Allow to scroll diffs horizontally (#1327)

CHANGELOG.md

@@ -90,6 +90,7 @@ Bugfix followup release - check `0.22.0` notes for more infos!
 * switch focus to index after staging last file ([#1169](https://github.com/extrawurst/gitui/pull/1169))
 * fix stashlist multi marking not updated after dropping ([#1207](https://github.com/extrawurst/gitui/pull/1207))
 * exact matches have a higher priority and are placed to the top of the list when fuzzily finding files ([#1183](https://github.com/extrawurst/gitui/pull/1183))
+* support horizontal scrolling in diff view ([#1017](https://github.com/extrawurst/gitui/issues/1017))
 
 ### Changed
 * minimum supported rust version bumped to 1.60 ([#1279](https://github.com/extrawurst/gitui/pull/1279))

src/components/blame_file.rs

@@ -123,6 +123,7 @@ impl DrawableComponent for BlameFileComponent {
 				//
 				// https://github.com/fdehau/tui-rs/issues/448
 				table_state.selected().unwrap_or(0),
+				ui::Orientation::Vertical,
 			);
 
 			self.table_state.set(table_state);

src/components/commitlist.rs

@@ -8,7 +8,7 @@ use crate::{
 	queue::{InternalEvent, Queue},
 	strings::{self, symbol},
 	ui::style::{SharedTheme, Theme},
-	ui::{calc_scroll_top, draw_scrollbar},
+	ui::{calc_scroll_top, draw_scrollbar, Orientation},
 };
 use anyhow::Result;
 use asyncgit::sync::{BranchInfo, CommitId, Tags};
@@ -501,6 +501,7 @@ impl DrawableComponent for CommitList {
 			&self.theme,
 			self.count_total,
 			self.selection,
+			Orientation::Vertical,
 		);
 
 		Ok(())

src/components/compare_commits.rs

@@ -44,7 +44,7 @@ impl DrawableComponent for CompareCommitsComponent {
 	) -> Result<()> {
 		if self.is_visible() {
 			let percentages = if self.diff.focused() {
-				(30, 70)
+				(0, 100)
 			} else {
 				(50, 50)
 			};
@@ -121,7 +121,12 @@ impl Component for CompareCommitsComponent {
 
 			if let Event::Key(e) = ev {
 				if key_match(e, self.key_config.keys.exit_popup) {
-					self.hide_stacked(false);
+					if self.diff.focused() {
+						self.details.focus(true);
+						self.diff.focus(false);
+					} else {
+						self.hide_stacked(false);
+					}
 				} else if key_match(
 					e,
 					self.key_config.keys.focus_right,
@@ -132,13 +137,6 @@ impl Component for CompareCommitsComponent {
 				} else if key_match(
 					e,
 					self.key_config.keys.focus_left,
-				) && self.diff.focused()
-				{
-					self.details.focus(true);
-					self.diff.focus(false);
-				} else if key_match(
-					e,
-					self.key_config.keys.focus_left,
 				) {
 					self.hide_stacked(false);
 				}

src/components/diff.rs

@@ -1,12 +1,14 @@
 use super::{
+	utils::scroll_horizontal::HorizontalScroll,
 	utils::scroll_vertical::VerticalScroll, CommandBlocking,
-	Direction, DrawableComponent, ScrollType,
+	Direction, DrawableComponent, HorizontalScrollType, ScrollType,
 };
 use crate::{
 	components::{CommandInfo, Component, EventState},
 	keys::{key_match, SharedKeyConfig},
 	queue::{Action, InternalEvent, NeedsUpdate, Queue, ResetItem},
 	string_utils::tabs_to_spaces,
+	string_utils::trim_offset,
 	strings, try_or_popup,
 	ui::style::SharedTheme,
 };
@@ -102,13 +104,15 @@ impl Selection {
 pub struct DiffComponent {
 	repo: RepoPathRef,
 	diff: Option<FileDiff>,
+	longest_line: usize,
 	pending: bool,
 	selection: Selection,
 	selected_hunk: Option<usize>,
 	current_size: Cell<(u16, u16)>,
 	focused: bool,
 	current: Current,
-	scroll: VerticalScroll,
+	vertical_scroll: VerticalScroll,
+	horizontal_scroll: HorizontalScroll,
 	queue: Queue,
 	theme: SharedTheme,
 	key_config: SharedKeyConfig,
@@ -131,9 +135,11 @@ impl DiffComponent {
 			pending: false,
 			selected_hunk: None,
 			diff: None,
+			longest_line: 0,
 			current_size: Cell::new((0, 0)),
 			selection: Selection::Single(0),
-			scroll: VerticalScroll::new(),
+			vertical_scroll: VerticalScroll::new(),
+			horizontal_scroll: HorizontalScroll::new(),
 			theme,
 			key_config,
 			is_immutable,
@@ -155,7 +161,9 @@ impl DiffComponent {
 	pub fn clear(&mut self, pending: bool) {
 		self.current = Current::default();
 		self.diff = None;
-		self.scroll.reset();
+		self.longest_line = 0;
+		self.vertical_scroll.reset();
+		self.horizontal_scroll.reset();
 		self.selection = Selection::Single(0);
 		self.selected_hunk = None;
 		self.pending = pending;
@@ -182,8 +190,27 @@ impl DiffComponent {
 
