Microsoft has big display plans for Windows 8, David Washington, a senior program manager on the Windows 8 User Experience team, in a March 21 blog post explained in more depth the choices Microsoft made in enabling its coming operating system to scale to differently sized and more pixel-rich screens.
"There's a ton of innovation in the world of displays--from pixel density, to aspect ratio, to core technologies. Windows 8 is designed to grow and improve as the display ecosystem grows and improves. Our goal is to support the broadest range of display technologies so PC makers can build PCs or you can use external displays that provide the best experience for your needs. To do this, we architected the WinRT to provide the platform necessary to support this diversity," blogged David.
He notes, "Windows 8 will power all these PCs and experiences, and as people transition between different sized screens in their day-to-day lives, they will be greeted with a consistent and familiar experience. This breadth of hardware choice is unique to Windows and is central to how we see Windows evolving."
Adding, "In Windows 8, apps power the user experience, so providing a development platform that makes it easy for developers to create a beautiful user interface that scales to all screens is paramount. For this primary reason, Windows 8 was engineered from the ground up to be a platform for making great apps that work on a variety of screens," he said.
Looking at the breadth of devices that will run Windows 8, we can classify their screens in several ways.
- Screen size: There will be PCs with different screen sizes, from the smaller screens on tablets, to medium sized laptops, and large desktops and all-in-ones. These screens will also come in different shapes or aspect ratios.
- Screen resolution: Screens will have an increasing number of pixels on screen, or screen resolution. In general, the larger the screen, the higher the screen resolution, but this isn't always the case.
- Pixel density: Screens will also have different pixel densities, which is the number of pixels within a physical area, or dots per inch (DPI.) The pixel density increases as the screen resolution increases, but the screen size remains constant.
"For users, Windows 8 offers an experience that is predictable and consistent across devices. On larger screens, they can see more content in each app. On higher pixel-density screens, they get a crisp, premium experience that is easy to read and easy to interact with via touch or keyboard and mouse," said David.
"For developers, Windows 8 makes it easy to support different screen sizes and pixel densities through standards-based and well known layout techniques, and by automatically scaling to pixel density. All while allowing developers to tailor their experiences to be great on each form factor," he added.
He said back at the //build/ conference in September 2011 the minimum screen resolution that Windows 8 supported was 1024X768. The resolution that supports all the features of Windows 8, including multitasking with snap, is 1366x768.
It's not just screen resolution that plays into how an operating system and apps look as they scale; pixel density -- the number of pixels in a physical area described in dots per inch (DPI) or pixels per inch (PPI) -- matters, too.
David said many of the coming Windows 8 tablets will have pixel densities of at least 135 DPI, with some HD tablets and quad-XGA tablets going as high as 190 DPI and 253 DPI, respectively.
"Pixel densities can increase even more on lesser aspect ratios and smaller screens as we see in the new iPad," Washington noted, which sports a retina screen displaying 234 PPI, or twice the pixel density as the iPad 2, on a screen with a resolution of 2048×1536. (Apple calls these pixelly-dense displays 'retina displays.')
He also mentioned Apple and the iPad in his post stating,
"Some might be curious about the new iPad screen. For this screen, Apple has chosen a scale factor of 200%. The new screen has twice the pixel density (132 PPI to 234 PPI) on the same size screen. Because iOS and developers only need to support the predefined resolutions, they only need to design for this one additional scaling factor. In the case of iPad 2 compared to new iPad the 200% scaling factor means that what you see on 1024×768 is exactly what you see on the new resolution, only sharper because more pixels are used (as in the image of the app above). Additionally, on higher pixel-density screens like the new iPad, developers for games and other performance-critical apps may decide the right balance between letterboxing and running at a lower fidelity to deliver the best experience (frame rate, for example)."