src/common/textmeasurecmn.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/common/textmeasurecmn.cpp
   3 // Purpose:     wxTextMeasureBase implementation
   4 // Author:      Manuel Martin
   5 // Created:     2012-10-05
   6 // RCS-ID:      $Id:
   7 // Copyright:   (c) 1997-2012 wxWidgets team
   8 // Licence:     wxWindows licence
   9 ///////////////////////////////////////////////////////////////////////////////
  10
  11 // ============================================================================
  12 // declarations
  13 // ============================================================================
  14
  15 // ----------------------------------------------------------------------------
  16 // headers
  17 // ----------------------------------------------------------------------------
  18
  19 // for compilers that support precompilation, includes "wx.h".
  20 #include "wx/wxprec.h"
  21
  22 #ifndef WX_PRECOMP
  23     #include "wx/dc.h"
  24     #include "wx/window.h"
  25 #endif //WX_PRECOMP
  26
  27 #include "wx/private/textmeasure.h"
  28
  29 // ============================================================================
  30 // wxTextMeasureBase implementation
  31 // ============================================================================
  32
  33 wxTextMeasureBase::wxTextMeasureBase(const wxDC *dc, const wxFont *theFont)
  34     : m_dc(dc),
  35       m_win(NULL),
  36       m_font(theFont)
  37 {
  38     wxASSERT_MSG( dc, wxS("wxTextMeasure needs a valid wxDC") );
  39
  40     // By default, use wxDC version, we'll explicitly reset this to false in
  41     // the derived classes if the DC is of native variety.
  42     m_useDCImpl = true;
  43 }
  44
  45 wxTextMeasureBase::wxTextMeasureBase(const wxWindow *win, const wxFont *theFont)
  46     : m_dc(NULL),
  47       m_win(win),
  48       m_font(theFont)
  49 {
  50     wxASSERT_MSG( win, wxS("wxTextMeasure needs a valid wxWindow") );
  51
  52     // We don't have any wxDC so we can't forward to it.
  53     m_useDCImpl = false;
  54 }
  55
  56 void wxTextMeasureBase::CallGetTextExtent(const wxString& string,
  57                                           wxCoord *width,
  58                                           wxCoord *height,
  59                                           wxCoord *descent,
  60                                           wxCoord *externalLeading)
  61 {
  62     if ( m_useDCImpl )
  63         m_dc->GetTextExtent(string, width, height, descent, externalLeading);
  64     else
  65         DoGetTextExtent(string, width, height, descent, externalLeading);
  66 }
  67
  68 void wxTextMeasureBase::GetTextExtent(const wxString& string,
  69                                       wxCoord *width,
  70                                       wxCoord *height,
  71                                       wxCoord *descent,
  72                                       wxCoord *externalLeading)
  73 {
  74     // To make the code simpler, make sure that the width and height pointers
  75     // are always valid, even if they point to dummy variables.
  76     int unusedWidth, unusedHeight;
  77     if ( !width )
  78         width = &unusedWidth;
  79     if ( !height )
  80         height = &unusedHeight;
  81
  82     if ( string.empty() )
  83     {
  84         *width =
  85         *height = 0;
  86
  87         return;
  88     }
  89
  90     MeasuringGuard guard(*this);
  91
  92     CallGetTextExtent(string, width, height, descent, externalLeading);
  93 }
  94
  95 void wxTextMeasureBase::GetMultiLineTextExtent(const wxString& text,
  96                                                wxCoord *width,
  97                                                wxCoord *height,
  98                                                wxCoord *heightOneLine)
  99 {
 100     MeasuringGuard guard(*this);
 101
 102     wxCoord widthTextMax = 0, widthLine,
 103             heightTextTotal = 0, heightLineDefault = 0, heightLine = 0;
 104
 105     wxString curLine;
 106     for ( wxString::const_iterator pc = text.begin(); ; ++pc )
 107     {
 108         if ( pc == text.end() || *pc == wxS('\n') )
 109         {
 110             if ( curLine.empty() )
 111             {
 112                 // we can't use GetTextExtent - it will return 0 for both width
 113                 // and height and an empty line should count in height
 114                 // calculation
 115
 116                 // assume that this line has the same height as the previous
 117                 // one
 118                 if ( !heightLineDefault )
 119                     heightLineDefault = heightLine;
 120
 121                 if ( !heightLineDefault )
 122                 {
 123                     // but we don't know it yet - choose something reasonable
 124                     int dummy;
 125                     CallGetTextExtent(wxS("W"), &dummy, &heightLineDefault);
 126                 }
 127
 128                 heightTextTotal += heightLineDefault;
 129             }
 130             else
 131             {
 132                 CallGetTextExtent(curLine, &widthLine, &heightLine);
 133                 if ( widthLine > widthTextMax )
 134                     widthTextMax = widthLine;
 135                 heightTextTotal += heightLine;
 136             }
 137
 138             if ( pc == text.end() )
 139             {
 140                break;
 141             }
 142             else // '\n'
 143             {
 144                curLine.clear();
 145             }
 146         }
 147         else
 148         {
 149             curLine += *pc;
 150         }
 151     }
 152
 153     if ( width )
 154         *width = widthTextMax;
 155     if ( height )
 156         *height = heightTextTotal;
 157     if ( heightOneLine )
 158         *heightOneLine = heightLine;
 159 }
 160
 161 wxSize wxTextMeasureBase::GetLargestStringExtent(size_t n,
 162                                                  const wxString* strings)
 163 {
 164     MeasuringGuard guard(*this);
 165
 166     wxCoord w, h, widthMax = 0, heightMax = 0;
 167     for ( size_t i = 0; i < n; ++i )
 168     {
 169         CallGetTextExtent(strings[i], &w, &h);
 170
 171         if ( w > widthMax )
 172             widthMax = w;
 173         if ( h > heightMax )
 174             heightMax = h;
 175     }
 176
 177     return wxSize(widthMax, heightMax);
 178 }
 179
 180 bool wxTextMeasureBase::GetPartialTextExtents(const wxString& text,
 181                                               wxArrayInt& widths,
 182                                               double scaleX)
 183 {
 184     widths.Empty();
 185     if ( text.empty() )
 186         return true;
 187
 188     MeasuringGuard guard(*this);
 189
 190     widths.Add(0, text.length());
 191
 192     return DoGetPartialTextExtents(text, widths, scaleX);
 193 }