Scaling Windows - The DPI Arms Race

Final Words

Windows has always had the burden of bringing forward legacy APIs and code to allow applications designed for previous versions to continue to operate on newer releases. It also supports a huge number of display sizes, screen resolutions, and form factors. Because of this, it often struggles when major changes are introduced. One such change was the new security model in Windows Vista where (finally) users were no longer administrators by default, and another such change is ultra-high resolution displays with the different goal of improving image quality rather than just increasing usable real estate on the desktop.

Windows 8.1 now officially has three different states for applications: DPI-Unaware, System DPI-Aware, and Per-Monitor DPI-Aware, and solutions are in place to handle all three. It also has a fourth unofficial state: DPI-Unaware masquerading as DPI-Aware applications. Unfortunately there is no current solution for these unofficial applications.

One interim solution would be to have a way to force such applications to scale up, and therefore ignore the DPI-aware flag set in the executable. This would allow DPI Virtualization to scale the applications as needed. This is certainly not ideal, but when you are dealing with a product like Windows with such an enormous catalog of applications, it’s necessary because many of these applications will never be updated to correct scaling issues. The correct solution is to have applications updated to take advantage of the High DPI systems to provide a better user experience, but again this doesn’t really work for legacy applications.

One of the problems holding developers back is that there have been few high resolution devices on the market, meaning few developers would even bother taking the time to correct these issues. Now that there are finally devices from virtually every single computer maker with high PPI panels, there is a market force that will hopefully pressure developers into using best coding practices for scaling DPI.

But what about the current state of things –is it worth avoiding High DPI devices until more applications work properly? My personal experience is no, it’s not worth avoiding them. This will of course depend on what applications you use, but the advantage of a high resolution display is that you can always set the resolution lower if necessary as a workaround on applications like Photoshop. The advantage is that in other applications, you can get very crisp, clear text and a fantastic display for media. Within the next year, I would imagine most major Win32 applications that are actively being developed will have to address these issues. When Apple launched the Retina MacBooks, its catalog of applications took some time to be updated; as that happens for Windows applications, the investment in a High DPI system will make even more sense.

The final piece of the puzzle is the next iteration of Windows. Already shown at BUILD were Modern apps running in a windowed mode on the desktop. These apps will of course have no issues scaling with DPI, providing the ideal “one size fits all” approach to DPI scaling. Figuring out a similar solution for legacy applications on the desktop may be a bit more difficult, but it’s certainly something Microsoft is working to address. Time will tell how well they manage to do so.

Sources:

http://blogs.windows.com/windows/b/extremewindows/archive/2013/07/15/windows-8-1-dpi-scaling-enhancements.aspx

http://msdn.microsoft.com/en-us/library/windows/desktop/dd464659(v=vs.85).aspx

http://msdn.microsoft.com/en-us/library/windows/desktop/dn469266(v=vs.85).aspx