merged with trunk so I can build again...

(bzr r10092.1.36)

26 files changed, 472 insertions, 450 deletions

diff --git a/src/trace/CMakeLists.txt b/src/trace/CMakeLists.txt
index 3cb378995..958907df6 100644
--- a/src/trace/CMakeLists.txt
+++ b/src/trace/CMakeLists.txt
@@ -1,13 +1,43 @@
-ADD_SUBDIRECTORY(potrace)
-SET(trace_SRC
-filterset.cpp
-imagemap.cpp
-imagemap-gdk.cpp
-quantize.cpp
-siox.cpp
-trace.cpp
-${trace_potrace_SRC}
+
+set(trace_SRC
+	filterset.cpp
+	imagemap.cpp
+	imagemap-gdk.cpp
+	quantize.cpp
+	siox.cpp
+	trace.cpp
+
+	potrace/curve.cpp
+	potrace/decompose.cpp
+	potrace/greymap.cpp
+	potrace/inkscape-potrace.cpp
+	potrace/potracelib.cpp
+	potrace/render.cpp
+	potrace/trace.cpp
+
+
+	# -------
+	# Headers
+	filterset.h
+	imagemap-gdk.h
+	imagemap.h
+	pool.h
+	quantize.h
+	siox.h
+	trace.h
+
+	potrace/auxiliary.h
+	potrace/bitmap.h
+	potrace/curve.h
+	potrace/decompose.h
+	potrace/greymap.h
+	potrace/inkscape-potrace.h
+	potrace/lists.h
+	potrace/potracelib.h
+	potrace/progress.h
+	potrace/render.h
+	potrace/trace.h
 )
-ADD_LIBRARY(trace STATIC ${trace_SRC})
-TARGET_LINK_LIBRARIES(trace
-2geom ${INKSCAPE_LIBS})
\ No newline at end of file
+
+# add_inkscape_lib(trace_LIB "${trace_SRC}")
+add_inkscape_source("${trace_SRC}")
diff --git a/src/trace/imagemap-gdk.cpp b/src/trace/imagemap-gdk.cpp
index e217dd619..e5ff23ad0 100644
--- a/src/trace/imagemap-gdk.cpp
+++ b/src/trace/imagemap-gdk.cpp
@@ -190,9 +190,9 @@ RgbMap *gdkPixbufToRgbMap(GdkPixbuf *buf)
             {
             int alpha = (int)p[3];
             int white = 255 - alpha;
-            int r     = (int)p[0];  r = r * alpha / 256 + white;
+            int r     = (int)p[2];  r = r * alpha / 256 + white;
             int g     = (int)p[1];  g = g * alpha / 256 + white;
-            int b     = (int)p[2];  b = b * alpha / 256 + white;
+            int b     = (int)p[0];  b = b * alpha / 256 + white;
 
             rgbMap->setPixel(rgbMap, x, y, r, g, b);
             p += n_channels;
diff --git a/src/trace/imagemap.cpp b/src/trace/imagemap.cpp
index a9ad9b9c8..c5a6bc2b5 100644
--- a/src/trace/imagemap.cpp
+++ b/src/trace/imagemap.cpp
@@ -78,10 +78,16 @@ GrayMap *GrayMapCreate(int width, int height)
     me->height = height;
     me->pixels = (unsigned long *)
               malloc(sizeof(unsigned long) * width * height);
+    if (!me->pixels)
+        {
+        free(me);
+        return NULL;
+        }
     me->rows = (unsigned long **)
               malloc(sizeof(unsigned long *) *  height);
-    if (!me->pixels || !me->rows)
+    if (!me->rows)
         {
+        free(me->pixels);
         free(me);
         return NULL;
         }
diff --git a/src/trace/potrace/CMakeLists.txt b/src/trace/potrace/CMakeLists.txt
deleted file mode 100644
index f61e8bcd1..000000000
--- a/src/trace/potrace/CMakeLists.txt
+++ /dev/null
@@ -1,9 +0,0 @@
-SET(trace_potrace_SRC
-curve.cpp
-decompose.cpp
-greymap.cpp
-inkscape-potrace.cpp
-potracelib.cpp
-render.cpp
-trace.cpp
-)
diff --git a/src/trace/potrace/auxiliary.h b/src/trace/potrace/auxiliary.h
index 7baab851c..b7480bbb8 100644
--- a/src/trace/potrace/auxiliary.h
+++ b/src/trace/potrace/auxiliary.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
@@ -75,4 +75,31 @@ static inline int floordiv(int a, int n) {
 #define sq(a) ((a)*(a))
 #define cu(a) ((a)*(a)*(a))
 
+/* ---------------------------------------------------------------------- */
+/* deterministically and efficiently hash (x,y) into a pseudo-random bit */
+static inline int detrand(int x, int y) {
+  unsigned int z;
+  static const unsigned char t[256] = { 
+    /* non-linear sequence: constant term of inverse in GF(8), 
+       mod x^8+x^4+x^3+x+1 */
+    0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 
+    0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 
+    0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 
+    1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1, 1, 
+    0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 
+    0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 
+    0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 
+    0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 
+    1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 
+    0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 
+    1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 
+  };
+
+  /* 0x04b3e375 and 0x05a8ef93 are chosen to contain every possible
+     5-bit sequence */
+  z = ((0x04b3e375 * x) ^ y) * 0x05a8ef93;
+  z = t[z & 0xff] ^ t[(z>>8) & 0xff] ^ t[(z>>16) & 0xff] ^ t[(z>>24) & 0xff];
+  return z;
+}
+
 #endif /* AUXILIARY_H */
diff --git a/src/trace/potrace/bitmap.h b/src/trace/potrace/bitmap.h
index 2a172b1ad..2df04b46f 100644
--- a/src/trace/potrace/bitmap.h
+++ b/src/trace/potrace/bitmap.h
@@ -1,14 +1,10 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
 #ifndef BITMAP_H
 #define BITMAP_H
 
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
-
 #include <string.h>
 #include <stdlib.h>
 
diff --git a/src/trace/potrace/curve.cpp b/src/trace/potrace/curve.cpp
index c9a6fbe04..d2e32aa7b 100644
--- a/src/trace/potrace/curve.cpp
+++ b/src/trace/potrace/curve.cpp
@@ -1,8 +1,7 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
-/* $Id$ */
 /* private part of the path and curve data structures */
 
 #include <stdio.h>
diff --git a/src/trace/potrace/curve.h b/src/trace/potrace/curve.h
index 45c0790be..6ceae0c3a 100644
--- a/src/trace/potrace/curve.h
+++ b/src/trace/potrace/curve.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
diff --git a/src/trace/potrace/decompose.cpp b/src/trace/potrace/decompose.cpp
index 15c39825e..708c17106 100644
--- a/src/trace/potrace/decompose.cpp
+++ b/src/trace/potrace/decompose.cpp
@@ -1,8 +1,7 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
-/* $Id$ */
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -12,11 +11,11 @@
 #include "potracelib.h"
 #include "curve.h"
 #include "lists.h"
-#include "auxiliary.h"
 #include "bitmap.h"
 #include "decompose.h"
 #include "progress.h"
 
+
 /* ---------------------------------------------------------------------- */
 /* auxiliary bitmap manipulations */
 
@@ -55,32 +54,6 @@ static void clear_bm_with_bbox(potrace_bitmap_t *bm, bbox_t *bbox) {
 /* ---------------------------------------------------------------------- */
 /* auxiliary functions */
 
