evas_vg_load_svg: Support "display" attribute.

Summary:
If the display attribute is "none", VG object is not show.
The default is "inline" which means visible and "none" means invisible.

Depending on the type of node, additional functionality may be required.
refer to https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/display

Test Plan:
[SVG]
<svg viewBox="0 0 220 100" xmlns="http://www.w3.org/2000/svg">
  <!-- Here the yellow rectangle is displayed -->
  <g display="none">
    <rect x="0" y="0" width="100" height="100" fill="skyblue"></rect>
  </g>
  <rect x="20" y="20" width="60" height="60" fill="yellow"></rect>

  <!-- Here the yellow rectangle is not displayed -->
  <rect x="120" y="0" width="100" height="100" fill="skyblue"></rect>
  <rect x="140" y="20" width="60" height="60" fill="yellow" display="none"></rect>
</svg>

[C CODE]
int main(int argc, char **argv)
{
   setenv("ECTOR_BACKEND", "default", 1);
   elm_init(argc, argv);

   Evas_Object *win = elm_win_util_standard_add(NULL, "test");
   evas_object_smart_callback_add(win, "delete,request", win_del, 0);
   elm_win_autodel_set(win, 1);

   Evas *evas = evas_object_evas_get(win);

   Evas_Object *vg = evas_object_vg_add(evas);
   evas_object_show(vg);
   Evas_Object *container = evas_vg_container_add(vg);
   evas_object_vg_root_node_set(vg, container);

   Evas_Object *svg = efl_add(EFL_CANVAS_VG_OBJECT_CLASS, container);
   efl_file_simple_load(svg, "./test.svg", NULL);
   efl_gfx_entity_size_set(svg, EINA_SIZE2D(600, 600));
   efl_gfx_entity_visible_set(svg, EINA_TRUE);
   evas_object_size_hint_weight_set(svg, EVAS_HINT_EXPAND, EVAS_HINT_EXPAND);
   evas_object_size_hint_align_set(svg, EVAS_HINT_FILL, EVAS_HINT_FILL);

   elm_win_resize_object_add(win, vg);
   evas_object_resize(win, WIDTH, HEIGHT);
   evas_object_show(win);
   elm_run();
   elm_shutdown();
   return 0;
}

Reviewers: Hermet, smohanty, kimcinoo

Reviewed By: Hermet

Subscribers: cedric, #reviewers, #committers

Tags: #efl

Differential Revision: https://phab.enlightenment.org/D9640

src/modules/evas/vg_loaders/svg/evas_vg_load_svg.c

@@ -911,6 +911,16 @@ _handle_transform_attr(Evas_SVG_Loader *loader EINA_UNUSED, Svg_Node* node, cons
    node->transform = _parse_transformation_matrix(value);
 }
 
+static void
+_handle_display_attr(Evas_SVG_Loader *loader EINA_UNUSED, Svg_Node* node, const char *value)
+{
+   //TODO : The display attribute can have various values as well as "none".
+   //       The default is "inline" which means visible and "none" means invisible.
+   //       Depending on the type of node, additional functionality may be required.
+   //       refer to https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/display
+   if (!strcmp(value, "none")) node->display = EINA_FALSE;
+   else node->display = EINA_TRUE;
+}
 
 typedef void (*Style_Method)(Evas_SVG_Loader *loader, Svg_Node *node, const char *value);
 
@@ -932,7 +942,8 @@ static const struct {
   STYLE_DEF(stroke-linejoin, stroke_linejoin),
   STYLE_DEF(stroke-linecap, stroke_linecap),
   STYLE_DEF(stroke-opacity, stroke_opacity),
-  STYLE_DEF(transform, transform)
+  STYLE_DEF(transform, transform),
+  STYLE_DEF(display, display)
 };
 
 static Eina_Bool
@@ -1030,6 +1041,9 @@ _create_node(Svg_Node *parent, Svg_Node_Type type)
    node->style->stroke.join = EFL_GFX_JOIN_MITER;
    node->style->stroke.scale = 1.0;
 
+   // default display is true("inline").
+   node->display = EINA_TRUE;
+
    node->parent = parent;
    node->type = type;
    node->child = NULL;

src/static_libs/vg_common/vg_common.h

@@ -283,6 +283,7 @@ struct _Svg_Node
    Eina_Stringshare    *id;
    Svg_Style_Property  *style;
    Eina_Matrix3        *transform;
+   Eina_Bool           display;
    union
      {
         Svg_G_Node   g;

src/static_libs/vg_common/vg_common_svg.c

@@ -441,6 +441,7 @@ vg_common_svg_node_eet(void)
    EET_DATA_DESCRIPTOR_ADD_BASIC(_eet_vg_node, Svg_Node, "id", id, EET_T_STRING);
    EET_DATA_DESCRIPTOR_ADD_SUB(_eet_vg_node, Svg_Node, "style", style, _eet_style_property_node);
    EET_DATA_DESCRIPTOR_ADD_SUB(_eet_vg_node, Svg_Node, "transform", transform, _eet_matrix3_node);
+   EET_DATA_DESCRIPTOR_ADD_BASIC(_eet_vg_node, Svg_Node, "display", display, EET_T_INT);
 
    return _eet_vg_node;
 }
@@ -715,6 +716,8 @@ _apply_vg_property(Svg_Node *node, Efl_VG *vg, Efl_VG *parent, Vg_File_Data *vg_
    // apply the transformation
    if (node->transform) efl_canvas_vg_node_transformation_set(vg, node->transform);
 
+   if (!node->display) efl_gfx_entity_visible_set(vg, EINA_FALSE);
+
    if ((node->type == SVG_NODE_G) || (node->type == SVG_NODE_DOC)) return;
 
    // apply the fill style property