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 wxFont wxTextMeasureBase::GetFont() const
  57 {
  58     return m_font ? *m_font
  59                   : m_win ? m_win->GetFont()
  60                           : m_dc->GetFont();
  61 }
  62
  63 void wxTextMeasureBase::CallGetTextExtent(const wxString& string,
  64                                           wxCoord *width,
  65                                           wxCoord *height,
  66                                           wxCoord *descent,
  67                                           wxCoord *externalLeading)
  68 {
  69     if ( m_useDCImpl )
  70         m_dc->GetTextExtent(string, width, height, descent, externalLeading);
  71     else
  72         DoGetTextExtent(string, width, height, descent, externalLeading);
  73 }
  74
  75 void wxTextMeasureBase::GetTextExtent(const wxString& string,
  76                                       wxCoord *width,
  77                                       wxCoord *height,
  78                                       wxCoord *descent,
  79                                       wxCoord *externalLeading)
  80 {
  81     // To make the code simpler, make sure that the width and height pointers
  82     // are always valid, even if they point to dummy variables.
  83     int unusedWidth, unusedHeight;
  84     if ( !width )
  85         width = &unusedWidth;
  86     if ( !height )
  87         height = &unusedHeight;
  88
  89     if ( string.empty() )
  90     {
  91         *width =
  92         *height = 0;
  93
  94         return;
  95     }
  96
  97     MeasuringGuard guard(*this);
  98
  99     CallGetTextExtent(string, width, height, descent, externalLeading);
 100 }
 101
 102 void wxTextMeasureBase::GetMultiLineTextExtent(const wxString& text,
 103                                                wxCoord *width,
 104                                                wxCoord *height,
 105                                                wxCoord *heightOneLine)
 106 {
 107     MeasuringGuard guard(*this);
 108
 109     wxCoord widthTextMax = 0, widthLine,
 110             heightTextTotal = 0, heightLineDefault = 0, heightLine = 0;
 111
 112     wxString curLine;
 113     for ( wxString::const_iterator pc = text.begin(); ; ++pc )
 114     {
 115         if ( pc == text.end() || *pc == wxS('\n') )
 116         {
 117             if ( curLine.empty() )
 118             {
 119                 // we can't use GetTextExtent - it will return 0 for both width
 120                 // and height and an empty line should count in height
 121                 // calculation
 122
 123                 // assume that this line has the same height as the previous
 124                 // one
 125                 if ( !heightLineDefault )
 126                     heightLineDefault = heightLine;
 127
 128                 if ( !heightLineDefault )
 129                 {
 130                     // but we don't know it yet - choose something reasonable
 131                     int dummy;
 132                     CallGetTextExtent(wxS("W"), &dummy, &heightLineDefault);
 133                 }
 134
 135                 heightTextTotal += heightLineDefault;
 136             }
 137             else
 138             {
 139                 CallGetTextExtent(curLine, &widthLine, &heightLine);
 140                 if ( widthLine > widthTextMax )
 141                     widthTextMax = widthLine;
 142                 heightTextTotal += heightLine;
 143             }
 144
 145             if ( pc == text.end() )
 146             {
 147                break;
 148             }
 149             else // '\n'
 150             {
 151                curLine.clear();
 152             }
 153         }
 154         else
 155         {
 156             curLine += *pc;
 157         }
 158     }
 159
 160     if ( width )
 161         *width = widthTextMax;
 162     if ( height )
 163         *height = heightTextTotal;
 164     if ( heightOneLine )
 165         *heightOneLine = heightLine;
 166 }
 167
 168 wxSize wxTextMeasureBase::GetLargestStringExtent(size_t n,
 169                                                  const wxString* strings)
 170 {
 171     MeasuringGuard guard(*this);
 172
 173     wxCoord w, h, widthMax = 0, heightMax = 0;
 174     for ( size_t i = 0; i < n; ++i )
 175     {
 176         CallGetTextExtent(strings[i], &w, &h);
 177
 178         if ( w > widthMax )
 179             widthMax = w;
 180         if ( h > heightMax )
 181             heightMax = h;
 182     }
 183
 184     return wxSize(widthMax, heightMax);
 185 }
 186
 187 bool wxTextMeasureBase::GetPartialTextExtents(const wxString& text,
 188                                               wxArrayInt& widths,
 189                                               double scaleX)
 190 {
 191     widths.Empty();
 192     if ( text.empty() )
 193         return true;
 194
 195     MeasuringGuard guard(*this);
 196
 197     widths.Add(0, text.length());
 198
 199     return DoGetPartialTextExtents(text, widths, scaleX);
 200 }