The WM_SIZE message is sent to a window after its size has changed.
WM_SIZE
fwSizeType = wParam; // resizing flag
nWidth = LOWORD(lParam); // width of client area
nHeight = HIWORD(lParam); // height of client area
Parameters
fwSizeType
Value of wParam. Specifies the type of resizing requested. This parameter can be one of the following values:
| Value | Meaning |
| SIZE_MAXHIDE | Message is sent to all pop-up windows when some other window is maximized. |
| SIZE_MAXIMIZED | Window has been maximized. |
| SIZE_MAXSHOW | Message is sent to all pop-up windows when some other window has been restored to its former size. |
| SIZE_MINIMIZED | Window has been minimized. |
| SIZE_RESTORED | Window has been resized, but neither the SIZE_MINIMIZED nor SIZE_MAXIMIZED value applies. |
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.
Return Values
If an application processes this message, it should return zero.
Remarks
If the SetScrollPos or MoveWindow function is called for a child window as a result of the WM_SIZE message, the bRedraw parameter should be nonzero to cause the window to be repainted.
Although the width and height of a window are 32-bit values, the nWidth and nHeight parameters of the WM_SIZE message contain only the low-order 16 bits.
See Also