 			self.diff = Some(diff);
 
+			self.longest_line = self
+				.diff
+				.iter()
+				.flat_map(|diff| diff.hunks.iter())
+				.flat_map(|hunk| hunk.lines.iter())
+				.map(|line| {
+					let converted_content = tabs_to_spaces(
+						line.content.as_ref().to_string(),
+					);
+
+					converted_content.len()
+				})
+				.max()
+				.map_or(0, |len| {
+					// Each hunk uses a 1-character wide vertical bar to its left to indicate
+					// selection.
+					len + 1
+				});
+
 			if reset_selection {
-				self.scroll.reset();
+				self.vertical_scroll.reset();
 				self.selection = Selection::Single(0);
 				self.update_selection(0);
 			} else {
@@ -241,6 +268,11 @@ impl DiffComponent {
 		self.diff.as_ref().map_or(0, |diff| diff.lines)
 	}
 
+	fn max_scroll_right(&self) -> usize {
+		self.longest_line
+			.saturating_sub(self.current_size.get().0.into())
+	}
+
 	fn modify_selection(&mut self, direction: Direction) {
 		if self.diff.is_some() {
 			self.selection.modify(direction, self.lines_count());
@@ -340,7 +372,7 @@ impl DiffComponent {
 					Span::raw(Cow::from(")")),
 				])]);
 			} else {
-				let min = self.scroll.get_top();
+				let min = self.vertical_scroll.get_top();
 				let max = min + height as usize;
 
 				let mut line_cursor = 0_usize;
@@ -378,6 +410,8 @@ impl DiffComponent {
 									hunk_selected,
 									i == hunk_len - 1,
 									&self.theme,
+									self.horizontal_scroll
+										.get_right(),
 								));
 								lines_added += 1;
 							}
@@ -400,6 +434,7 @@ impl DiffComponent {
 		selected_hunk: bool,
 		end_of_hunk: bool,
 		theme: &SharedTheme,
+		scrolled_right: usize,
 	) -> Spans<'a> {
 		let style = theme.diff_hunk_marker(selected_hunk);
 
@@ -418,18 +453,22 @@ impl DiffComponent {
 			}
 		};
 
+		let content =
+			tabs_to_spaces(line.content.as_ref().to_string());
+		let content = trim_offset(&content, scrolled_right);
+
 		let filled = if selected {
 			// selected line
-			format!("{:w$}\n", line.content, w = width as usize)
+			format!("{content:w$}\n", w = width as usize)
 		} else {
 			// weird eof missing eol line
-			format!("{}\n", line.content)
+			format!("{content}\n")
 		};
 
 		Spans::from(vec![
 			left_side_of_line,
 			Span::styled(
-				Cow::from(tabs_to_spaces(filled)),
+				Cow::from(filled),
 				theme.diff_line(line.line_type, selected),
 			),
 		])
@@ -606,14 +645,20 @@ impl DrawableComponent for DiffComponent {
 			r.height.saturating_sub(2),
 		));
 
+		let current_width = self.current_size.get().0;
 		let current_height = self.current_size.get().1;
 
-		self.scroll.update(
+		self.vertical_scroll.update(
 			self.selection.get_end(),
 			self.lines_count(),
 			usize::from(current_height),
 		);
 