-/* deterministically and efficiently hash (x,y) into a pseudo-random bit */
-static inline int detrand(int x, int y) {
-  unsigned int z;
-  static const unsigned char t[256] = { 
-    /* non-linear sequence: constant term of inverse in GF(8), 
-       mod x^8+x^4+x^3+x+1 */
-    0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 
-    0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 
-    0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 
-    1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0, 1, 1, 
-    0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 
-    0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 
-    0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 
-    0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 
-    1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 
-    0, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 
-    1, 1, 0, 0, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 
-  };
-
-  /* 0x04b3e375 and 0x05a8ef93 are chosen to contain every possible
-     5-bit sequence */
-  z = ((0x04b3e375 * x) ^ y) * 0x05a8ef93;
-  z = t[z & 0xff] ^ t[(z>>8) & 0xff] ^ t[(z>>16) & 0xff] ^ t[(z>>24) & 0xff];
-  return z & 1;
-}
-
 /* return the "majority" value of bitmap bm at intersection (x,y). We
    assume that the bitmap is balanced at "radius" 1.  */
 static int majority(potrace_bitmap_t *bm, int x, int y) {
@@ -304,7 +277,8 @@ static void pathlist_to_tree(path_t *plist, potrace_bitmap_t *bm) {
   path_t *heap, *heap1;
   path_t *cur;
   path_t *head;
-  path_t **hook, **hook_in, **hook_out; /* for fast appending to linked list */
+  path_t **plist_hook;          /* for fast appending to linked list */
+  path_t **hook_in, **hook_out; /* for fast appending to linked list */
   bbox_t bbox;
   
   bm_clear(bm, 0);
@@ -391,18 +365,18 @@ static void pathlist_to_tree(path_t *plist, potrace_bitmap_t *bm) {
     heap->next = NULL;  /* heap is a linked list of childlists */
   }
   plist = NULL;
-  hook = &plist;
+  plist_hook = &plist;
   while (heap) {
     heap1 = heap->next;
     for (p=heap; p; p=p->sibling) {
       /* p is a positive path */
       /* append to linked list */
-      list_insert_beforehook(p, hook);
+      list_insert_beforehook(p, plist_hook);
       
       /* go through its children */
       for (p1=p->childlist; p1; p1=p1->sibling) {
 	/* append to linked list */
-	list_insert_beforehook(p1, hook);
+	list_insert_beforehook(p1, plist_hook);
 	/* append its childlist to heap, if non-empty */
 	if (p1->childlist) {
 	  list_append(path_t, heap1, p1->childlist);
@@ -423,9 +397,12 @@ static void pathlist_to_tree(path_t *plist, potrace_bitmap_t *bm) {
 static int findnext(potrace_bitmap_t *bm, int *xp, int *yp) {
   int x;
   int y;
+  int x0;
+
+  x0 = (*xp) & ~(BM_WORDBITS-1);
 
   for (y=*yp; y>=0; y--) {
-    for (x=0; x<bm->w; x+=BM_WORDBITS) {
+    for (x=x0; x<bm->w; x+=BM_WORDBITS) {
       if (*bm_index(bm, x, y)) {
 	while (!BM_GET(bm, x, y)) {
 	  x++;
@@ -436,6 +413,7 @@ static int findnext(potrace_bitmap_t *bm, int *xp, int *yp) {
 	return 0;
       }
     }
+    x0 = 0;
   }
   /* not found */
   return 1;
@@ -451,7 +429,7 @@ int bm_to_pathlist(const potrace_bitmap_t *bm, path_t **plistp, const potrace_pa
   int y;
   path_t *p;
   path_t *plist = NULL;  /* linked list of path objects */
-  path_t **hook = &plist;  /* used to speed up appending to linked list */
+  path_t **plist_hook = &plist;  /* used to speed up appending to linked list */
   potrace_bitmap_t *bm1 = NULL;
   int sign;
 
@@ -465,6 +443,7 @@ int bm_to_pathlist(const potrace_bitmap_t *bm, path_t **plistp, const potrace_pa
   bm_clearexcess(bm1);
 
   /* iterate through components */
+  x = 0;
   y = bm1->h - 1;
   while (findnext(bm1, &x, &y) == 0) { 
     /* calculate the sign by looking at the original */
@@ -483,7 +462,7 @@ int bm_to_pathlist(const potrace_bitmap_t *bm, path_t **plistp, const potrace_pa
     if (p->area <= param->turdsize) {
       path_free(p);
     } else {
-      list_insert_beforehook(p, hook);
+      list_insert_beforehook(p, plist_hook);
     }
 
     if (bm1->h > 0) { /* to be sure */
diff --git a/src/trace/potrace/decompose.h b/src/trace/potrace/decompose.h
index 5552fa0a1..89b01e504 100644
--- a/src/trace/potrace/decompose.h
+++ b/src/trace/potrace/decompose.h
@@ -1,14 +1,14 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
-/* $Id$ */
 
 #ifndef DECOMPOSE_H
 #define DECOMPOSE_H
 
 #include "potracelib.h"
 #include "progress.h"
+#include "curve.h"
 
 int bm_to_pathlist(const potrace_bitmap_t *bm, path_t **plistp, const potrace_param_t *param, progress_t *progress);
 
diff --git a/src/trace/potrace/greymap.cpp b/src/trace/potrace/greymap.cpp
index 646ecc3a5..2495575e8 100644
--- a/src/trace/potrace/greymap.cpp
+++ b/src/trace/potrace/greymap.cpp
@@ -1,14 +1,12 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
-/* $Id$ */
 
 /* Routines for manipulating greymaps, including reading pgm files. We
    only deal with greymaps of depth 8 bits. */
 
 #include <stdlib.h>
-#include <errno.h>
 #include <string.h>
 #include <math.h>
 
@@ -28,7 +26,6 @@ static int gm_readbody_bmp(FILE *f, greymap_t **gmp);
 
 greymap_t *gm_new(int w, int h) {
   greymap_t *gm;
-  int errno_save;
 
   gm = (greymap_t *) malloc(sizeof(greymap_t));
   if (!gm) {
@@ -38,9 +35,7 @@ greymap_t *gm_new(int w, int h) {
   gm->h = h;
   gm->map = (signed short int *) malloc(w*h*sizeof(signed short int));
   if (!gm->map) {
-    errno_save = errno;
     free(gm);
-    errno = errno_save;
     return NULL;
   }
   return gm;
@@ -60,7 +55,7 @@ greymap_t *gm_dup(greymap_t *gm) {
   if (!gm1) {
     return NULL;
   }
-  memcpy(gm1->map, gm->map, gm->w*gm->h*2);
+  memcpy(gm1->map, gm->map, gm->w*gm->h*sizeof(signed short int));
   return gm1;
 }
 
@@ -69,7 +64,7 @@ void gm_clear(greymap_t *gm, int b) {
   int i;
 
   if (b==0) {
-    memset(gm->map, 0, gm->w*gm->h*2);
+    memset(gm->map, 0, gm->w*gm->h*sizeof(signed short int));
   } else {
     for (i=0; i<gm->w*gm->h; i++) {
       gm->map[i] = b;
@@ -161,16 +156,16 @@ static int readbit(FILE *f) {
 
 /* ---------------------------------------------------------------------- */
 
-char const *gm_read_error = NULL;
-
-/** Read a PNM stream: P1-P6 format (see pnm(5)), or a BMP stream, and
+/* read a PNM stream: P1-P6 format (see pnm(5)), or a BMP stream, and
    convert the output to a greymap. Return greymap in *gmp. Return 0
    on success, -1 on error with errno set, -2 on bad file format (with
    error message in gm_read_error), and 1 on premature end of file, -3
    on empty file (including files with only whitespace and comments),
    -4 if wrong magic number. If the return value is >=0, *gmp is
-   valid.
-   */
+   valid. */
+
+char const *gm_read_error = NULL;
+
 int gm_read(FILE *f, greymap_t **gmp) {
   int magic[2];
 
@@ -413,6 +408,7 @@ struct bmp_info_s {
   unsigned int ncolors;        /* number of colors in palette */
   unsigned int ColorsImportant;
   unsigned int ctbits;         /* sample size for color table */
+  int topdown;                 /* top-down mode? */
 };
 typedef struct bmp_info_s bmp_info_t;
 
@@ -481,6 +477,9 @@ static int bmp_forward(FILE *f, int pos) {
 #define TRY(x) if (x) goto try_error
 #define TRY_EOF(x) if (x) goto eof
 
+/* correct y-coordinate for top-down format */
+#define ycorr(y) (bmpinfo.topdown ? bmpinfo.h-1-y : y)
+
 /* read BMP stream after magic number. Return values as for gm_read.
    We choose to be as permissive as possible, since there are many
    programs out there which produce BMP. For instance, ppmtobmp can
@@ -512,7 +511,8 @@ static int gm_readbody_bmp(FILE *f, greymap_t **gmp) {
 
