windows wallpaper questions

[Ashmoor]

I am learning how to set a windows desktop wallpaper using my own image.

I found this topic:
https://www.syntaxbomb.com/index.php/topic,2281.msg3270.html#msg3270

For some reason SystemParametersInfoA only changes the wallpaper if the source file path is somewhere in my AppData/Roaming folder.

Why does this happen?
Is there a way to change that?
Where can I find info to learn about this issue in particular and windows specific functions in general?

I've checked this link but I does not help: https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-systemparametersinfoa

[_PJ_]

For some reason SystemParametersInfoA only changes the wallpaper if the source file path is somewhere in my AppData/Roaming folder.

Assignment of desktop wallpaper will copy to a image theme in the requisite location. This needs to be acceisible to roaming profile to ensure that the same wallpaper is correctly assigned across all your sync'd devices
Further, this process protects against instances of source image files being moved/deleted after assigning as Wallpaper.

I am not sure, but I think these should be shared on the current device with %localappdata%\Microsoft\Windows\Themes\RoamedThemeFiles

[Henri]

Hi,

this works for me (Win10, file was jpg loaded from the root of C:\ )

Code: BlitzMax

1. Strict
2.  
3. Const SPI_SETDESKWALLPAPER:Int = 20
4.  
5. Extern "win32"
6.         Function SystemParametersInfo:Int(uiAction:Int, uiParam:Int, pvParam:Byte Ptr, fWinIni:Int) = "SystemParametersInfoA@16"
7. EndExtern
8.  
9. Local filter:String="Image Files:png,jpg,bmp"
10. Local src:String = RequestFile("Give desktop picture..", filter)
11. If Not src Then
12.         DebugLog "No file. Ending.."; End
13. Else
14.         DebugLog "Processing " + src + ".."
15. EndIf
16.  
17. DebugLog "Calling function -> Return value = " + SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, src.ToCString(), 0)
18.  

-Henri

[Ashmoor]

@Henri

Thanks. From your example it appears that you cannot pass relative file paths to the system. What I was doing was passing something like "graphics/wallpapers/wallpp.bmp" but for the the "roaming" case I was giving the full path.

@_PJ_
"Assignment of desktop wallpaper will copy to a image theme in the requisite location. This needs to be acceisible to roaming profile to ensure that the same wallpaper is correctly assigned across all your sync'd devices
Further, this process protects against instances of source image files being moved/deleted after assigning as Wallpaper."

Where do you get this kind of information? Is there some windows manual or something?

[_PJ_]

@_PJ_
"Assignment of desktop wallpaper will copy to a image theme in the requisite location. This needs to be acceisible to roaming profile to ensure that the same wallpaper is correctly assigned across all your sync'd devices
Further, this process protects against instances of source image files being moved/deleted after assigning as Wallpaper."

Where do you get this kind of information? Is there some windows manual or something?

It's just "general knowledge"/common sense of how Windows operates using Roaming Profiles synchronised across multiple AD or devices.

If you set your account's desktop wallpaper in one environment, obviously it will need to be reproduced on other locations you log onto. The original image itself may be in an inaccessible location or access could represent a security or data integrity risk - therefore, it is copied to the roaming directory. Similar practive ahs been in place with Themes and UAP/UAI since earlier iterations of NT