Check for amount of line breaks — winapi c++ - c++

Question

I have a static text control that should resize along with the window, its text width is smaller than the whole line of text at first, so it clips like I need by default.
I would like to center the text vertically. When it is clipped the whole height is occupied, but when static's width is large enough and the whole text fits into one line it is up high. How can I center it wherever it is?

Answer 1

After some research, I found that you can customize the height of the upper left corner of the text to achieve vertical centering. Of course, the text can be truncated.
When the length of the static control is less than the length of the text, the text will be truncated. So we need to calculate the height and length of the text, with the help of GetTextExtentPoint32. Then DrawText does the rest, DT_WORDBREAK and DT_CENTER should be added.
See my code for specific details:
// Parent Hwnd
HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
0, 0, 800, 600, nullptr, nullptr, hInstance, nullptr);
// Window Process
float nScale_x = 1.0, nScale_y = 1.0;
HWND static_hwnd;
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
RECT rc; // the size of text
RECT rect; // the size of Rectangle
switch (message)
{
case WM_CREATE:
{
static_hwnd = CreateWindow(L"STATIC",
L"Some clipping text example",
WS_CHILD | WS_VISIBLE | WS_TABSTOP | SS_OWNERDRAW,
100, 100, 200, 50,
hWnd,
NULL,
NULL,
NULL);
return 1;
}
case WM_DRAWITEM:
{
LPDRAWITEMSTRUCT pDIS = (LPDRAWITEMSTRUCT)lParam;
if (pDIS->hwndItem == static_hwnd)
{
const wchar_t* text = L"Some clipping text example";
HDC hDC = pDIS->hDC;
RECT rect = pDIS->rcItem;
RECT rc;
int w = rect.right - rect.left;
int h;
if (w >= 180) // the length of "Some clipping text example"
{
h = 16;
}
else if (w < 92) //the length of "Some clipping"
{
h = 16 * 3;
}
else if (w < 180)
{
h = 16 * 2;
}
rc.left = rect.left;
rc.right = rect.right;
rc.top = ((rect.bottom - rect.top) - h) / 2;
rc.bottom = rect.bottom;
HBRUSH bg = (HBRUSH)(::GetStockObject(LTGRAY_BRUSH));
HPEN pn = (HPEN)(::GetStockObject(BLACK_PEN));
::SelectObject(hDC, bg);
//SIZE sz;
//GetTextExtentPoint32(hDC, text, 13, &sz);
::SelectObject(hDC, pn);
::SetTextColor(hDC, RGB(0, 0, 0));
::Rectangle(hDC, rect.left, rect.top, rect.right, rect.bottom);
::DrawText(hDC, text, wcslen(text), &rc, DT_WORDBREAK | DT_CENTER);
}
return TRUE;
}
case WM_SIZE:
{
GetWindowRect(hWnd, &rc);
nScale_x = (rc.right - rc.left) / 800.0;
nScale_y = (rc.bottom - rc.top) / 600.0;
SetWindowPos(static_hwnd, NULL, 100, 100, 200 * nScale_x, 50 * nScale_y, SWP_SHOWWINDOW);
}
...
Debug: