Mouse scroll events are properly compressed and summed up

backends/x/event.go

@@ -8,6 +8,23 @@ import "github.com/jezek/xgbutil/xevent"
 
 import "git.tebibyte.media/sashakoshka/stone"
 
+type scrollSum struct {
+	x, y int
+}
+
+func (sum *scrollSum) add (button xproto.Button) {
+	switch button {
+	case 4:
+		sum.y --
+	case 5:
+		sum.y ++
+	case 6:
+		sum.x --
+	case 7:
+		sum.x ++
+	}
+}
+
 func (backend *Backend) Run () {
 	backend.callbackManager.RunStart()
 	backend.Draw()
@@ -69,16 +86,10 @@ func (backend *Backend) handleButtonPress (
 ) {
 	buttonEvent := *event.ButtonPressEvent
 	if buttonEvent.Detail >= 4 && buttonEvent.Detail <= 7 {
-		switch buttonEvent.Detail {
-		case 4:
-			backend.callbackManager.RunScroll(0, -1)
-		case 5:
-			backend.callbackManager.RunScroll(0, 1)
-		case 6:
-			backend.callbackManager.RunScroll(-1, 0)
-		case 7:
-			backend.callbackManager.RunScroll(1, 0)
-		}
+		sum := scrollSum { }
+		sum.add(buttonEvent.Detail)
+		backend.compressScrollSum(&sum)
+		backend.callbackManager.RunScroll(sum.x, sum.y)
 	} else {
 		backend.callbackManager.RunPress(stone.Button(buttonEvent.Detail + 127))
 	}
@@ -170,3 +181,23 @@ func (backend *Backend) compressMotionNotify (
 
 	return
 }
+
+func (backend *Backend) compressScrollSum (sum *scrollSum) {
+	backend.connection.Sync()
+	xevent.Read(backend.connection, false)
+	
+	
+	for index, untypedEvent := range xevent.Peek(backend.connection) {
+		if untypedEvent.Err != nil { continue }
+		
+		typedEvent, ok := untypedEvent.Event.(xproto.ButtonPressEvent)
+		if !ok { continue }
+
+		sum.add(typedEvent.Detail)
+		defer func (index int) {
+			xevent.DequeueAt(backend.connection, index)
+		} (index)
+	}
+
+	return
+}