diff --git a/tools/convbdf.c b/tools/convbdf.c
old mode 100644
new mode 100755
index aae5b43..f09ec07
--- a/tools/convbdf.c
+++ b/tools/convbdf.c
@@ -443,6 +443,9 @@ int bdf_read_header(FILE *fp, struct font* pf)
     /* use the font boundingbox to get initial maxwidth*/
     /*maxwidth = pf->fbbw - pf->fbbx;*/
     maxwidth = pf->fbbw;
+    if (pf->fbbx < 0)
+       maxwidth -= pf->fbbx;
+    pf->maxwidth = maxwidth;
 
     /* initially use font maxwidth * height for bits allocation*/
     pf->bits_size = nchars * BITMAP_WORDS(maxwidth) * pf->height;
@@ -535,12 +538,19 @@ int bdf_read_bitmaps(FILE *fp, struct font* pf)
             /* calc char width*/
             if (bbx < 0) {
                 width -= bbx;
-				/*if (width > maxwidth)
-                                  width = maxwidth;*/
+                /*if (width > maxwidth)
+                      width = maxwidth;*/
                 bbx = 0;
             }
             if (width > maxwidth)
                 maxwidth = width;
+            if (maxwidth > pf->maxwidth)
+            {
+                fprintf(stderr,
+                        "Error: %s character %d protrudes from bounding box\n",
+                        pf->facename, encoding);
+                return 0;
+            }
             pf->width[encoding-pf->firstchar] = width;
 
             /* clear bitmap*/