   /* info header */
   TRY(bmp_readint(f, 4, &bmpinfo.InfoSize));
-  if (bmpinfo.InfoSize == 40 || bmpinfo.InfoSize == 64) {
+  if (bmpinfo.InfoSize == 40 || bmpinfo.InfoSize == 64
+      || bmpinfo.InfoSize == 108 || bmpinfo.InfoSize == 124) {
     /* Windows or new OS/2 format */
     bmpinfo.ctbits = 32; /* sample size in color table */
     TRY(bmp_readint(f, 4, &bmpinfo.w));
@@ -525,6 +525,12 @@ static int gm_readbody_bmp(FILE *f, greymap_t **gmp) {
     TRY(bmp_readint(f, 4, &bmpinfo.YpixelsPerM));
     TRY(bmp_readint(f, 4, &bmpinfo.ncolors));
     TRY(bmp_readint(f, 4, &bmpinfo.ColorsImportant));
+    if ((signed int)bmpinfo.h < 0) {
+      bmpinfo.h = -bmpinfo.h;
+      bmpinfo.topdown = 1;
+    } else {
+      bmpinfo.topdown = 0;
+    }
   } else if (bmpinfo.InfoSize == 12) {
     /* old OS/2 format */
     bmpinfo.ctbits = 24; /* sample size in color table */
@@ -534,11 +540,12 @@ static int gm_readbody_bmp(FILE *f, greymap_t **gmp) {
     TRY(bmp_readint(f, 2, &bmpinfo.bits));
     bmpinfo.comp = 0;
     bmpinfo.ncolors = 0;
+    bmpinfo.topdown = 0;
   } else {
     goto format_error;
   }
 
-  /* forward to color table (i.e., if bmpinfo.InfoSize == 64) */
+  /* forward to color table (e.g., if bmpinfo.InfoSize == 64) */
   TRY(bmp_forward(f, 14+bmpinfo.InfoSize));
 
   if (bmpinfo.Planes != 1) {
@@ -593,7 +600,7 @@ static int gm_readbody_bmp(FILE *f, greymap_t **gmp) {
       for (i=0; 8*i<bmpinfo.w; i++) {
 	TRY_EOF(bmp_readint(f, 1, &b));
 	for (j=0; j<8; j++) {
-	  GM_PUT(gm, i*8+j, y, b & (0x80 >> j) ? coltable[1] : coltable[0]);
+	  GM_PUT(gm, i*8+j, ycorr(y), b & (0x80 >> j) ? coltable[1] : coltable[0]);
 	}
       }
       TRY(bmp_pad(f));
@@ -620,7 +627,7 @@ static int gm_readbody_bmp(FILE *f, greymap_t **gmp) {
 	b = bitbuf >> (INTBITS - bmpinfo.bits);
 	bitbuf <<= bmpinfo.bits;
 	n -= bmpinfo.bits;
-	GM_UPUT(gm, x, y, coltable[b]);
+	GM_UPUT(gm, x, ycorr(y), coltable[b]);
       }
       TRY(bmp_pad(f));
     }
@@ -640,7 +647,7 @@ static int gm_readbody_bmp(FILE *f, greymap_t **gmp) {
       for (x=0; x<bmpinfo.w; x++) {
         TRY_EOF(bmp_readint(f, bmpinfo.bits/8, &c));
 	c = ((c>>16) & 0xff) + ((c>>8) & 0xff) + (c & 0xff);
-        GM_UPUT(gm, x, y, c/3);
+        GM_UPUT(gm, x, ycorr(y), c/3);
       }
       TRY(bmp_pad(f));
     }
@@ -664,7 +671,7 @@ static int gm_readbody_bmp(FILE *f, greymap_t **gmp) {
 	  if (y>=bmpinfo.h) {
 	    break;
 	  }
-	  GM_UPUT(gm, x, y, col[i&1]);
+	  GM_UPUT(gm, x, ycorr(y), col[i&1]);
 	  x++;
 	}
       } else if (c == 0) {
@@ -693,7 +700,7 @@ static int gm_readbody_bmp(FILE *f, greymap_t **gmp) {
 	  if (y>=bmpinfo.h) {
 	    break;
 	  }
-	  GM_PUT(gm, x, y, coltable[(b>>(4-4*(i&1))) & 0xf]);
+	  GM_PUT(gm, x, ycorr(y), coltable[(b>>(4-4*(i&1))) & 0xf]);
 	  x++;
 	}
 	if ((c+1) & 2) {
@@ -720,7 +727,7 @@ static int gm_readbody_bmp(FILE *f, greymap_t **gmp) {
 	  if (y>=bmpinfo.h) {
 	    break;
 	  }
-	  GM_UPUT(gm, x, y, coltable[c]);
+	  GM_UPUT(gm, x, ycorr(y), coltable[c]);
 	  x++;
 	}
       } else if (c == 0) {
@@ -747,7 +754,7 @@ static int gm_readbody_bmp(FILE *f, greymap_t **gmp) {
           if (y>=bmpinfo.h) {
             break;
           }
-	  GM_PUT(gm, x, y, coltable[b]);
+	  GM_PUT(gm, x, ycorr(y), coltable[b]);
 	  x++;
 	}
 	if (c & 1) {
diff --git a/src/trace/potrace/greymap.h b/src/trace/potrace/greymap.h
index 059fec4e4..1fb5426c1 100644
--- a/src/trace/potrace/greymap.h
+++ b/src/trace/potrace/greymap.h
@@ -1,11 +1,10 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
-/* $Id$ */
 
-#ifndef PGM_H
-#define PGM_H
+#ifndef GREYMAP_H
+#define GREYMAP_H
 
 #include <stdio.h>
 
@@ -55,4 +54,4 @@ int gm_read(FILE *f, greymap_t **gmp);
 int gm_writepgm(FILE *f, greymap_t *gm, char *comment, int raw, int mode, double gamma);
 int gm_print(FILE *f, greymap_t *gm);
 
-#endif /* PGM_H */
+#endif /* GREYMAP_H */
diff --git a/src/trace/potrace/inkscape-potrace.cpp b/src/trace/potrace/inkscape-potrace.cpp
index 2f4dc7a6f..0907573e9 100644
--- a/src/trace/potrace/inkscape-potrace.cpp
+++ b/src/trace/potrace/inkscape-potrace.cpp
@@ -18,6 +18,7 @@
 
 #include <glibmm/i18n.h>
 #include <gtkmm.h>
+#include <iomanip>
 
 #include "trace/filterset.h"
 #include "trace/quantize.h"
@@ -31,7 +32,7 @@
 #include "curve.h"
 #include "bitmap.h"
 
-
+using Glib::ustring;
 
 static void updateGui()
 {
@@ -57,6 +58,12 @@ static void potraceStatusCallback(double /*progress*/, void *userData) /* callba
 }
 
 
+namespace {
+ustring twohex( int value )
+{
+    return ustring::format(std::hex, std::setfill(L'0'), std::setw(2), value);
+}
+} // namespace
 
 
 //required by potrace
@@ -70,20 +77,23 @@ namespace Potrace {
 /**
  *
  */
-PotraceTracingEngine::PotraceTracingEngine()
+PotraceTracingEngine::PotraceTracingEngine() :
+    keepGoing(1),
+    traceType(TRACE_BRIGHTNESS),
+    invert(false),
+    quantizationNrColors(8),
+    brightnessThreshold(0.45),
+    brightnessFloor(0),
+    cannyHighThreshold(0.65),
+    multiScanNrColors(8),
+    multiScanStack(true),
+    multiScanSmooth(false),
+    multiScanRemoveBackground(false)
 {
     /* get default parameters */
     potraceParams = potrace_param_default();
     potraceParams->progress.callback = potraceStatusCallback;
     potraceParams->progress.data = (void *)this;
-
-    //##### Our defaults
-    invert    = false;
-    traceType = TRACE_BRIGHTNESS;
-    quantizationNrColors = 8;
-    brightnessThreshold  = 0.45;
-    cannyHighThreshold   = 0.65;
-
 }
 
