split scroll/zoom into two modes

accidentally switching to zoom mode ended up being pretty annoying

src/controller/controls/scroll.rs

@@ -0,0 +1,50 @@
+use crate::controller::{ControlMode, ControlModeMeta};
+use crate::dial_device::DialHaptics;
+use crate::fake_input::{FakeInput, ScrollStep};
+use crate::DynResult;
+
+pub struct Scroll {
+    fake_input: FakeInput,
+}
+
+impl Scroll {
+    pub fn new() -> Scroll {
+        Scroll {
+            fake_input: FakeInput::new(),
+        }
+    }
+}
+
+impl ControlMode for Scroll {
+    fn meta(&self) -> ControlModeMeta {
+        ControlModeMeta {
+            name: "Scroll",
+            icon: "input-mouse",
+        }
+    }
+
+    fn on_start(&mut self, haptics: &DialHaptics) -> DynResult<()> {
+        haptics.set_mode(false, Some(90))?;
+        Ok(())
+    }
+
+    fn on_btn_press(&mut self, _: &DialHaptics) -> DynResult<()> {
+        Ok(())
+    }
+
+    fn on_btn_release(&mut self, _haptics: &DialHaptics) -> DynResult<()> {
+        Ok(())
+    }
+
+    fn on_dial(&mut self, _: &DialHaptics, delta: i32) -> DynResult<()> {
+        if delta > 0 {
+            eprintln!("scroll down");
+            self.fake_input.scroll_step(ScrollStep::Down)?;
+        } else {
+            eprintln!("scroll up");
+            self.fake_input.scroll_step(ScrollStep::Up)?;
+        }
+
+        Ok(())
+    }
+}