Method ButtonSubclassProc

src/Utils/Theme.cpp:603–937

#endif

LRESULT CTheme::ButtonSubclassProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam, UINT_PTR /*uIdSubclass*/, DWORD_PTR /*dwRefData*/)
{
	switch (uMsg)
	{
	case WM_SETTEXT:
	case WM_ENABLE:
	case WM_STYLECHANGED:
		{
			LRESULT res = DefSubclassProc(hWnd, uMsg, wParam, lParam);
			InvalidateRgn(hWnd, nullptr, FALSE);
			return res;
		}
	case WM_PAINT:
		{
			PAINTSTRUCT ps;
			HDC hdc = BeginPaint(hWnd, &ps);
			if (hdc)
			{
				LONG_PTR dwStyle = GetWindowLongPtr(hWnd, GWL_STYLE);
				LONG_PTR dwButtonStyle = LOWORD(dwStyle);
				LONG_PTR dwButtonType = dwButtonStyle & 0xF;
				RECT rcClient;
				GetClientRect(hWnd, &rcClient);

				if ((dwButtonType & BS_GROUPBOX) == BS_GROUPBOX)
				{
					if (CAutoThemeData hTheme = OpenThemeData(hWnd, L"Button"))
					{
						BP_PAINTPARAMS params = { sizeof(BP_PAINTPARAMS) };
						params.dwFlags = BPPF_ERASE;

						RECT rcExclusion = rcClient;
						params.prcExclude = &rcExclusion;

						// We have to calculate the exclusion rect and therefore
						// calculate the font height. We select the control's font
						// into the DC and fake a drawing operation:
						auto hFontOld = reinterpret_cast<HFONT>(SendMessage(hWnd, WM_GETFONT, 0L, 0));
						if (hFontOld)
							hFontOld = static_cast<HFONT>(SelectObject(hdc, hFontOld));

						RECT rcDraw = rcClient;
						DWORD dwFlags = DT_SINGLELINE;

						// we use uppercase A to determine the height of text, so we
						// can draw the upper line of the groupbox:
						DrawTextW(hdc, L"A", -1, &rcDraw, dwFlags | DT_CALCRECT);

						if (hFontOld)
						{
							SelectObject(hdc, hFontOld);
							hFontOld = nullptr;
						}

						rcExclusion.left += 2;
						rcExclusion.top += RECTHEIGHT(rcDraw);
						rcExclusion.right -= 2;
						rcExclusion.bottom -= 2;