 PotraceTracingEngine::~PotraceTracingEngine()
@@ -471,67 +481,56 @@ PotraceTracingEngine::traceGrayMap(GrayMap *grayMap)
 /**
  *  Called for multiple-scanning algorithms
  */
-std::vector<TracingEngineResult>
-PotraceTracingEngine::traceBrightnessMulti(GdkPixbuf * thePixbuf)
+std::vector<TracingEngineResult> PotraceTracingEngine::traceBrightnessMulti(GdkPixbuf * thePixbuf)
 {
-
     std::vector<TracingEngineResult> results;
 
-    if (!thePixbuf)
-        return results;
+    if ( thePixbuf ) {
+        double low     = 0.2; //bottom of range
+        double high    = 0.9; //top of range
+        double delta   = (high - low ) / ((double)multiScanNrColors);
 
-    double low     = 0.2; //bottom of range
-    double high    = 0.9; //top of range
-    double delta   = (high - low ) / ((double)multiScanNrColors);
+        brightnessFloor = 0.0; //Set bottom to black
 
-    brightnessFloor = 0.0; //Set bottom to black
+        int traceCount = 0;
 
-    int traceCount = 0;
+        for ( brightnessThreshold = low ;
+              brightnessThreshold <= high ;
+              brightnessThreshold += delta) {
+            GrayMap *grayMap = filter(*this, thePixbuf);
+            if ( grayMap ) {
+                long nodeCount;
+                std::string d = grayMapToPath(grayMap, &nodeCount);
 
-    for ( brightnessThreshold = low ;
-          brightnessThreshold <= high ;
-          brightnessThreshold += delta)
-
-        {
+                grayMap->destroy(grayMap);
 
-        GrayMap *grayMap = filter(*this, thePixbuf);
-        if (!grayMap)
-            return results;
+                if ( !d.empty() ) {
+                    //### get style info
+                    int grayVal = (int)(256.0 * brightnessThreshold);
+                    ustring style = ustring::compose("fill-opacity:1.0;fill:%1%2%3", twohex(grayVal), twohex(grayVal), twohex(grayVal) );
 
-        long nodeCount;
-        std::string d = grayMapToPath(grayMap, &nodeCount);
+                    //g_message("### GOT '%s' \n", style.c_str());
+                    TracingEngineResult result(style, d, nodeCount);
+                    results.push_back(result);
 
-        grayMap->destroy(grayMap);
+                    if (!multiScanStack) {
+                        brightnessFloor = brightnessThreshold;
+                    }
 
-        if (d.size() == 0)
-            return results;
-
-        int grayVal = (int)(256.0 * brightnessThreshold);
-        char style[31];
-        sprintf(style, "fill-opacity:1.0;fill:#%02x%02x%02x",
-                    grayVal, grayVal, grayVal);
-
-        //g_message("### GOT '%s' \n", d);
-        TracingEngineResult result(style, d, nodeCount);
-        results.push_back(result);
-
-        if (!multiScanStack)
-            brightnessFloor = brightnessThreshold;
-
-        SPDesktop *desktop = SP_ACTIVE_DESKTOP;
-        if (desktop)
-            {
-            gchar *msg = g_strdup_printf(_("Trace: %d.  %ld nodes"), traceCount++, nodeCount);
-            sp_desktop_message_stack(desktop)->flash(Inkscape::NORMAL_MESSAGE, msg);
-            g_free(msg);
+                    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+                    if (desktop) {
+                        ustring msg = ustring::compose(_("Trace: %1.  %2 nodes"), traceCount++, nodeCount);
+                        sp_desktop_message_stack(desktop)->flash(Inkscape::NORMAL_MESSAGE, msg);
+                    }
+                }
             }
         }
 
-    //# Remove the bottom-most scan, if requested
-    if (results.size() > 1 && multiScanRemoveBackground)
-        {
-        results.erase(results.end() - 1);
+        //# Remove the bottom-most scan, if requested
+        if (results.size() > 1 && multiScanRemoveBackground) {
+            results.erase(results.end() - 1);
         }
+    }
 
     return results;
 }
@@ -540,77 +539,64 @@ PotraceTracingEngine::traceBrightnessMulti(GdkPixbuf * thePixbuf)
 /**
  *  Quantization
  */
-std::vector<TracingEngineResult>
-PotraceTracingEngine::traceQuant(GdkPixbuf * thePixbuf)
+std::vector<TracingEngineResult> PotraceTracingEngine::traceQuant(GdkPixbuf * thePixbuf)
 {
-
     std::vector<TracingEngineResult> results;
 
-    if (!thePixbuf)
-        return results;
-
-    IndexedMap *iMap = filterIndexed(*this, thePixbuf);
-    if (!iMap)
-        return results;
-
-    //Create and clear a gray map
-    GrayMap *gm = GrayMapCreate(iMap->width, iMap->height);
-    for (int row=0 ; row<gm->height ; row++)
-        for (int col=0 ; col<gm->width ; col++)
-            gm->setPixel(gm, col, row, GRAYMAP_WHITE);
-
-
-    for (int colorIndex=0 ; colorIndex<iMap->nrColors ; colorIndex++)
-        {
-
-        /*Make a gray map for each color index */
-        for (int row=0 ; row<iMap->height ; row++)
-            {
-            for (int col=0 ; col<iMap->width ; col++)
-                {
-                int indx = (int) iMap->getPixel(iMap, col, row);
-                if (indx == colorIndex)
-                    gm->setPixel(gm, col, row, GRAYMAP_BLACK); //black
-                else if (!multiScanStack)
-                    gm->setPixel(gm, col, row, GRAYMAP_WHITE); //white
+    if (thePixbuf) {
+        IndexedMap *iMap = filterIndexed(*this, thePixbuf);
+        if ( iMap ) {
+            //Create and clear a gray map
+            GrayMap *gm = GrayMapCreate(iMap->width, iMap->height);
+            for (int row=0 ; row<gm->height ; row++) {
+                for (int col=0 ; col<gm->width ; col++) {
+                    gm->setPixel(gm, col, row, GRAYMAP_WHITE);
                 }
             }
 
-        //## Now we have a traceable graymap
-        long nodeCount;
-        std::string d = grayMapToPath(gm, &nodeCount);
-
-        if (d.size() == 0)
-            return results;
-
-        //### get style info
-        char style[13];
-        RGB rgb = iMap->clut[colorIndex];
-        sprintf(style, "fill:#%02x%02x%02x", rgb.r, rgb.g, rgb.b);
+            for (int colorIndex=0 ; colorIndex<iMap->nrColors ; colorIndex++) {
+                // Make a gray map for each color index
+                for (int row=0 ; row<iMap->height ; row++) {
+                    for (int col=0 ; col<iMap->width ; col++) {
+                        int indx = (int) iMap->getPixel(iMap, col, row);
+                        if (indx == colorIndex) {
+                            gm->setPixel(gm, col, row, GRAYMAP_BLACK); //black
+                        } else if (!multiScanStack) {
+                            gm->setPixel(gm, col, row, GRAYMAP_WHITE); //white
+                        }
+                    }
+                }
 
-        //g_message("### GOT '%s' \n", d);
-        TracingEngineResult result(style, d, nodeCount);
-        results.push_back(result);
+                //## Now we have a traceable graymap
+                long nodeCount;
+                std::string d = grayMapToPath(gm, &nodeCount);
 
-        SPDesktop *desktop = SP_ACTIVE_DESKTOP;
-        if (desktop)
-            {
-            gchar *msg = g_strdup_printf(_("Trace: %d.  %ld nodes"), colorIndex, nodeCount);
-            sp_desktop_message_stack(desktop)->flash(Inkscape::NORMAL_MESSAGE, msg);
-            g_free(msg);
-            }
+                if ( !d.empty() ) {
+                    //### get style info
+                    RGB rgb = iMap->clut[colorIndex];
+                    ustring style = ustring::compose("fill:#%1%2%3", twohex(rgb.r), twohex(rgb.g), twohex(rgb.b) );
 
+                    //g_message("### GOT '%s' \n", style.c_str());
+                    TracingEngineResult result(style, d, nodeCount);
+                    results.push_back(result);
 
-        }// for colorIndex
+                    SPDesktop *desktop = SP_ACTIVE_DESKTOP;
+                    if (desktop) {
+                        ustring msg = ustring::compose(_("Trace: %1.  %2 nodes"), colorIndex, nodeCount);
+                        sp_desktop_message_stack(desktop)->flash(Inkscape::NORMAL_MESSAGE, msg);
+                    }
+                }
+            }// for colorIndex
 
