X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/e0da9e871a3184daa1a32bcacbfdf6ddb9ed7db4..ad653fa23069c5d9378247084f03c9a718c3ad62:/src/common/textmeasurecmn.cpp

diff --git a/src/common/textmeasurecmn.cpp b/src/common/textmeasurecmn.cpp
index 4db3b892fb..f583662cd1 100644
--- a/src/common/textmeasurecmn.cpp
+++ b/src/common/textmeasurecmn.cpp
@@ -86,7 +86,9 @@ void wxTextMeasureBase::GetTextExtent(const wxString& string,
     if ( !height )
         height = &unusedHeight;
 
-    if ( string.empty() )
+    // Avoid even setting up the DC for measuring if we don't actually need to
+    // measure anything.
+    if ( string.empty() && !descent && !externalLeading )
     {
         *width =
         *height = 0;
@@ -198,3 +200,82 @@ bool wxTextMeasureBase::GetPartialTextExtents(const wxString& text,
 
     return DoGetPartialTextExtents(text, widths, scaleX);
 }
+
+// ----------------------------------------------------------------------------
+// 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;
+}
+