Code

Gradient tool: fork gradients when adding a stop
[inkscape.git] / src / style.cpp
index e0d6532d451a760b72f6b91e0f389e076e59ad28..722f1677d6cdbff319a81aafe9b076970dfe0aea 100644 (file)
@@ -30,7 +30,6 @@
 #include "attributes.h"
 #include "document.h"
 #include "extract-uri.h"
-#include "marker-status.h"
 #include "uri-references.h"
 #include "sp-paint-server.h"
 #include "streq.h"
@@ -118,7 +117,7 @@ static void sp_style_clear(SPStyle *style);
 static void sp_style_merge_property(SPStyle *style, gint id, gchar const *val);
 
 static void sp_style_merge_ipaint(SPStyle *style, SPIPaint *paint, SPIPaint const *parent);
-static void sp_style_merge_ifilter(SPIFilter *child, SPIFilter const *parent);
+static void sp_style_merge_ifilter(SPStyle *style, SPIFilter const *parent);
 static void sp_style_read_dash(SPStyle *style, gchar const *str);
 
 static SPTextStyle *sp_text_style_new(void);
@@ -138,7 +137,7 @@ static void sp_style_read_itextdecoration(SPITextDecoration *val, gchar const *s
 static void sp_style_read_icolor(SPIPaint *paint, gchar const *str, SPStyle *style, SPDocument *document);
 static void sp_style_read_ipaint(SPIPaint *paint, gchar const *str, SPStyle *style, SPDocument *document);
 static void sp_style_read_ifontsize(SPIFontSize *val, gchar const *str);
-static void sp_style_read_ifilter(SPIFilter *f, gchar const *str, SPDocument *document);
+static void sp_style_read_ifilter(gchar const *str, SPStyle *style, SPDocument *document);
 
 static void sp_style_read_penum(SPIEnum *val, Inkscape::XML::Node *repr, gchar const *key, SPStyleEnum const *dict, bool can_explicitly_inherit);
 static void sp_style_read_plength(SPILength *val, Inkscape::XML::Node *repr, gchar const *key);
@@ -156,10 +155,10 @@ static gint sp_style_write_ilengthornormal(gchar *p, gint const len, gchar const
 static gint sp_style_write_itextdecoration(gchar *p, gint const len, gchar const *const key, SPITextDecoration const *const val, SPITextDecoration const *const base, guint const flags);
 static gint sp_style_write_ifilter(gchar *b, gint len, gchar const *key, SPIFilter const *filter, SPIFilter const *base, guint flags);
 
-static void css2_unescape_unquote(SPIString *val);
-
 static void sp_style_paint_clear(SPStyle *style, SPIPaint *paint);
 
+static void sp_style_filter_clear(SPStyle *style);
+
 #define SPS_READ_IENUM_IF_UNSET(v,s,d,i) if (!(v)->set) {sp_style_read_ienum((v), (s), (d), (i));}
 #define SPS_READ_PENUM_IF_UNSET(v,r,k,d,i) if (!(v)->set) {sp_style_read_penum((v), (r), (k), (d), (i));}
 
@@ -372,6 +371,12 @@ static SPStyleEnum const enum_text_rendering[] = {
     {NULL, -1}
 };
 
+static SPStyleEnum const enum_enable_background[] = {
+    {"accumulate", SP_CSS_BACKGROUND_ACCUMULATE},
+    {"new", SP_CSS_BACKGROUND_NEW},
+    {NULL, -1}
+};
+
 /**
  * Release callback.
  */
@@ -403,6 +408,9 @@ sp_style_new()
 
     style->fill_hreffed = false;
     style->stroke_hreffed = false;
+    style->filter_hreffed = false;
+
+    new (&style->release_connection) sigc::connection();
 
     new (&style->fill_release_connection) sigc::connection();
     new (&style->fill_modified_connection) sigc::connection();
@@ -410,6 +418,9 @@ sp_style_new()
     new (&style->stroke_release_connection) sigc::connection();
     new (&style->stroke_modified_connection) sigc::connection();
 
+    new (&style->filter_release_connection) sigc::connection();
+    new (&style->filter_modified_connection) sigc::connection();
+
     return style;
 }
 
@@ -425,7 +436,7 @@ sp_style_new_from_object(SPObject *object)
 