+		self.horizontal_scroll.update_no_selection(
+			self.longest_line,
+			current_width.into(),
+		);
+
 		let title = format!(
 			"{}{}",
 			strings::title_diff(&self.key_config),
@@ -643,7 +688,11 @@ impl DrawableComponent for DiffComponent {
 		);
 
 		if self.focused() {
-			self.scroll.draw(f, r, &self.theme);
+			self.vertical_scroll.draw(f, r, &self.theme);
+
+			if self.max_scroll_right() > 0 {
+				self.horizontal_scroll.draw(f, r, &self.theme);
+			}
 		}
 
 		Ok(())
@@ -754,6 +803,18 @@ impl Component for DiffComponent {
 				{
 					self.move_selection(ScrollType::PageDown);
 					Ok(EventState::Consumed)
+				} else if key_match(
+					e,
+					self.key_config.keys.move_right,
+				) {
+					self.horizontal_scroll
+						.move_right(HorizontalScrollType::Right);
+					Ok(EventState::Consumed)
+				} else if key_match(e, self.key_config.keys.move_left)
+				{
+					self.horizontal_scroll
+						.move_right(HorizontalScrollType::Left);
+					Ok(EventState::Consumed)
 				} else if key_match(
 					e,
 					self.key_config.keys.stage_unstage_item,

src/components/file_revlog.rs

@@ -11,7 +11,7 @@ use crate::{
 	keys::SharedKeyConfig,
 	queue::{InternalEvent, NeedsUpdate, Queue},
 	strings,
-	ui::{draw_scrollbar, style::SharedTheme},
+	ui::{draw_scrollbar, style::SharedTheme, Orientation},
 };
 use anyhow::Result;
 use asyncgit::{
@@ -412,6 +412,7 @@ impl FileRevlogComponent {
 			&self.theme,
 			self.count_total,
 			table_state.selected().unwrap_or(0),
+			Orientation::Vertical,
 		);
 
 		self.table_state.set(table_state);
@@ -445,7 +446,7 @@ impl DrawableComponent for FileRevlogComponent {
 	) -> Result<()> {
 		if self.visible {
 			let percentages = if self.diff.focused() {
-				(30, 70)
+				(0, 100)
 			} else {
 				(50, 50)
 			};
@@ -485,20 +486,17 @@ impl Component for FileRevlogComponent {
 
 			if let Event::Key(key) = event {
 				if key_match(key, self.key_config.keys.exit_popup) {
-					self.hide_stacked(false);
+					if self.diff.focused() {
+						self.diff.focus(false);
+					} else {
+						self.hide_stacked(false);
+					}
 				} else if key_match(
 					key,
 					self.key_config.keys.focus_right,
 				) && self.can_focus_diff()
 				{
 					self.diff.focus(true);
-				} else if key_match(
-					key,
-					self.key_config.keys.focus_left,
-				) {
-					if self.diff.focused() {
-						self.diff.focus(false);
-					}
 				} else if key_match(key, self.key_config.keys.enter) {
 					if let Some(commit_id) = self.selected_commit() {
 						self.hide_stacked(true);

src/components/inspect_commit.rs

@@ -71,7 +71,7 @@ impl DrawableComponent for InspectCommitComponent {
 	) -> Result<()> {
 		if self.is_visible() {
 			let percentages = if self.diff.focused() {
-				(30, 70)
+				(0, 100)
 			} else {
 				(50, 50)
 			};
@@ -126,7 +126,7 @@ impl Component for InspectCommitComponent {
 			));
 
 			out.push(CommandInfo::new(
-				strings::commands::diff_focus_left(&self.key_config),
+				strings::commands::close_popup(&self.key_config),
 				true,
 				self.diff.focused() || force_all,
 			));
@@ -157,7 +157,12 @@ impl Component for InspectCommitComponent {
 
