Apple Watch Screen Resolution, App Limitations are Laid Bare by Developer Kit

Apple, Inc. (AAPL) today let many a metaphorical cat out of the metaphorical bag with its introduction of the Apple Watch software development kit (SDK), a collection of APIs used to program for the device.  It calls the new SDK the “Apple Watchkit” and it hopes the early release will help developers start baking apps in the simulator in advance of its wearable’s market entrance early next year.

Here’s among the discoveries

  • Display
    • Two 4:5 aspect ratio Retina display sizes
      • 272 x 340 pixel for the 38 mm watch face
      • 312 x 390 pixel for the 42 mm face


  • Battery Life and Apps
    • Current generation apps must do most of their processing on the iPhone (this likely saves battery).
    • Current generation apps are limited in their layout and graphics
      • Up to 20 MB of images can be stored on device
      • Programmatic GIF like animation coding is an option.
      • Video is not supported (yet).
      • You may add more imagery to the iPhone site, to serve to the device.
      • App UIs are laid out in visual layout code that’s nested and non-specific. In other words you tell it to draw text ABC inside object D, not to draw ABC at coordinates <20,20>, like on the iPhone
    • Native apps will be coming next year (presumably with direct rendering at given coordinates)
    • Apps have two kinds of notification actions.
      • Short look
        • Happens when user raises wrist to response to notification tap
      • Long look
        • If the user’s eyes are detected to be on the watch for a prolonged time, a longer notification, including, optionally, a menu of actions is displayed.
    • Glances
      • Single screen read-only information display tiles.
  • UI
    • Font
      • “San Francisco”


      • Does not scale directly, resizes dependently to preserve delicate features like punctuation
    • Gestures
      • Swipe up or down — Scroll up/down in current page
      • “Digital Crown” turn — fast scroll up or down in current page
      • Swipe left or right — Scroll between pages
      • Tap — selection
      • Force Touch — open context menu (up to 4 options, developer specified)
      • Edge swipe up — Go to “Glance” view
      • Edge swipe left — Goes back or up a page
  • Miscellaneous
    • Air Play transfers are supported
    • Third party support via API only provides static, non scrollable maps.  Users can click map to enter dynamic Apple Maps app, though

All things said, there’s some clever bits and interest themes here.  Android smartwatch may look to borrow some of the features, much as Apple surely has borrowed an idea or two from its Android smatwatch predecessors (or at least learned from their errors).  The Apple Watch will be priced at $349 USD and up, depending on the hardware model.