src/msw/textmeasure.cpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/msw/textmeasure.cpp
   3 // Purpose:     wxTextMeasure implementation for wxMSW
   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 #ifdef __BORLANDC__
  23     #pragma hdrstop
  24 #endif
  25
  26 #include "wx/msw/private.h"
  27 #include "wx/msw/dc.h"
  28
  29 #ifndef WX_PRECOMP
  30     #include "wx/window.h"
  31     #include "wx/font.h"
  32 #endif //WX_PRECOMP
  33
  34 #include "wx/private/textmeasure.h"
  35
  36 // ============================================================================
  37 // wxTextMeasure implementation
  38 // ============================================================================
  39
  40 void wxTextMeasure::Init()
  41 {
  42     m_hdc = NULL;
  43     m_hfontOld = NULL;
  44 }
  45
  46 void wxTextMeasure::BeginMeasuring()
  47 {
  48     if ( m_dc )
  49     {
  50         m_hdc = m_dc->GetHDC();
  51
  52         // Non-native wxDC subclasses should override their DoGetTextExtent()
  53         // and other methods.
  54         wxASSERT_MSG( m_hdc, wxS("Must not be used with non-native wxDCs") );
  55     }
  56     else if ( m_win )
  57     {
  58         m_hdc = ::GetDC(GetHwndOf(m_win));
  59     }
  60
  61     if ( m_font )
  62         m_hfontOld = (HFONT)::SelectObject(m_hdc, GetHfontOf(*m_font));
  63 }
  64
  65 void wxTextMeasure::EndMeasuring()
  66 {
  67     if ( m_hfontOld )
  68     {
  69         ::SelectObject(m_hdc, m_hfontOld);
  70         m_hfontOld = NULL;
  71     }
  72
  73     if ( m_win )
  74         ::ReleaseDC(GetHwndOf(m_win), m_hdc);
  75     //else: our HDC belongs to m_dc, don't touch it
  76
  77     m_hdc = NULL;
  78 }
  79
  80 // Notice we don't check here the font. It is supposed to be OK before the call.
  81 void wxTextMeasure::DoGetTextExtent(const wxString& string,
  82                                        wxCoord *width,
  83                                        wxCoord *height,
  84                                        wxCoord *descent,
  85                                        wxCoord *externalLeading)
  86 {
  87     SIZE sizeRect;
  88     const size_t len = string.length();
  89     if ( !::GetTextExtentPoint32(m_hdc, string.t_str(), len, &sizeRect) )
  90     {
  91         wxLogLastError(wxT("GetTextExtentPoint32()"));
  92     }
  93
  94 #if !defined(_WIN32_WCE) || (_WIN32_WCE >= 400)
  95     // the result computed by GetTextExtentPoint32() may be too small as it
  96     // accounts for under/overhang of the first/last character while we want
  97     // just the bounding rect for this string so adjust the width as needed
  98     // (using API not available in 2002 SDKs of WinCE)
  99     if ( len > 0 )
 100     {
 101         ABC widthABC;
 102         const wxChar chFirst = *string.begin();
 103         if ( ::GetCharABCWidths(m_hdc, chFirst, chFirst, &widthABC) )
 104         {
 105             if ( widthABC.abcA < 0 )
 106                 sizeRect.cx -= widthABC.abcA;
 107
 108             if ( len > 1 )
 109             {
 110                 const wxChar chLast = *string.rbegin();
 111                 ::GetCharABCWidths(m_hdc, chLast, chLast, &widthABC);
 112             }
 113             //else: we already have the width of the last character
 114
 115             if ( widthABC.abcC < 0 )
 116                 sizeRect.cx -= widthABC.abcC;
 117         }
 118         //else: GetCharABCWidths() failed, not a TrueType font?
 119     }
 120 #endif // !defined(_WIN32_WCE) || (_WIN32_WCE >= 400)
 121
 122     *width = sizeRect.cx;
 123     *height = sizeRect.cy;
 124
 125     if ( descent || externalLeading )
 126     {
 127         TEXTMETRIC tm;
 128         ::GetTextMetrics(m_hdc, &tm);
 129         if ( descent )
 130             *descent = tm.tmDescent;
 131         if ( externalLeading )
 132             *externalLeading = tm.tmExternalLeading;
 133     }
 134 }
 135
 136 bool wxTextMeasure::DoGetPartialTextExtents(const wxString& text,
 137                                             wxArrayInt& widths,
 138                                             double WXUNUSED(scaleX))
 139 {
 140     static int maxLenText = -1;
 141     static int maxWidth = -1;
 142
 143     if (maxLenText == -1)
 144     {
 145         // Win9x and WinNT+ have different limits
 146         int version = wxGetOsVersion();
 147         maxLenText = version == wxOS_WINDOWS_NT ? 65535 : 8192;
 148         maxWidth =   version == wxOS_WINDOWS_NT ? INT_MAX : 32767;
 149     }
 150
 151     int len = text.length();
 152     if ( len > maxLenText )
 153         len = maxLenText;
 154
 155     int fit = 0;
 156     SIZE sz = {0,0};
 157     if ( !::GetTextExtentExPoint(m_hdc,
 158                                  text.t_str(), // string to check
 159                                  len,
 160                                  maxWidth,
 161                                  &fit,         // [out] count of chars
 162                                                // that will fit
 163                                  &widths[0],   // array to fill
 164                                  &sz) )
 165     {
 166         wxLogLastError(wxT("GetTextExtentExPoint"));
 167
 168         return false;
 169     }
 170
 171     return true;
 172 }