Introduction
In my Tray Calendar application I wanted to make the "About" box and Options dialog
appear to expand and contract into and out of the system tray. The animation was taken care of by using the
DrawAnimatedRects
function (see the article "Using the DrawAnimatedRects() function"), but I need to know where the system tray was.
Finding the System Tray
My first thought was to simply use FindWindow
using the window name "TrayNotifyWnd",
but unfortunately this did not work as planned. Instead I was able to get a handle to "Shell_TrayWnd",
and from there work my way down using EnumChildWindows
to get a hold of the system tray
and the clock window. Subtracting the size of the system clock window from that of the system tray
then gave me the working area of the system tray.
The code is shown below:
BOOL CALLBACK FindTrayWnd(HWND hwnd, LPARAM lParam)
{
TCHAR szClassName[256];
GetClassName(hwnd, szClassName, 255);
if (_tcscmp(szClassName, _T("TrayNotifyWnd")) == 0)
{
CRect *pRect = (CRect*) lParam;
::GetWindowRect(hwnd, pRect);
return TRUE;
}
if (_tcscmp(szClassName, _T("TrayClockWClass")) == 0)
{
CRect *pRect = (CRect*) lParam;
CRect rectClock;
::GetWindowRect(hwnd, rectClock);
if (rectClock.bottom < lpRect->bottom-5)
lpRect->top = rectClock.bottom;
else
lpRect->right = rectClock.left;
return FALSE;
}
return TRUE;
}
void GetTrayWndRect(LPRECT lprect)
{
#define DEFAULT_RECT_WIDTH 150
#define DEFAULT_RECT_HEIGHT 30
HWND hShellTrayWnd = ::FindWindow(_T("Shell_TrayWnd"), NULL);
if (hShellTrayWnd)
{
::GetWindowRect(hShellTrayWnd, lprect);
EnumChildWindows(hShellTrayWnd, FindTrayWnd, (LPARAM)lprect);
return;
}
APPBARDATA appBarData;
appBarData.cbSize=sizeof(appBarData);
if (SHAppBarMessage(ABM_GETTASKBARPOS,&appBarData))
{
switch(appBarData.uEdge)
{
case ABE_LEFT:
case ABE_RIGHT:
lprect->top = appBarData.rc.bottom-100;
lprect->bottom = appBarData.rc.bottom-16;
lprect->left = appBarData.rc.left;
lprect->right = appBarData.rc.right;
break;
case ABE_TOP:
case ABE_BOTTOM:
lprect->top = appBarData.rc.top;
lprect->bottom = appBarData.rc.bottom;
lprect->left = appBarData.rc.right-100;
lprect->right = appBarData.rc.right-16;
break;
}
return;
}
if (hShellTrayWnd)
{
::GetWindowRect(hShellTrayWnd, lprect);
if (lprect->right - lprect->left > DEFAULT_RECT_WIDTH)
lprect->left = lprect->right - DEFAULT_RECT_WIDTH;
if (lprect->bottom - lprect->top > DEFAULT_RECT_HEIGHT)
lprect->top = lprect->bottom - DEFAULT_RECT_HEIGHT;
return;
}
SystemParametersInfo(SPI_GETWORKAREA,0,lprect, 0);
lprect->left = lprect->right - DEFAULT_RECT_WIDTH;
lprect->top = lprect->bottom - DEFAULT_RECT_HEIGHT;
}
Updates
Compensation was made for the case where the system clock is above the system tray,
and Matthew Ellis improved the GetTrayWndRect to provide more fallbacks.