Edje: Add clip as a property of a part description

Since masking, for performance and themeing reasons, it becomes
interesting to be able to switch clippers on the fly. In particular,
switching from an IMAGE mask to a standard RECT clipper can save a
lot of power when masking is not required.

This new flag "description.clip_to" will behave a bit like a mix of
rel.to and visible:

- It points to a part by name, just like part.clip_to. This will
  override the clipper set by the part, or override the default clipper.

- Like "visible", it can not be interpolated between two values, so
  it will switch only at the end of a transition.

- By default there is no clip override, which means Edje will fallback
  to the part's clipper, if any, or the base (group's) clipper.

NOTE:
- Since a clipper that does not clip anything becomes a standard object,
  it is visible and rendered. This will in 99.999% cases not be the
  intended behaviour. Currently we can simply use a transparent RECT
  in order to always have something clipped by the clipper, but this is
  a hack and this will trigger rendering of masks in their surfaces even
  when they are not actually used.
  Ideally, there should be a flag indicating to Edje & Evas that an object
  should be considered a clipper in all situations, and never be rendered
  on screen.

TODO:
- Support Edje Edit
- Add Embryo & Lua functions
- Add support in edje_convert
- Add Edje/Evas flag to mark objects as "no_render"

@feature

2 files changed, 44 insertions, 6 deletions

diff --git a/src/bin/edje/edje_cc_handlers.c b/src/bin/edje/edje_cc_handlers.c
index 1cb5b6ef10..b371aec5ca 100644
--- a/src/bin/edje/edje_cc_handlers.c
+++ b/src/bin/edje/edje_cc_handlers.c
@@ -326,6 +326,7 @@ static void st_collections_group_parts_part_description_rel2_to_set(const char *
 static void st_collections_group_parts_part_description_rel2_to(void);
 static void st_collections_group_parts_part_description_rel2_to_x(void);
 static void st_collections_group_parts_part_description_rel2_to_y(void);
+static void st_collections_group_parts_part_description_clip_to_id(void);
 static void st_collections_group_parts_part_description_image_normal(void);
 static void st_collections_group_parts_part_description_image_tween(void);
 static void st_collections_group_parts_part_description_image_border(void);
@@ -771,6 +772,7 @@ New_Statement_Handler statement_handlers[] =
      {"collections.group.parts.part.description.rel2.to", st_collections_group_parts_part_description_rel2_to},
      {"collections.group.parts.part.description.rel2.to_x", st_collections_group_parts_part_description_rel2_to_x},
      {"collections.group.parts.part.description.rel2.to_y", st_collections_group_parts_part_description_rel2_to_y},
+     {"collections.group.parts.part.description.clip_to", st_collections_group_parts_part_description_clip_to_id},
      {"collections.group.parts.part.description.image.normal", st_collections_group_parts_part_description_image_normal},
      {"collections.group.parts.part.description.image.tween", st_collections_group_parts_part_description_image_tween},
      IMAGE_SET_STATEMENTS("collections.group.parts.part.description.image")
@@ -1496,6 +1498,7 @@ _edje_part_description_alloc(unsigned char type, const char *collection, const c
    result->physics.depth = 30;
 #endif
 
+   result->clip_to_id = -1;
    return result;
 }
 
@@ -4581,6 +4584,7 @@ _part_desc_free(Edje_Part_Collection *pc,
    part_lookup_del(pc, &(ed->rel1.id_y));
    part_lookup_del(pc, &(ed->rel2.id_x));
    part_lookup_del(pc, &(ed->rel2.id_y));
+   part_lookup_del(pc, &(ed->clip_to_id));
    part_lookup_del(pc, &(ed->map.id_persp));
    part_lookup_del(pc, &(ed->map.id_light));
    part_lookup_del(pc, &(ed->map.rot.id_center));
@@ -5381,11 +5385,11 @@ st_collections_group_parts_part_clip_to_id(void)
 
    pc = eina_list_data_get(eina_list_last(edje_collections));
      {
-        char *name;
+        char *name;
 
-        name = parse_str(0);
-        data_queue_part_lookup(pc, name, &(current_part->clip_to_id));
-        free(name);
+        name = parse_str(0);
+        data_queue_part_lookup(pc, name, &(current_part->clip_to_id));
+        free(name);
      }
 }
 
