experimental multitouch based smooth scrolling

high-resolution mouse wheels aren't supported in userland yet, so why
don't we fake a high resolution touchpad instead 😄

it's somewhat working, though it seems to crash on startup when
installed (among other weird bugs).

Cargo.lock

@@ -71,6 +71,12 @@ version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
 
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
+
 [[package]]
 name = "chrono"
 version = "0.4.19"
@@ -84,6 +90,15 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "cloudabi"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4344512281c643ae7638bbabc3af17a11307803ec8f0fcad9fae512a8bf36467"
+dependencies = [
+ "bitflags 1.2.1",
+]
+
 [[package]]
 name = "constant_time_eq"
 version = "0.1.5"
@@ -97,7 +112,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c3c7c73a2d1e9fc0886a08b93e98eb643461230d5f1925e4036204d5f2e261a8"
 dependencies = [
  "autocfg",
- "cfg-if",
+ "cfg-if 0.1.10",
  "lazy_static",
 ]
 
@@ -169,7 +184,7 @@ version = "0.1.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fc587bc0ec293155d5bfa6b9891ec18a1e330c234f896ea47fbada4cadbe47e6"
 dependencies = [
- "cfg-if",
+ "cfg-if 0.1.10",
  "libc",
  "wasi 0.9.0+wasi-snapshot-preview1",
 ]
@@ -185,6 +200,15 @@ dependencies = [
  "pkg-config",
 ]
 
+[[package]]
+name = "instant"
+version = "0.1.8"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cb1fc4429a33e1f80d41dc9fea4d108a88bec1de8053878898ae448a0b52f613"
+dependencies = [
+ "cfg-if 1.0.0",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -206,13 +230,22 @@ dependencies = [
  "pkg-config",
 ]
 
+[[package]]
+name = "lock_api"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "28247cc5a5be2f05fbcd76dd0cf2c7d3b5400cb978a28042abcd4fa0b3f8261c"
+dependencies = [
+ "scopeguard",
+]
+
 [[package]]
 name = "log"
 version = "0.4.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4fabed175da42fed1fa0746b0ea71f412aa9d35e76e95e59b192c64b9dc2bf8b"
 dependencies = [
- "cfg-if",
+ "cfg-if 0.1.10",
 ]
 
 [[package]]
@@ -295,6 +328,32 @@ dependencies = [
  "objc",
 ]
 
+[[package]]
+name = "parking_lot"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a4893845fa2ca272e647da5d0e46660a314ead9c2fdd9a883aabc32e481a8733"
+dependencies = [
+ "instant",
+ "lock_api",
+ "parking_lot_core",
+]
+
+[[package]]
+name = "parking_lot_core"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c361aa727dd08437f2f1447be8b59a33b0edd15e0fcee698f935613d9efbca9b"
+dependencies = [
+ "cfg-if 0.1.10",
+ "cloudabi",
+ "instant",
+ "libc",
+ "redox_syscall",
+ "smallvec",
+ "winapi",
+]
+
 [[package]]
 name = "pkg-config"
 version = "0.3.19"
@@ -336,6 +395,12 @@ dependencies = [
  "crossbeam-utils",
 ]
 
+[[package]]
+name = "scopeguard"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d29ab0c6d3fc0ee92fe66e2d99f700eab17a8d57d1c1d3b748380fb20baa78cd"
+
 [[package]]
 name = "signal-hook"
 version = "0.1.16"
@@ -356,6 +421,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "smallvec"
+version = "1.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fbee7696b84bbf3d89a1c2eccff0850e3047ed46bfcd2e92c29a2d074d57e252"
+
 [[package]]
 name = "strum"
 version = "0.8.0"
@@ -379,7 +450,9 @@ dependencies = [
  "directories",
  "evdev-rs",
  "hidapi",
+ "lazy_static",
  "notify-rust",
+ "parking_lot",
  "signal-hook",
 ]
 

