switch panels

Makefile

@@ -4,7 +4,8 @@ demos = just-text \
 	window-with-text\
 	two-windows \
 	doupdate \
-	panels
+	panels \
+	panels-switch
 demos_files = $(patsubst %, %.exe, $(demos))
 
 .PHONY: all

curses-panel.vapi

@@ -4,6 +4,14 @@ namespace Curses {
   public class Panel {
     [CCode (cname = "new_panel")]
     public Panel(Window win);
+    public void * userptr {
+      [CCode (cname = "panel_userptr")]     get;
+      [CCode (cname = "set_panel_userptr")] set;
+    }
+    [CCode (cname = "top_panel")]
+    public int top();
+    [CCode (cname = "bottom_panel")]
+    public int botton();
 
     public static void update_panels();
   }

panels-switch.vala

@@ -0,0 +1,85 @@
+using Curses;
+using Posix;
+
+public class Demo {
+  public MainLoop loop;
+  private IOChannel io_channel;
+  internal IOSource io;
+
+  public Demo() {
+    loop = new MainLoop();
+
+    io_channel = new IOChannel.unix_new(Posix.STDIN_FILENO);
+    io = new IOSource(io_channel, IOCondition.IN);
+    io.attach(loop.get_context());
+  }
+
+  public void start() {
+    initscr();
+    noecho();
+  }
+
+  public void stop() {
+    endwin();
+  }
+
+  private Window window1;
+  private Window window2;
+
+  private Panel panel1;
+  private Panel panel2;
+  public void activate() {
+    this.window1 = new Window(5, 20, 1, 1);
+    panel1 = new Panel(window1);
+    this.window1.box(0, 0);
+    this.window1.mvprintw(1, 1, "I am in window 1");
+    //this.window1.noutrefresh();
+
+    this.window2 = new Window(5, 20, 2, 19);
+    panel2 = new Panel(window2);
+    this.window2.box(0, 0);
+    this.window2.mvprintw(1, 1, "I am in window 2");
+    //this.window2.noutrefresh();
+
+    panel1.userptr = panel2;
+    panel2.userptr = panel1;
+
+    unowned Panel top_panel = panel2;
+
+    io.set_callback(() => {
+      var c = getch();
+
+      if (c == Key.F0) {
+        loop.quit();
+      } else {
+        top_panel = (Panel) top_panel.userptr;
+        top_panel.top();
+        Panel.update_panels();
+        doupdate();
+      }
+
+      return Source.CONTINUE;
+    });
+  }
+
+  public void run() {
+    loop.run();
+  }
+
+  public void redraw() {
+    Panel.update_panels();
+    doupdate();
+  }
+
+  static int main(string[] args) {
+    var app = new Demo();
+
+    app.start();
+    app.activate();
+    app.redraw();
+    app.run();
+    app.stop();
+
+    return EXIT_SUCCESS;
+  }
+}