Put all egui_demo_lib tests into their own files in their own folder (#4691)

crates/egui_demo_lib/src/demo/tests/input_test.rs

@@ -0,0 +1,186 @@
+struct HistoryEntry {
+    text: String,
+    repeated: usize,
+}
+
+#[derive(Default)]
+struct DeduplicatedHistory {
+    history: std::collections::VecDeque<HistoryEntry>,
+}
+
+impl DeduplicatedHistory {
+    fn add(&mut self, text: String) {
+        if let Some(entry) = self.history.back_mut() {
+            if entry.text == text {
+                entry.repeated += 1;
+                return;
+            }
+        }
+        self.history.push_back(HistoryEntry { text, repeated: 1 });
+        if self.history.len() > 100 {
+            self.history.pop_front();
+        }
+    }
+
+    fn ui(&self, ui: &mut egui::Ui) {
+        egui::ScrollArea::vertical()
+            .auto_shrink(false)
+            .show(ui, |ui| {
+                ui.spacing_mut().item_spacing.y = 4.0;
+                for HistoryEntry { text, repeated } in self.history.iter().rev() {
+                    ui.horizontal(|ui| {
+                        if text.is_empty() {
+                            ui.weak("(empty)");
+                        } else {
+                            ui.label(text);
+                        }
+                        if 1 < *repeated {
+                            ui.weak(format!(" x{repeated}"));
+                        }
+                    });
+                }
+            });
+    }
+}
+
+#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
+#[derive(Default)]
+pub struct InputTest {
+    #[cfg_attr(feature = "serde", serde(skip))]
+    history: [DeduplicatedHistory; 4],
+
+    late_interaction: bool,
+
+    show_hovers: bool,
+}
+
+impl crate::Demo for InputTest {
+    fn name(&self) -> &'static str {
+        "Input Test"
+    }
+
+    fn show(&mut self, ctx: &egui::Context, open: &mut bool) {
+        egui::Window::new(self.name())
+            .default_width(800.0)
+            .open(open)
+            .resizable(true)
+            .scroll(false)
+            .show(ctx, |ui| {
+                use crate::View as _;
+                self.ui(ui);
+            });
+    }
+}
+
+impl crate::View for InputTest {
+    fn ui(&mut self, ui: &mut egui::Ui) {
+        ui.spacing_mut().item_spacing.y = 8.0;
+
+        ui.vertical_centered(|ui| {
+            ui.add(crate::egui_github_link_file!());
+        });
+
+        ui.horizontal(|ui| {
+            if ui.button("Clear").clicked() {
+                *self = Default::default();
+            }
+
+            ui.checkbox(&mut self.show_hovers, "Show hover state");
+        });
+
+        ui.checkbox(&mut self.late_interaction, "Use Response::interact");
+
+        ui.label("This tests how egui::Response reports events.\n\
+        The different buttons are sensitive to different things.\n\
+        Try interacting with them with any mouse button by clicking, double-clicking, triple-clicking, or dragging them.");
+
+        ui.columns(4, |columns| {
+            for (i, (sense_name, sense)) in [
+                ("Sense::hover", egui::Sense::hover()),
+                ("Sense::click", egui::Sense::click()),
+                ("Sense::drag", egui::Sense::drag()),
+                ("Sense::click_and_drag", egui::Sense::click_and_drag()),
+            ]
+            .into_iter()
+            .enumerate()
+            {
+                columns[i].push_id(i, |ui| {
+                    let response = if self.late_interaction {
+                        let first_response =
+                            ui.add(egui::Button::new(sense_name).sense(egui::Sense::hover()));
+                        first_response.interact(sense)
+                    } else {
+                        ui.add(egui::Button::new(sense_name).sense(sense))
+                    };
+                    let info = response_summary(&response, self.show_hovers);
+                    self.history[i].add(info.trim().to_owned());
+                    self.history[i].ui(ui);
+                });
+            }
+        });
+    }
+}
+
+fn response_summary(response: &egui::Response, show_hovers: bool) -> String {
+    use std::fmt::Write as _;
+
+    let mut new_info = String::new();
+
+    if show_hovers {
+        if response.hovered() {
+            writeln!(new_info, "hovered").ok();
+        }
+        if response.contains_pointer() {
+            writeln!(new_info, "contains_pointer").ok();
+        }
+        if response.is_pointer_button_down_on() {
+            writeln!(new_info, "pointer_down_on").ok();
+        }
+        if let Some(pos) = response.interact_pointer_pos() {
+            writeln!(new_info, "response.interact_pointer_pos: {pos:?}").ok();
+        }
+    }
+
+    for &button in &[
+        egui::PointerButton::Primary,
+        egui::PointerButton::Secondary,
+        egui::PointerButton::Middle,
+        egui::PointerButton::Extra1,
+        egui::PointerButton::Extra2,
+    ] {
+        let button_suffix = if button == egui::PointerButton::Primary {
+            // Reduce visual clutter in common case:
+            String::default()
+        } else {
+            format!(" by {button:?} button")
+        };
+
+        // These are in inverse logical/chonological order, because we show them in the ui that way:
+
+        if response.triple_clicked_by(button) {
+            writeln!(new_info, "Triple-clicked{button_suffix}").ok();
+        }
+        if response.double_clicked_by(button) {
+            writeln!(new_info, "Double-clicked{button_suffix}").ok();
+        }
+        if response.clicked_by(button) {
+            writeln!(new_info, "Clicked{button_suffix}").ok();
+        }
+
+        if response.drag_stopped_by(button) {
+            writeln!(new_info, "Drag stopped{button_suffix}").ok();
+        }
+        if response.dragged_by(button) {
+            writeln!(new_info, "Dragged{button_suffix}").ok();
+        }
+        if response.drag_started_by(button) {
+            writeln!(new_info, "Drag started{button_suffix}").ok();
+        }
+    }
+
+    if response.long_touched() {
+        writeln!(new_info, "Clicked with long-press").ok();
+    }
+
+    new_info
+}