-    gm->destroy(gm);
-    iMap->destroy(iMap);
+            gm->destroy(gm);
+            iMap->destroy(iMap);
+        }
 
-    //# Remove the bottom-most scan, if requested
-    if (results.size() > 1 && multiScanRemoveBackground)
-        {
-        results.erase(results.end() - 1);
+        //# Remove the bottom-most scan, if requested
+        if (results.size() > 1 && multiScanRemoveBackground) {
+            results.erase(results.end() - 1);
         }
+    }
 
     return results;
 }
@@ -667,3 +653,13 @@ PotraceTracingEngine::abort()
 }  // namespace Trace
 }  // namespace Inkscape
 
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :
diff --git a/src/trace/potrace/inkscape-potrace.h b/src/trace/potrace/inkscape-potrace.h
index b32ab6461..f2fc9a71f 100644
--- a/src/trace/potrace/inkscape-potrace.h
+++ b/src/trace/potrace/inkscape-potrace.h
@@ -245,7 +245,7 @@ class PotraceTracingEngine : public TracingEngine
     potrace_param_t *potraceParams;
     TraceType traceType;
 
-    //## do i invert at the end?
+    //## do I invert at the end?
     bool invert;
 
     //## Color-->b&w quantization
@@ -286,3 +286,13 @@ class PotraceTracingEngine : public TracingEngine
 #endif  //__INKSCAPE_POTRACE_H__
 
 
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :
diff --git a/src/trace/potrace/lists.h b/src/trace/potrace/lists.h
index fc853398a..078129afc 100644
--- a/src/trace/potrace/lists.h
+++ b/src/trace/potrace/lists.h
@@ -1,8 +1,7 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
-/* $Id$ */
 
 #ifndef _PS_LISTS_H
 #define _PS_LISTS_H
diff --git a/src/trace/potrace/potracelib.cpp b/src/trace/potrace/potracelib.cpp
index 17e04cabb..0fb835593 100644
--- a/src/trace/potrace/potracelib.cpp
+++ b/src/trace/potrace/potracelib.cpp
@@ -1,10 +1,10 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
 #include <stdlib.h>
 #include <string.h>
-#include <glib/gstrfuncs.h>
+#include <glib.h>
 
 #include "potracelib.h"
 #include "inkscape-version.h"
@@ -35,79 +35,80 @@ static const potrace_param_t param_default = {
 /* Return a fresh copy of the set of default parameters, or NULL on
    failure with errno set. */
 potrace_param_t *potrace_param_default(void) {
-    potrace_param_t *p;
-
-    p = (potrace_param_t *) malloc(sizeof(potrace_param_t));
-    if (!p) {
-        return NULL;
-    }
-    memcpy(p, &param_default, sizeof(potrace_param_t));
-    return p;
+  potrace_param_t *p;
+
+  p = (potrace_param_t *) malloc(sizeof(potrace_param_t));
+  if (!p) {
+    return NULL;
+  }
+  memcpy(p, &param_default, sizeof(potrace_param_t));
+  return p;
 }
 
 /* On success, returns a Potrace state st with st->status ==
    POTRACE_STATUS_OK. On failure, returns NULL if no Potrace state
    could be created (with errno set), or returns an incomplete Potrace
-   state (with st->status == POTRACE_STATUS_INCOMPLETE). Complete or
-   incomplete Potrace state can be freed with potrace_state_free(). */
+   state (with st->status == POTRACE_STATUS_INCOMPLETE, and with errno
+   set). Complete or incomplete Potrace state can be freed with
+   potrace_state_free(). */
 potrace_state_t *potrace_trace(const potrace_param_t *param, const potrace_bitmap_t *bm) {
-    int r;
-    path_t *plist = NULL;
-    potrace_state_t *st;
-    progress_t prog;
-    progress_t subprog;
-
-    /* prepare private progress bar state */
-    prog.callback = param->progress.callback;
-    prog.data = param->progress.data;
-    prog.min = param->progress.min;
-    prog.max = param->progress.max;
-    prog.epsilon = param->progress.epsilon;
-    prog.d_prev = param->progress.min;
-
-    /* allocate state object */
-    st = (potrace_state_t *)malloc(sizeof(potrace_state_t));
-    if (!st) {
-        return NULL;
-    }
-
-    progress_subrange_start(0.0, 0.1, &prog, &subprog);
-
-    /* process the image */
-    r = bm_to_pathlist(bm, &plist, param, &subprog);
-    if (r) {
-        free(st);
-        return NULL;
-    }
-
-    st->status = POTRACE_STATUS_OK;
-    st->plist = plist;
-    st->priv = NULL;  /* private state currently unused */
-
-    progress_subrange_end(&prog, &subprog);
-
-    progress_subrange_start(0.1, 1.0, &prog, &subprog);
-
-    /* partial success. */
-    r = process_path(plist, param, &subprog);
-    if (r) {
-        st->status = POTRACE_STATUS_INCOMPLETE;
-    }
-
-    progress_subrange_end(&prog, &subprog);
-
-    return st;
+  int r;
+  path_t *plist = NULL;
+  potrace_state_t *st;
+  progress_t prog;
+  progress_t subprog;
+  
+  /* prepare private progress bar state */
+  prog.callback = param->progress.callback;
+  prog.data = param->progress.data;
+  prog.min = param->progress.min;
+  prog.max = param->progress.max;
+  prog.epsilon = param->progress.epsilon;
+  prog.d_prev = param->progress.min;
+
+  /* allocate state object */
+  st = (potrace_state_t *)malloc(sizeof(potrace_state_t));
+  if (!st) {
+    return NULL;
+  }
+
+  progress_subrange_start(0.0, 0.1, &prog, &subprog);
+
+  /* process the image */
+  r = bm_to_pathlist(bm, &plist, param, &subprog);
+  if (r) {
+    free(st);
+    return NULL;
+  }
+
+  st->status = POTRACE_STATUS_OK;
+  st->plist = plist;
+  st->priv = NULL;  /* private state currently unused */
+
+  progress_subrange_end(&prog, &subprog);
+
+  progress_subrange_start(0.1, 1.0, &prog, &subprog);
+
+  /* partial success. */
+  r = process_path(plist, param, &subprog);
+  if (r) {
+    st->status = POTRACE_STATUS_INCOMPLETE;
+  }
+
+  progress_subrange_end(&prog, &subprog);
+
+  return st;
 }
 
 /* free a Potrace state, without disturbing errno. */
 void potrace_state_free(potrace_state_t *st) {
-    pathlist_free(st->plist);
-    free(st);
+  pathlist_free(st->plist);
+  free(st);
 }
 
 /* free a parameter list, without disturbing errno. */
 void potrace_param_free(potrace_param_t *p) {
-    free(p);
+  free(p);
 }
 
 char *potrace_version(void) {
diff --git a/src/trace/potrace/potracelib.h b/src/trace/potrace/potracelib.h
index 0b93d65de..cd142a6e1 100644
--- a/src/trace/potrace/potracelib.h
+++ b/src/trace/potrace/potracelib.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
@@ -6,7 +6,11 @@
 #define POTRACELIB_H
 
 /* this file defines the API for the core Potrace library. For a more
-   detailed description of the API, see doc/potracelib.txt */
+   detailed description of the API, see potracelib.pdf */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 /* ---------------------------------------------------------------------- */
 /* tracing parameters */
@@ -128,4 +132,8 @@ void potrace_state_free(potrace_state_t *st);
    of potracelib */
 char *potrace_version(void);
 
+#ifdef  __cplusplus
+} /* end of extern "C" */
+#endif
+
 #endif /* POTRACELIB_H */
diff --git a/src/trace/potrace/progress.h b/src/trace/potrace/progress.h
index 0e077430d..93a1fa3f0 100644
--- a/src/trace/potrace/progress.h
+++ b/src/trace/potrace/progress.h
@@ -1,4 +1,4 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
@@ -28,7 +28,7 @@ typedef struct progress_s progress_t;
 static inline void progress_update(double d, progress_t *prog) {
   double d_scaled;
 