Cargo.toml

@@ -9,5 +9,7 @@ directories = "3.0"
 # master includes a PR that implements `Send` for `Device` and `UInputDevice`
 evdev-rs = { git = "https://github.com/ndesh26/evdev-rs.git", rev = "8e995b8bf" }
 hidapi = { version = "1.2.3", default-features = false, features = ["linux-shared-hidraw"] }
+lazy_static = "1.4"
 notify-rust = "4"
+parking_lot = "0.11.0"
 signal-hook = "0.1.16"

src/controller/controls/mod.rs

@@ -2,6 +2,7 @@ mod media;
 mod null;
 mod paddle;
 mod scroll;
+mod scroll_mt;
 mod volume;
 mod zoom;
 
@@ -9,5 +10,6 @@ pub use self::media::*;
 pub use self::null::*;
 pub use self::paddle::*;
 pub use self::scroll::*;
+pub use self::scroll_mt::*;
 pub use self::volume::*;
 pub use self::zoom::*;

src/controller/controls/scroll_mt.rs

@@ -0,0 +1,61 @@
+use crate::controller::{ControlMode, ControlModeMeta};
+use crate::dial_device::DialHaptics;
+use crate::fake_input::FakeInput;
+use crate::DynResult;
+
+pub struct ScrollMT {
+    acc_delta: i32,
+
+    fake_input: FakeInput,
+}
+
+impl ScrollMT {
+    pub fn new() -> ScrollMT {
+        ScrollMT {
+            acc_delta: 0,
+            fake_input: FakeInput::new(),
+        }
+    }
+}
+
+impl ControlMode for ScrollMT {
+    fn meta(&self) -> ControlModeMeta {
+        ControlModeMeta {
+            name: "Scroll",
+            icon: "input-mouse",
+        }
+    }
+
+    fn on_start(&mut self, haptics: &DialHaptics) -> DynResult<()> {
+        haptics.set_mode(false, Some(3600))?;
+        self.acc_delta = 0;
+
+        self.fake_input.scroll_mt_start()?;
+
+        Ok(())
+    }
+
+    fn on_end(&mut self, _haptics: &DialHaptics) -> DynResult<()> {
+        self.fake_input.scroll_mt_end()?;
+        Ok(())
+    }
+
+    // HACK: the button will reset the scroll event, which sometimes helps
+
+    fn on_btn_press(&mut self, _: &DialHaptics) -> DynResult<()> {
+        self.fake_input.scroll_mt_end()?;
+        Ok(())
+    }
+
+    fn on_btn_release(&mut self, _haptics: &DialHaptics) -> DynResult<()> {
+        self.fake_input.scroll_mt_start()?;
+        Ok(())
+    }
+
+    fn on_dial(&mut self, _: &DialHaptics, delta: i32) -> DynResult<()> {
+        self.acc_delta += delta;
+        self.fake_input.scroll_mt_step(self.acc_delta)?;
+
+        Ok(())
+    }
+}

src/fake_input.rs

@@ -2,12 +2,13 @@ use std::io;
 
 use evdev_rs::enums::*;
 use evdev_rs::{Device, InputEvent, TimeVal, UInputDevice};
+use parking_lot::ReentrantMutex;
 
-static mut FAKE_INPUT: Option<UInputDevice> = None;
+lazy_static::lazy_static! {
-fn get_fake_input() -> io::Result<&'static UInputDevice> {
+    static ref FAKE_KEYBOARD: ReentrantMutex<UInputDevice> = {
-    if unsafe { FAKE_INPUT.is_none() } {
+        (|| -> io::Result<_> {
             let device = Device::new().unwrap();
-        device.set_name("Surface Dial Virtual Input");
+            device.set_name("Surface Dial Virtual Keyboard/Mouse");
 
             device.enable(&EventType::EV_SYN)?;
             device.enable(&EventCode::EV_SYN(EV_SYN::SYN_REPORT))?;
@@ -41,15 +42,82 @@ fn get_fake_input() -> io::Result<&'static UInputDevice> {
                 device.enable(&EventCode::EV_REL(EV_REL::REL_WHEEL_HI_RES))?;
             }
 
