WndProc hook for FancyZones fullscreen-in-zone

[Taloth]

Continuation from microsoft#279

[Taloth]

Do you mind posting a link to your code? I didn't see it in the comments you linked. I'll kick myself if all this effort was spent duplicating an approach someone else tried.

@peddamat I pushed it here Taloth@80ddcd0
It's 2 year old code though, and very 'work in process', I stopped working on it once I realized that DLL injection wouldn't be permitted and never get merged in.

A few differences:

• I didn't subclass windows because that's, imo, more prone to side-effects and you have to track individual windows. Instead I hook the entire process WndProc. When a relevant message comes around that requires us to change the parameters, I use a temporary injection mechanism to leapfrog into the actual WndProc, which allows you to fiddle with the actual parameters (which are readonly in the other handler). So basically 'inject when needed' not 'always inject'.
  That said, I never measured the overhead of SetWindowLong, I believe it's a wrapper function that simply sets an array value, but never checked.
• I store the x/y & sizes via SetPropW as 'short' instead of 'int'. This is important, as you only have 4 bytes on x86 processes, so can only fit two shorts.
• Had a separate x86 loader that deals with loading the hook in 32 bit processes. But I didn't (yet) bother with having the main FancyZone process starting that loader, I just did it manually.

None of what I did should be taken as 'the way to go'.

[peddamat]

Awesome, thank you. I like your lower-touch approach, I had the exact same initial idea, but thought the implementation I ended up with had less moving parts.

May or may not be true, as the side-effects that you mentioned, are brutal.

I'll take a closer look at the code and see what I can borrow.

In the end, I'm happy maintaining a fork, as all I use PowerToys for is FancyZones.

Without it, and either of my Maximize in Zone hacks, my ultrawide is useless.