From dd52e9cd7239276745c2fbad02a63931327a8e48 Mon Sep 17 00:00:00 2001 From: mo8it Date: Tue, 27 Aug 2024 00:03:50 +0200 Subject: [PATCH] Separate the scroll state --- src/list.rs | 1 + src/list/scroll_state.rs | 104 +++++++++++++++++++++++++++++++++++++++ src/list/state.rs | 104 +++++++++++---------------------------- 3 files changed, 135 insertions(+), 74 deletions(-) create mode 100644 src/list/scroll_state.rs diff --git a/src/list.rs b/src/list.rs index a8e5225..481fb2f 100644 --- a/src/list.rs +++ b/src/list.rs @@ -16,6 +16,7 @@ use crate::app_state::AppState; use self::state::{Filter, ListState}; +mod scroll_state; mod state; fn handle_list(app_state: &mut AppState, stdout: &mut StdoutLock) -> Result<()> { diff --git a/src/list/scroll_state.rs b/src/list/scroll_state.rs new file mode 100644 index 0000000..25a7373 --- /dev/null +++ b/src/list/scroll_state.rs @@ -0,0 +1,104 @@ +pub struct ScrollState { + n_rows: usize, + max_n_rows_to_display: usize, + selected: Option, + offset: usize, + scroll_padding: usize, + max_scroll_padding: usize, +} + +impl ScrollState { + pub fn new(n_rows: usize, selected: Option, max_scroll_padding: usize) -> Self { + Self { + n_rows, + max_n_rows_to_display: 0, + selected, + offset: selected.map_or(0, |selected| selected.saturating_sub(max_scroll_padding)), + scroll_padding: 0, + max_scroll_padding, + } + } + + #[inline] + pub fn offset(&self) -> usize { + self.offset + } + + fn update_offset(&mut self) { + let Some(selected) = self.selected else { + return; + }; + + let min_offset = (selected + self.scroll_padding) + .saturating_sub(self.max_n_rows_to_display.saturating_sub(1)); + let max_offset = selected.saturating_sub(self.scroll_padding); + let global_max_offset = self.n_rows.saturating_sub(self.max_n_rows_to_display); + + self.offset = self + .offset + .max(min_offset) + .min(max_offset) + .min(global_max_offset); + } + + #[inline] + pub fn selected(&self) -> Option { + self.selected + } + + fn set_selected(&mut self, selected: usize) { + self.selected = Some(selected); + self.update_offset(); + } + + pub fn select_next(&mut self) { + if let Some(selected) = self.selected { + self.set_selected((selected + 1).min(self.n_rows - 1)); + } + } + + pub fn select_previous(&mut self) { + if let Some(selected) = self.selected { + self.set_selected(selected.saturating_sub(1)); + } + } + + pub fn select_first(&mut self) { + if self.n_rows > 0 { + self.set_selected(0); + } + } + + pub fn select_last(&mut self) { + if self.n_rows > 0 { + self.set_selected(self.n_rows - 1); + } + } + + pub fn set_n_rows(&mut self, n_rows: usize) { + self.n_rows = n_rows; + + if self.n_rows == 0 { + self.selected = None; + return; + } + + self.set_selected(self.selected.map_or(0, |selected| selected.min(n_rows - 1))); + } + + #[inline] + fn update_scroll_padding(&mut self) { + self.scroll_padding = (self.max_n_rows_to_display / 4).min(self.max_scroll_padding); + } + + #[inline] + pub fn max_n_rows_to_display(&self) -> usize { + self.max_n_rows_to_display + } + + pub fn set_max_n_rows_to_display(&mut self, max_n_rows_to_display: usize) { + self.max_n_rows_to_display = max_n_rows_to_display; + self.update_scroll_padding(); + self.update_offset(); + } +} diff --git a/src/list/state.rs b/src/list/state.rs index 3876884..e263b7e 100644 --- a/src/list/state.rs +++ b/src/list/state.rs @@ -17,7 +17,8 @@ use crate::{ MAX_EXERCISE_NAME_LEN, }; -const MAX_SCROLL_PADDING: usize = 5; +use super::scroll_state::ScrollState; + // +1 for column padding. const SPACE: &[u8] = &[b' '; MAX_EXERCISE_NAME_LEN + 1]; @@ -39,19 +40,14 @@ pub struct ListState<'a> { /// Footer message to be displayed if not empty. pub message: String, app_state: &'a mut AppState, + scroll_state: ScrollState, name_col_width: usize, filter: Filter, - n_rows_with_filter: usize, - /// Selected row out of the filtered ones. - selected_row: Option, - row_offset: usize, term_width: u16, term_height: u16, separator_line: Vec, narrow_term: bool, show_footer: bool, - max_n_rows_to_display: usize, - scroll_padding: usize, } impl<'a> ListState<'a> { @@ -70,50 +66,29 @@ impl<'a> ListState<'a> { let n_rows_with_filter = app_state.exercises().len(); let selected = app_state.current_exercise_ind(); + let (width, height) = terminal::size()?; + let scroll_state = ScrollState::new(n_rows_with_filter, Some(selected), 5); + let mut slf = Self { message: String::with_capacity(128), app_state, + scroll_state, name_col_width, filter, - n_rows_with_filter, - selected_row: Some(selected), - row_offset: selected.saturating_sub(MAX_SCROLL_PADDING), // Set by `set_term_size` term_width: 0, term_height: 0, separator_line: Vec::new(), narrow_term: false, show_footer: true, - max_n_rows_to_display: 0, - scroll_padding: 0, }; - let (width, height) = terminal::size()?; slf.set_term_size(width, height); slf.draw(stdout)?; Ok(slf) } - fn update_offset(&mut self) { - let Some(selected) = self.selected_row