Don't call scrollbar functions if disabled in config

This fixes issues in tests, where alacritty is tested without display
and therefore also without scrollbar. Previously it panicked because the
display was unimplemented.

alacritty/src/input.rs

@@ -39,6 +39,7 @@ use alacritty_terminal::term::{ClipboardType, Term, TermMode};
 use alacritty_terminal::vi_mode::ViMotion;
 
 use crate::clipboard::Clipboard;
+use crate::config::ui_config::ScrollbarMode;
 use crate::config::{
  Action, BindingKey, BindingMode, MouseAction, SearchAction, UiConfig, ViAction,
 };
@@ -626,12 +627,14 @@ impl<T: EventListener, A: ActionContext<T>> Processor<T, A> {
 
  /// Handle left click selection and vi mode cursor movement.
  fn on_left_click(&mut self, point: Point) {
- let size_info = self.ctx.size_info();
- let mouse_x = self.ctx.mouse().x;
- let mouse_y = self.ctx.mouse().y;
- if self.ctx.display().scrollbar.try_start_drag(size_info, mouse_x, mouse_y) {
- return;
- };
+ if self.ctx.config().scrollbar.mode != ScrollbarMode::Never {
+ let size_info = self.ctx.size_info();
+ let mouse_x = self.ctx.mouse().x;
+ let mouse_y = self.ctx.mouse().y;
+ if self.ctx.display().scrollbar.try_start_drag(size_info, mouse_x, mouse_y) {
+ return;
+ };
+ }
 
  let side = self.ctx.mouse().cell_side;
 
@@ -668,7 +671,7 @@ impl<T: EventListener, A: ActionContext<T>> Processor<T, A> {
  }
 
  fn on_mouse_release(&mut self, button: MouseButton) {
- if self.ctx.display().scrollbar.is_dragging() {
+ if self.ctx.config().scrollbar.mode != ScrollbarMode::Never && self.ctx.display().scrollbar.is_dragging() {
  self.ctx.display().scrollbar.stop_dragging();
  // Mouse icon is different, when not scrolling.
  let mouse_state = self.cursor_state();
@@ -834,13 +837,17 @@ impl<T: EventListener, A: ActionContext<T>> Processor<T, A> {
  let old_touch_purpose = mem::take(self.ctx.touch_purpose());
  let new_touch_purpose = match old_touch_purpose {
  TouchPurpose::None => {
- let size_info = self.ctx.size_info();
- let mouse_x = touch.location.x as usize;
- let mouse_y = touch.location.y as usize;
- if self.ctx.display().scrollbar.try_start_drag( size_info, mouse_x, mouse_y) {
- TouchPurpose::ScrollbarDrag(touch)
- } else {
+ if self.ctx.config().scrollbar.mode == ScrollbarMode::Never {
  TouchPurpose::Tap(touch)
+ } else {
+ let size_info = self.ctx.size_info();
+ let mouse_x = touch.location.x as usize;
+ let mouse_y = touch.location.y as usize;
+ if self.ctx.display().scrollbar.try_start_drag( size_info, mouse_x, mouse_y) {
+ TouchPurpose::ScrollbarDrag(touch)
+ } else {
+ TouchPurpose::Tap(touch)
+ }
  }
  },
  TouchPurpose::Tap(start) => TouchPurpose::Zoom(TouchZoom::new((start, touch))),