WM_SIZE
fwSizeType = wParam; /* sizing-type flag */
nWidth = LOWORD(lParam); /* width of client area */
nHeight = HIWORD(lParam); /* height of client area */The WM_SIZE message is sent to a window after its size has changed.
fwSizeType
Value of wParam. Specifies the type of resizing requested. This parameter can be one of the following values:
| Value | Description |
| SIZE_MAXIMIZED | Window has been maximized. |
| SIZE_MINIMIZED | Window has been minimized. |
| SIZE_RESTORED | Window has been resized, but neither SIZE_MINIMIZED nor SIZE_MAXIMIZED applies. |
| SIZE_MAXHIDE | Message is sent to all pop-up windows when some other window is maximized. |
| SIZE_MAXSHOW | Message is sent to all pop-up windows when some other window has been restored to its former size. |
nWidth
Value of the low-order word of lParam. Specifies the new width of the client area.
nHeight
Value of the high-order word of lParam. Specifies the new height of the client area.
An application should return zero if it processes this message.
If the SetScrollPos or MoveWindow function is called for a child window as a result of the WM_SIZE message, the fRepaint parameter should be nonzero to cause the window to be repainted.