 			if let Event::Key(e) = ev {
 				if key_match(e, self.key_config.keys.exit_popup) {
-					self.hide_stacked(false);
+					if self.diff.focused() {
+						self.details.focus(true);
+						self.diff.focus(false);
+					} else {
+						self.hide_stacked(false);
+					}
 				} else if key_match(
 					e,
 					self.key_config.keys.focus_right,
@@ -168,13 +173,6 @@ impl Component for InspectCommitComponent {
 				} else if key_match(
 					e,
 					self.key_config.keys.focus_left,
-				) && self.diff.focused()
-				{
-					self.details.focus(true);
-					self.diff.focus(false);
-				} else if key_match(
-					e,
-					self.key_config.keys.focus_left,
 				) {
 					self.hide_stacked(false);
 				}

src/components/mod.rs

@@ -185,6 +185,12 @@ pub enum ScrollType {
 	PageDown,
 }
 
+#[derive(Copy, Clone)]
+pub enum HorizontalScrollType {
+	Left,
+	Right,
+}
+
 #[derive(Copy, Clone)]
 pub enum Direction {
 	Up,

src/components/syntax_text.rs

@@ -238,6 +238,7 @@ impl DrawableComponent for SyntaxTextComponent {
 					state.height().saturating_sub(2),
 				)),
 				usize::from(state.scroll().y),
+				ui::Orientation::Vertical,
 			);
 		}
 

src/components/taglist.rs

@@ -128,6 +128,7 @@ impl DrawableComponent for TagListComponent {
 				&self.theme,
 				number_of_rows,
 				table_state.selected().unwrap_or(0),
+				ui::Orientation::Vertical,
 			);
 
 			self.table_state.set(table_state);

src/components/utils/mod.rs

@@ -5,6 +5,7 @@ use unicode_width::UnicodeWidthStr;
 pub mod emoji;
 pub mod filetree;
 pub mod logitems;
+pub mod scroll_horizontal;
 pub mod scroll_vertical;
 pub mod statustree;
 

src/components/utils/scroll_horizontal.rs

@@ -0,0 +1,140 @@
+use std::cell::Cell;
+
+use tui::{backend::Backend, layout::Rect, Frame};
+
+use crate::{
+	components::HorizontalScrollType,
+	ui::{draw_scrollbar, style::SharedTheme, Orientation},
+};
+
+pub struct HorizontalScroll {
+	right: Cell<usize>,
+	max_right: Cell<usize>,
+}
+
+impl HorizontalScroll {
+	pub const fn new() -> Self {
+		Self {
+			right: Cell::new(0),
+			max_right: Cell::new(0),
+		}
+	}
+
+	pub fn get_right(&self) -> usize {
+		self.right.get()
+	}
+
+	pub fn reset(&self) {
+		self.right.set(0);
+	}
+
+	pub fn move_right(
+		&self,
+		move_type: HorizontalScrollType,
+	) -> bool {
+		let old = self.right.get();
+		let max = self.max_right.get();
+
+		let new_scroll_right = match move_type {
+			HorizontalScrollType::Left => old.saturating_sub(1),
+			HorizontalScrollType::Right => old.saturating_add(1),
+		};
+
+		let new_scroll_right = new_scroll_right.clamp(0, max);
+
+		if new_scroll_right == old {
+			return false;
+		}
+
+		self.right.set(new_scroll_right);
+
+		true
+	}
+
+	pub fn update(
+		&self,
+		selection: usize,
+		max_selection: usize,
+		visual_width: usize,
+	) -> usize {
+		let new_right = calc_scroll_right(
+			self.get_right(),
+			visual_width,
+			selection,
+			max_selection,
+		);
+		self.right.set(new_right);
+
+		if visual_width == 0 {
+			self.max_right.set(0);
+		} else {
+			let new_max_right =
+				max_selection.saturating_sub(visual_width);
+			self.max_right.set(new_max_right);
+		}
+
+		new_right
+	}
+
+	pub fn update_no_selection(
+		&self,
+		column_count: usize,
+		visual_width: usize,
+	) -> usize {
+		self.update(self.get_right(), column_count, visual_width)
+	}
+
+	pub fn draw<B: Backend>(
+		&self,
+		f: &mut Frame<B>,
+		r: Rect,
+		theme: &SharedTheme,
+	) {
+		draw_scrollbar(
+			f,
+			r,
+			theme,
+			self.max_right.get(),
+			self.right.get(),
+			Orientation::Horizontal,
+		);
+	}
+}
+
+const fn calc_scroll_right(
+	current_right: usize,
+	width_in_lines: usize,
+	selection: usize,
+	selection_max: usize,
+) -> usize {
+	if width_in_lines == 0 {
+		return 0;
+	}
+	if selection_max <= width_in_lines {
+		return 0;
+	}
+
+	if current_right + width_in_lines <= selection {
+		selection.saturating_sub(width_in_lines) + 1
+	} else if current_right > selection {
+		selection
+	} else {
+		current_right
+	}
+}
+
+#[cfg(test)]
+mod tests {
+	use super::*;
+	use pretty_assertions::assert_eq;
+
+	#[test]
+	fn test_scroll_no_scroll_to_right() {
+		assert_eq!(calc_scroll_right(1, 10, 4, 4), 0);
+	}
+
+	#[test]
+	fn test_scroll_zero_width() {
+		assert_eq!(calc_scroll_right(4, 0, 4, 3), 0);
+	}
+}

