Only report windows on current desktop as "visible"

data.go

@@ -92,6 +92,10 @@ type Window struct {
 	// ID is the numerical identifier of the window.
 	ID int64
 
+	// Desktop is the numerical identifier of the desktop the
+	// window belongs to.  Equal to -1 if the window is sticky.
+	Desktop int64
+
 	// Name is the display name of the window (typically what the
 	// windowing system shows in the top bar of the window).
 	Name string
@@ -118,6 +122,18 @@ func (w *Window) IsSystem() bool {
 	return false
 }
 
+// IsSticky returns true if the window is a sticky window (i.e.
+// present on all desktops)
+func (w *Window) IsSticky() bool {
+	return w.Desktop == -1
+}
+
+// IsOnDesktop returns true if the window is present on the specified
+// desktop
+func (w *Window) IsOnDesktop(desktop int64) bool {
+	return w.IsSticky() || w.Desktop == desktop
+}
+
 // Info returns more structured metadata about a window. The metadata
 // is extracted using heuristics.
 func (w *Window) Info() *Winfo {

linux.go

@@ -61,18 +61,45 @@ func (t *LinuxTracker) Snap() (*Snapshot, error) {
 			if len(fields) < 4 {
 				continue
 			}
-			id_, name := fields[0], strings.Join(fields[3:], " ")
+			id_, desktop_, name := fields[0], fields[1], strings.Join(fields[3:], " ")
 			id, err := strconv.ParseInt(id_, 0, 64)
 			if err != nil {
 				return nil, err
 			}
-			w := Window{ID: id, Name: name}
+			desktop, err := strconv.ParseInt(desktop_, 0, 64)
+			if err != nil {
+				return nil, err
+			}
+			w := Window{ID: id, Desktop: desktop, Name: name}
 			if !w.IsSystem() {
 				windows = append(windows, &w)
 			}
 		}
 	}
 
+	var currentDesktop int64
+	{
+		out, err := exec.Command("wmctrl", "-d").Output()
+		if err != nil {
+			return nil, err
+		}
+		lines := strings.Split(string(out), "\n")
+		for _, line := range lines {
+			fields := strings.Fields(line)
+			if len(fields) < 2 {
+				continue
+			}
+			id_, mode := fields[0], fields[1]
+			id, err := strconv.ParseInt(id_, 0, 64)
+			if err != nil {
+				return nil, err
+			}
+			if "*" == mode {
+				currentDesktop = id
+			}
+		}
+	}
+
 	var visible []int64
 	{
 		for _, window := range windows {
@@ -97,7 +124,7 @@ func (t *LinuxTracker) Snap() (*Snapshot, error) {
 			if err != nil {
 				return nil, err
 			}
-			if isVisible(x, y, w, h, viewHeight, viewWidth) {
+			if window.IsOnDesktop(currentDesktop) && isVisible(x, y, w, h, viewHeight, viewWidth) {
 				visible = append(visible, window.ID)
 			}
 		}