Michel de Graaf
0cacc8cc10
Four panes had grown the same dance around ratatui's table: clamp the selection, take the visible page, hand the table a page-local state, keep the page start. It is now page_window and render_page in a paging module beside page_of, and the two popups page by the same count they draw, tab bar or header included. Five typed filters had grown the same key handling too. edit_filter now takes a key for all of them, which also stops a control or alt chord from typing its letter into a filter, stops Enter, which keeps a filter, from resetting the view it is over, and lets the results and room-list filters page like the others. Their titles and the typing shortcuts come from one place as well.
105 lines
3.4 KiB
Rust
105 lines
3.4 KiB
Rust
//! How a pane's table shows one page of a list that may run to tens of
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//! thousands of rows: which rows those are, and how ratatui is handed just
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//! those. Paging and drawing both count rows here, so they agree on what a
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//! page is.
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use crate::ui::pane_block;
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use ratatui::{
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Frame,
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layout::Rect,
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widgets::{Table, TableState},
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};
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use std::ops::Range;
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/// Rows a list in `area` shows at once, less the `chrome` rows above it: a
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/// table header, a popup's tab bar. At least one, so a page key always
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/// moves, even before the first draw.
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#[must_use]
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pub fn page_of(area: Option<Rect>, chrome: u16) -> usize {
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area.map_or(0, |area| {
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usize::from(pane_block(false).inner(area).height.saturating_sub(chrome))
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})
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.max(1)
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}
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/// The page a table over `area` shows of `len` rows, `chrome` rows of the
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/// area being above them: where the last frame left off, moved only as far
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/// as keeps the selection in view. A selection past the end lands on the
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/// last row, as the table would have put it.
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pub fn page_window(
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state: &mut TableState,
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len: usize,
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area: Rect,
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chrome: u16,
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) -> Range<usize> {
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if let Some(selected) = state.selected_mut() {
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*selected = (*selected).min(len.saturating_sub(1));
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}
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visible_range(
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state.offset(),
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state.selected(),
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len,
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page_of(Some(area), chrome),
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)
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}
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/// Draw `table`, holding the rows of the page that starts at `start`, with
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/// `state` shifted onto that page. The page start is kept for the next
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/// frame.
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pub fn render_page(
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frame: &mut Frame,
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table: Table,
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area: Rect,
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state: &mut TableState,
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start: usize,
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) {
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let mut page_state = TableState::default()
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.with_selected(state.selected().map(|selected| selected - start));
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frame.render_stateful_widget(table, area, &mut page_state);
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*state.offset_mut() = start;
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}
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/// The page a `height`-tall table shows, by ratatui's rule (its
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/// `visible_rows` is private): the offset, moved only as far as keeps the
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/// selection in view. A selection past the end counts as the last row.
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fn visible_range(
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offset: usize,
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selected: Option<usize>,
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len: usize,
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height: usize,
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) -> Range<usize> {
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let height = height.max(1);
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let last = len.saturating_sub(1);
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let start = match selected.map(|selected| selected.min(last)) {
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Some(selected) => {
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offset.clamp((selected + 1).saturating_sub(height), selected)
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}
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None => offset.min(last),
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};
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start..(start + height).min(len)
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}
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#[cfg(test)]
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mod tests {
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use super::{page_window, visible_range};
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use ratatui::{layout::Rect, widgets::TableState};
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#[test]
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fn the_page_follows_the_selection_and_is_never_longer_than_the_pane() {
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assert_eq!(visible_range(500, Some(505), 10_000, 10), 500..510);
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assert_eq!(visible_range(0, Some(9_999), 10_000, 10), 9_990..10_000);
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assert_eq!(visible_range(500, Some(499), 10_000, 10), 499..509);
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assert_eq!(visible_range(9_995, None, 10_000, 10), 9_995..10_000);
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assert_eq!(visible_range(0, Some(9), 3, 2), 1..3);
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}
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#[test]
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fn a_window_pulls_a_selection_past_the_end_onto_the_last_row() {
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// 6 rows tall: 2 border, 1 header, 3 of the list.
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let area = Rect::new(0, 0, 40, 6);
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let mut state = TableState::default().with_selected(Some(9));
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assert_eq!(page_window(&mut state, 5, area, 1), 2..5);
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assert_eq!(state.selected(), Some(4));
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}
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}
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