-        unsafe { FAKE_INPUT = Some(UInputDevice::create_from_device(&device)?) }
+            Ok(ReentrantMutex::new(UInputDevice::create_from_device(&device)?))
+        })().expect("failed to install virtual mouse/keyboard device")
+    };
+
+    static ref FAKE_TOUCHPAD: ReentrantMutex<UInputDevice> = {
+        (|| -> io::Result<_> {
+            let device = Device::new().unwrap();
+            device.set_name("Surface Dial Virtual Touchpad");
+
+            device.enable(&InputProp::INPUT_PROP_BUTTONPAD)?;
+            device.enable(&InputProp::INPUT_PROP_POINTER)?;
+
+            device.enable(&EventType::EV_SYN)?;
+            device.enable(&EventCode::EV_SYN(EV_SYN::SYN_REPORT))?;
+
+            device.enable(&EventType::EV_KEY)?;
+            {
+                device.enable(&EventCode::EV_KEY(EV_KEY::BTN_LEFT))?;
+                device.enable(&EventCode::EV_KEY(EV_KEY::BTN_TOOL_FINGER))?;
+                device.enable(&EventCode::EV_KEY(EV_KEY::BTN_TOUCH))?;
+                device.enable(&EventCode::EV_KEY(EV_KEY::BTN_TOOL_DOUBLETAP))?;
+                device.enable(&EventCode::EV_KEY(EV_KEY::BTN_TOOL_TRIPLETAP))?;
+                device.enable(&EventCode::EV_KEY(EV_KEY::BTN_TOOL_QUADTAP))?;
             }
-    unsafe { Ok(FAKE_INPUT.as_ref().unwrap()) }
+
+            // roughly copied from my laptop's trackpad (Aero 15x)
+            device.enable(&EventType::EV_ABS)?;
+            {
+                let mut abs_info = evdev_rs::AbsInfo {
+                    value: 0,
+                    minimum: 0,
+                    maximum: 0,
+                    fuzz: 0,
+                    flat: 0,
+                    resolution: 0,
+                };
+
+                abs_info.minimum = 0;
+                abs_info.maximum = 4;
+                device.enable_event_code(&EventCode::EV_ABS(EV_ABS::ABS_MT_SLOT), Some(&abs_info))?;
+
+                abs_info.minimum = 0;
+                abs_info.maximum = 65535;
+                device.enable_event_code(
+                    &EventCode::EV_ABS(EV_ABS::ABS_MT_TRACKING_ID),
+                    Some(&abs_info),
+                )?;
+
+                // higher = more sensitive
+                const SENSITIVITY: i32 = 64;
+
+                abs_info.minimum = 0;
+                abs_info.maximum = std::i32::MAX;
+                abs_info.resolution = SENSITIVITY;
+                device.enable_event_code(
+                    &EventCode::EV_ABS(EV_ABS::ABS_MT_POSITION_X),
+                    Some(&abs_info),
+                )?;
+
+                abs_info.minimum = 0;
+                abs_info.maximum = std::i32::MAX;
+                abs_info.resolution = SENSITIVITY;
+                device.enable_event_code(
+                    &EventCode::EV_ABS(EV_ABS::ABS_MT_POSITION_Y),
+                    Some(&abs_info),
+                )?;
+            }
+
+            Ok(ReentrantMutex::new(UInputDevice::create_from_device(&device)?))
+        })().expect("failed to install virtual touchpad device")
+    };
+
 }
 
 #[non_exhaustive]
-pub struct FakeInput {
+pub struct FakeInput {}
-    uinput: &'static UInputDevice,
-}
 
 macro_rules! input_event {
     ($type:ident, $code:ident, $value:expr) => {
@@ -70,14 +138,11 @@ impl Default for FakeInput {
 
 impl FakeInput {
     pub fn new() -> FakeInput {
-        FakeInput {
+        FakeInput {}
-            uinput: get_fake_input().expect("could not install fake input device"),
-        }
     }
 
