Windows 8 finally fixes high-resolution

Windows 8

Almost certainly in response to the recent release of the Retina display-toting iPad 3, Microsoft has published details of how Windows 8 will cope with a huge range of screen resolutions and sizes, from the cheapest 1366×768 (112 PPI) laptops to 2560×1440 (291 PPI) tablets, and everything in between. At long last, Windows will gracefully deal with pixel densities above 96 PPI. Unfortunately, and much to the chagrin of dedicated, veteran Windows users, these much-needed fixes will only apply to the Metro interface, and not the conventional desktop.

Historically, Windows has been utterly atrocious at handling any display with greater than 96 PPI — but, until recently, this hasn’t posed much of a problem because displays with a pixel density over 96 PPI (the Windows default since the ’80s) have been few and far between. With the emergence of laptops that cram in 1920×1080 pixels into 14-inch displays (157 PPI), and the 2048×1536 iPad proving that tablets will soon have a PPI in 200s, Microsoft has been forced to make some changes.

Without scaling, the physical size of UI elements decrease as the PPI increases. On desktops with a mouse and keyboard (and assuming good eyesight), this doesn’t matter too much. The story is very different with touchpads (75% of all consumer Windows PCs are laptops) and touchscreens. To get around this, the operating system must zoom the interface — an icon that’s 32 pixels wide on a 96 PPI display must be scaled up to 64 pixels (for example) on higher-density displays. In the picture below you can see the effects of a PPI increase without scaling; as screen resolution increases, as does the difficulty of hitting a button with your finger.

In Windows 8, the Metro interface (the new Start Screen and Metro apps) will have three different “zoom” levels: 100%, which represents a 11.6-inch 1366×768 (112 PPI) display; 140%, which represents a 11.6-inch 1920×1080 (190 PPI) full HD display; and 180%, which represents a 11.6-inch 2560×1440 (253 PPI) WQHD display. Almost every desktop monitor falls into the 100% category (a 27-inch 2560×1440 display is only 109 PPI), while many laptops and tablets will use the 140 and 180% zoom. The Building Windows 8 blog post doesn’t mention the Desktop side of things at all, so it looks like it will be stuck with its current, crummy zoom controls

As far as developers are concerned, creating a scalable app is easy: If you provide vector graphics, Windows 8 will take care of everything for you; otherwise, you just need to provide bitmap images for each of the three zoom levels. Windows will automatically manage the scaling of interface elements. It obviously helps that Metro is made up almost entirely of rectangles and typography, both of which are easily scaled.

In effect, Windows 8 will be doing exactly what iOS has to do when scaling up original iPhone and iPad apps for the iPhone 4 or iPad 3 with a Retina display. There is one fairly sizable difference, though: With the Apple devices, because of the fixed aspect ratio and screen sizes, the image simply has to be doubled in size (scaled 200%). This is easy to do and has no risk of causing any graphical anomalies. Windows 8 doesn’t have it so easy: If you scale a 32×32-pixel icon by 140%, you end up with 44.8×44.8 — which then has to be rounded up or down to 44 or 45. It’s the same story for 180%.