     SPStyle *style = sp_style_new();
     style->object = object;
-    g_signal_connect(G_OBJECT(object), "release", G_CALLBACK(sp_style_object_release), style);
+    style->release_connection = object->connectRelease(sigc::bind<1>(sigc::ptr_fun(&sp_style_object_release), style));
 
     if (object && SP_OBJECT_IS_CLONED(object)) {
         style->cloned = true;
@@ -462,12 +473,12 @@ sp_style_unref(SPStyle *style)
     style->refcount -= 1;
 
     if (style->refcount < 1) {
-        if (style->object)
-            g_signal_handlers_disconnect_matched(G_OBJECT(style->object),
-                                                 G_SIGNAL_MATCH_DATA, 0, 0, NULL, NULL, style);
+        style->release_connection.disconnect();
+        style->release_connection.~connection();
         if (style->text) sp_text_style_unref(style->text);
         sp_style_paint_clear(style, &style->fill);
         sp_style_paint_clear(style, &style->stroke);
+        sp_style_filter_clear(style);
         style->fill_release_connection.disconnect();
         style->fill_release_connection.~connection();
         style->fill_modified_connection.disconnect();
@@ -476,6 +487,10 @@ sp_style_unref(SPStyle *style)
         style->stroke_release_connection.~connection();
         style->stroke_modified_connection.disconnect();
         style->stroke_modified_connection.~connection();
+        style->filter_modified_connection.disconnect();
+        style->filter_modified_connection.~connection();
+        style->filter_release_connection.disconnect();
+        style->filter_release_connection.~connection();
         g_free(style->stroke_dash.dash);
         g_free(style);
     }
@@ -499,7 +514,7 @@ sp_style_read(SPStyle *style, SPObject *object, Inkscape::XML::Node *repr)
         style->cloned = true;
     }
 
-    /* 1. Style itself */
+    /* 1. Style attribute */
     gchar const *val = repr->attribute("style");
     if (val != NULL) {
         sp_style_merge_from_style_string(style, val);
@@ -660,8 +675,9 @@ sp_style_read(SPStyle *style, SPObject *object, Inkscape::XML::Node *repr)
         val = repr->attribute("font-family");
         if (val) {
             if (!style->text_private) sp_style_privatize_text(style);
-            sp_style_read_istring(&style->text->font_family, val);
-            css2_unescape_unquote(&style->text->font_family);
+            gchar *val_unquoted = attribute_unquote(val);
+            sp_style_read_istring(&style->text->font_family, val_unquoted);
+            if (val_unquoted) g_free (val_unquoted);
         }
     }
 
@@ -669,9 +685,11 @@ sp_style_read(SPStyle *style, SPObject *object, Inkscape::XML::Node *repr)
     if (!style->filter.set) {
         val = repr->attribute("filter");
         if (val) {
-            sp_style_read_ifilter(&style->filter, val, (object) ? SP_OBJECT_DOCUMENT(object) : NULL);
+               sp_style_read_ifilter(val, style, (object) ? SP_OBJECT_DOCUMENT(object) : NULL);
         }
     }
+    SPS_READ_PENUM_IF_UNSET(&style->enable_background, repr,
+                            "enable-background", enum_enable_background, true);
             
     /* 3. Merge from parent */
     if (object) {
@@ -758,8 +776,9 @@ sp_style_merge_property(SPStyle *style, gint id, gchar const *val)
         case SP_PROP_FONT_FAMILY:
             if (!style->text_private) sp_style_privatize_text(style);
             if (!style->text->font_family.set) {
-                sp_style_read_istring(&style->text->font_family, val);
-                css2_unescape_unquote(&style->text->font_family);
+                gchar *val_unquoted = attribute_unquote(val);
+                sp_style_read_istring(&style->text->font_family, val_unquoted);
+                if (val_unquoted) g_free (val_unquoted);
             }
             break;
         case SP_PROP_FONT_SIZE:
@@ -901,12 +920,13 @@ sp_style_merge_property(SPStyle *style, gint id, gchar const *val)
             }
             break;
         case SP_PROP_ENABLE_BACKGROUND:
-            g_warning("Unimplemented style property SP_PROP_ENABLE_BACKGROUND: value: %s", val);
+            SPS_READ_IENUM_IF_UNSET(&style->enable_background, val,
+                                    enum_enable_background, true);
             break;
             /* Filter */
         case SP_PROP_FILTER:
             if (!style->filter.set && !style->filter.inherit) {
-                sp_style_read_ifilter(&style->filter, val, (style->object) ? SP_OBJECT_DOCUMENT(style->object) : NULL);
+                sp_style_read_ifilter(val, style, (style->object) ? SP_OBJECT_DOCUMENT(style->object) : NULL);
             }
             break;
         case SP_PROP_FLOOD_COLOR:
@@ -969,7 +989,6 @@ sp_style_merge_property(SPStyle *style, gint id, gchar const *val)
         case SP_PROP_MARKER:
             /* TODO:  Call sp_uri_reference_resolve(SPDocument *document, guchar const *uri) */
             /* style->marker[SP_MARKER_LOC] = g_quark_from_string(val); */
-            marker_status("Setting SP_PROP_MARKER");
             if (!style->marker[SP_MARKER_LOC].set) {
                 g_free(style->marker[SP_MARKER_LOC].value);
                 style->marker[SP_MARKER_LOC].value = g_strdup(val);
@@ -980,7 +999,6 @@ sp_style_merge_property(SPStyle *style, gint id, gchar const *val)
 
