ext/ResizableLib/ResizableComboBox.cpp

   1 // ResizableComboBox.cpp : implementation file
   2 //
   3 /////////////////////////////////////////////////////////////////////////////
   4 //
   5 // Copyright (C) 2000-2004 by Paolo Messina
   6 // (http://www.geocities.com/ppescher - ppescher@hotmail.com)
   7 //
   8 // The contents of this file are subject to the Artistic License (the "License").
   9 // You may not use this file except in compliance with the License.
  10 // You may obtain a copy of the License at:
  11 // http://www.opensource.org/licenses/artistic-license.html
  12 //
  13 // If you find this code useful, credits would be nice!
  14 //
  15 /////////////////////////////////////////////////////////////////////////////
  16
  17 #include "stdafx.h"
  18 #include "ResizableComboBox.h"
  19
  20 #ifdef _DEBUG
  21 #define new DEBUG_NEW
  22 #undef THIS_FILE
  23 static char THIS_FILE[] = __FILE__;
  24 #endif
  25
  26 /////////////////////////////////////////////////////////////////////////////
  27 // CResizableComboBox
  28
  29 CResizableComboBox::CResizableComboBox()
  30 {
  31         m_bClipMaxHeight = TRUE;
  32         m_bIntegralHeight = TRUE;
  33 }
  34
  35 CResizableComboBox::~CResizableComboBox()
  36 {
  37         if (m_ctrlListBox.GetSafeHwnd() != NULL)
  38                 m_ctrlListBox.UnsubclassWindow();
  39 }
  40
  41
  42 BEGIN_MESSAGE_MAP(CResizableComboBox, CComboBox)
  43         //{{AFX_MSG_MAP(CResizableComboBox)
  44         ON_WM_CTLCOLOR()
  45         //}}AFX_MSG_MAP
  46 END_MESSAGE_MAP()
  47
  48 /////////////////////////////////////////////////////////////////////////////
  49 // CResizableComboBox message handlers
  50
  51 HBRUSH CResizableComboBox::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)
  52 {
  53         HBRUSH hbr = CComboBox::OnCtlColor(pDC, pWnd, nCtlColor);
  54
  55         if (nCtlColor == CTLCOLOR_LISTBOX)
  56         {
  57                 if (!(GetStyle() & CBS_SIMPLE)
  58                         && (m_ctrlListBox.m_hWnd == NULL))
  59                 {
  60                         TRACE("ComboLBox: 0x%08X\n", pWnd->m_hWnd);
  61
  62                         // attach to the owned listbox
  63                         m_ctrlListBox.m_pOwnerCombo = this;
  64                         m_ctrlListBox.SubclassWindow(pWnd->m_hWnd);
  65                 }
  66         }
  67
  68         return hbr;
  69 }
  70
  71 LRESULT CResizableComboBox::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
  72 {
  73         switch (message)
  74         {
  75         case CB_GETDROPPEDCONTROLRECT:
  76                 *(LPRECT)lParam = m_rectDropDown;
  77                 MapWindowPoints(NULL, (LPRECT)lParam);
  78                 return TRUE;
  79         }
  80
  81         LRESULT lResult = CComboBox::WindowProc(message, wParam, lParam);
  82
  83         // if listbox is attached, update horizontal extent
  84
  85         switch (message)
  86         {
  87         case CB_INSERTSTRING:
  88         case CB_ADDSTRING:
  89                 if (lResult != CB_ERR && lResult != CB_ERRSPACE)
  90                         UpdateHorizontalExtent((LPCTSTR)lParam);
  91                 break;
  92
  93         case CB_DIR:
  94                 if (lResult != CB_ERR && lResult != CB_ERRSPACE)
  95                         InitHorizontalExtent();
  96                 break;
  97
  98         case CB_RESETCONTENT:
  99                 InitHorizontalExtent();
 100                 break;
 101         }
 102
 103         return lResult;
 104 }
 105
 106 void CResizableComboBox::InitHorizontalExtent()
 107 {
 108         CClientDC dc(this);
 109         CFont* pOldFont = dc.SelectObject(GetFont());
 110
 111         CString str;
 112
 113         m_iExtent = 0;
 114         int n = GetCount();
 115         for (int i=0; i<n; i++)
 116         {