-  if (prog->callback != NULL) {
+  if (prog != NULL && prog->callback != NULL) {
     d_scaled = prog->min * (1-d) + prog->max * d;
     if (d == 1.0 || d_scaled >= prog->d_prev + prog->epsilon) {
       prog->callback(prog->min * (1-d) + prog->max * d, prog->data);
@@ -43,7 +43,7 @@ static inline void progress_update(double d, progress_t *prog) {
 static inline void progress_subrange_start(double a, double b, const progress_t *prog, progress_t *sub) {
   double min, max;
 
-  if (prog->callback == NULL) {
+  if (prog == NULL || prog->callback == NULL) {
     sub->callback = NULL;
     return;
   }
@@ -66,7 +66,7 @@ static inline void progress_subrange_start(double a, double b, const progress_t
 }
 
 static inline void progress_subrange_end(progress_t *prog, progress_t *sub) {
-  if (prog->callback != NULL) {
+  if (prog != NULL && prog->callback != NULL) {
     if (sub->callback == NULL) {
       progress_update(sub->b, prog);
     } else {
diff --git a/src/trace/potrace/render.cpp b/src/trace/potrace/render.cpp
index f9183b931..3c8f79c05 100644
--- a/src/trace/potrace/render.cpp
+++ b/src/trace/potrace/render.cpp
@@ -1,8 +1,7 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
-/* $Id$ */
 
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/src/trace/potrace/render.h b/src/trace/potrace/render.h
index 9c9d921d2..ad600156a 100644
--- a/src/trace/potrace/render.h
+++ b/src/trace/potrace/render.h
@@ -1,8 +1,7 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
-/* $Id$ */
 
 #ifndef RENDER_H
 #define RENDER_H
diff --git a/src/trace/potrace/trace.cpp b/src/trace/potrace/trace.cpp
index 909ffb712..f1e88a908 100644
--- a/src/trace/potrace/trace.cpp
+++ b/src/trace/potrace/trace.cpp
@@ -1,8 +1,7 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
-/* $Id$ */
 /* transform jaggy paths into smooth curves */
 
 #include <stdio.h>
@@ -483,28 +482,38 @@ static double penalty3(privpath_t *pp, int i, int j) {
   double a, b, c, s;
   double px, py, ex, ey;
 
-  int r=0; /* rotations from i to j */
+  int r = 0; /* rotations from i to j */
 
   if (j>=n) {
-    j-=n;
-    r+=1;
+    j -= n;
+    r = 1;
   }
   
-  x = sums[j+1].x-sums[i].x+r*sums[n].x;
-  y = sums[j+1].y-sums[i].y+r*sums[n].y;
-  x2 = sums[j+1].x2-sums[i].x2+r*sums[n].x2;
-  xy = sums[j+1].xy-sums[i].xy+r*sums[n].xy;
-  y2 = sums[j+1].y2-sums[i].y2+r*sums[n].y2;
-  k = j+1-i+r*n;
-  
-  px = (pt[i].x+pt[j].x)/2.0-pt[0].x;
-  py = (pt[i].y+pt[j].y)/2.0-pt[0].y;
-  ey = (pt[j].x-pt[i].x);
-  ex = -(pt[j].y-pt[i].y);
-
-  a = ((x2-2*x*px)/k+px*px);
-  b = ((xy-x*py-y*px)/k+px*py);
-  c = ((y2-2*y*py)/k+py*py);
+  /* critical inner loop: the "if" gives a 4.6 percent speedup */
+  if (r == 0) {
+    x = sums[j+1].x - sums[i].x;
+    y = sums[j+1].y - sums[i].y;
+    x2 = sums[j+1].x2 - sums[i].x2;
+    xy = sums[j+1].xy - sums[i].xy;
+    y2 = sums[j+1].y2 - sums[i].y2;
+    k = j+1 - i;
+  } else {
+    x = sums[j+1].x - sums[i].x + sums[n].x;
+    y = sums[j+1].y - sums[i].y + sums[n].y;
+    x2 = sums[j+1].x2 - sums[i].x2 + sums[n].x2;
+    xy = sums[j+1].xy - sums[i].xy + sums[n].xy;
+    y2 = sums[j+1].y2 - sums[i].y2 + sums[n].y2;
+    k = j+1 - i + n;
+  } 
+
+  px = (pt[i].x + pt[j].x) / 2.0 - pt[0].x;
+  py = (pt[i].y + pt[j].y) / 2.0 - pt[0].y;
+  ey = (pt[j].x - pt[i].x);
+  ex = -(pt[j].y - pt[i].y);
+
+  a = ((x2 - 2*x*px) / k + px*px);
+  b = ((xy - x*py - y*px) / k + px*py);
+  c = ((y2 - 2*y*py) / k + py*py);
   
   s = ex*ex*a + 2*ex*ey*b + ey*ey*c;
 
@@ -513,7 +522,7 @@ static double penalty3(privpath_t *pp, int i, int j) {
 
 /* find the optimal polygon. Fill in the m and po components. Return 1
    on failure with errno set, else 0. Non-cyclic version: assumes i=0
-   is in the polygon. Fixme: ### implement cyclic version. */
+   is in the polygon. Fixme: implement cyclic version. */
 static int bestpolygon(privpath_t *pp)
 {
   int i, j, m, k;     
@@ -576,7 +585,7 @@ static int bestpolygon(privpath_t *pp)
   seg1[0] = 0;
 
   /* now find the shortest path with m segments, based on penalty3 */
-  /* note: the outer 2 loops jointly have at most n interations, thus
+  /* note: the outer 2 loops jointly have at most n iterations, thus
      the worst-case behavior here is quadratic. In practice, it is
      close to linear since the inner loop tends to be short. */
   pen[0]=0;
@@ -828,24 +837,27 @@ static int adjust_vertices(privpath_t *pp) {
 /* ---------------------------------------------------------------------- */
 /* Stage 4: smoothing and corner analysis (Sec. 2.3.3) */
 
-/* Always succeeds and returns 0 */
-static int smooth(privcurve_t *curve, int sign, double alphamax) {
+/* reverse orientation of a path */
+static void reverse(privcurve_t *curve) {
+  int m = curve->n;
+  int i, j;
+  dpoint_t tmp;
+
+  for (i=0, j=m-1; i<j; i++, j--) {
+    tmp = curve->vertex[i];
+    curve->vertex[i] = curve->vertex[j];
+    curve->vertex[j] = tmp;
+  }
+}
+
+/* Always succeeds */
+static void smooth(privcurve_t *curve, double alphamax) {
   int m = curve->n;
 
   int i, j, k;
   double dd, denom, alpha;
   dpoint_t p2, p3, p4;
 
-  if (sign == '-') {
-    /* reverse orientation of negative paths */
-    for (i=0, j=m-1; i<j; i++, j--) {
-      dpoint_t tmp;
-      tmp = curve->vertex[i];
-      curve->vertex[i] = curve->vertex[j];
-      curve->vertex[j] = tmp;
-    }
-  }
-
   /* examine each vertex and find its best fit */
   for (i=0; i<m; i++) {
     j = mod(i+1, m);
@@ -885,7 +897,7 @@ static int smooth(privcurve_t *curve, int sign, double alphamax) {
   }
   curve->alphacurve = 1;
 
-  return 0;
+  return;
 }
 
 /* ---------------------------------------------------------------------- */
@@ -1098,7 +1110,7 @@ static int opticurve(privpath_t *pp, double opttolerance) {
   len[0] = 0;
 
   /* Fixme: we always start from a fixed point -- should find the best
-     curve cyclically ### */
+     curve cyclically */
 
   for (j=1; j<=m; j++) {
     /* calculate best path from 0 to j */
@@ -1206,7 +1218,10 @@ int process_path(path_t *plist, const potrace_param_t *param, progress_t *progre
     TRY(calc_lon(p->priv));
     TRY(bestpolygon(p->priv));
     TRY(adjust_vertices(p->priv));
-    TRY(smooth(&p->priv->curve, p->sign, param->alphamax));
+    if (p->sign == '-') {   /* reverse orientation of negative paths */
+      reverse(&p->priv->curve);
+    }
+    smooth(&p->priv->curve, param->alphamax);
     if (param->opticurve) {
       TRY(opticurve(p->priv, param->opttolerance));
       p->priv->fcurve = &p->priv->ocurve;
diff --git a/src/trace/potrace/trace.h b/src/trace/potrace/trace.h
index b33f8ba4d..dc2b9247a 100644
--- a/src/trace/potrace/trace.h
+++ b/src/trace/potrace/trace.h
@@ -1,14 +1,14 @@
-/* Copyright (C) 2001-2007 Peter Selinger.
+/* Copyright (C) 2001-2011 Peter Selinger.
    This file is part of Potrace. It is free software and it is covered
    by the GNU General Public License. See the file COPYING for details. */
 