         case SP_PROP_MARKER_START:
             /* TODO:  Call sp_uri_reference_resolve(SPDocument *document, guchar const *uri) */
-            marker_status("Setting SP_PROP_MARKER_START");
             if (!style->marker[SP_MARKER_LOC_START].set) {
                 g_free(style->marker[SP_MARKER_LOC_START].value);
                 style->marker[SP_MARKER_LOC_START].value = g_strdup(val);
@@ -990,7 +1008,6 @@ sp_style_merge_property(SPStyle *style, gint id, gchar const *val)
             break;
         case SP_PROP_MARKER_MID:
             /* TODO:  Call sp_uri_reference_resolve(SPDocument *document, guchar const *uri) */
-            marker_status("Setting SP_PROP_MARKER_MID");
             if (!style->marker[SP_MARKER_LOC_MID].set) {
                 g_free(style->marker[SP_MARKER_LOC_MID].value);
                 style->marker[SP_MARKER_LOC_MID].value = g_strdup(val);
@@ -1000,7 +1017,6 @@ sp_style_merge_property(SPStyle *style, gint id, gchar const *val)
             break;
         case SP_PROP_MARKER_END:
             /* TODO:  Call sp_uri_reference_resolve(SPDocument *document, guchar const *uri) */
-            marker_status("Setting SP_PROP_MARKER_END");
             if (!style->marker[SP_MARKER_LOC_END].set) {
                 g_free(style->marker[SP_MARKER_LOC_END].value);
                 style->marker[SP_MARKER_LOC_END].value = g_strdup(val);
@@ -1444,8 +1460,12 @@ sp_style_merge_from_parent(SPStyle *const style, SPStyle const *const parent)
     }
 
     /* Filter effects */
-    if(style->filter.set && style->filter.inherit) {
-        sp_style_merge_ifilter(&style->filter, &parent->filter);
+    if (style->filter.inherit) {
+        sp_style_merge_ifilter(style, &parent->filter);
+    }
+
+    if(style->enable_background.inherit) {
+        style->enable_background.value = parent->enable_background.value;
     }
 }
 
@@ -1900,6 +1920,26 @@ sp_style_merge_from_dying_parent(SPStyle *const style, SPStyle const *const pare
             /* Leave as is.  (display doesn't inherit by default.) */
         }
 
+        /* enable-background - this is rather complicated, because
+         * it is valid only when applied to container elements.
+         * Let's check a simple case anyhow. */
+        if (parent->enable_background.set
+            && !parent->enable_background.inherit
+            && style->enable_background.inherit)
+        {
+            style->enable_background.set = true;
+            style->enable_background.inherit = false;
+            style->enable_background.value = parent->enable_background.value;
+        }
+
+        if (!style->filter.set || style->filter.inherit)
+        {
+            // FIXME: 
+            // instead of just copying over, we need to _really merge_ the two filters by combining their
+            // filter primitives
+            sp_style_merge_ifilter(style, &parent->filter);
+        }
+
         /** \todo
          * fixme: Check that we correctly handle all properties that don't
          * inherit by default (as shown in
@@ -1957,8 +1997,6 @@ sp_style_merge_from_dying_parent(SPStyle *const style, SPStyle const *const pare
          * represent it as a normal SPILength; though will need to do something about existing
          * users of stroke_dash.offset and stroke_dashoffset_set. */
     }
-
-    /* TODO: deal with filters */
 }
 
