A fast and lightweight cell control

/*----------------------------------------------------------------------
Copyright (c)  Gipsysoft. All Rights Reserved.
Please see the file "licence.txt" for licencing details.
File:	AddCheckbox.cpp
Owner:	russf@gipsysoft.com
Purpose:	Adds the "never show this again" type checkbox to the messagebox
----------------------------------------------------------------------*/
#include "stdafx.h"
#include "InternalStructures.h"

static const g_knButtonID = 19671;

static void GetCheckSize( HFONT hFont, LPCTSTR pcszText, SIZE &size )
{
	HDC hdc = GetDC( NULL );
	VAPI( hdc );

	HDC hdc2 = CreateCompatibleDC( hdc );
	VAPI( hdc );

	hFont = (HFONT)SelectObject( hdc2, hFont );
	VAPI( GetTextExtentPoint32( hdc2, pcszText, _tcslen( pcszText ), &size ) );
	hFont = (HFONT)SelectObject( hdc2, hFont );

	VAPI( DeleteDC( hdc2 ) );

	VAPI( ReleaseDC( NULL, hdc ) );
	size.cx += GetSystemMetrics( SM_CXMENUCHECK ) + 5;
	size.cy = max( size.cy, GetSystemMetrics( SM_CYMENUCHECK ) );
}


void AddCheckbox( HWND hwnd, SWindowData *pwnddata )
{
	HINSTANCE hInstance = reinterpret_cast<HINSTANCE>( GetWindowLong( hwnd, GWL_HINSTANCE ) );
	RECT rcWindow;
	VAPI( GetWindowRect( hwnd, &rcWindow ) );

	pwnddata->m_uCheckBoxID = g_knButtonID;

	//
	//	Get the font so we can measure and use it in our new control.
	HFONT hfont = (HFONT)SendMessage( hwnd, WM_GETFONT, 0, 0 );

	//
	//	Get the size of the checkbox to be...
	SIZE sizeCheckbox;
	GetCheckSize( hfont, pwnddata->m_MsgOpt.pcszCheckBoxText, sizeCheckbox );


	//
	//	Determine where the checkbox is going...
	RECT rcStatic;
	VAPI( GetWindowRect( pwnddata->m_hwndStatic, &rcStatic ) );
	POINT pt = { rcStatic.left, rcStatic.bottom };
	VAPI( MapWindowPoints( NULL, hwnd, &pt, 1 ) );

	RECT rcDLUs = { 0, 0, 0, 2 };
	VAPI( MapDialogRect( hwnd, &rcDLUs ) );
	pt.y += rcDLUs.bottom;

	int nYToAdd = sizeCheckbox.cy + ( rcDLUs.bottom * 2 );

	VAPI( SetWindowPos( hwnd, NULL, rcWindow.left, rcWindow.top, rcWindow.right - rcWindow.left, (rcWindow.bottom - rcWindow.top) + nYToAdd, SWP_NOZORDER ) );


	//
	//	Move all buttons by the delta between the new and old size of the dialog
	HWND hwndButton = GetWindow( hwnd, GW_CHILD );
	static const TCHAR szButton[] = _T("BUTTON");
	TCHAR szTest[]                = _T("      ");
	while( hwndButton )
	{
		if( GetClassName( hwndButton, szTest, countof( szTest ) ) )
		{
			if( !_tcsnicmp( szTest, szButton, countof( szTest ) - 1 ) )
			{
				RECT rcButton;
				GetWindowRect( hwndButton, &rcButton );
				OffsetRect( &rcButton, 0, nYToAdd );
				MapWindowPoints( HWND_DESKTOP, hwnd, reinterpret_cast<LPPOINT>(&rcButton.left), 2 );
				SetWindowPos( hwndButton, NULL, rcButton.left, rcButton.top, 0, 0, SWP_NOZORDER | SWP_NOSIZE | SWP_NOSENDCHANGING );
			}
		}
		hwndButton = GetWindow( hwndButton, GW_HWNDNEXT );
	}

	HWND hwndCheck = CreateWindowEx( 0, _T("Button"), pwnddata->m_MsgOpt.pcszCheckBoxText, WS_TABSTOP | WS_CHILD | WS_VISIBLE | BS_AUTOCHECKBOX, pt.x, pt.y, sizeCheckbox.cx, sizeCheckbox.cy, hwnd, (HMENU)g_knButtonID, hInstance, NULL );
	SendMessage( hwndCheck, WM_SETFONT, (WPARAM)hfont, 0 );	
	if( *pwnddata->m_MsgOpt.puValue )
	{
		SendMessage( hwndCheck, BM_SETCHECK, BST_CHECKED, 0 );
	}

	//
	//	NOTE: We don't need to alter the Z-Order of the new checkbox because the static doesn't have it and it will *appear*
	//	like it's correctly placed simply due to the fact that it appears after the buttons.
}