Available in LEADTOOLS Imaging Pro, Vector, Document, and Medical Imaging toolkits. |
At the end of the Color.CPP file, add the new local function, CalcClientMetrics, which interprets the WM_SIZE message's client area parameters.
/*---[CalcClientMetrics]------------------------------------------------------- Parameters: HWND hWnd Window handle int *nClientWidth Width in and width out int *nClientHeight Height in and height out int *nRightBarThickness Resulting thickness of the Y scrollbar int *nBottomBarThickness Resulting thickness of the X scrollbar ProtoType: Color.h Notes: Use this function to interpret the client area width and height parameters from the WM_SIZE message. The incoming parameters attempt to give us the correct client area, excluding scrollbars. But, because while processing this message we show or hide the scrollbars, the incoming parameters often are not correct. Therefore, we must get the true client area dimensions, including scrollbars, and get the thickness of scrollbars. The caller can then make its own decisions about the size of the client area. --------------------------------------------------------------------------*/ void CalcClientMetrics (HWND hWnd, int *nClientWidth, int *nClientHeight, int *nRightBarThickness, int *nBottomBarThickness) { DWORD dwStyle, dwVersion; int cxClient, cyClient, cxScroll, cyScroll; /* Initialize local variables */ cxClient = *nClientWidth; cyClient = *nClientHeight; cxScroll = GetSystemMetrics(SM_CXVSCROLL); cyScroll = GetSystemMetrics(SM_CYHSCROLL); dwStyle = GetWindowLong(hWnd, GWL_STYLE); /* Adjust for the difference in how newer WIN32 versions report scrollbar thickness when there is a window border */ dwVersion = GetVersion(); if (LOBYTE(LOWORD(dwVersion)) >= 4) { cxScroll += GetSystemMetrics(SM_CXBORDER); cyScroll += GetSystemMetrics(SM_CYBORDER); } /* If there is a window border, subtract it from the scrollbar thickness */ if (dwStyle & WS_BORDER) { cxScroll -= GetSystemMetrics(SM_CXBORDER); cyScroll -= GetSystemMetrics(SM_CYBORDER); } /* Add the scrollbar thickness to the client area */ if (dwStyle & WS_VSCROLL) cxClient += cxScroll; if (dwStyle & WS_HSCROLL) cyClient += cyScroll; /* Update the caller's variables */ *nClientWidth = cxClient; *nClientHeight = cyClient; *nRightBarThickness = cxScroll; *nBottomBarThickness = cyScroll; }