 
@@ -2022,6 +2060,36 @@ sp_style_paint_server_modified(SPObject *obj, guint flags, SPStyle *style)
 
 
 
+/**
+ * Disconnects from filter.
+ */
+static void
+sp_style_filter_release(SPObject *obj, SPStyle *style)
+{
+    SPFilter *filter=static_cast<SPFilter *>(obj);
+    if (style->filter.filter == filter)
+    {
+        sp_style_filter_clear(style);
+    }
+}
+
+
+/**
+ * Emit style modified signal on style's object if the filter changed.
+ */
+static void
+sp_style_filter_modified(SPObject *obj, guint flags, SPStyle *style)
+{
+    SPFilter *filter=static_cast<SPFilter *>(obj);
+    if (style->filter.filter == filter)
+    {
+        if (style->object) {
+            style->object->requestModified(SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_STYLE_MODIFIED_FLAG);
+        }
+    } 
+}
+
+
 /**
  *
  */
@@ -2086,12 +2154,26 @@ sp_style_merge_ipaint(SPStyle *style, SPIPaint *paint, SPIPaint const *parent)
  * Filter effects do not inherit by default
  */
 static void
-sp_style_merge_ifilter(SPIFilter *child, SPIFilter const *parent)
+sp_style_merge_ifilter(SPStyle *style, SPIFilter const *parent)
 {
-    child->set = parent->set;
-    child->inherit = parent->inherit;
-    child->filter = parent->filter;
-    child->uri = parent->uri;
+    sp_style_filter_clear(style);
+    style->filter.set = parent->set;
+    style->filter.inherit = parent->inherit;
+    style->filter.filter = parent->filter;
+    style->filter.uri = parent->uri;
+    if (style->filter.filter) {
+        if (style->object && !style->cloned) { // href filter for style of non-clones only
+            sp_object_href(SP_OBJECT(style->filter.filter), style);
+            style->filter_hreffed = true;
+        }
+        if (style->object || style->cloned) { // connect to signals for style of real objects or clones (this excludes temp styles)
+            SPObject *filter = style->filter.filter;
+            style->filter_release_connection
+                = filter->connectRelease(sigc::bind<1>(sigc::ptr_fun(&sp_style_filter_release), style));
+            style->filter_modified_connection
+                = filter->connectModified(sigc::bind<2>(sigc::ptr_fun(&sp_style_filter_modified), style));
+        }
+    }
 }
 
 /**
@@ -2151,7 +2233,6 @@ sp_style_write_string(SPStyle const *const style, guint const flags)
     p += sp_style_write_ienum(p, c + BMAX - p, "stroke-linecap", enum_stroke_linecap, &style->stroke_linecap, NULL, flags);
     p += sp_style_write_ienum(p, c + BMAX - p, "stroke-linejoin", enum_stroke_linejoin, &style->stroke_linejoin, NULL, flags);
 
-    marker_status("sp_style_write_string:  Writing markers");
     if (style->marker[SP_MARKER_LOC].set) {
         p += g_snprintf(p, c + BMAX - p, "marker:%s;", style->marker[SP_MARKER_LOC].value);
     } else if (flags == SP_STYLE_FLAG_ALWAYS) {
@@ -2218,6 +2299,8 @@ sp_style_write_string(SPStyle const *const style, guint const flags)
     /* filter: */
     p += sp_style_write_ifilter(p, c + BMAX - p, "filter", &style->filter, NULL, flags);
 
+    p += sp_style_write_ienum(p, c + BMAX - p, "enable-background", enum_enable_background, &style->enable_background, NULL, flags);
+
     /* fixme: */
     p += sp_text_style_write(p, c + BMAX - p, style->text, flags);
 
@@ -2314,7 +2397,6 @@ sp_style_write_difference(SPStyle const *const from, SPStyle const *const to)
     p += sp_style_write_iscale24(p, c + BMAX - p, "stroke-opacity", &from->stroke_opacity, &to->stroke_opacity, SP_STYLE_FLAG_IFDIFF);
 
