add support for "pixel-perfect" scrolling

main.go

@@ -51,6 +51,9 @@ func processCommand(plugin Plugin, command string) error {
 	if len(command) == 0 {
 		return errors.New("empty command")
 	}
+	if command == "sf" {
+		return plugin.PointerScrollFinish()
+	}
 	if command[0] == 't' {
 		text := command[1:]
 		if !utf8.ValidString(text) {

plugin.go

@@ -42,5 +42,6 @@ type Plugin interface {
 	KeyboardText(text string) error
 	PointerButton(button uint, press bool) error
 	PointerMove(deltaX, deltaY int) error
-	PointerScroll(stepsHorizontal, stepsVertical int) error
+	PointerScroll(deltaHorizontal, deltaVertical int) error
+	PointerScrollFinish() error
 }

plugin_windows.go

@@ -44,7 +44,7 @@ const (
 	mouseeventfWheel      uint32 = 0x800
 	mouseeventfHwheel     uint32 = 0x1000
 
-	wheelDelta int = 120
+	scrollMult int = 6
 )
 
 type mouseInput struct {
@@ -146,20 +146,20 @@ func (p *windowsPlugin) PointerMove(deltaX, deltaY int) error {
 	return nil
 }
 
-func (p *windowsPlugin) PointerScroll(stepsHorizontal, stepsVertical int) error {
+func (p *windowsPlugin) PointerScroll(deltaHorizontal, deltaVertical int) error {
 	inputs := make([]mouseInput, 0, 2)
-	if stepsHorizontal != 0 {
+	if deltaHorizontal != 0 {
 		inputs = append(inputs, mouseInput{
 			typ:       inputMouse,
 			dwFlags:   mouseeventfHwheel,
-			mouseData: uint32(stepsHorizontal * wheelDelta),
+			mouseData: uint32(deltaHorizontal * scrollMult),
 		})
 	}
-	if stepsVertical != 0 {
+	if deltaVertical != 0 {
 		inputs = append(inputs, mouseInput{
 			typ:       inputMouse,
 			dwFlags:   mouseeventfWheel,
-			mouseData: uint32(stepsVertical * wheelDelta),
+			mouseData: uint32(deltaVertical * scrollMult),
 		})
 	}
 	if len(inputs) == 0 {
@@ -172,3 +172,7 @@ func (p *windowsPlugin) PointerScroll(stepsHorizontal, stepsVertical int) error
 	}
 	return nil
 }
+
+func (p *windowsPlugin) PointerScrollFinish() error {
+	return nil
+}

plugin_x11.go

@@ -35,11 +35,15 @@ import (
 	"unsafe"
 )
 
-const typingDelay time.Duration = 100 * time.Millisecond
+const (
+	typingDelay time.Duration = 100 * time.Millisecond
+	scrollDiv   int           = 20
+)
 
 type x11Plugin struct {
-	display *C.Display
+	display                          *C.Display
-	lock    sync.Mutex
+	lock                             sync.Mutex
+	scrollHorizontal, scrollVertical int
 }
 
 func InitX11Plugin() (Plugin, error) {
@@ -157,7 +161,13 @@ func (p *x11Plugin) PointerMove(deltaX, deltaY int) error {
 	return nil
 }
 
-func (p *x11Plugin) PointerScroll(stepsHorizontal, stepsVertical int) error {
+func (p *x11Plugin) PointerScroll(deltaHorizontal, deltaVertical int) error {
+	p.lock.Lock()
+	stepsHorizontal := (p.scrollHorizontal + deltaHorizontal) / scrollDiv
+	stepsVertical := (p.scrollVertical + deltaVertical) / scrollDiv
+	p.scrollHorizontal = (p.scrollHorizontal + deltaHorizontal) % scrollDiv
+	p.scrollVertical = (p.scrollVertical + deltaVertical) % scrollDiv
+	p.lock.Unlock()
 	var buttonHorizontal uint = 7
 	if stepsHorizontal < 0 {
 		buttonHorizontal = 6
@@ -186,3 +196,11 @@ func (p *x11Plugin) PointerScroll(stepsHorizontal, stepsVertical int) error {
 	}
 	return nil
 }
+
+func (p *x11Plugin) PointerScrollFinish() error {
+	p.lock.Lock()
+	defer p.lock.Unlock()
+	p.scrollHorizontal = 0
+	p.scrollVertical = 0
+	return nil
+}

webdata/fn.js

@@ -20,8 +20,6 @@
  // [1 Touch, 2 Touches, 3 Touches]
 const TOUCH_MOVE_THRESHOLD = [10, 15, 15];
 const TOUCH_TIMEOUT = 250;
-const MOVE_MULT = 1;
-const SCROLL_MULT = 0.05;
 // [[px/s, mult], ...]
 const POINTER_ACCELERATION = [[0, 0], [87, 1], [173, 1], [553, 2]];
 
@@ -40,6 +38,7 @@ var scrollXSum = 0;
 var scrollYSum = 0;
 var dragging = false;
 var draggingTimeout = null;
+var scrolling = false;
 
 function fullscreenEnabled() {
     return (document.fullscreenEnabled ||
@@ -153,6 +152,7 @@ function updateMoveAndScroll() {
     if (Math.abs(scrollX) >= 1 || Math.abs(scrollY) >= 1) {
         scrollXSum -= scrollX;
         scrollYSum -= scrollY;
+        scrolling = true;
         ws.send("s" + scrollX + ";" + scrollY);
     }
 }
@@ -183,6 +183,10 @@ function handleStart(evt) {
             draggingTimeout = null;
             dragging = true;
         }
+        if (scrolling) {
+            ws.send("sf");
+            scrolling = false;
+        }
     }
 }
 
@@ -196,6 +200,10 @@ function handleEnd(evt) {
         ongoingTouches.splice(idx, 1);
         touchReleasedCount++;
         touchLastEnd = evt.timeStamp;
+        if (scrolling) {
+            ws.send("sf");
+            scrolling = false;
+        }
     }
     if (touchReleasedCount > TOUCH_MOVE_THRESHOLD.length) {
         touchMoved = true;
@@ -234,6 +242,10 @@ function handleCancel(evt) {
         touchReleasedCount++;
         touchLastEnd = evt.timeStamp;
         touchMoved = true;
+        if (scrolling) {
+            ws.send("sf");
+            scrolling = false;
+        }
     }
 }
 
@@ -261,11 +273,11 @@ function handleMove(evt) {
     }
     if (touchMoved && evt.timeStamp - touchLastEnd >= TOUCH_TIMEOUT) {
         if (ongoingTouches.length == 1 || dragging) {
-            moveXSum += sumX * MOVE_MULT;
+            moveXSum += sumX;
-            moveYSum += sumY * MOVE_MULT;
+            moveYSum += sumY;
         } else if (ongoingTouches.length == 2) {
-            scrollXSum -= sumX * SCROLL_MULT;
+            scrollXSum -= sumX;
-            scrollYSum -= sumY * SCROLL_MULT;
+            scrollYSum -= sumY;
         }
         updateMoveAndScroll();
     }