If a window places information on the clipboard by using the CF_OWNERDISPLAY clipboard format, it must do the following:
Typically, a window responds to this message by setting the scroll positions and ranges for the clipboard viewer window. In response to this message, the Label application also updates a SIZE structure for the clipboard viewer window.
The window procedure for the Label application processes these messages, as follows.
LRESULT CALLBACK MainWindowProc(hwnd, msg, wParam, lParam)
HWND hwnd;
UINT msg;
WPARAM wParam;
LPARAM lParam;
{
static RECT rcViewer;
RECT rc;
LPRECT lprc;
LPPAINTSTRUCT lpps;
switch (msg)
{
//
// Handle other messages.
//
case WM_PAINTCLIPBOARD:
// Determine the dimensions of the label.
SetRect(&rc, 0, 0,
pboxLocalClip->rcText.right + CX_MARGIN,
pboxLocalClip->rcText.top * 2 + cyText
);
// Center the image in the clipboard viewer window.
if (rc.right < rcViewer.right)
{
rc.left = (rcViewer.right - rc.right) / 2;
rc.right += rc.left;
}
if (rc.bottom < rcViewer.bottom)
{
rc.top = (rcViewer.bottom - rc.bottom) / 2;
rc.bottom += rc.top;
}
// Paint the image, using the specified PAINTSTRUCT
// structure, by calling the application-defined
// PaintLabel function.
lpps = (LPPAINTSTRUCT) GlobalLock((HGLOBAL) lParam);
PaintLabel(lpps, pboxLocalClip, &rc);
GlobalUnlock((HGLOBAL) lParam);
break;
case WM_SIZECLIPBOARD:
// Save the dimensions of the window in a static
// RECT structure.
lprc = (LPRECT) GlobalLock((HGLOBAL) lParam);
memcpy(&rcViewer, lprc, sizeof(RECT));
GlobalUnlock((HGLOBAL) lParam);
// Set the scroll ranges to zero (thus eliminating
// the need to process the WM_HSCROLLCLIPBOARD and
// WM_VSCROLLCLIPBOARD messages).
SetScrollRange((HWND) wParam, SB_HORZ, 0, 0, TRUE);
SetScrollRange((HWND) wParam, SB_VERT, 0, 0, TRUE);
break;
case WM_ASKCBFORMATNAME:
LoadString(hinst, IDS_OWNERDISPLAY,
(LPSTR) lParam, wParam);
break;
default:
return DefWindowProc(hwnd, msg, wParam, lParam);
}
return 0;
}