Add perfect cursors crate

crates/perfect_cursors/Cargo.toml

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+[package]
+name = "perfect_cursors"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+web-time = "1"
+
+[dev-dependencies]
+eframe = "0.26.2"

crates/perfect_cursors/README.md

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+# perfect_cursors
+
+Rust port of [perfect-cursors](https://github.com/steveruizok/perfect-cursors) from Steve Ruiz.

crates/perfect_cursors/examples/perfect_cursors_egui.rs

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+use std::time::{Duration, Instant};
+
+use eframe::egui::{CentralPanel, Pos2, Vec2};
+use eframe::{egui, NativeOptions};
+
+use perfect_cursors::PerfectCursor;
+
+struct CursorSim {
+    delay: Duration,
+    last_time: Instant,
+    cursor: PerfectCursor,
+    offset: Vec2,
+    next_point: Option<Pos2>,
+    received_point: Option<Pos2>,
+    last_point: Option<Pos2>,
+}
+
+pub fn main() -> eframe::Result<()> {
+    let mut cursors = vec![
+        CursorSim {
+            delay: Duration::from_millis(80),
+            last_time: Instant::now(),
+            cursor: PerfectCursor::new(),
+            offset: Vec2::new(60.0, 0.0),
+            next_point: None,
+            received_point: None,
+            last_point: None,
+        },
+        CursorSim {
+            delay: Duration::from_millis(160),
+            last_time: Instant::now(),
+            cursor: PerfectCursor::new(),
+            offset: Vec2::new(120.0, 0.0),
+            next_point: None,
+            received_point: None,
+            last_point: None,
+        },
+        CursorSim {
+            delay: Duration::from_millis(250),
+            last_time: Instant::now(),
+            cursor: PerfectCursor::new(),
+            offset: Vec2::new(180.0, 0.0),
+            next_point: None,
+            received_point: None,
+            last_point: None,
+        },
+    ];
+
+    let mut show_update_events = false;
+    let mut use_perfect_cursors = true;
+
+    eframe::run_simple_native(
+        "Perfect Cursors Egui Example",
+        NativeOptions::default(),
+        move |ctx, _frame| {
+            CentralPanel::default().show(ctx, |ui| {
+                ui.horizontal(|ui| {
+                    ui.checkbox(&mut show_update_events, "Show update events");
+                    ui.checkbox(&mut use_perfect_cursors, "Use Perfect Cursors");
+                });
+
+                cursors.iter_mut().for_each(|cursor| {
+                    if cursor.last_time.elapsed() > cursor.delay {
+                        cursor.last_time = Instant::now();
+
+                        if let Some(next) = cursor.next_point.take() {
+                            if use_perfect_cursors {
+                                cursor.cursor.add_point(next.into());
+                            } else {
+                                cursor.received_point = Some(next);
+                            }
+                            if show_update_events {
+                                ui.painter().circle(
+                                    next + cursor.offset,
+                                    15.0,
+                                    egui::Color32::BLUE,
+                                    egui::Stroke::new(1.0, egui::Color32::WHITE),
+                                );
+                            }
+                        }
+
+                        if let Some(pos) = ui.input(|i| i.pointer.hover_pos()) {
+                            if cursor.last_point != Some(pos) {
+                                cursor.next_point = Some(pos);
+                            }
+                            cursor.last_point = Some(pos);
+                        }
+                    }
+                });
+
+                for cursor in &mut cursors {
+                    let current_pos = if use_perfect_cursors {
+                        cursor.cursor.tick().map(|p| p.into())
+                    } else {
+                        cursor.received_point
+                    };
+
+                    if let Some(pos) = current_pos {
+                        ui.painter().circle(
+                            pos + cursor.offset,
+                            10.0,
+                            egui::Color32::RED,
+                            egui::Stroke::new(1.0, egui::Color32::WHITE),
+                        );
+                    }
+
+                    ui.ctx().request_repaint();
+                }
+            });
+        },
+    )
+}