src/components/utils/scroll_vertical.rs

@@ -4,7 +4,7 @@ use tui::{backend::Backend, layout::Rect, Frame};
 
 use crate::{
 	components::ScrollType,
-	ui::{draw_scrollbar, style::SharedTheme},
+	ui::{draw_scrollbar, style::SharedTheme, Orientation},
 };
 
 pub struct VerticalScroll {
@@ -95,6 +95,7 @@ impl VerticalScroll {
 			theme,
 			self.max_top.get(),
 			self.top.get(),
+			Orientation::Vertical,
 		);
 	}
 }

src/string_utils.rs

@@ -1,3 +1,6 @@
+use unicode_segmentation::UnicodeSegmentation;
+use unicode_width::UnicodeWidthStr;
+
 ///
 pub fn trim_length_left(s: &str, width: usize) -> &str {
 	let len = s.len();
@@ -21,6 +24,22 @@ pub fn tabs_to_spaces(input: String) -> String {
 	}
 }
 
+/// This function will return a str slice which start at specified offset.
+/// As src is a unicode str, start offset has to be calculated with each character.
+pub fn trim_offset(src: &str, mut offset: usize) -> &str {
+	let mut start = 0;
+	for c in UnicodeSegmentation::graphemes(src, true) {
+		let w = c.width();
+		if w <= offset {
+			offset -= w;
+			start += c.len();
+		} else {
+			break;
+		}
+	}
+	&src[start..]
+}
+
 #[cfg(test)]
 mod test {
 	use pretty_assertions::assert_eq;

src/tabs/status.rs

@@ -105,8 +105,8 @@ impl DrawableComponent for Status {
 			.constraints(
 				if self.focus == Focus::Diff {
 					[
-						Constraint::Percentage(30),
-						Constraint::Percentage(70),
+						Constraint::Percentage(0),
+						Constraint::Percentage(100),
 					]
 				} else {
 					[
@@ -674,7 +674,7 @@ impl Status {
 		let focus_on_diff = self.is_focus_on_diff();
 		out.push(
 			CommandInfo::new(
-				strings::commands::diff_focus_left(&self.key_config),
+				strings::commands::close_popup(&self.key_config),
 				true,
 				(self.visible && focus_on_diff) || force_all,
 			)
@@ -846,7 +846,7 @@ impl Component for Status {
 					self.switch_focus(Focus::Diff).map(Into::into)
 				} else if key_match(
 					k,
-					self.key_config.keys.focus_left,
+					self.key_config.keys.exit_popup,
 				) {
 					self.switch_focus(match self.diff_target {
 						DiffTarget::Stage => Focus::Stage,

src/ui/mod.rs

@@ -6,7 +6,7 @@ pub mod style;
 mod syntax_text;
 
 use filetreelist::MoveSelection;
-pub use scrollbar::draw_scrollbar;
+pub use scrollbar::{draw_scrollbar, Orientation};
 pub use scrolllist::{draw_list, draw_list_block};
 pub use stateful_paragraph::{
 	ParagraphState, ScrollPos, StatefulParagraph,

src/ui/reflow.rs

@@ -1,6 +1,6 @@
+use crate::string_utils::trim_offset;
 use easy_cast::Cast;
 use tui::text::StyledGrapheme;
-use unicode_segmentation::UnicodeSegmentation;
 use unicode_width::UnicodeWidthStr;
 
 const NBSP: &str = "\u{00a0}";
@@ -233,22 +233,6 @@ impl<'a, 'b> LineComposer<'a> for LineTruncator<'a, 'b> {
 	}
 }
 
