Merge example_web into egui_demo_lib

2026-09-01 06:10:06 -04:00 · 2021-01-01 17:11:05 +01:00
parent 375e317547
commit defad4ed51
38 changed files with 441 additions and 1334 deletions
--- a/egui_demo_lib/src/apps/demo/scrolls.rs
+++ b/egui_demo_lib/src/apps/demo/scrolls.rs
@@ -0,0 +1,87 @@
+use egui::{color::*, *};
+
+#[derive(serde::Deserialize, serde::Serialize)]
+#[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(crate::LOREM_IPSUM_LONG);
+            ui.label(crate::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));
+            }
+        });
+    }
+}