+
+// ----------------------------------------------------------------------------
+// Generic and inefficient DoGetPartialTextExtents() implementation.
+// ----------------------------------------------------------------------------
+
+// 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 wxTextMeasureBase::DoGetPartialTextExtents(const wxString& text,
+ wxArrayInt& widths,
+ double scaleX)
+{
+ int totalWidth = 0;
+
+ // reset the cache if font or horizontal scale have changed
+ if ( !s_fontWidthCache.m_widths ||
+ !wxIsSameDouble(s_fontWidthCache.m_scaleX, scaleX) ||
+ (s_fontWidthCache.m_font != *m_font) )
+ {
+ s_fontWidthCache.Reset();
+ s_fontWidthCache.m_font = *m_font;
+ s_fontWidthCache.m_scaleX = scaleX;
+ }
+
+ // Calculate the position of each character based on the widths of
+ // the previous characters. This is inexact for not fixed fonts.
+ int n = 0;
+ for ( wxString::const_iterator it = text.begin();
+ it != text.end();
+ ++it )
+ {
+ const wxChar c = *it;
+ unsigned int c_int = (unsigned int)c;
+
+ int w;
+ if ((c_int < FWC_SIZE) && (s_fontWidthCache.m_widths[c_int] != 0))
+ {
+ w = s_fontWidthCache.m_widths[c_int];
+ }
+ else
+ {
+ DoGetTextExtent(c, &w, NULL);
+ if (c_int < FWC_SIZE)
+ s_fontWidthCache.m_widths[c_int] = w;
+ }
+
+ totalWidth += w;
+ widths[n++] = totalWidth;
+ }
+
+ return true;
+}
+