WM_MOUSEMOVE
fwKeys = wParam; /* key flags */
xPos = LOWORD(lParam); /* horizontal position of cursor */
yPos = HIWORD(lParam); /* vertical position of cursor */
The WM_MOUSEMOVE message is posted to a window when the mouse cursor moves. If the mouse is not captured, the message is posted to the window that contains the cursor. Otherwise, the message is posted to the window that has captured the mouse.
fwKeys
Value of wParam. Indicates whether various virtual keys are down. This parameter can be any combination of the following values:
| Value | Description |
| MK_CONTROL | Set if CTRL key is down. |
| MK_LBUTTON | Set if left mouse button is down. |
| MK_MBUTTON | Set if middle mouse button is down. |
| MK_RBUTTON | Set if right mouse button is down. |
| MK_SHIFT | Set if SHIFT key is down. |
xPos
Value of the low-order word of lParam. Specifies the x-coordinate of the mouse cursor. The coordinate is relative to the upper-left corner of the client area.
yPos
Value of the high-order word of lParam. Specifies the y-coordinate of the mouse cursor. The coordinate is relative to the upper-left corner of the client area.
The MAKEPOINTS macro can be used to convert the lParam parameter to a POINTS structure.
GetCapture, SetCapture