Add GetMainId and IsMain function support

robotgo.go

@@ -215,6 +215,11 @@ func GetMouseColor(displayId ...int) string {
 	return GetPixelColor(x, y, displayId...)
 }
 
+// IsMain is main display
+func IsMain(displayId int) bool {
+	return displayId == GetMainId()
+}
+
 func displayIdx(id ...int) int {
 	display := -1
 	if DisplayID != -1 {

robotgo_mac.go

@@ -0,0 +1,24 @@
+// Copyright 2016 The go-vgo Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// https://github.com/go-vgo/robotgo/blob/master/LICENSE
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+//go:build darwin
+// +build darwin
+
+package robotgo
+
+/*
+#include <CoreGraphics/CoreGraphics.h>
+*/
+import "C"
+
+// GetMianId get the main display id
+func GetMainId() int {
+	return int(C.CGMainDisplayID())
+}

robotgo_win.go

@@ -42,8 +42,8 @@ func SendMsg(hwnd win.HWND, msg uint32, wParam, lParam uintptr) uintptr {
 	return win.SendMessage(hwnd, msg, wParam, lParam)
 }
 
-// SetActiveWindow set window active with hwnd
+// SetActive set window active with hwnd
-func SetActiveWindow(hwnd win.HWND) win.HWND {
+func SetActive(hwnd win.HWND) win.HWND {
 	return win.SetActiveWindow(hwnd)
 }
 
@@ -52,6 +52,16 @@ func SetFocus(hwnd win.HWND) win.HWND {
 	return win.SetFocus(hwnd)
 }
 
+// GetMian get the main display hwnd
+func GetMain() win.HWND {
+	return win.GetActiveWindow()
+}
+
+// GetMianId get the main display id
+func GetMainId() int {
+	return int(GetMain())
+}
+
 // ScaleF get the system scale val
 func ScaleF(displayId ...int) (f float64) {
 	if len(displayId) > 0 && displayId[0] != -1 {

robotgo_x11.go

@@ -191,6 +191,25 @@ func DisplaysNum() int {
 	return int(reply.Number)
 }
 
+// GetMianId get the main display id
+func GetMainId() int {
+	conn, err := xgb.NewConn()
+	if err != nil {
+		return -1
+	}
+
+	setup := xproto.Setup(conn)
+	defaultScreen := setup.DefaultScreen(conn)
+	id := -1
+	for i, screen := range setup.Roots {
+		if defaultScreen.Root == screen.Root {
+			id = i
+			break
+		}
+	}
+	return id
+}
+
 // Alert show a alert window
 // Displays alert with the attributes.
 // If cancel button is not given, only the default button is displayed