Nearest Neighbour Scaling not working with Windows 10 Scaling

[gameshistory]

If I set my Windows 10 Display Scaling to 100%, the nearest neighbour scaling works perfectly.
But if I set it to any other value (I normally use 150%), the image starts to blur.

Here is a comparison: https://i.imgur.com/F3diLIj.png

On the left is SDLPoP with 100% scaling. On the right is SDLPoP with 125% scaling.

If you zoom in, you can see that the left is crisp, while the right is blurry.

[NagyD]

Here's a workaround:
Right-click on prince.exe, click Properties, go to the Compatibility tab, click the High DPI settings button, enable override, and select "Application".
This should disable the bitmap-stretching that Windows does after SDLPoP has already scaled the image.

Notes:

• This issue is similar to integer scaling on a Mac Retina screen #173, in that the application can't use the full pixel density of the screen without specifically asking for it.
• This behavior could be made default by including an appropriate manifest in the EXE.
  @Falcury, do you think it's a good idea? (By the way, DOSBox does the same, although without a manifest.)

[Falcury]

I'll try to look into this. Maybe SDL_GetRendererOutputSize() will be of help in some way (see for example here).

[Falcury]

Maybe SDL_GetRendererOutputSize() will be of help

Ah, no, I was wrong, it does not look like something that an SDL call can fix.
However, instead of using a manifest you can apparently also call a Windows API to get the same effect:
https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-setprocessdpiaware?redirectedfrom=MSDN

Calling one of the APIs directly (e.g. SetProcessDPIAware) seems to be the easier method.
Although Microsoft for some reason recommends the manifest approach (I have no clue why).

I made a pull request for the API in #192

[NagyD]

I've merged the pull request.

@i-hate-drm2, can you compile the source for yourself to try it?