-    fn syn_report(&self) -> io::Result<()> {
+    fn kbd_syn_report(&self) -> io::Result<()> {
-        self.uinput
+        (FAKE_KEYBOARD.lock()).write_event(&input_event!(EV_SYN, SYN_REPORT, 0))
-            .write_event(&input_event!(EV_SYN, SYN_REPORT, 0))
     }
 
     pub fn key_click(&self, keys: &[EV_KEY]) -> io::Result<()> {
@@ -87,34 +152,40 @@ impl FakeInput {
     }
 
     pub fn key_press(&self, keys: &[EV_KEY]) -> io::Result<()> {
+        let keyboard = FAKE_KEYBOARD.lock();
+
         for key in keys {
-            self.uinput.write_event(&InputEvent {
+            keyboard.write_event(&InputEvent {
                 time: TimeVal::new(0, 0),
                 event_code: EventCode::EV_KEY(*key),
                 event_type: EventType::EV_KEY,
                 value: 1,
             })?;
         }
-        self.syn_report()?;
+        self.kbd_syn_report()?;
         Ok(())
     }
 
     pub fn key_release(&self, keys: &[EV_KEY]) -> io::Result<()> {
+        let keyboard = FAKE_KEYBOARD.lock();
+
         for key in keys.iter().clone() {
-            self.uinput.write_event(&InputEvent {
+            keyboard.write_event(&InputEvent {
                 time: TimeVal::new(0, 0),
                 event_code: EventCode::EV_KEY(*key),
                 event_type: EventType::EV_KEY,
                 value: 0,
             })?;
         }
-        self.syn_report()?;
+        self.kbd_syn_report()?;
         Ok(())
     }
 
     pub fn scroll_step(&self, dir: ScrollStep) -> io::Result<()> {
+        let keyboard = FAKE_KEYBOARD.lock();
+
         // copied from my razer blackwidow chroma mouse
-        self.uinput.write_event(&InputEvent {
+        keyboard.write_event(&InputEvent {
             time: TimeVal::new(0, 0),
             event_code: EventCode::EV_REL(EV_REL::REL_WHEEL),
             event_type: EventType::EV_REL,
@@ -123,7 +194,7 @@ impl FakeInput {
                 ScrollStep::Up => 1,
             },
         })?;
-        self.uinput.write_event(&InputEvent {
+        keyboard.write_event(&InputEvent {
             time: TimeVal::new(0, 0),
             event_code: EventCode::EV_REL(EV_REL::REL_WHEEL_HI_RES),
             event_type: EventType::EV_REL,
@@ -132,11 +203,89 @@ impl FakeInput {
                 ScrollStep::Up => 120,
             },
         })?;
-        self.syn_report()?;
+        self.kbd_syn_report()?;
+        Ok(())
+    }
+
+    fn touch_syn_report(&self) -> io::Result<()> {
+        (FAKE_TOUCHPAD.lock()).write_event(&input_event!(EV_SYN, SYN_REPORT, 0))
+    }
+
+    pub fn scroll_mt_start(&self) -> io::Result<()> {
+        let touchpad = FAKE_TOUCHPAD.lock();
+
+        {
+            touchpad.write_event(&input_event!(EV_ABS, ABS_MT_SLOT, 0))?;
+            touchpad.write_event(&input_event!(EV_ABS, ABS_MT_TRACKING_ID, 1))?;
+            touchpad.write_event(&input_event!(EV_ABS, ABS_MT_POSITION_X, MT_BASELINE))?;
+            touchpad.write_event(&input_event!(EV_ABS, ABS_MT_POSITION_Y, MT_BASELINE))?;
+
+            touchpad.write_event(&input_event!(EV_KEY, BTN_TOUCH, 1))?;
+            touchpad.write_event(&input_event!(EV_KEY, BTN_TOOL_FINGER, 1))?;
+
+            touchpad.write_event(&input_event!(EV_ABS, ABS_X, MT_BASELINE))?;
+            touchpad.write_event(&input_event!(EV_ABS, ABS_Y, MT_BASELINE))?;
+        }
+
+        self.touch_syn_report()?;
+
+        {
+            touchpad.write_event(&input_event!(EV_ABS, ABS_MT_SLOT, 1))?;
+            touchpad.write_event(&input_event!(EV_ABS, ABS_MT_TRACKING_ID, 2))?;
+            touchpad.write_event(&input_event!(EV_ABS, ABS_MT_POSITION_X, std::i32::MAX / 3))?;
+            touchpad.write_event(&input_event!(EV_ABS, ABS_MT_POSITION_Y, MT_BASELINE))?;
+
+            touchpad.write_event(&input_event!(EV_KEY, BTN_TOOL_FINGER, 0))?;
+            touchpad.write_event(&input_event!(EV_KEY, BTN_TOOL_DOUBLETAP, 1))?;
+        }
+
+        self.touch_syn_report()?;
+
+        Ok(())
+    }
+
+    pub fn scroll_mt_step(&self, delta: i32) -> io::Result<()> {
+        let touchpad = FAKE_TOUCHPAD.lock();
+
+        touchpad.write_event(&input_event!(EV_ABS, ABS_MT_SLOT, 0))?;
+        touchpad.write_event(&input_event!(
+            EV_ABS,
+            ABS_MT_POSITION_Y,
+            MT_BASELINE + delta
+        ))?;
+        touchpad.write_event(&input_event!(EV_ABS, ABS_MT_SLOT, 1))?;
+        touchpad.write_event(&input_event!(
+            EV_ABS,
+            ABS_MT_POSITION_Y,
+            MT_BASELINE + delta
+        ))?;
+
+        touchpad.write_event(&input_event!(EV_ABS, ABS_Y, MT_BASELINE + delta))?;
+
+        self.touch_syn_report()?;
+
+        Ok(())
+    }
+
+    pub fn scroll_mt_end(&self) -> io::Result<()> {
+        let touchpad = FAKE_TOUCHPAD.lock();
+
+        touchpad.write_event(&input_event!(EV_ABS, ABS_MT_SLOT, 0))?;
+        touchpad.write_event(&input_event!(EV_ABS, ABS_MT_TRACKING_ID, -1))?;
+        touchpad.write_event(&input_event!(EV_ABS, ABS_MT_SLOT, 1))?;
+        touchpad.write_event(&input_event!(EV_ABS, ABS_MT_TRACKING_ID, -1))?;
+
+        touchpad.write_event(&input_event!(EV_KEY, BTN_TOUCH, 0))?;
+        touchpad.write_event(&input_event!(EV_KEY, BTN_TOOL_DOUBLETAP, 0))?;
+
+        self.touch_syn_report()?;
+
         Ok(())
     }
 }
 