 117                 GetLBText(i, str);
 118                 int cx = dc.GetTextExtent(str).cx;
 119                 if (cx > m_iExtent)
 120                         m_iExtent = cx;
 121         }
 122
 123         SetHorizontalExtent(m_iExtent
 124                 + LOWORD(GetDialogBaseUnits()));
 125
 126         dc.SelectObject(pOldFont);
 127 }
 128
 129 void CResizableComboBox::UpdateHorizontalExtent(LPCTSTR szText)
 130 {
 131         CClientDC dc(this);
 132         CFont* pOldFont = dc.SelectObject(GetFont());
 133
 134         int cx = dc.GetTextExtent(szText, lstrlen(szText)).cx;
 135         if (cx > m_iExtent)
 136         {
 137                 m_iExtent = cx;
 138
 139                 SetHorizontalExtent(m_iExtent
 140                         + LOWORD(GetDialogBaseUnits()));
 141         }
 142
 143         dc.SelectObject(pOldFont);
 144 }
 145
 146 void CResizableComboBox::PreSubclassWindow()
 147 {
 148         ASSERT(GetStyle() & CBS_NOINTEGRALHEIGHT);
 149
 150         InitHorizontalExtent();
 151
 152         GetDroppedControlRect(&m_rectDropDown);
 153         ::MapWindowPoints(NULL, GetSafeHwnd(),
 154                 (LPPOINT)&m_rectDropDown, 2);
 155
 156         CComboBox::PreSubclassWindow();
 157 }
 158
 159 int CResizableComboBox::MakeIntegralHeight(const int height)
 160 {
 161         int inth = height;      // integral height (result)
 162         int availh = height;    // available height
 163         int n = GetCount();
 164
 165         DWORD dwStyle = GetStyle();
 166
 167         if (!m_bIntegralHeight || n == 0)
 168                 return inth;
 169
 170         if (dwStyle & CBS_OWNERDRAWVARIABLE)
 171         {
 172                 inth = 0;       // try to reach availh by integral steps
 173                 int i = 0;
 174                 // use items below the first visible
 175                 for (i=GetTopIndex(); availh>0 && i<n; i++)
 176                 {
 177                         int h = GetItemHeight(i);
 178                         if (h == CB_ERR)
 179                                 break;
 180
 181                         inth += h;
 182                         availh -= h;
 183                 }
 184                 // to fill the remaining height, use items above
 185                 for (i=GetTopIndex()-1; availh>0 && i>=0; i--)
 186                 {
 187                         int h = GetItemHeight(i);
 188                         if (h == CB_ERR)
 189                                 break;
 190
 191                         inth += h;
 192                         availh -= h;
 193                 }
 194                 // scroll into view
 195                 SetTopIndex(i);
 196
 197                 if (!m_bClipMaxHeight) // it can be higher than all the items
 198                 {
 199                         // to fill the remaining height, use last item
 200                         int h = GetItemHeight(n-1);
 201                         if (h != CB_ERR)
 202                         {
 203                                 inth += availh - availh % h;
 204                         }
 205                 }
 206         }
 207         else
 208         {
 209                 // every item has the same height (take the first)
 210                 int h = GetItemHeight(0);
 211                 if (h != CB_ERR && n != CB_ERR)
 212                 {
 213                         int rows = availh / h;
 214                         // can't be higher than all the items
 215                         if (m_bClipMaxHeight && rows > n)
 216                                 rows = n;
 217                         inth = rows * h;
 218                         // scroll into view
 219                         if (n - rows < GetTopIndex())
 220                                 SetTopIndex(n-rows);
 221                 }
 222         }
 223
 224         return inth;
 225 }