[dia] svg: improved viewBox interpretation

[Hans Breuer <hans src gnome org>]

commit dc61e85f3e7cf83a064e903900810ef44e5de282
Author: Hans Breuer <hans breuer org>
Date:   Sun Sep 1 15:00:28 2013 +0200

    svg: improved viewBox interpretation
    
    - respect the viewBox attribute including floats and
      typical SVG number separators
    - improve round-trip by only using viewBox width and
      height to calculate the user scale

 plug-ins/svg/svg-import.c |   29 +++++++++++++++++++++++------
 1 files changed, 23 insertions(+), 6 deletions(-)
---
diff --git a/plug-ins/svg/svg-import.c b/plug-ins/svg/svg-import.c
index 8193dc9..331fa7a 100644
--- a/plug-ins/svg/svg-import.c
+++ b/plug-ins/svg/svg-import.c
@@ -1184,17 +1184,34 @@ _node_read_viewbox (xmlNodePtr root, DiaMatrix **mat)
   xmlChar *sviewbox = xmlGetProp(root, (const xmlChar *)"viewBox");
 
   if (swidth && sheight && sviewbox) {
-    real width = get_value_as_cm ((const char *)swidth, NULL);
-    real height = get_value_as_cm ((const char *)sheight, NULL);
-    gint x1 = 0, y1 = 0, x2 = 0, y2 = 0;
+    real width, height;
+    gchar *remains = NULL;
+    gboolean percent;
+    gchar **vals;
       
-    if (4 == sscanf ((const char *)sviewbox, "%d %d %d %d", &x1, &y1, &x2, &y2)) {
+    width = get_value_as_cm ((const char *)swidth, &remains);
+    percent = (remains && *remains == '%');
+    height = get_value_as_cm ((const char *)sheight, &remains);
+    percent |= (remains && *remains == '%');
+    vals = g_regex_split_simple ("[\\s,;]+", (const char *)sviewbox, 0, 0);
+
+    if (vals && vals[0] && vals[1] && vals[2] && vals[3]) {
+      real x1, y1, x2, y2;
       real xs, ys;
+      x1 = g_ascii_strtod (vals[0], NULL);
+      y1 = g_ascii_strtod (vals[1], NULL);
+      x2 = g_ascii_strtod (vals[2], NULL);
+      y2 = g_ascii_strtod (vals[3], NULL);
       g_debug ("viewBox(%d %d %d %d) = (%f,%f)\n", x1, y1, x2, y2, width, height);
       /* some basic sanity check */
       if (x2 > x1 && y2 > y1 && width > 0 && height > 0) {
-       xs = ((real)x2 - x1) / width;
-       ys = ((real)y2 - y1) / height;
+       if (!percent) {
+         /* viwBox is x-min y-min width height - so only use the latter for scaling */
+         xs = (real)x2 / width;
+         ys = (real)y2 / height;
+       } else {
+         xs = ys = DEFAULT_SVG_SCALE * (100.0 / sqrt(width*height));
+       }
        /* plausibility check, strictly speaking these are not required to be the same 
         * /or/ are they and Dia is writting a bogus viewBox?
         */