+const MT_BASELINE: i32 = std::i32::MAX / 2;
+
 pub enum ScrollStep {
     Up,
     Down,

src/main.rs

@@ -62,8 +62,8 @@ fn main() {
         println!("{}", e);
     }
 
-    kill_notif_tx.send(None).unwrap(); // silently shut down
+    let _ = kill_notif_tx.send(None); // silently shut down
-    handle.join().unwrap();
+    let _ = handle.join();
 }
 
 fn true_main(kill_notif_tx: mpsc::Sender<Option<(String, &'static str)>>) -> DynResult<()> {
@@ -78,9 +78,10 @@ fn true_main(kill_notif_tx: mpsc::Sender<Option<(String, &'static str)>>) -> Dyn
         let signals = Signals::new(&[SIGTERM, SIGINT]).unwrap();
         for sig in signals.forever() {
             eprintln!("received signal {:?}", sig);
-            kill_notif_tx
+            match kill_notif_tx.send(Some(("Terminated!".into(), "dialog-warning"))) {
-                .send(Some(("Terminated!".into(), "dialog-warning")))
+                Ok(_) => {}
-                .unwrap();
+                Err(_) => std::process::exit(1),
+            }
         }
     });
 
@@ -88,6 +89,7 @@ fn true_main(kill_notif_tx: mpsc::Sender<Option<(String, &'static str)>>) -> Dyn
         dial,
         cfg.last_mode,
         vec![
+            // Box::new(controller::controls::ScrollMT::new()),
             Box::new(controller::controls::Scroll::new()),
             Box::new(controller::controls::Zoom::new()),
             Box::new(controller::controls::Volume::new()),