-/// This function will return a str slice which start at specified offset.
-/// As src is a unicode str, start offset has to be calculated with each character.
-fn trim_offset(src: &str, mut offset: usize) -> &str {
-	let mut start = 0;
-	for c in UnicodeSegmentation::graphemes(src, true) {
-		let w = c.width();
-		if w <= offset {
-			offset -= w;
-			start += c.len();
-		} else {
-			break;
-		}
-	}
-	&src[start..]
-}
-
 #[cfg(test)]
 mod test {
 	use super::*;

src/ui/scrollbar.rs

@@ -6,32 +6,40 @@ use tui::{
 	buffer::Buffer,
 	layout::{Margin, Rect},
 	style::Style,
-	symbols::{block::FULL, line::DOUBLE_VERTICAL},
+	symbols::{
+		block::FULL,
+		line::{DOUBLE_HORIZONTAL, DOUBLE_VERTICAL},
+	},
 	widgets::Widget,
 	Frame,
 };
 
+pub enum Orientation {
+	Vertical,
+	Horizontal,
+}
+
 ///
 struct Scrollbar {
 	max: u16,
 	pos: u16,
 	style_bar: Style,
 	style_pos: Style,
+	orientation: Orientation,
 }
 
 impl Scrollbar {
-	fn new(max: usize, pos: usize) -> Self {
+	fn new(max: usize, pos: usize, orientation: Orientation) -> Self {
 		Self {
 			max: u16::try_from(max).unwrap_or_default(),
 			pos: u16::try_from(pos).unwrap_or_default(),
 			style_pos: Style::default(),
 			style_bar: Style::default(),
+			orientation,
 		}
 	}
-}
 
-impl Widget for Scrollbar {
-	fn render(self, area: Rect, buf: &mut Buffer) {
+	fn render_vertical(self, area: Rect, buf: &mut Buffer) {
 		if area.height <= 2 {
 			return;
 		}
@@ -67,6 +75,59 @@ impl Widget for Scrollbar {
 
 		buf.set_string(right, bar_top + pos, FULL, self.style_pos);
 	}
+
+	fn render_horizontal(self, area: Rect, buf: &mut Buffer) {
+		if area.width <= 2 {
+			return;
+		}
+
+		if self.max == 0 {
+			return;
+		}
+
+		let bottom = area.bottom().saturating_sub(1);
+		if bottom <= area.top() {
+			return;
+		};
+
+		let (bar_left, bar_width) = {
+			let scrollbar_area = area.inner(&Margin {
+				horizontal: 1,
+				vertical: 0,
+			});
+
+			(scrollbar_area.left(), scrollbar_area.width)
+		};
+
+		for x in bar_left..(bar_left + bar_width) {
+			buf.set_string(
+				x,
+				bottom,
+				DOUBLE_HORIZONTAL,
+				self.style_bar,
+			);
+		}
+
+		let progress = f32::from(self.pos) / f32::from(self.max);
+		let progress = if progress > 1.0 { 1.0 } else { progress };
+		let pos = f32::from(bar_width) * progress;
+
+		let pos: u16 = pos.cast_nearest();
+		let pos = pos.saturating_sub(1);
+
+		buf.set_string(bar_left + pos, bottom, FULL, self.style_pos);
+	}
+}
+
+impl Widget for Scrollbar {
+	fn render(self, area: Rect, buf: &mut Buffer) {
+		match &self.orientation {
+			Orientation::Vertical => self.render_vertical(area, buf),
+			Orientation::Horizontal => {
+				self.render_horizontal(area, buf);
+			}
+		}
+	}
 }
 
 pub fn draw_scrollbar<B: Backend>(
@@ -75,8 +136,9 @@ pub fn draw_scrollbar<B: Backend>(
 	theme: &SharedTheme,
 	max: usize,
 	pos: usize,
+	orientation: Orientation,
 ) {
-	let mut widget = Scrollbar::new(max, pos);
+	let mut widget = Scrollbar::new(max, pos, orientation);
 	widget.style_pos = theme.scroll_bar_pos();
 	f.render_widget(widget, r);
 }