egui/egui_demo_lib/src/scrolls.rs

88 lines
3.1 KiB
Rust

use crate::LOREM_IPSUM_LONG;
use egui::{color::*, *};
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
#[cfg_attr(feature = "serde", serde(default))]
pub struct Scrolls {
track_item: usize,
tracking: bool,
offset: f32,
}
impl Default for Scrolls {
fn default() -> Self {
Self {
track_item: 25,
tracking: true,
offset: 0.0,
}
}
}
impl Scrolls {
pub fn ui(&mut self, ui: &mut Ui) {
ScrollArea::from_max_height(200.0).show(ui, |ui| {
ui.label(LOREM_IPSUM_LONG);
ui.label(LOREM_IPSUM_LONG);
});
ui.separator();
ui.horizontal(|ui| {
ui.checkbox(&mut self.tracking, "Track")
.on_hover_text("The scroll position will track the selected item");
ui.add(Slider::usize(&mut self.track_item, 1..=50).text("Track Item"));
});
let (scroll_offset, _) = ui.horizontal(|ui| {
let scroll_offset = ui.small_button("Scroll Offset").clicked;
ui.add(DragValue::f32(&mut self.offset).speed(1.0).suffix("px"));
scroll_offset
});
let scroll_top = ui.button("Scroll to top").clicked;
let scroll_bottom = ui.button("Scroll to bottom").clicked;
if scroll_bottom || scroll_top {
self.tracking = false;
}
const TITLES: [&str; 3] = ["Top", "Middle", "Bottom"];
const ALIGNS: [Align; 3] = [Align::Min, Align::Center, Align::Max];
ui.columns(3, |cols| {
for (i, col) in cols.iter_mut().enumerate() {
col.colored_label(WHITE, TITLES[i]);
let mut scroll_area = ScrollArea::from_max_height(200.0).id_source(i);
if scroll_offset {
self.tracking = false;
scroll_area = scroll_area.scroll_offset(self.offset);
}
let (current_scroll, max_scroll) = scroll_area.show(col, |ui| {
if scroll_top {
ui.scroll_to_cursor(Align::top());
}
ui.vertical(|ui| {
for item in 1..=50 {
if self.tracking && item == self.track_item {
let response = ui.colored_label(YELLOW, format!("Item {}", item));
response.scroll_to_me(ALIGNS[i]);
} else {
ui.label(format!("Item {}", item));
}
}
});
if scroll_bottom {
ui.scroll_to_cursor(Align::bottom());
}
let margin = ui.style().visuals.clip_rect_margin;
(
ui.clip_rect().top() - ui.min_rect().top() + margin,
ui.min_rect().height() - ui.clip_rect().height() + 2.0 * margin,
)
});
col.colored_label(WHITE, format!("{:.0}/{:.0}", current_scroll, max_scroll));
}
});
}
}