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use ratatui::{
buffer::Buffer,
layout::Rect,
style::{Color, Style},
Frame,
};
use crate::app::AppState;
use crate::layout::PaneInfo;
pub(crate) fn pane_scrollbar_rect(info: &PaneInfo) -> Option<Rect> {
info.scrollbar_rect
}
pub(crate) fn release_notes_scrollbar_rect(
body: Rect,
metrics: crate::pane::ScrollMetrics,
) -> Option<Rect> {
(should_show_scrollbar(metrics) && body.width > 1).then_some(Rect::new(
body.x + body.width - 1,
body.y,
1,
body.height,
))
}
pub(crate) fn should_show_scrollbar(metrics: crate::pane::ScrollMetrics) -> bool {
metrics.max_offset_from_bottom > 0
}
#[derive(Debug, Clone, Copy, PartialEq, Eq)]
pub(crate) struct ScrollbarThumb {
pub top: u16,
pub len: u16,
}
pub(crate) fn scrollbar_thumb(
metrics: crate::pane::ScrollMetrics,
track: Rect,
) -> Option<ScrollbarThumb> {
if metrics.max_offset_from_bottom == 0 || track.height == 0 {
return None;
}
let track_height = track.height as usize;
let total_rows = metrics.max_offset_from_bottom + metrics.viewport_rows;
if total_rows == 0 {
return None;
}
let thumb_len = ((metrics.viewport_rows * track_height) as f32 / total_rows as f32)
.round()
.max(1.0)
.min(track_height as f32) as usize;
let max_thumb_top = track_height.saturating_sub(thumb_len);
let scrolled_from_top = metrics
.max_offset_from_bottom
.saturating_sub(metrics.offset_from_bottom);
let thumb_top = if max_thumb_top == 0 || metrics.max_offset_from_bottom == 0 {
0
} else {
((scrolled_from_top * max_thumb_top) as f32 / metrics.max_offset_from_bottom as f32)
.round()
.clamp(0.0, max_thumb_top as f32) as usize
};
Some(ScrollbarThumb {
top: track.y + thumb_top as u16,
len: thumb_len as u16,
})
}
pub(crate) fn scrollbar_thumb_grab_offset(
metrics: crate::pane::ScrollMetrics,
track: Rect,
row: u16,
) -> Option<u16> {
let thumb = scrollbar_thumb(metrics, track)?;
(row >= thumb.top && row < thumb.top + thumb.len).then(|| row - thumb.top)
}
fn scrollbar_offset_from_thumb_top(
metrics: crate::pane::ScrollMetrics,
track: Rect,
thumb_top: usize,
) -> usize {
if metrics.max_offset_from_bottom == 0 {
return 0;
}
let thumb_len = scrollbar_thumb(metrics, track)
.map(|thumb| thumb.len as usize)
.unwrap_or(1);
let max_thumb_top = track.height as usize - thumb_len.min(track.height as usize);
if max_thumb_top == 0 {
return 0;
}
let desired_top = thumb_top.min(max_thumb_top);
let scrolled_from_top = ((desired_top * metrics.max_offset_from_bottom) as f32
/ max_thumb_top as f32)
.round() as usize;
metrics
.max_offset_from_bottom
.saturating_sub(scrolled_from_top)
}
pub(crate) fn scrollbar_offset_from_row(
metrics: crate::pane::ScrollMetrics,
track: Rect,
row: u16,
) -> usize {
let thumb = match scrollbar_thumb(metrics, track) {
Some(thumb) => thumb,
None => return 0,
};
let clamped_row = row.clamp(track.y, track.y + track.height.saturating_sub(1));
let row_offset = clamped_row.saturating_sub(track.y) as usize;
let thumb_center = (thumb.len as usize) / 2;
let desired_top = row_offset.saturating_sub(thumb_center);
scrollbar_offset_from_thumb_top(metrics, track, desired_top)
}
pub(crate) fn scrollbar_offset_from_drag_row(
metrics: crate::pane::ScrollMetrics,
track: Rect,
row: u16,
grab_row_offset: u16,
) -> usize {
let clamped_row = row.clamp(track.y, track.y + track.height.saturating_sub(1));
let row_offset = clamped_row.saturating_sub(track.y) as usize;
let desired_top = row_offset.saturating_sub(grab_row_offset as usize);
scrollbar_offset_from_thumb_top(metrics, track, desired_top)
}
pub(crate) fn render_scrollbar_buffer(
buffer: &mut Buffer,
metrics: crate::pane::ScrollMetrics,
track: Rect,
track_color: Color,
thumb_color: Color,
thumb_symbol: &str,
) {
if metrics.max_offset_from_bottom == 0 {
return;
}
let Some(thumb) = scrollbar_thumb(metrics, track) else {
return;
};
for y in track.y..track.y + track.height {
let cell = &mut buffer[(track.x, y)];
cell.set_symbol("▕");
cell.set_style(Style::default().fg(track_color));
}
for y in thumb.top..thumb.top + thumb.len {
let cell = &mut buffer[(track.x, y)];
cell.set_symbol(thumb_symbol);
cell.set_style(Style::default().fg(thumb_color));
}
}
pub(crate) fn render_pane_scrollbar_buffer(
buffer: &mut Buffer,
metrics: crate::pane::ScrollMetrics,
track: Rect,
palette: &crate::app::state::Palette,
focused: bool,
) {
let (track_color, thumb_color, thumb_symbol) = if focused {
(palette.overlay0, palette.overlay1, "▐")
} else {
(palette.surface_dim, palette.overlay0, "▕")
};
render_scrollbar_buffer(
buffer,
metrics,
track,
track_color,
thumb_color,
thumb_symbol,
);
}
pub(super) fn render_pane_scrollbar(
app: &AppState,
frame: &mut Frame,
info: &PaneInfo,
rt: &crate::terminal::TerminalRuntime,
) {
let Some(metrics) = rt.scroll_metrics() else {
return;
};
let Some(track) = pane_scrollbar_rect(info) else {
return;
};
render_pane_scrollbar_buffer(
frame.buffer_mut(),
metrics,
track,
&app.palette,
info.is_focused,
);
}
|
