src/svgtiny_css.c: add some default user-agent properties after all

We tried to avoid populating ua_default_for_property() with any
default properties, but it looks like some are "required." Without
them, the style-composition process gets crashy while trying to set
initial values. Thanks to the libcss example program for the idea.

diff --git a/src/svgtiny_css.c b/src/svgtiny_css.c
index 3da3c8e165f34b0d6fb09cdcc04c488ecda3e0f8..be2460279a1a18a46f3586880eb61c13016be7b0 100644 (file)
--- a/src/svgtiny_css.c
+++ b/src/svgtiny_css.c
@@ -1870,8 +1870,10 @@ css_error node_presentational_hint(void *pw, void *node,
 /**
  * User-agent defaults for CSS properties
  *
- * For the moment, we provide no defaults, because libsvgtiny does not
- * yet support any CSS properties that might need them.
+ * Ideally we would provide _no_ defaults here, because we don't yet
+ * support any CSS properties that can use them. However, we run into
+ * libcss parent/child style composition issues unless these defaults
+ * are provided. And it's harmless to provide them, so let's do it.
  *
  * \param pw            Pointer to the current SVG parser state; unused
  * \param property      LibCSS property identifier; unused
@@ -1883,9 +1885,28 @@ css_error ua_default_for_property(void *pw, uint32_t property,
        css_hint *hint)
 {
        UNUSED(pw);
-       UNUSED(property);
-       UNUSED(hint);
-       return CSS_INVALID;
+       switch (property) {
+       case CSS_PROP_COLOR:
+               hint->data.color = 0xff000000;
+               hint->status = CSS_COLOR_COLOR;
+               break;
+       case CSS_PROP_FONT_FAMILY:
+               hint->data.strings = NULL;
+               hint->status = CSS_FONT_FAMILY_SANS_SERIF;
+               break;
+       case CSS_PROP_QUOTES:
+               hint->data.strings = NULL;
+               hint->status = CSS_QUOTES_NONE;
+               break;
+       case CSS_PROP_VOICE_FAMILY:
+               hint->data.strings = NULL;
+               hint->status = 0;
+               break;
+       default:
+               return CSS_INVALID;
+       }
+
+       return CSS_OK;
 }