-/* $Id$ */
 
 #ifndef TRACE_H
 #define TRACE_H
 
 #include "potracelib.h"
 #include "progress.h"
+#include "curve.h"
 
 int process_path(path_t *plist, const potrace_param_t *param, progress_t *progress);
 
diff --git a/src/trace/siox.cpp b/src/trace/siox.cpp
index b3404fc00..4c6cf1eac 100644
--- a/src/trace/siox.cpp
+++ b/src/trace/siox.cpp
@@ -584,7 +584,7 @@ void SioxImage::assign(const SioxImage &other)
 /**
  * Write the image to a PPM file
  */
-bool SioxImage::writePPM(const std::string fileName)
+bool SioxImage::writePPM(const std::string &fileName)
 {
 
     FILE *f = fopen(fileName.c_str(), "wb");
@@ -736,19 +736,33 @@ const float Siox::CERTAIN_BACKGROUND_CONFIDENCE=0.0f;
 /**
  *  Construct a Siox engine
  */
-Siox::Siox()
+Siox::Siox() :
+    sioxObserver(0),
+    keepGoing(true),
+    width(0),
+    height(0),
+    pixelCount(0),
+    image(0),
+    cm(0),
+    labelField(0)
 {
-    sioxObserver = NULL;
     init();
 }
 
 /**
  *  Construct a Siox engine
  */
-Siox::Siox(SioxObserver *observer)
+Siox::Siox(SioxObserver *observer) :
+    sioxObserver(observer),
+    keepGoing(true),
+    width(0),
+    height(0),
+    pixelCount(0),
+    image(0),
+    cm(0),
+    labelField(0)
 {
     init();
-    sioxObserver = observer;
 }
 
 
@@ -1011,7 +1025,7 @@ SioxImage Siox::extractForeground(const SioxImage &originalImage,
                     }
                 tupel.minFgDist  = minFg;
                 tupel.indexMinFg = minIndex;
-                if (fgSignature.size() == 0)
+                if (fgSignature.empty())
                     {
                     isBackground = (minBg <= clusterSize);
                     // remove next line to force behaviour of old algorithm
@@ -1414,7 +1428,7 @@ int Siox::depthFirstSearch(int startPos,
         }
 
 
-    while (pixelsToVisit.size() > 0)
+    while (!pixelsToVisit.empty())
         {
         int pos = pixelsToVisit[pixelsToVisit.size() - 1];
         pixelsToVisit.erase(pixelsToVisit.end() - 1);
@@ -1486,7 +1500,7 @@ void Siox::fillColorRegions()
         // int componentSize = 1;
         pixelsToVisit.push_back(i);
         // depth first search to fill region
-        while (pixelsToVisit.size() > 0)
+        while (!pixelsToVisit.empty())
             {
             int pos = pixelsToVisit[pixelsToVisit.size() - 1];
             pixelsToVisit.erase(pixelsToVisit.end() - 1);
diff --git a/src/trace/siox.h b/src/trace/siox.h
index 6b7256fe0..9a44ce1cf 100644
--- a/src/trace/siox.h
+++ b/src/trace/siox.h
@@ -1,6 +1,6 @@
-#ifndef __SIOX_H__
-#define __SIOX_H__
-/**
+#ifndef SEEN_SIOX_H
+#define SEEN_SIOX_H
+/*
  *  Copyright 2005, 2006 by Gerald Friedland, Kristian Jantz and Lars Knipping
  *
  *  Conversion to C++ for Inkscape by Bob Jamison
@@ -18,7 +18,7 @@
  *  limitations under the License.
  */
 
-/**
+/*
  * Note by Bob Jamison:
  * After translating the siox.org Java API to C++ and receiving an
  * education into this wonderful code,  I began again,
@@ -316,7 +316,7 @@ public:
     /**
      * Saves this image as a simple color PPM
      */
-    bool writePPM(const std::string fileName);
+    bool writePPM(const std::string &fileName);
 
 
 
@@ -508,11 +508,6 @@ private:
     bool keepGoing;
 
     /**
-     * Our signature limits
-     */
-    float limits[3];
-
-    /**
      * Image width
      */
     unsigned int width;
@@ -544,6 +539,11 @@ private:
 
 
     /**
+     * Our signature limits
+     */
+    float limits[3];
+
+    /**
      * Maximum distance of two lab values.
      */
     float clusterSize;
@@ -649,9 +649,6 @@ private:
      */
     float sqrEuclidianDist(float *p, int pSize, float *q);
 
-
-
-
 };
 
 
@@ -660,10 +657,7 @@ private:
 } // namespace siox
 } // namespace org
 
-#endif /* __SIOX_H__ */
+#endif // SEEN_SIOX_H
 //########################################################################
 //#  E N D    O F    F I L E
 //########################################################################
-
-
-
diff --git a/src/trace/trace.cpp b/src/trace/trace.cpp
index 1ee32e6bf..8f04d7a2d 100644
--- a/src/trace/trace.cpp
+++ b/src/trace/trace.cpp
@@ -1,4 +1,4 @@
-/**
+/*
  * A generic interface for plugging different
  *  autotracers into Inkscape.
  *
@@ -12,50 +12,33 @@
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
 
-
-
 #include "trace/potrace/inkscape-potrace.h"
 
-#include <inkscape.h>
-#include <desktop.h>
-#include <desktop-handles.h>
-#include <document.h>
-#include <message-stack.h>
+#include "inkscape.h"
+#include "desktop.h"
+#include "desktop-handles.h"
+#include "document.h"
+#include "message-stack.h"
 #include <gtkmm.h>
 #include <glibmm/i18n.h>
-#include <selection.h>
-#include <xml/repr.h>
-#include <xml/attribute-record.h>
-#include <sp-item.h>
-#include <sp-shape.h>
-#include <sp-image.h>
-#include <libnr/nr-matrix-ops.h>
+#include "selection.h"
+#include "xml/repr.h"
+#include "xml/attribute-record.h"
+#include "sp-item.h"
+#include "sp-shape.h"
+#include "sp-image.h"
 #include <2geom/transforms.h>
 
-#include <display/nr-arena.h>
-#include <display/nr-arena-shape.h>
+#include "display/drawing.h"
+#include "display/drawing-shape.h"
 
 #include "siox.h"
 #include "imagemap-gdk.h"
 
+namespace Inkscape {
+namespace Trace {
 
-
-namespace Inkscape
-{
-
-namespace Trace
-{
-
-
-
-
-
-/**
- * Get the selected image.  Also check for any SPItems over it, in
- * case the user wants SIOX pre-processing.
- */
-SPImage *
-Tracer::getSelectedSPImage()
+SPImage *Tracer::getSelectedSPImage()
 {
 
     SPDesktop *desktop = SP_ACTIVE_DESKTOP;
@@ -98,7 +81,7 @@ Tracer::getSelectedSPImage()
             items.insert(items.begin(), item);
             }
         std::vector<SPItem *>::iterator iter;
-        for (iter = items.begin() ; iter!= items.end() ; iter++)
+        for (iter = items.begin() ; iter!= items.end() ; ++iter)
             {
             SPItem *item = *iter;
             if (SP_IS_IMAGE(item))
@@ -210,13 +193,7 @@ public:
 
 
 
-/**
- * Process a GdkPixbuf, according to which areas have been
- * obscured in the GUI.
- */
-Glib::RefPtr<Gdk::Pixbuf>
-Tracer::sioxProcessImage(SPImage *img,
-             Glib::RefPtr<Gdk::Pixbuf>origPixbuf)
+Glib::RefPtr<Gdk::Pixbuf> Tracer::sioxProcessImage(SPImage *img, Glib::RefPtr<Gdk::Pixbuf>origPixbuf)
 {
     if (!sioxEnabled)
         return origPixbuf;
@@ -248,25 +225,25 @@ Tracer::sioxProcessImage(SPImage *img,
         return Glib::RefPtr<Gdk::Pixbuf>(NULL);
         }
 