     /* markers */
-    marker_status("sp_style_write_difference:  Writing markers");
     if (from->marker[SP_MARKER_LOC].value != NULL) {
         p += g_snprintf(p, c + BMAX - p, "marker:%s;",       from->marker[SP_MARKER_LOC].value);
     }
@@ -2335,6 +2417,8 @@ sp_style_write_difference(SPStyle const *const from, SPStyle const *const to)
     /* filter: */
     p += sp_style_write_ifilter(p, c + BMAX - p, "filter", &from->filter, &to->filter, SP_STYLE_FLAG_IFDIFF);
 
+    p += sp_style_write_ienum(p, c + BMAX - p, "enable-background", enum_enable_background, &from->enable_background, &to->enable_background, SP_STYLE_FLAG_IFSET);
+
     p += sp_text_style_write(p, c + BMAX - p, from->text, SP_STYLE_FLAG_IFDIFF);
 
     /** \todo
@@ -2366,6 +2450,7 @@ sp_style_clear(SPStyle *style)
 
     sp_style_paint_clear(style, &style->fill);
     sp_style_paint_clear(style, &style->stroke);
+    sp_style_filter_clear(style);
     if (style->stroke_dash.dash) {
         g_free(style->stroke_dash.dash);
     }
@@ -2487,11 +2572,12 @@ sp_style_clear(SPStyle *style)
     }
 
     style->filter.set = FALSE;
-//Are these really needed?
-    style->filter.inherit = FALSE;
     style->filter.uri = NULL;
-    style->filter.filter = FALSE;
+    style->filter.filter = NULL;
 
+    style->enable_background.value = SP_CSS_BACKGROUND_ACCUMULATE;
+    style->enable_background.set = false;
+    style->enable_background.inherit = false;
 }
 
 
@@ -3066,8 +3152,9 @@ sp_style_read_ifontsize(SPIFontSize *val, gchar const *str)
  * Set SPIFilter object from string.
  */
 static void
-sp_style_read_ifilter(SPIFilter *f, gchar const *str, SPDocument *document)
+sp_style_read_ifilter(gchar const *str, SPStyle * style, SPDocument *document)
 {
+    SPIFilter *f = &(style->filter);
     /* Try all possible values: inherit, none, uri */
     if (streq(str, "inherit")) {
         f->set = TRUE;
@@ -3090,14 +3177,20 @@ sp_style_read_ifilter(SPIFilter *f, gchar const *str, SPDocument *document)
         f->inherit = FALSE;
         f->filter = NULL;
         if (document) {
-            SPObject *obj;
-            obj = sp_uri_reference_resolve(document, str);
+            SPObject *obj = sp_uri_reference_resolve(document, str);
             if (SP_IS_FILTER(obj)) {
                 f->filter = SP_FILTER(obj);
-                //g_signal_connect(G_OBJECT(f->filter), "release",
-                //                 G_CALLBACK(sp_style_filter_release), style);
-                //g_signal_connect(G_OBJECT(f->filter), "modified",
-                //                 G_CALLBACK(sp_style_filter_modified), style);
+                if (style->object && !style->cloned) {
+                    sp_object_href(obj, style);
+                    style->filter_hreffed = true;
+                }
+                if (style->object || style->cloned) { // connect to signals for style of real objects or clones (this excludes temp styles)
+                    SPObject *filter = style->filter.filter;
+                    style->filter_release_connection
+                        = filter->connectRelease(sigc::bind<1>(sigc::ptr_fun(&sp_style_filter_release), style));
+                    style->filter_modified_connection
+                        = filter->connectModified(sigc::bind<2>(sigc::ptr_fun(&sp_style_filter_modified), style));
+                }
             } else {
                 g_warning("Element '%s' not found or is not a filter", f->uri);
             }
@@ -3259,7 +3352,9 @@ sp_style_write_istring(gchar *p, gint const len, gchar const *const key,
         if (val->inherit) {
             return g_snprintf(p, len, "%s:inherit;", key);
         } else {
-            return g_snprintf(p, len, "%s:%s;", key, val->value);
+            gchar *val_quoted = css2_escape_quote(val->value);
+            return g_snprintf(p, len, "%s:%s;", key, val_quoted);
+            g_free (val_quoted);
         }
     }
     return 0;
@@ -3630,6 +3725,50 @@ sp_style_paint_clear(SPStyle *style, SPIPaint *paint)
     paint->iccColor = NULL;
 }
 
