tengri/tui/src/tui_content/tui_scroll.rs

use crate::*;
use ratatui::{prelude::Position, style::Color::*};

pub struct ScrollbarV {
    pub offset: usize,
    pub length: usize,
    pub total:  usize,
}

pub struct ScrollbarH {
    pub offset: usize,
    pub length: usize,
    pub total:  usize,
}

impl ScrollbarV {
    const ICON_DEC: &[char] = &['▲'];
    const ICON_INC: &[char] = &['▼'];
}

impl ScrollbarH {
    const ICON_DEC: &[char] = &[' ', '🞀', ' '];
    const ICON_INC: &[char] = &[' ', '🞂', ' '];
}

impl Content<TuiOut> for ScrollbarV {
    fn render (&self, to: &mut TuiOut) {
        let [x, y1, _w, h] = to.area().xywh();
        let y2 = y1 + h;
        for (i, y) in (y1..=y2).enumerate() {
            if let Some(cell) = to.buffer.cell_mut(Position::from((x, y))) {
                if (i as usize) < (Self::ICON_DEC.len()) {
                    cell.set_fg(Rgb(255, 255, 255));
                    cell.set_bg(Rgb(0, 0, 0));
                    cell.set_char(Self::ICON_DEC[i as usize]);
                } else if (i as usize) > (h as usize - Self::ICON_INC.len()) {
                    cell.set_fg(Rgb(255, 255, 255));
                    cell.set_bg(Rgb(0, 0, 0));
                    cell.set_char(Self::ICON_INC[h as usize - i]);
                } else if false {
                    cell.set_fg(Rgb(255, 255, 255));
                    cell.set_bg(Reset);
                    cell.set_char('‖'); // ━
                } else {
                    cell.set_fg(Rgb(0, 0, 0));
                    cell.set_bg(Reset);
                    cell.set_char('╎'); // ━
                }
            }
        }
    }
}

impl Content<TuiOut> for ScrollbarH {
    fn render (&self, to: &mut TuiOut) {
        let [x1, y, w, _h] = to.area().xywh();
        let x2 = x1 + w;
        for (i, x) in (x1..=x2).enumerate() {
            if let Some(cell) = to.buffer.cell_mut(Position::from((x, y))) {
                if i < (Self::ICON_DEC.len()) {
                    cell.set_fg(Rgb(255, 255, 255));
                    cell.set_bg(Rgb(0, 0, 0));
                    cell.set_char(Self::ICON_DEC[i as usize]);
                } else if i > (w as usize - Self::ICON_INC.len()) {
                    cell.set_fg(Rgb(255, 255, 255));
                    cell.set_bg(Rgb(0, 0, 0));
                    cell.set_char(Self::ICON_INC[w as usize - i]);
                } else if false {
                    cell.set_fg(Rgb(255, 255, 255));
                    cell.set_bg(Reset);
                    cell.set_char('━');
                } else {
                    cell.set_fg(Rgb(0, 0, 0));
                    cell.set_bg(Reset);
                    cell.set_char('╌');
                }
            }
        }
    }
}