static extern bool GetMonitorInfo(IntPtr hMonitor, MONITORINFO lpmi);
/// <summary>
/// Get the min/max window size for this window
/// Correctly accounting for the taskbar size and position
/// </summary>
/// <param name="hwnd"></param>
/// <param name="lParam"></param>
private void WmGetMinMaxInfo(System.IntPtr hwnd, System.IntPtr lParam)
{
// Get the point position to determine what screen we are on
GetCursorPos(out POINT lMousePosition);
// Now get the current screen
var lCurrentScreen = MonitorFromPoint(lMousePosition, MonitorOptions.MONITOR_DEFAULTTONEAREST);
var lPrimaryScreen = MonitorFromPoint(new POINT(0, 0), MonitorOptions.MONITOR_DEFAULTTOPRIMARY);
// Try and get the current screen information
var lCurrentScreenInfo = new MONITORINFO();
if (GetMonitorInfo(lCurrentScreen, lCurrentScreenInfo) == false)
{
return;
}
// Try and get the primary screen information
var lPrimaryScreenInfo = new MONITORINFO();
if (GetMonitorInfo(lPrimaryScreen, lPrimaryScreenInfo) == false)
{
return;
}
// If this has changed from the last one, update the transform
if (lCurrentScreen != mLastScreen || mMonitorDpi == null)
{
mMonitorDpi = VisualTreeHelper.GetDpi(mWindow);
}
// Store last know screen
mLastScreen = lCurrentScreen;
// Get work area sizes and rations
var currentX = lCurrentScreenInfo.rcWork.Left - lCurrentScreenInfo.rcMonitor.Left;
var currentY = lCurrentScreenInfo.rcWork.Top - lCurrentScreenInfo.rcMonitor.Top;
var currentWidth = (lCurrentScreenInfo.rcWork.Right - lCurrentScreenInfo.rcWork.Left);
var currentHeight = (lCurrentScreenInfo.rcWork.Bottom - lCurrentScreenInfo.rcWork.Top);
var currentRatio = (float)currentWidth / (float)currentHeight;
var primaryX = lPrimaryScreenInfo.rcWork.Left - lPrimaryScreenInfo.rcMonitor.Left;
var primaryY = lPrimaryScreenInfo.rcWork.Top - lPrimaryScreenInfo.rcMonitor.Top;
var primaryWidth = (lPrimaryScreenInfo.rcWork.Right - lPrimaryScreenInfo.rcWork.Left);
var primaryHeight = (lPrimaryScreenInfo.rcWork.Bottom - lPrimaryScreenInfo.rcWork.Top);
var primaryRatio = (float)primaryWidth / (float)primaryHeight;
// Get min/max structure to fill with information
var lMmi = (MINMAXINFO)Marshal.PtrToStructure(lParam, typeof(MINMAXINFO));
// NOTE: rcMonitor is the monitor size
// rcWork is the available screen size (so the area inside the taskbar start menu for example)
// Size size limits (used by Windows when maximized)
// relative to 0,0 being the current screens top-left corner
//
// - Position
lMmi.ptMaxPosition.X = currentX;
lMmi.ptMaxPosition.Y = currentY;
//
// - Size
lMmi.ptMaxSize.X = currentWidth;
lMmi.ptMaxSize.Y = currentHeight;
//
// BUG:
// NOTE: I've noticed a bug which I think is Windows itself
// If your non-primary monitor has a greater width than your primary
// (or possibly due to the screen ratio's being different)
// then setting the max X on the monitor to the correct value causes
// it to scale wrong.
//
// The fix seems to be to set the max width only (height is fine)
// to that of the primary monitor, not the current monitor
//
// However, 1 pixel different and the size goes totally wrong again
// so the fix doesn't work when the taskbar is on the left or right
//
// Set monitor size
CurrentMonitorSize = new Rectangle(lMmi.ptMaxPosition.X, lMmi.ptMaxPosition.Y, lMmi.ptMaxSize.X + lMmi.ptMaxPosition.X, lMmi.ptMaxSize.Y + lMmi.ptMaxPosition.Y);
// Set min size
var minSize = new Point(mWindow.MinWidth * mMonitorDpi.Value.DpiScaleX, mWindow.MinHeight * mMonitorDpi.Value.DpiScaleX);
lMmi.ptMinTrackSize.X = (int)minSize.X;
lMmi.ptMinTrackSize.Y = (int)minSize.Y;
// Store new size
mScreenSize = new Rect(lCurrentScreenInfo.rcWork.Left, lCurrentScreenInfo.rcWork.Top, lMmi.ptMaxSize.X, lMmi.ptMaxSize.Y);
// Now we have the max size, allow the host to tweak as needed
Marshal.StructureToPtr(lMmi, lParam, true);
}