+// ----------------------------------------------------------------------------
+// Partial Text Extents
+// ----------------------------------------------------------------------------
+
+
+// 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 wxDCBase::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
+ {
+ GetTextExtent(c, &w, &h);
+ if (c_int < FWC_SIZE)
+ s_fontWidthCache.m_widths[c_int] = w;
+ }
+
+ totalWidth += w;
+ widths[i] = totalWidth;
+ }
+
+ return true;
+}
+
+
projects / wxWidgets.git / blobdiff