else { - return; - }; - - let min_offset = (selected + self.scroll_padding) - .saturating_sub(self.max_n_rows_to_display.saturating_sub(1)); - let max_offset = selected.saturating_sub(self.scroll_padding); - let global_max_offset = self - .n_rows_with_filter - .saturating_sub(self.max_n_rows_to_display); - - self.row_offset = self - .row_offset - .max(min_offset) - .min(max_offset) - .min(global_max_offset); - } - pub fn set_term_size(&mut self, width: u16, height: u16) { self.term_width = width; self.term_height = height; @@ -124,7 +99,7 @@ impl<'a> ListState<'a> { let wide_help_footer_width = 95; // The help footer is shorter when nothing is selected. - self.narrow_term = width < wide_help_footer_width && self.selected_row.is_some(); + self.narrow_term = width < wide_help_footer_width && self.scroll_state.selected().is_some(); let header_height = 1; // 2 separator, 1 progress bar, 1-2 footer message. @@ -135,13 +110,10 @@ impl<'a> ListState<'a> { self.separator_line = "─".as_bytes().repeat(width as usize); } - self.max_n_rows_to_display = height - .saturating_sub(header_height + u16::from(self.show_footer) * footer_height) - as usize; - - self.scroll_padding = (self.max_n_rows_to_display / 4).min(MAX_SCROLL_PADDING); - - self.update_offset(); + self.scroll_state.set_max_n_rows_to_display( + height.saturating_sub(header_height + u16::from(self.show_footer) * footer_height) + as usize, + ); } fn draw_rows( @@ -150,15 +122,16 @@ impl<'a> ListState<'a> { filtered_exercises: impl Iterator, ) -> io::Result { let current_exercise_ind = self.app_state.current_exercise_ind(); + let row_offset = self.scroll_state.offset(); let mut n_displayed_rows = 0; for (exercise_ind, exercise) in filtered_exercises - .skip(self.row_offset) - .take(self.max_n_rows_to_display) + .skip(row_offset) + .take(self.scroll_state.max_n_rows_to_display()) { let mut writer = MaxLenWriter::new(stdout, self.term_width as usize); - if self.selected_row == Some(self.row_offset + n_displayed_rows) { + if self.scroll_state.selected() == Some(row_offset + n_displayed_rows) { writer.stdout.queue(SetBackgroundColor(Color::Rgb { r: 40, g: 40, @@ -225,7 +198,7 @@ impl<'a> ListState<'a> { Filter::None => self.draw_rows(stdout, iter)?, }; - for _ in 0..self.max_n_rows_to_display - n_displayed_rows { + for _ in 0..self.scroll_state.max_n_rows_to_display() - n_displayed_rows { next_ln(stdout)?; } @@ -247,7 +220,7 @@ impl<'a> ListState<'a> { let mut writer = MaxLenWriter::new(stdout, self.term_width as usize); if self.message.is_empty() { // Help footer message - if self.selected_row.is_some() { + if self.scroll_state.selected().is_some() { writer.write_str("↓/j ↑/k home/g end/G | ontinue at | eset exercise")?; if self.narrow_term { next_ln(stdout)?; @@ -298,13 +271,8 @@ impl<'a> ListState<'a> { stdout.queue(EndSynchronizedUpdate)?.flush() } - fn set_selected(&mut self, selected: usize) { - self.selected_row = Some(selected); - self.update_offset(); - } - fn update_rows(&mut self) { - self.n_rows_with_filter = match self.filter { + let n_rows = match self.filter { Filter::Done => self .app_state .exercises() @@ -320,15 +288,7 @@ impl<'a> ListState<'a> { Filter::None => self.app_state.exercises().len(), }; - if self.n_rows_with_filter == 0 { - self.selected_row = None; - return; - } - - self.set_selected( - self.selected_row - .map_or(0, |selected| selected.min(self.n_rows_with_filter - 1)), - ); + self.scroll_state.set_n_rows(n_rows); } #[inline] @@ -341,28 +301,24 @@ impl<'a> ListState<'a> { self.update_rows(); } + #[inline] pub fn select_next(&mut self) { - if let Some(selected) = self.selected_row { - self.set_selected((selected + 1).min(self.n_rows_with_filter - 1)); - } + self.scroll_state.select_next(); } + #[inline] pub fn select_previous(&mut self) { - if let Some(selected) = self.selected_row { - self.set_selected(selected.saturating_sub(1)); - } + self.scroll_state.select_previous(); } + #[inline] pub fn select_first(&mut self) { - if self.n_rows_with_filter > 0 { - self.set_selected(0); - } + self.scroll_state.select_first(); } + #[inline] pub fn select_last(&mut self) { - if self.n_rows_with_filter > 0 { - self.set_selected(self.n_rows_with_filter - 1); - } + self.scroll_state.select_last(); } fn selected_to_exercise_ind(&self, selected: usize) -> Result { @@ -390,7 +346,7 @@ impl<'a> ListState<'a> { } pub fn reset_selected(&mut self) -> Result<()> { - let Some(selected) = self.selected_row else { + let Some(selected) = self.scroll_state.selected() else { self.message.push_str("Nothing selected to reset!"); return Ok(()); }; @@ -408,7 +364,7 @@ impl<'a> ListState<'a> { // Return `true` if there was something to select. pub fn selected_to_current_exercise(&mut self) -> Result { - let Some(selected) = self.selected_row else { + let Some(selected) = self.scroll_state.selected() else { self.message.push_str("Nothing selected to continue at!"); return Ok(false); };