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         m_iExtent = 0;
  34 }
  35
  36 CResizableComboBox::~CResizableComboBox()
  37 {
  38         if (m_ctrlListBox.GetSafeHwnd() != NULL)
  39                 m_ctrlListBox.UnsubclassWindow();
  40 }
  41
  42
  43 BEGIN_MESSAGE_MAP(CResizableComboBox, CComboBox)
  44         //{{AFX_MSG_MAP(CResizableComboBox)
  45         ON_WM_CTLCOLOR()
  46         //}}AFX_MSG_MAP
  47 END_MESSAGE_MAP()
  48
  49 /////////////////////////////////////////////////////////////////////////////
  50 // CResizableComboBox message handlers
  51
  52 HBRUSH CResizableComboBox::OnCtlColor(CDC* pDC, CWnd* pWnd, UINT nCtlColor)
  53 {
  54         HBRUSH hbr = CComboBox::OnCtlColor(pDC, pWnd, nCtlColor);
  55
  56         if (nCtlColor == CTLCOLOR_LISTBOX)
  57         {
  58                 if (!(GetStyle() & CBS_SIMPLE)
  59                         && (m_ctrlListBox.m_hWnd == NULL))
  60                 {
  61                         TRACE("ComboLBox: 0x%08X\n", pWnd->m_hWnd);
  62
  63                         // attach to the owned listbox
  64                         m_ctrlListBox.m_pOwnerCombo = this;
  65                         m_ctrlListBox.SubclassWindow(pWnd->m_hWnd);
  66                 }
  67         }
  68
  69         return hbr;
  70 }
  71
  72 LRESULT CResizableComboBox::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
  73 {
  74         switch (message)
  75         {
  76         case CB_GETDROPPEDCONTROLRECT:
  77                 *(LPRECT)lParam = m_rectDropDown;
  78                 MapWindowPoints(NULL, (LPRECT)lParam);
  79                 return TRUE;
  80         }
  81
  82         LRESULT lResult = CComboBox::WindowProc(message, wParam, lParam);
  83
  84         // if listbox is attached, update horizontal extent
  85
  86         switch (message)
  87         {
  88         case CB_INSERTSTRING:
  89         case CB_ADDSTRING:
  90                 if (lResult != CB_ERR && lResult != CB_ERRSPACE)
  91                         UpdateHorizontalExtent((LPCTSTR)lParam);
  92                 break;
  93
  94         case CB_DIR:
  95                 if (lResult != CB_ERR && lResult != CB_ERRSPACE)
  96                         InitHorizontalExtent();
  97                 break;
  98
  99         case CB_RESETCONTENT:
 100                 InitHorizontalExtent();
 101                 break;
 102         }
 103
 104         return lResult;
 105 }
 106
 107 void CResizableComboBox::InitHorizontalExtent()
 108 {
 109         CClientDC dc(this);
 110         CFont* pOldFont = dc.SelectObject(GetFont());
 111
 112         CString str;
 113
 114         m_iExtent = 0;
 115         int n = GetCount();
 116         for (int i=0; i<n; i++)
 117         {
 118                 GetLBText(i, str);
 119                 int cx = dc.GetTextExtent(str).cx;
 120                 if (cx > m_iExtent)
 121                         m_iExtent = cx;
 122         }
 123
 124         SetHorizontalExtent(m_iExtent
 125                 + LOWORD(GetDialogBaseUnits()));
 126
 127         dc.SelectObject(pOldFont);
 128 }
 129
 130 void CResizableComboBox::UpdateHorizontalExtent(LPCTSTR szText)
 131 {
 132         CClientDC dc(this);
 133         CFont* pOldFont = dc.SelectObject(GetFont());
 134
 135         int cx = dc.GetTextExtent(szText, lstrlen(szText)).cx;
 136         if (cx > m_iExtent)
 137         {
 138                 m_iExtent = cx;
 139
 140                 SetHorizontalExtent(m_iExtent
 141                         + LOWORD(GetDialogBaseUnits()));
 142         }
 143
 144         dc.SelectObject(pOldFont);
 145 }
 146
 147 void CResizableComboBox::PreSubclassWindow()
 148 {
 149         ASSERT(GetStyle() & CBS_NOINTEGRALHEIGHT);
 150
 151         InitHorizontalExtent();
 152
 153         GetDroppedControlRect(&m_rectDropDown);
 154         ::MapWindowPoints(NULL, GetSafeHwnd(),
 155                 (LPPOINT)&m_rectDropDown, 2);
 156
 157         CComboBox::PreSubclassWindow();
 158 }
 159
 160 int CResizableComboBox::MakeIntegralHeight(const int height)
 161 {
 162         int inth = height;      // integral height (result)
 163         int availh = height;    // available height
 164         int n = GetCount();
 165
 166         DWORD dwStyle = GetStyle();
 167
 168         if (!m_bIntegralHeight || n == 0)
 169                 return inth;
 170
 171         if (dwStyle & CBS_OWNERDRAWVARIABLE)
 172         {
 173                 inth = 0;       // try to reach availh by integral steps
 174                 int i = 0;
 175                 // use items below the first visible
 176                 for (i=GetTopIndex(); availh>0 && i<n; i++)
 177                 {
 178                         int h = GetItemHeight(i);
 179                         if (h == CB_ERR)
 180                                 break;
 181
 182                         inth += h;
 183                         availh -= h;
 184                 }
 185                 // to fill the remaining height, use items above
 186                 for (i=GetTopIndex()-1; availh>0 && i>=0; i--)
 187                 {
 188                         int h = GetItemHeight(i);
 189                         if (h == CB_ERR)
 190                                 break;
 191
 192                         inth += h;
 193                         availh -= h;
 194                 }
 195                 // scroll into view
 196                 SetTopIndex(i);
 197
 198                 if (!m_bClipMaxHeight) // it can be higher than all the items
 199                 {
 200                         // to fill the remaining height, use last item
 201                         int h = GetItemHeight(n-1);
 202                         if (h != CB_ERR)
 203                         {
 204                                 inth += availh - availh % h;
 205                         }
 206                 }
 207         }
 208         else
 209         {
 210                 // every item has the same height (take the first)
 211                 int h = GetItemHeight(0);
 212                 if (h != CB_ERR && n != CB_ERR)
 213                 {
 214                         int rows = availh / h;
 215                         // can't be higher than all the items
 216                         if (m_bClipMaxHeight && rows > n)
 217                                 rows = n;
 218                         inth = rows * h;
 219                         // scroll into view
 220                         if (n - rows < GetTopIndex())
 221                                 SetTopIndex(n-rows);
 222                 }
 223         }
 224
 225         return inth;
 226 }