learning.md

4)

Today i was able to use multiple windows of the explorer to display 3 mpv video (1 each screen) but the problem was that the mpvs were behind the taskbar but in front of the desktop icons..

i need to learn more about how this works..

3)

I found a way to use a WorkerW to display mpv behind desktop icons, got some graphical bugs but i think i understood & fixed thoses.

I still don't know if there is a way to display multiple mpv for multiple screens. WorkerW is only one window for all the screens connected to the machine (hence it's size & position).

For a triple screen setup:

Monitor position: (0, 0), size: 1920 x 1080

Monitor position: (1920, 0), size: 1366 x 768

Monitor position: (-1280, 0), size: 1024 x 819

It's size is x-1280, y0, w4566, h1080.

2)

Then i checked livewallpaper which was very interesting.

it uses mpv to display a video in background

Might be a good idea to test this route

1)

The only thing that is currently holding me from doing it is taht i don't have a stable method to set a different wallpaper on each screen on windows

i checked more-wallpapers but the feature im looking for is not available on windows

While reading the Lively source code

I found

public void SetWallpaper(ILibraryModel wallpaper, IDisplayMonitor display)

Line 97

Which calls SendMessageTimeout at Line 115

With the comment // Send 0x052C to Progman. This message directs Progman to spawn a WorkerW behind the desktop icons. If it is already there, nothing happens. progman = program manager. Microsoft docs says Sends the specified message to one or more windows. about this SendMessageTimeout function

Lively uses this function to create a window behind the desktop icons (as the comment says), or at least ping it if it already exists.

Then on line 135 Lively is looking for a window that has SHELLDLL_DefView as a child Once it found that window, Lively looks for its 'next sibling' that is the WorkerW

Then, if found WorkerW Lively starts WatchDog

Then my comprehension of C# show it's limits, soo the next part will not be certain

Then, on line 194 it calls

IWallpaper instance = wallpaperFactory.CreateWallpaper(wallpaper, display, userSettings);

and then

instance.Show();

The CreateWallpaper function returns all sort of structures depending on the wallpaper type (video(what format), gif, static image(url ?) etc) all implementing the IWallpaper interface The C# 'interface' system works a bit like a rust trait, but it can be used more like enum_dispatch

Anyways.

This IWallpaper interface has a .Show() function (that is different depending on what structure implement that interface).

I checked the implementation of this function for some structs and it appears that it's just booting up a process VideoMpvPlayer.cs, ExtPrograms except for PictureWinAPI that appears to be placing the image on the given monitor (This is what i would like to do)

The thing i don't understand yet is:

WindowInitialized?.Invoke(this, new WindowInitializedArgs()
{
    Success = true,
    Error = null,
    Msg = null
});

But i did not found any declaration of this WindowInitialized object.