C# - Multiple Desktop Wallpaper App - Logic Problems

Question

I'm currently tearing my hair out with this problem.

Where I'm up to:

I can

• Generate an image for each screen
• Create a mega-image for two screens next to each other.
• Setting this as a tiled wallpaper.

What I want to do:

• Support any number of monitors
• Support all offsets of monitors, such as monitors above, or below, or diagonal.

I have read this MSDN article and found it very helpful:

http://blogs.msdn.com/b/oldnewthing/archive/2007/09/24/5083738.aspx

But I am still stuck on the logic I need to use to:

• Calculate what size image I need for any variation of monitors
• Create the wallpaper applying the offset of monitors

My program is laid out as follows:

ScreenInfo Class:

public Bitmap ChosenWallPaper { get; private set; }
public Rectangle ScreenArea { get; private set; }

int ScreenNumber { get; set; }

public string ScreenDescription { get { return "Screen: " + ScreenNumber + " " + ScreenArea.ToString(); } }

public ScreenInfo(int screenNumber)
{
    this.ScreenNumber = screenNumber;
    ScreenArea = new Rectangle(Screen.AllScreens[screenNumber].Bounds.X, Screen.AllScreens[screenNumber].Bounds.Y, Screen.AllScreens[screenNumber].Bounds.Width, Screen.AllScreens[screenNumber].Bounds.Height);
}

ScreenCollection Class

public List<ScreenInfo> ScreenList { get; private set; }

public ScreenCollection()
{
    ScreenList = new List<ScreenInfo>();

    for (int i = 0; i < Screen.AllScreens.Count(); i++)
    {
        ScreenList.Add(new ScreenInfo(i));
    }
}

public Rectangle CalculateMainBitmapSize()
{

}

The rest of my source code hasn't been implemented yet.

Thanks!

EDIT:

I've figured out how to represent two monitors with each other with some REALLY hacky, horrible code, but I'm starting to understand how the monitors are laid out a bit more...

private void SizeScreens()
{
    pictureBox1.Height = Desktops.ScreenList[0].ScreenArea.Height / 10;
    pictureBox1.Width = Desktops.ScreenList[0].ScreenArea.Width / 10;

    pictureBox2.Height = Desktops.ScreenList[1].ScreenArea.Height / 10;
    pictureBox2.Width = Desktops.ScreenList[1].ScreenArea.Width / 10;
}

private void PositionScreens()
{
    Point Screen1Location = new Point(Desktops.ScreenList[0].ScreenArea.X,Desktops.ScreenList[0].ScreenArea.Y);
    Point Screen2Location = new Point(Origin.X + (Desktops.ScreenList[1].ScreenArea.X / 10),Origin.Y + (Desktops.ScreenList[1].ScreenArea.Y / 10));

    pictureBox1.Location = Origin;
    pictureBox2.Location = Screen2Location;
}

Answer 1

You can query the size of the virtual screen using the GetSystemMetrics function with the parameters SM_CXVIRTUALSCREEN and SM_CYVIRTUALSCREEN. That should give you the size of your image.

The positions of the monitors can be obtained through ´EnumDisplayMonitors`, but this is a bit more complicated as it requires a callback function.

// edit: Wasn't aware of Screen.AllScreens, but I guess you get the positions of the screens there.
You should just put you wallpapers at these positions, wrapping screens with negative coordinates to the right. The origin of the virtual screen is in the top left corner of the main monitor.