From 2297530cb1149752445b586b337e5c8d3b7bb108 Mon Sep 17 00:00:00 2001
From: Alexis Hovorka <alexisspacegirl@gmail.com>
Date: Sun, 16 May 2021 22:40:33 -0600
Subject: [feat] Long press 3+ fingers to set home position

---
 index.js | 105 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 102 insertions(+), 3 deletions(-)

(limited to 'index.js')

diff --git a/index.js b/index.js
index 72c8f66..ff1d144 100755
--- a/index.js
+++ b/index.js
@@ -2,12 +2,111 @@
 const Device = require("./lib/device");
 const Motion = require("./lib/motion");
 
+//const clone = x => JSON.parse(JSON.stringify(x)); // Deep
+//const clone = x => Object.assign({}, x); // Shallow
+
 const path = "/dev/input/"+process.argv[2];
 console.log("Opening %s", path);
 
 const device = new Device(path);
-const motion = new Motion(device);
+const motion = new Motion(device, 600/*ms for long*/);
+
 device.on("open", () => { console.log(device.id); device.grab(); });
+//device.on("EV_ABS", e => console.log(e));
+//device.on("EV_SYN", e => console.log(e));
+
 motion.on("error", console.error)
-      .on("short", e => console.log("short", e))
-      .on("long",  e => console.log("long",  e));
+      //.on("short", e => console.log("short", e))
+      //.on("long", e => console.log("long",  e))
+      .on("short", doShort).on("long", doLong);
+
+const flipBits = (n,w) => parseInt(n.toString(2).padStart(w,0).split("").reverse().join(""),2);
+
+const eucDist   = (a,b)   => Math.sqrt((a.x-b.x)**2 + (a.y-b.y)**2);
+//const avgDist   = (a,b)   => (eucDist(a.i,b.i) + eucDist(a.f,b.f))/2;
+const selfDist  =  a      => eucDist(a.i, a.f);
+const getAngle2 = (a,b)   => Math.atan2(a.y-b.y, b.x-a.x)*180/Math.PI;
+const getAngle  =  a      => getAngle2(a.i,a.f);
+const isLeft    = (a,b,c) => ((b.x-a.x)*(c.y-a.y) - (b.y-a.y)*(c.x-a.x))>0; // What side of a-b is c on
+
+const state = {
+  homed: false,
+  homes: [],
+  angle: 0,
+  fingerDist: 0,
+};
+
+const dotRadius = 0.3; // Tap/reach boundary in terms of between-finger distance
+const swipeLength = 0.2; // Tap/swipe threshold in terms of between-finger distance
+
+function doLong(e) {
+  if (e.length < 3) return; // Pinky finger optional!
+
+  const between = [];
+  for (let i=0;i<e.length;i++)
+    for (let j=i+1;j<e.length;j++)
+      between.push({a:i, b:j, dist:eucDist(e[i].m, e[j].m)});
+  between.sort((a,b) => a.dist-b.dist);
+
+  const fingerDist = between[0].dist;
+  if (e.map(p => selfDist(p)).reduce((a,d) =>
+    a || (d >= fingerDist*swipeLength), false)) return; // Moved too far
+
+  const biggest = between.pop();
+  const sides = e.reduce((a,p,i) => {
+    if (i != biggest.a && i != biggest.b)
+      a.push({i:i,s:isLeft(e[biggest.a].m, e[biggest.b].m, p.m)});
+    return a; }, []);
+  const side = 2*sides.reduce((a,s)=>a+s.s,0)>sides.length;
+
+  const indexFinger = biggest[side?"b":"a"];
+
+  state.homes = [];
+  state.homes.push(e[indexFinger].m);
+  sides.map(f => Object.assign({d:eucDist(e[indexFinger].m, e[f.i].m)}, f))
+    .sort((a,b) => a.d-b.d).forEach(f => state.homes.push(e[f.i].m));
+  state.homes.push(e[biggest[side?"a":"b"]].m);
+
+  state.angle = getAngle2(state.homes[0], state.homes[state.homes.length-1]);
+  state.fingerDist = fingerDist;
+  state.homed = true;
+
+  //console.log(JSON.stringify(state.homes), state.angle, state.fingerDist);
+  console.log("Homed");
+}
+
+const prettyFingers = n => "("+n.toString(2).padStart(state.homes.length,0)
+  .split("").map(f => f=="1"?"#":" ").reverse().join("")+")";
+
+function doShort(e) {
+  if (!state.homed) return;
+
+  // Gesture types:
+  // - Tap:
+  //   - inside tap       | 0
+  //   - reaching tap     | 1
+  // - Swipe:
+  //   - Vertical:
+  //     - from in down   | 2
+  //     - from up in     | 3
+  //     - swipe up       | 4
+  //   - Horizontal:
+  //     - from in left   | 5
+  //     - from in right  | 6
+
+  const isTap = (e.reduce((a,p) => a+selfDist(p),0) /
+    e.length) < state.fingerDist * swipeLength;
+
+  if (isTap) {
+    const fingers = e.map(p => state.homes
+      .map((f,i) => ({i,d:eucDist(f, p.m)}))
+      .sort((a,b)=>a.d-b.d)[0]);
+    const fingerCode = fingers.reduce((a,f) => a+2**f.i, 0);
+
+    // TODO reaching taps
+    console.log("tap", prettyFingers(fingerCode));
+
+  } else { // TODO swipes
+    console.log("swipe");
+  }
+}
-- 
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