Change Wallpaper

[skpskpskp]

I am using SystemParametersInfo(SPI_SETDESKWALLPAPER,0,path,SPIF_SENDCHANGE);
to change the desktop in C++.

My question is how to set the wallpaper options Position(Stretched or Centered or Titled)

[Marc G]

One way:

USES_CONVERSION;  // First line in your function
...
IActiveDesktop *pActiveDesktop = NULL;
HRESULT hr = CoCreateInstance(CLSID_ActiveDesktop, NULL, CLSCTX_INPROC_SERVER,
      IID_IActiveDesktop, (void**)&pActiveDesktop);
if (hr == S_OK)
{
  WALLPAPEROPT wallpaperopt = {0};
  wallpaperopt.dwSize = sizeof(WALLPAPEROPT);
  wallpaperopt.dwStyle = WPSTYLE_TILE;
  pActiveDesktop->SetWallpaperOptions(&wallpaperopt, NULL);
  LPWSTR wstrImg = T2W(pszFile);
  pActiveDesktop->SetWallpaper(wstrImg, NULL);
  pActiveDesktop->ApplyChanges(AD_APPLY_ALL);
  pActiveDesktop->Release();
}

[skpskpskp]

Thanks,but because i have been learning WinAPI since last week and I understand 90% of your code and if you have time to explain every line and function i will be very grateful

Can you give me some links with more informations about it to read

[Marc G]

Well, the first line "USES_CONVERSION" is needed because I'm using T2W. See MSDN for the T2W explanation.

Then I get a IActiveDesktop interface using CoCreateInstance. Again, see MSDN for more information on CoCreateInstance.

Once you have your interface, we can start calling functions on it and one of its functions is SetWallpaperOptions which accepts a WALLPAPEROPT structure with information.

Then I use the SetWallpaper function to set the actual wallpaper and use ApplyChanges to instruct Windows to apply the changes and refresh the desktop.

When you're finished with an interface obtained through CoCreateInstance you should call Release on it.

[ugurkoltuk]

i couldn't figure out, is including shlobj.h enough for that?

[Marc G]

Yes, you have to include shlobj.h.
Do you have any compilation errors?

[ugurkoltuk]

yes i did have some, it said "error C2065: 'IActiveDesktop' : undeclared identifier" for example, but i figured out the problem about SystemParametersInfo, so everythings ok now.

by the way, thank you for your interest in my problem, and your replies.