added safe check for Pango version and use it to avoid underline hack in wxDC::DrawText() (modified patch 1702301)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@45564 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/private.h

@@ -23,6 +23,16 @@
     #define GTK_CHECK_VERSION(a, b, c) 0
 #endif
 
+// pango_version_check symbol is quite recent ATM (4/2007)... so we
+// use our own wrapper which implements a smart trick.
+// Use this function as you'd use pango_version_check:
+//
+//  if (!wx_pango_version_check(1,18,0))
+//     ... call to a function available only in pango >= 1.18 ...
+//
+// and use it only to test for pango versions >= 1.16.0
+extern const gchar *wx_pango_version_check(int major, int minor, int micro);
+
 #if wxUSE_UNICODE
     #define wxGTK_CONV(s) wxConvUTF8.cWX2MB((s))
     #define wxGTK_CONV_ENC(s, enc) wxGTK_CONV((s))

src/gtk/dcclient.cpp

@@ -1472,11 +1472,11 @@ void wxWindowDC::DoDrawText( const wxString &text, wxCoord x, wxCoord y )
         return;
     size_t datalen = strlen(data);
 
-    // TODO: as soon as Pango provides a function to check at runtime its
-    //       version, we can use it to disable the underline hack for
-    //       Pango >= 1.16 as the "underline of leading/trailing spaces"
-    //       has been fixed there
-    bool needshack = underlined;
+    // in Pango >= 1.16 the "underline of leading/trailing spaces" bug
+    // has been fixed and thus the hack implemented below should never be used
+    static bool pangoOk = !wx_pango_version_check(1, 16, 0);
+
+    bool needshack = underlined && !pangoOk;
     char *hackstring = NULL;
 
     if (needshack)

src/gtk/utilsgtk.cpp

@@ -224,6 +224,28 @@ wxCharBuffer wxConvertFromGTK(const wxString& s, wxFontEncoding enc)
 
 #endif // !wxUSE_UNICODE
 
+// Returns false if version is certainly greater or equal than major.minor.micro
+// Returns true if version is lower than major.minor.micro OR it cannot be
+// determined and one should not rely on the availability of pango version
+// major.minor.micro, nor the non-availability
+const gchar *wx_pango_version_check (int major, int minor, int micro)
+{
+#ifdef PANGO_VERSION_MAJOR
+    if (!gtk_check_version (2,11,0))
+    {
+        // GTK+ 2.11 requires Pango >= 1.15.3 and pango_version_check
+        // was added in Pango 1.15.2 thus we know for sure the pango lib we're
+        // using has the pango_version_check function:
+        return pango_version_check (major, minor, micro);
+    }
+
+    return "can't check";
+#else // !PANGO_VERSION_MAJOR
+    return "too old headers";
+#endif
+}
+
+
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 // subprocess routines
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