I have a Windows Phone App for WP 8.1 (Not Windows Phone Silverlight) and I've specified all splash screen sizes in the package manifest. However, for 720p phones (like the Lumia 720) I'm getting letterboxing of the splash screen.
I've also tried adding the Windows Phone Silverlight splash screens from the documented spec, but I get the following error in the build:
MakePRI : warning 0xdef00520: Invalid qualifier: SCREEN-720P
And then I still don't get a full screen splash screen.
Is there any way to prevent this letterboxing?
I believe the only way to solve this is by making the borders of your splash screen of uniform color fill, and set that color as background color in the Package.appxmanifest, so the letterboxing is not seen.
Thing is, Windows Phone 8 and 8.1 devices come in on of four resolutions: 480x800, 720x768, 720x1768 and 1920x1080. From these you can see there are two ratios, 15:9 and 16:9. And the splash screen images you set in the manifest, are all 15:9, just for various screen densities of the 15:9 ratio. So, no way to avoid the letterboxing, as the OS obviously "fits" the splash image into the screen.