@@ -6397,6 +6401,7 @@ _copied_map_colors_get(Edje_Part_Description_Common *parent)
             fixed: 0 0;
             step: 0 0;
             aspect: 1 1;
+            clip_to: "clip_override_part_name";
 
             rel1 {
                 ..
@@ -6428,6 +6433,7 @@ ob_collections_group_parts_part_description(void)
    ed->rel1.id_y = -1;
    ed->rel2.id_x = -1;
    ed->rel2.id_y = -1;
+   ed->clip_to_id = -1;
 
    if (!ep->default_desc)
      {
@@ -6628,6 +6634,8 @@ st_collections_group_parts_part_description_inherit(void)
    data_queue_copied_part_lookup(pc, &parent->rel2.id_x, &ed->rel2.id_x);
    data_queue_copied_part_lookup(pc, &parent->rel2.id_y, &ed->rel2.id_y);
 
+   data_queue_copied_part_lookup(pc, &parent->clip_to_id, &ed->clip_to_id);
+
    data_queue_copied_part_lookup(pc, &parent->map.id_persp, &ed->map.id_persp);
    data_queue_copied_part_lookup(pc, &parent->map.id_light, &ed->map.id_light);
    data_queue_copied_part_lookup(pc, &parent->map.rot.id_center, &ed->map.rot.id_center);
@@ -7625,6 +7633,23 @@ st_collections_group_parts_part_description_rel2_to_y(void)
    }
 }
 
+static void
+st_collections_group_parts_part_description_clip_to_id(void)
+{
+   Edje_Part_Collection *pc;
+
+   check_arg_count(1);
+
+   pc = eina_list_data_get(eina_list_last(edje_collections));
+     {
+        char *name;
+
+        name = parse_str(0);
+        data_queue_part_lookup(pc, name, &(current_desc->clip_to_id));
+        free(name);
+     }
+}
+
 /** @edcsubsection{collections_group_parts_description_image,
  *                 Group.Parts.Part.Description.Image} */
 
diff --git a/src/bin/edje/edje_cc_out.c b/src/bin/edje/edje_cc_out.c
index 485aa8c0dc..78d3fab431 100755
--- a/src/bin/edje/edje_cc_out.c
+++ b/src/bin/edje/edje_cc_out.c
@@ -465,6 +465,19 @@ check_nameless_state(Edje_Part_Collection *pc, Edje_Part *ep, Edje_Part_Descript
 }
 
 static void
+check_state(Edje_Part_Collection *pc, Edje_Part *ep, Edje_Part_Description_Common *ed, Eet_File *ef)
+{
+   /* FIXME: When smart masks are supported, remove this check */
+   if (ed->clip_to_id != -1 &&
+       (pc->parts[ed->clip_to_id]->type != EDJE_PART_TYPE_RECTANGLE) &&
+       (pc->parts[ed->clip_to_id]->type != EDJE_PART_TYPE_IMAGE))
+     error_and_abort(ef, "Collection %i: description.clip_to point to a non RECT/IMAGE part '%s' !",
+                     pc->id, pc->parts[ed->clip_to_id]->name);
+
+   check_nameless_state(pc, ep, ed, ef);
+}
+
+static void
 check_part(Edje_Part_Collection *pc, Edje_Part *ep, Eet_File *ef)
 {
    unsigned int i;
@@ -475,7 +488,7 @@ check_part(Edje_Part_Collection *pc, Edje_Part *ep, Eet_File *ef)
                      "for part \"%s\"", pc->id, ep->name);
 
    for (i = 0; i < ep->other.desc_count; ++i)
-     check_nameless_state(pc, ep, ep->other.desc[i], ef);
+     check_state(pc, ep, ep->other.desc[i], ef);
 
    if (ep->type == EDJE_PART_TYPE_IMAGE)
      {
@@ -490,7 +503,7 @@ check_part(Edje_Part_Collection *pc, Edje_Part *ep, Eet_File *ef)
    else if (ep->type == EDJE_PART_TYPE_GROUP)
      check_source_links(pc, ep, ef, group_path);
 
-   /* FIXME: When mask are supported remove this check */
+   /* FIXME: When smart masks are supported, remove this check */
    if (ep->clip_to_id != -1 &&
        (pc->parts[ep->clip_to_id]->type != EDJE_PART_TYPE_RECTANGLE) &&
        (pc->parts[ep->clip_to_id]->type != EDJE_PART_TYPE_IMAGE))