Factor out text measurement from wxDC and wxWindow into wxTextMeasure.

Add a new private wxTextMeasure class implementing methods for measuring text
and move the often duplicated (but not always identically) code for doing the
same from wxDC and wxWindow into it.

Currently this class is only really implemented in wxMSW and wxGTK.

Also extend the test for text measuring functions and rename it to
MeasuringTextTestCase from MeasuringContextTestCase as it's not wxGC-specific
any more.

Closes #14705.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@72699 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/dcbase.cpp

@@ -38,6 +38,8 @@
     #include "wx/window.h"
 #endif
 
+#include "wx/private/textmeasure.h"
+
 #ifdef __WXMSW__
     #include "wx/msw/dcclient.h"
     #include "wx/msw/dcmemory.h"
@@ -511,78 +513,10 @@ void wxDCImpl::SetAxisOrientation( bool xLeftRight, bool yBottomUp )
     ComputeScaleAndOrigin();
 }
 
-
-// Each element of the widths array will be the width of the string up to and
-// including the corresponding character in text.  This is the generic
-// implementation, the port-specific classes should do this with native APIs
-// if available and if faster.  Note: pango_layout_index_to_pos is much slower
-// than calling GetTextExtent!!
-
-#define FWC_SIZE 256
-
-class FontWidthCache
-{
-public:
-    FontWidthCache() : m_scaleX(1), m_widths(NULL) { }
-    ~FontWidthCache() { delete []m_widths; }
-
-    void Reset()
-    {
-        if (!m_widths)
-            m_widths = new int[FWC_SIZE];
-
-        memset(m_widths, 0, sizeof(int)*FWC_SIZE);
-    }
-
-    wxFont m_font;
-    double m_scaleX;
-    int *m_widths;
-};
-
-static FontWidthCache s_fontWidthCache;
-
 bool wxDCImpl::DoGetPartialTextExtents(const wxString& text, wxArrayInt& widths) const
 {
-    int totalWidth = 0;
-
-    const size_t len = text.length();
-    widths.Empty();
-    widths.Add(0, len);
-
-    // reset the cache if font or horizontal scale have changed
-    if ( !s_fontWidthCache.m_widths ||
-         !wxIsSameDouble(s_fontWidthCache.m_scaleX, m_scaleX) ||
-         (s_fontWidthCache.m_font != GetFont()) )
-    {
-        s_fontWidthCache.Reset();
-        s_fontWidthCache.m_font = GetFont();
-        s_fontWidthCache.m_scaleX = m_scaleX;
-    }
-
-    // Calculate the position of each character based on the widths of
-    // the previous characters
-    int w, h;
-    for ( size_t i = 0; i < len; i++ )
-    {
-        const wxChar c = text[i];
-        unsigned int c_int = (unsigned int)c;
-
-        if ((c_int < FWC_SIZE) && (s_fontWidthCache.m_widths[c_int] != 0))
-        {
-            w = s_fontWidthCache.m_widths[c_int];
-        }
-        else
-        {
-            DoGetTextExtent(c, &w, &h);
-            if (c_int < FWC_SIZE)
-                s_fontWidthCache.m_widths[c_int] = w;
-        }
-
-        totalWidth += w;
-        widths[i] = totalWidth;
-    }
-
-    return true;
+    wxTextMeasure tm(GetOwner(), &m_font);
+    return tm.GetPartialTextExtents(text, widths, m_scaleX);
 }
 
 void wxDCImpl::GetMultiLineTextExtent(const wxString& text,
@@ -591,64 +525,8 @@ void wxDCImpl::GetMultiLineTextExtent(const wxString& text,
                                       wxCoord *h,
                                       const wxFont *font) const
 {
-    wxCoord widthTextMax = 0, widthLine,
-            heightTextTotal = 0, heightLineDefault = 0, heightLine = 0;
-
-    wxString curLine;
-    for ( wxString::const_iterator pc = text.begin(); ; ++pc )
-    {
-        if ( pc == text.end() || *pc == wxT('\n') )
-        {
-            if ( curLine.empty() )
-            {
-                // we can't use GetTextExtent - it will return 0 for both width
-                // and height and an empty line should count in height
-                // calculation
-
-                // assume that this line has the same height as the previous
-                // one
-                if ( !heightLineDefault )
-                    heightLineDefault = heightLine;
-
-                if ( !heightLineDefault )
-                {
-                    // but we don't know it yet - choose something reasonable
-                    DoGetTextExtent(wxT("W"), NULL, &heightLineDefault,
-                                  NULL, NULL, font);
-                }
-
-                heightTextTotal += heightLineDefault;
-            }
-            else
-            {
-                DoGetTextExtent(curLine, &widthLine, &heightLine,
-                              NULL, NULL, font);
-                if ( widthLine > widthTextMax )
-                    widthTextMax = widthLine;
-                heightTextTotal += heightLine;
-            }
-
-            if ( pc == text.end() )
-            {
-               break;
-            }
-            else // '\n'
-            {
-               curLine.clear();
-            }
-        }
-        else
-        {
-            curLine += *pc;
-        }
-    }
-
-    if ( x )
-        *x = widthTextMax;
-    if ( y )
-        *y = heightTextTotal;
-    if ( h )
-        *h = heightLine;
+    wxTextMeasure tm(GetOwner(), font && font->IsOk() ? font : &m_font);
+    tm.GetMultiLineTextExtent(text, x, y, h);
 }
 
 void wxDCImpl::DoDrawCheckMark(wxCoord x1, wxCoord y1,