-    NRArenaItem *aImg = img->get_arenaitem(desktop->dkey);
+    Inkscape::DrawingItem *aImg = img->get_arenaitem(desktop->dkey);
     //g_message("img: %d %d %d %d\n", aImg->bbox.x0, aImg->bbox.y0,
     //                                aImg->bbox.x1, aImg->bbox.y1);
 
-    double width  = (double)(aImg->bbox.x1 - aImg->bbox.x0);
-    double height = (double)(aImg->bbox.y1 - aImg->bbox.y0);
+    double width  = aImg->geometricBounds()->width();
+    double height = aImg->geometricBounds()->height();
 
-    double iwidth  = (double)simage.getWidth();
-    double iheight = (double)simage.getHeight();
+    double iwidth  = simage.getWidth();
+    double iheight = simage.getHeight();
 
     double iwscale = width  / iwidth;
     double ihscale = height / iheight;
 
-    std::vector<NRArenaItem *> arenaItems;
+    std::vector<Inkscape::DrawingItem *> arenaItems;
     std::vector<SPShape *>::iterator iter;
-    for (iter = sioxShapes.begin() ; iter!=sioxShapes.end() ; iter++)
+    for (iter = sioxShapes.begin() ; iter!=sioxShapes.end() ; ++iter)
         {
         SPItem *item = *iter;
-        NRArenaItem *aItem = item->get_arenaitem(desktop->dkey);
+        Inkscape::DrawingItem *aItem = item->get_arenaitem(desktop->dkey);
         arenaItems.push_back(aItem);
         }
 
@@ -279,25 +256,22 @@ Tracer::sioxProcessImage(SPImage *img,
 
     for (int row=0 ; row<iheight ; row++)
         {
-        double ypos = ((double)aImg->bbox.y0) + ihscale * (double) row;
+        double ypos = aImg->geometricBounds()->top() + ihscale * (double) row;
         for (int col=0 ; col<simage.getWidth() ; col++)
             {
             //Get absolute X,Y position
-            double xpos = ((double)aImg->bbox.x0) + iwscale * (double)col;
+            double xpos = aImg->geometricBounds()->left() + iwscale * (double)col;
             Geom::Point point(xpos, ypos);
-            if (aImg->transform)
-                point *= *aImg->transform;
+            point *= aImg->transform();
             //point *= imgMat;
             //point = desktop->doc2dt(point);
             //g_message("x:%f    y:%f\n", point[0], point[1]);
             bool weHaveAHit = false;
-            std::vector<NRArenaItem *>::iterator aIter;
-            for (aIter = arenaItems.begin() ; aIter!=arenaItems.end() ; aIter++)
+            std::vector<Inkscape::DrawingItem *>::iterator aIter;
+            for (aIter = arenaItems.begin() ; aIter!=arenaItems.end() ; ++aIter)
                 {
-                NRArenaItem *arenaItem = *aIter;
-                NRArenaItemClass *arenaClass =
-                    (NRArenaItemClass *) NR_OBJECT_GET_CLASS (arenaItem);
-                if (arenaClass->pick(arenaItem, point, 1.0f, 1))
+                Inkscape::DrawingItem *arenaItem = *aIter;
+                if (arenaItem->pick(point, 1.0f, 1))
                     {
                     weHaveAHit = true;
                     break;
@@ -339,17 +313,6 @@ Tracer::sioxProcessImage(SPImage *img,
 
     //result.writePPM("siox2.ppm");
 
-    /* Free Arena and ArenaItem */
-    /*
-    std::vector<NRArenaItem *>::iterator aIter;
-    for (aIter = arenaItems.begin() ; aIter!=arenaItems.end() ; aIter++)
-       {
-       NRArenaItem *arenaItem = *aIter;
-       nr_arena_item_unref(arenaItem);
-       }
-    nr_object_unref((NRObject *) arena);
-    */
-
     Glib::RefPtr<Gdk::Pixbuf> newPixbuf = Glib::wrap(result.getGdkPixbuf());
 
     //g_message("siox: done");
@@ -360,11 +323,7 @@ Tracer::sioxProcessImage(SPImage *img,
 }
 
 
-/**
- *
- */
-Glib::RefPtr<Gdk::Pixbuf>
-Tracer::getSelectedImage()
+Glib::RefPtr<Gdk::Pixbuf> Tracer::getSelectedImage()
 {
 
 
@@ -404,18 +363,12 @@ Tracer::getSelectedImage()
 //#  T R A C E
 //#########################################################################
 
-/**
- *  Whether we want to enable SIOX subimage selection
- */
 void Tracer::enableSiox(bool enable)
 {
     sioxEnabled = enable;
 }
 
 
-/**
- *  Threaded method that does single bitmap--->path conversion
- */
 void Tracer::traceThread()
 {
     //## Remember. NEVER leave this method without setting
@@ -585,9 +538,6 @@ void Tracer::traceThread()
 
 
 
-/**
- *  Main tracing method
- */
 void Tracer::trace(TracingEngine *theEngine)
 {
     //Check if we are already running
@@ -614,9 +564,6 @@ void Tracer::trace(TracingEngine *theEngine)
 
 
 
-/**
- *  Abort the thread that is executing trace()
- */
 void Tracer::abort()
 {
 
diff --git a/src/trace/trace.h b/src/trace/trace.h
index 2c9922e10..a7fbe0cc8 100644
--- a/src/trace/trace.h
+++ b/src/trace/trace.h
@@ -1,7 +1,4 @@
-/**
- * A generic interface for plugging different
- *  autotracers into Inkscape.
- *
+/*
  * Authors:
  *   Bob Jamison <rjamison@titan.com>
  *
@@ -9,8 +6,8 @@
  *
  * Released under GNU GPL, read the file 'COPYING' for more information
  */
-#ifndef __TRACE_H__
-#define __TRACE_H__
+#ifndef SEEN_TRACE_H
+#define SEEN_TRACE_H
 
 #ifdef HAVE_CONFIG_H
 # include "config.h"
@@ -30,7 +27,7 @@
 #include <sp-shape.h>
 
 struct SPImage;
-struct SPItem;
+class  SPItem;
 
 namespace Inkscape {
 
@@ -110,7 +107,8 @@ private:
 
 
 /**
- *
+ * A generic interface for plugging different
+ *  autotracers into Inkscape.
  */
 class TracingEngine
 {
@@ -209,7 +207,7 @@ public:
     void abort();
 
     /**
-     *  Whether we want to enable SIOX subimage selection
+     *  Whether we want to enable SIOX subimage selection.
      */
     void enableSiox(bool enable);
 
@@ -218,6 +216,7 @@ private:
 
     /**
      * This is the single path code that is called by its counterpart above.
+     * Threaded method that does single bitmap--->path conversion.
      */
     void traceThread();
 
@@ -233,14 +232,21 @@ private:
      */
     TracingEngine *engine;
 
+    /**
+     * Get the selected image.  Also check for any SPItems over it, in
+     * case the user wants SIOX pre-processing.
+     */
     SPImage *getSelectedSPImage();
 
     std::vector<SPShape *> sioxShapes;
 
     bool sioxEnabled;
 
-    Glib::RefPtr<Gdk::Pixbuf> sioxProcessImage(
-           SPImage *img, Glib::RefPtr<Gdk::Pixbuf> origPixbuf);
+    /**
+     * Process a GdkPixbuf, according to which areas have been
+     * obscured in the GUI.
+     */
+    Glib::RefPtr<Gdk::Pixbuf> sioxProcessImage(SPImage *img, Glib::RefPtr<Gdk::Pixbuf> origPixbuf);
 
     Glib::RefPtr<Gdk::Pixbuf> lastSioxPixbuf;
     Glib::RefPtr<Gdk::Pixbuf> lastOrigPixbuf;
@@ -256,7 +262,7 @@ private:
 
 
 
-#endif //__TRACE_H__
+#endif // SEEN_TRACE_H
 
 //#########################################################################
 //# E N D   O F   F I L E