Add getMonitorFromWindow and getScaleFactor methods

Author: sentialx

src/bindings/windows.ts

@@ -47,7 +47,9 @@ export const user32 = new ffi.Library("User32.dll", {
   // https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-bringwindowtotop
   SetForegroundWindow: ["bool", ["int64"]],
   // https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-setlayeredwindowattributes
-  SetLayeredWindowAttributes: ["bool", ["int64", "int", "int", "int64"]]
+  SetLayeredWindowAttributes: ["bool", ["int64", "int", "int", "int64"]],
+  // https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-monitorfromwindow
+  MonitorFromWindow: ["int64", ["int64", "int64"]]
 });
 
 export const kernel32 = new ffi.Library("kernel32", {
@@ -62,6 +64,10 @@ export const kernel32 = new ffi.Library("kernel32", {
   ]
 });
 
+export const shellScaling = new ffi.Library("SHCore.dll", {
+  GetScaleFactorForMonitor: ["int64", ["int64", "int*"]]
+});
+
 export const getProcessId = (handle: number) => {
   const processIdBuffer = ref.alloc("uint32");
   user32.GetWindowThreadProcessId(handle, processIdBuffer);
@@ -120,3 +126,5 @@ export const getWindowBounds = (handle: number) => {
     height: bounds.bottom - bounds.top
   };
 };
+
+export const getScaleFactor = (handle: number) => {};

src/classes/window.ts

@@ -4,9 +4,12 @@ import {
   getProcessPath,
   getWindowBounds,
   getWindowTitle,
-  user32
+  user32,
+  shellScaling,
+  getScaleFactor
 } from "../bindings/windows";
 import { basename } from "path";
+import { windowManager } from "..";
 
 const ffi = require("ffi");
 
@@ -58,6 +61,7 @@ export class Window {
 
   setBounds(bounds: Rectangle) {
     const { x, y, height, width } = { ...this.getBounds(), ...bounds };
+
     user32.MoveWindow(this.handle, x, y, width, height, true);
   }
 

src/index.ts

@@ -1,8 +1,13 @@
 import { Window } from "./classes/window";
 import { EventEmitter } from "events";
-import { getActiveWindowHandle, user32 } from "./bindings/windows";
+import {
+  getActiveWindowHandle,
+  user32,
+  shellScaling
+} from "./bindings/windows";
 
 const ffi = require("ffi");
+const ref = require("ref");
 
 let interval: any = null;
 
@@ -61,6 +66,17 @@ class WindowManager extends EventEmitter {
     user32.EnumWindows(callback, 0);
     return windows;
   };
+
+  getMonitorFromWindow = (window: Window) => {
+    return user32.MonitorFromWindow(window.handle, 0);
+  };
+
+  getScaleFactor = (monitor: number) => {
+    const sfRef = ref.alloc("int");
+    shellScaling.GetScaleFactorForMonitor(monitor, sfRef);
+
+    return sfRef.deref() / 100;
+  };
 }
 
 const windowManager = new WindowManager();