+
+/**
+ * Clear filter object, and disconnect style from paintserver (if present).
+ */
+static void
+sp_style_filter_clear(SPStyle *style)
+{
+
+    if (style->filter_hreffed) {
+        sp_object_hunref(SP_OBJECT(style->filter.filter), style);
+        style->filter_hreffed = false;
+    }
+    style->filter_release_connection.disconnect();
+    style->filter_modified_connection.disconnect();
+
+    style->filter.filter = NULL;
+}
+
+
+// FIXME: Everything below this line belongs in a different file - css-chemistry?
+
+void
+sp_style_set_property_url (SPObject *item, gchar const *property, SPObject *linked, bool recursive)
+{
+    Inkscape::XML::Node *repr = SP_OBJECT_REPR(item);
+
+    if (repr == NULL) return;
+
+    g_return_if_fail(linked != NULL);
+
+    gchar *val = g_strdup_printf("url(#%s)", SP_OBJECT_ID(linked));
+
+    SPCSSAttr *css = sp_repr_css_attr_new();
+    sp_repr_css_set_property(css, property, val);
+    g_free(val);
+    if (recursive) {
+        sp_repr_css_change_recursive(repr, css, "style");
+    } else {
+        sp_repr_css_change(repr, css, "style");
+    }
+    sp_repr_css_attr_unref(css);
+}
+
+
 /**
  * Clear all style property attributes in object.
  */
@@ -3704,6 +3843,9 @@ sp_style_unset_property_attrs(SPObject *o)
     if (style->filter.set) {
         repr->setAttribute("filter", NULL);
     }
+    if (style->enable_background.set) {
+        repr->setAttribute("enable-background", NULL);
+    }
 }
 
 /**
@@ -3887,28 +4029,63 @@ sp_css_attr_scale(SPCSSAttr *css, double ex)
 
 
 /**
- * Remove quotes from SPIString object value.
- *
- * \todo FIXME: now used for font family, but perhaps this should apply to
- * ALL strings (check CSS spec), in which case this should be part of
- * read_istring.
+ * Remove quotes and escapes from a string. Returned value must be g_free'd.
+ * Note: in CSS (in style= and in stylesheets), unquoting and unescaping is done 
+ * by libcroco, our CSS parser, though it adds a new pair of "" quotes for the strings
+ * it parsed for us. So this function is only used to remove those quotes and for 
+ * presentation attributes, without any unescaping. (XML unescaping
+ * (&amp; etc) is done by XML parser.)
  */
-static void
-css2_unescape_unquote(SPIString *val)
+gchar *
+attribute_unquote(gchar const *val)
 {
-    if (val->set && val->value && strlen(val->value) >= 2) {
+    if (val) {
+        if (*val == '\'' || *val == '"') {
+            int l = strlen(val);
+            if (l >= 2) {
+                if ( ( val[0] == '"' && val[l - 1] == '"' )  ||
+                     ( val[0] == '\'' && val[l - 1] == '\'' )  ) {
+                    return (g_strndup (val+1, l-2));
+                } 
+            }
+        }
+    }
 
-        /// \todo unescape all \-escaped chars
+    return (val? g_strdup (val) : NULL);
+}
 
-        int l = strlen(val->value);
-        if ( ( val->value[0] == '"' && val->value[l - 1] == '"' )  ||
-             ( val->value[0] == '\'' && val->value[l - 1] == '\'' )  ) {
-            memcpy(val->value, val->value + 1, l - 2);
-            val->value[l - 2] = '\0';
+/**
+ * Quote and/or escape string for writing to CSS (style=). Returned value must be g_free'd.
+ */
+gchar *
+css2_escape_quote(gchar const *val) {
+
+    Glib::ustring t;
+    bool quote = false;
+
+    for (gchar const *i = val; *i; i++) {
+        if (g_ascii_isalnum(*i) || *i=='-' || *i=='_') {
+            t.push_back(*i);
+        } else if (*i=='\'') {
+            t.push_back('\\');
+            t.push_back(*i);
+            quote = true;
+        } else {
+            t.push_back(*i);
+            quote = true;
+        } 
+        if (i == val && !g_ascii_isalpha(*i)) {
+            quote = true;
         }
     }
-}
 
+    if (quote) { // we use the ' quotes so the result can go to the XML attribute
+        t.insert(t.begin(), '\'');
+        t.push_back('\'');
+    }
+
+    return (t.empty() ? NULL : g_strdup (t.c_str()));
+}
 
 /*
   Local Variables: