(#3) Added macOS implementation of configurable, transparent highlight window

Author: s1hofmann

src/window.h

@@ -0,0 +1,17 @@
+#pragma once
+#ifndef WINDOW_H
+#define WINDOW_H
+
+class Window {
+    public:
+        Window(int x, int y, int width, int height);
+        void show(int duration, float opacity);
+
+    private:
+        int _x;
+        int _y;
+        int _width;
+        int _height;
+};
+
+#endif

src/window_macos.mm

@@ -0,0 +1,33 @@
+#include "window.h"
+#import <Cocoa/Cocoa.h>
+
+
+Window::Window(int x, int y, int width, int height) {
+    this->_x = x;
+    this->_y = y;
+    this->_width = width;
+    this->_height = height;
+}
+
+void Window::show(int duration, float opacity) {
+    NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
+    [NSApplication sharedApplication];
+
+    NSRect frame = NSMakeRect(this->_x, this->_y, this->_width, this->_height);
+    NSUInteger styleMask = NSWindowStyleMaskBorderless;
+    NSWindow * window =  [[[NSWindow alloc] initWithContentRect:frame styleMask:styleMask backing:NSBackingStoreBuffered defer:NO] autorelease];
+    [window setBackgroundColor:[NSColor redColor]];
+    [window setAlphaValue:opacity];
+    [window orderFrontRegardless];
+
+    [NSTimer scheduledTimerWithTimeInterval: duration
+                repeats: NO
+                block: ^(NSTimer * timer){
+                [NSApp stop:0];
+                NSRect f = [window frame];
+                f.size = CGSizeMake(0, 0);
+                [window setFrame: f display: YES animate: NO];
+            }];
+    [NSApp run];
+    [pool release];
+}