mouse_click_pos != col {
+                        should_render = true;
+                        self.should_change_tab = true;
+                    }
                     self.mouse_click_pos = col;
-                    self.should_render = true;
                 },
                 Mouse::ScrollUp(_) => {
+                    should_render = true;
                     switch_tab_to(min(self.active_tab_idx + 1, self.tabs.len()) as u32);
                 },
                 Mouse::ScrollDown(_) => {
+                    should_render = true;
                     switch_tab_to(max(self.active_tab_idx.saturating_sub(1), 1) as u32);
                 },
                 _ => {},
@@ -68,6 +83,7 @@ impl ZellijPlugin for State {
                 eprintln!("Got unrecognized event: {:?}", event);
             },
         }
+        should_render
     }
 
     fn render(&mut self, _rows: usize, cols: usize) {
@@ -110,7 +126,7 @@ impl ZellijPlugin for State {
         for bar_part in tab_line {
             s = format!("{}{}", s, &bar_part.part);
 
-            if self.should_render
+            if self.should_change_tab
                 && self.mouse_click_pos >= len_cnt
                 && self.mouse_click_pos < len_cnt + bar_part.len
                 && bar_part.tab_index.is_some()
@@ -133,6 +149,6 @@ impl ZellijPlugin for State {
                 print!("{}\u{1b}[48;5;{}m\u{1b}[0K", s, color);
             },
         }
-        self.should_render = false;
+        self.should_change_tab = false;
     }
 }