1 files changed, 20 insertions, 9 deletions

diff --git a/src/FbTk/XftFontImp.cc b/src/FbTk/XftFontImp.cc
index 6568457..fa34404 100644
--- a/src/FbTk/XftFontImp.cc
+++ b/src/FbTk/XftFontImp.cc
@@ -23,12 +23,14 @@
 #include "App.hh"
 #include "FbDrawable.hh"
 
-#include <math.h>
+#include <cmath>
+#include <cstdio>
+#include <algorithm>
 
 namespace FbTk {
 
 XftFontImp::XftFontImp(const char *name, bool utf8):
-    m_utf8mode(utf8), m_name("") {
+    m_utf8mode(utf8), m_name(""), m_maxlength(0x8000) {
 
     for (int r = ROT0; r <= ROT270; r++) {
         m_xftfonts[r] = 0;
@@ -56,12 +58,12 @@ bool XftFontImp::load(const std::string &name) {
         if (newxftfont == 0)
             return false;
     }
-    
+
     // destroy all old fonts and set new
     for (int r = ROT0; r <= ROT270; r++) {
         m_xftfonts_loaded[r] = false;
         if (m_xftfonts[r] != 0) {
-            XftFontClose(App::instance()->display(), m_xftfonts[r]);
+            XftFontClose(disp, m_xftfonts[r]);
             m_xftfonts[r] = 0;
         }
     }
@@ -70,6 +72,15 @@ bool XftFontImp::load(const std::string &name) {
     m_xftfonts_loaded[ROT0] = true;
     m_name = name;
 
+    // XGlyphInfo (used by XftFontImp::textWidth() / XftTextExtents8() etc)
+    // holds only type 'short' or 'unsigned short'. any text bigger than that
+    // yields either some negative or some 'wrapped' values ('integer
+    // overflow'). to prevent something like this we detect the maximium
+    // number of glyphs by calculating the amount of 'WW' (pretending a 'wide'
+    // glyph) fitting into 32k pixels 
+    unsigned int tw = textWidth("WW", 2);
+    m_maxlength = 0x8000 / tw;
+
     return true;
 }
 
@@ -156,15 +167,15 @@ unsigned int XftFontImp::textWidth(const char* text, unsigned int len) const {
 
     XftFont *font = m_xftfonts[ROT0];
 
+    len = std::min(len, m_maxlength);
+
 
 #ifdef HAVE_XFT_UTF8_STRING
     if (m_utf8mode) {
-        XftTextExtentsUtf8(disp,
-                           font,
-                           (XftChar8 *)text, len,
-                           &ginfo);
-        if (ginfo.xOff != 0)
+        XftTextExtentsUtf8(disp, font, (XftChar8 *)text, len, &ginfo);
+        if (ginfo.xOff != 0) {
             return ginfo.xOff;
+        }
 
         // the utf8 failed, try normal extents
     }