// ResizableComboBox.cpp : implementation file
//
/////////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2000-2004 by Paolo Messina
// (http://www.geocities.com/ppescher - ppescher@hotmail.com)
//
// The contents of this file are subject to the Artistic License (the "License").
// You may not use this file except in compliance with the License.
// You may obtain a copy of the License at:
// http://www.opensource.org/licenses/artistic-license.html
//
// If you find this code useful, credits would be nice!
//
/////////////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "ResizableComboBox.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CResizableComboBox

CResizableComboBox::CResizableComboBox()
{
    m_bClipMaxHeight = TRUE;
    m_bIntegralHeight = TRUE;
    m_iExtent = 0;
}

CResizableComboBox::~CResizableComboBox()
{
    if (m_ctrlListBox.GetSafeHwnd() != NULL)
        m_ctrlListBox.UnsubclassWindow();
}


BEGIN_MESSAGE_MAP(CResizableComboBox, CComboBox)
    //{{AFX_MSG_MAP(CResizableComboBox)
    ON_WM_CTLCOLOR()
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CResizableComboBox message handlers

HBRUSH CResizableComboBox::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)
{
    HBRUSH hbr = CComboBox::OnCtlColor(pDC, pWnd, nCtlColor);

    if (nCtlColor == CTLCOLOR_LISTBOX)
    {
        if (!(GetStyle() & CBS_SIMPLE)
            && (m_ctrlListBox.m_hWnd == NULL))
        {
            TRACE("ComboLBox: 0x%08X\n", pWnd->m_hWnd);

            // attach to the owned listbox
            m_ctrlListBox.m_pOwnerCombo = this;
            m_ctrlListBox.SubclassWindow(pWnd->m_hWnd);
        }
    }

    return hbr;
}

LRESULT CResizableComboBox::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case CB_GETDROPPEDCONTROLRECT:
        *(LPRECT)lParam = m_rectDropDown;
        MapWindowPoints(NULL, (LPRECT)lParam);
        return TRUE;
    }

    LRESULT lResult = CComboBox::WindowProc(message, wParam, lParam);

    // if listbox is attached, update horizontal extent

    switch (message)
    {
    case CB_INSERTSTRING:
    case CB_ADDSTRING:
        if (lResult != CB_ERR && lResult != CB_ERRSPACE)
            UpdateHorizontalExtent((LPCTSTR)lParam);
        break;

    case CB_DIR:
        if (lResult != CB_ERR && lResult != CB_ERRSPACE)
            InitHorizontalExtent();
        break;

    case CB_RESETCONTENT:
        InitHorizontalExtent();
        break;
    }

    return lResult;
}

void CResizableComboBox::InitHorizontalExtent()
{
    CClientDC dc(this);
    CFont* pOldFont = dc.SelectObject(GetFont());

    CString str;

    m_iExtent = 0;
    int n = GetCount();
    for (int i=0; i<n; i++)
    {
        GetLBText(i, str);
        int cx = dc.GetTextExtent(str).cx;
        if (cx > m_iExtent)
            m_iExtent = cx;
    }

    SetHorizontalExtent(m_iExtent
        + LOWORD(GetDialogBaseUnits()));

    dc.SelectObject(pOldFont);
}

void CResizableComboBox::UpdateHorizontalExtent(LPCTSTR szText)
{
    CClientDC dc(this);
    CFont* pOldFont = dc.SelectObject(GetFont());

    int cx = dc.GetTextExtent(szText, lstrlen(szText)).cx;
    if (cx > m_iExtent)
    {
        m_iExtent = cx;

        SetHorizontalExtent(m_iExtent
            + LOWORD(GetDialogBaseUnits()));
    }

    dc.SelectObject(pOldFont);
}

void CResizableComboBox::PreSubclassWindow()
{
    ASSERT(GetStyle() & CBS_NOINTEGRALHEIGHT);

    InitHorizontalExtent();

    GetDroppedControlRect(&m_rectDropDown);
    ::MapWindowPoints(NULL, GetSafeHwnd(),
        (LPPOINT)&m_rectDropDown, 2);

    CComboBox::PreSubclassWindow();
}

int CResizableComboBox::MakeIntegralHeight(const int height)
{
    int inth = height;  // integral height (result)
    int availh = height;    // available height
    int n = GetCount();

    DWORD dwStyle = GetStyle();

    if (!m_bIntegralHeight || n == 0)
        return inth;

    if (dwStyle & CBS_OWNERDRAWVARIABLE)
    {
        inth = 0;   // try to reach availh by integral steps
        int i = 0;
        // use items below the first visible
        for (i=GetTopIndex(); availh>0 && i<n; i++)
        {
            int h = GetItemHeight(i);
            if (h == CB_ERR)
                break;

            inth += h;
            availh -= h;
        }
        // to fill the remaining height, use items above
        for (i=GetTopIndex()-1; availh>0 && i>=0; i--)
        {
            int h = GetItemHeight(i);
            if (h == CB_ERR)
                break;

            inth += h;
            availh -= h;
        }
        // scroll into view
        SetTopIndex(i);

        if (!m_bClipMaxHeight) // it can be higher than all the items
        {
            // to fill the remaining height, use last item
            int h = GetItemHeight(n-1);
            if (h != CB_ERR)
            {
                inth += availh - availh % h;
            }
        }
    }
    else
    {
        // every item has the same height (take the first)
        int h = GetItemHeight(0);
        if (h != CB_ERR && n != CB_ERR)
        {
            int rows = availh / h;
            // can't be higher than all the items
            if (m_bClipMaxHeight && rows > n)
                rows = n;
            inth = rows * h;
            // scroll into view
            if (n - rows < GetTopIndex())
                SetTopIndex(n-rows);
        }
    }

    return inth;
}