Tiling windows in Mac OS X with Slate

I hate moving windows around. I’m comfortable with a mouse and a keyboard, often at the same time. But I still hate having to move windows around. I’ve been looking for a way to replicate the functionality of tiling window managers like Awesome, dwm and xmonad on the Mac for quite some time.

There have been quite a few tools over the years, like Divvy, but I’m cheap and kept holding out for free alternatives. Spectacle was what I used for quite a while, and over time most of the engineers in the office also adopted it. It’s still not ideal, however, because windows need to be manually positioned, and the presets are quite limited.

Xnomad was a notable development, because it did succeed in replicating much of the behavior of Linux tiling window managers. However, it relied on a homegrown bastard child of Objective-C and Ruby, and you need to have that installed before the application works. I’ve a strong aversion to one-man language interfaces and additional dependencies, so this was a no-go for me.

Around this time a coworker introduced me to Slate. I was originally turned off by the need for extreme configuration, but after reading up a bit more, it turned out to have a number of very promising features:

There’s really endless possibility here, and people have set up some very complex layouts. Slate’s notion of a Layout is nice if you have a static environment, but it won’t automatically adapt to new applications. However, the configuration scheme does allow you to at least emulate automatic tiling. Here’s a basic tiling function:

var retile = function(windowObject) {
  var windows = [];
  slate.eachApp(function(app) {
    app.eachWindow(function(win) {
      if (win.isMinimizedOrHidden()) return;
      if (null == win.title() || win.title() === "") return;

  var ss          = s.rect();
  var windowSizeX = ss.width * 0.4;
  var windowSizeY = ss.height / (windows.length - 1);
  var winPosY     = 0;

  for (i = 0; i < windows.length; i++) {
    w = windows[i];

    if (w.title() == windowObject.title()) {
      mainWidth = (windows.length > 1) ? "screenSizeX*0.6" : "screenSizeX";

      w.doOperation("move", {
        "x": "screenOriginX",
        "y": "screenOriginY",
        "width": mainWidth,
        "height": "screenSizeY"
    else {
      w.doOperation("move", {
        "x": "screenSizeX*0.6",
        "y": winPosY,
        "width": windowSizeX,
        "height": windowSizeY

      winPosY += windowSizeY;

// Basic keybinds
  "f:cmd,alt": slate.op("move", {"x": "screenOriginX", "y": "screenOriginY",
    "width": "screenSizeX", "height": "screenSizeY"}),
  "left:cmd,alt": slate.op("push", {"direction": "left", "style":
  "right:cmd,alt": slate.op("push", {"direction": "right", "style":

  "r:cmd,alt": retile,
  "w:alt": slate.op("hint"),

Hitting Cmd+Opt+r will tile all windows on the current screen/space so that they don’t overlap. A single window will be full-screened, and additional windows will start to divide up the screen space. I’m keeping the notion of a “master” window from dwm/Awesome/scrotwm, and the way things work right now, the currently focused window is promoted to the master.

Now, let’s see about automatically calling the retile function on window events. Turns out, this is pretty simple:

slate.on("windowOpened", function(event, win) { retile(win); });
slate.on("windowClosed", function(event, win) { retile(win); });
slate.on("appOpened", function(event, win) { retile(win); });
slate.on("appClosed", function(event, win) { retile(win); });
slate.on("appHidden", function(event, win) { retile(win); });
slate.on("appUnhidden", function(event, win) { retile(win); });

That’s all there is to it, with a couple limitations. The Javascript API won’t let you inspect things like AXRole or AXSubrole in the Objective-C world, which means you won’t necessarily be able to distinguish between dialog boxes and primary application windows. Slate also isn’t Spaces aware, which is a bit of a problem for a virtual desktop junkie like me.

It’s a great start, however, and if I get the chance I’ll see about adding in the hooks needed for even better tiling support. Or, you could beat me to it.