Rewrite of list template system

This patch frees list ui items from their dependencies to Panel, and hence from all the limitations this implied (mostly, the "only one list per panel" one).

It introduces a new (py-extendable and registrable) RNA type, UIList (roughly similar to Panel one), which currently contains only "standard" list's scroll pos and size (but may be expended to include e.g. some filtering data, etc.), which now makes lists completely independent from Panels!

This UIList has a draw_item callback which allows to customize items' drawing from python, which all addons can now use.

To make all this work, other changes were also necessary:

* Now all buttons (uiBut struct) have a 'custom_data' void pointer, used currently to store the uiList struct associated with a given uiLayoutListBox.

* DynamicPaintSurface now exposes a new bool, use_color_preview (readonly), saying whether that surface has some 3D view preview data or not.

* UILayout class has now four new functions, to get the actual icon of any RNA object (important e.g. with materials or textures), and to get an enum item's UI name, description and icon.
  Note: Is UILayout the best place for these funcs??? Probably not, but where then? WindowManager? Or even Context itself?

* UILayout's label() func now takes an optional 'icon_value' integer parameter, which if not zero will override the 'icon' one (mandatory to use "custom" icons as generated for material/texture/... previews).
  Note: not sure whether we should add that one to all UILayout's prop funcs?

[ideasman42, 2012-12-11 13:41:42]

Quick review...
- Calling into python per item seems a bit heavy, would try avoid.

- Code looks fine, though I didnt go though in great detail, It follows the rest
of our integrated classes and can be made to work if there are glitches.

- Id like to review design a bit more and consider if there are nicer ways to do
this.

https://codereview.appspot.com/6854125/diff/1/release/scripts/startup/bl_ui/p...
File release/scripts/startup/bl_ui/properties_data_mesh.py (right):

https://codereview.appspot.com/6854125/diff/1/release/scripts/startup/bl_ui/p...
release/scripts/startup/bl_ui/properties_data_mesh.py:59: if not
isinstance(item, bpy.types.VertexGroup):
why would a vgroup instance not be a vertex group?

https://codereview.appspot.com/6854125/diff/1/source/blender/editors/include/...
File source/blender/editors/include/UI_interface.h (right):

https://codereview.appspot.com/6854125/diff/1/source/blender/editors/include/...
source/blender/editors/include/UI_interface.h:831: void uiTemplateList2(uiLayout
*layout, struct bContext *C, const char *listtype_name, const char *list_id,
maybe call uiTemplateListCustom / uiTemplateListType ?

https://codereview.appspot.com/6854125/diff/1/source/blender/editors/interfac...
File source/blender/editors/interface/interface_templates.c (right):

https://codereview.appspot.com/6854125/diff/1/source/blender/editors/interfac...
source/blender/editors/interface/interface_templates.c:2887: for (uilst =
ar->uiLists.first; uilst; uilst = uilst->next) {
 should use BLI_findstring

https://codereview.appspot.com/6854125/diff/1/source/blender/makesrna/intern/...
File source/blender/makesrna/intern/rna_ui.c (right):

https://codereview.appspot.com/6854125/diff/1/source/blender/makesrna/intern/...
source/blender/makesrna/intern/rna_ui.c:276: func = &rna_UIList_draw_item_func;
/* RNA_struct_find_function(&ultr, "draw_item"); */
this seems a bit heavy to function call python for each item... would try to
find a way to avoid this.

[mont29, 2012-12-14 18:00:04]

Ok, took me some time to finalize that (hit some issues, as previous C code used
a few low-level "hacks" for some lists...

Patch (with a rough log of "side" changes) following.

https://codereview.appspot.com/6854125/diff/1/release/scripts/startup/bl_ui/p...
File release/scripts/startup/bl_ui/properties_data_mesh.py (right):

https://codereview.appspot.com/6854125/diff/1/release/scripts/startup/bl_ui/p...
release/scripts/startup/bl_ui/properties_data_mesh.py:59: if not
isinstance(item, bpy.types.VertexGroup):
On 2012/12/11 13:41:42, ideasman42 wrote:
> why would a vgroup instance not be a vertex group?

Well, once defined, MESH_UL_vgroups can be used with any tipe of collection, so
better test there was no mistake here :)

https://codereview.appspot.com/6854125/diff/1/source/blender/editors/include/...
File source/blender/editors/include/UI_interface.h (right):

https://codereview.appspot.com/6854125/diff/1/source/blender/editors/include/...
source/blender/editors/include/UI_interface.h:831: void uiTemplateList2(uiLayout
*layout, struct bContext *C, const char *listtype_name, const char *list_id,
On 2012/12/11 13:41:42, ideasman42 wrote:
> maybe call uiTemplateListCustom / uiTemplateListType ?
Actually, this is supposed to completely replace uiTemplateList (which I only
kept here as ref/comparison ;) ).

https://codereview.appspot.com/6854125/diff/1/source/blender/editors/interfac...
File source/blender/editors/interface/interface_templates.c (right):

https://codereview.appspot.com/6854125/diff/1/source/blender/editors/interfac...
source/blender/editors/interface/interface_templates.c:2887: for (uilst =
ar->uiLists.first; uilst; uilst = uilst->next) {
On 2012/12/11 13:41:42, ideasman42 wrote:
>  should use BLI_findstring

OK, will do.

[mont29, 2012-12-14 18:00:55]

This commit refactors how template_list works.  It introduces a new
(py-extendable and registrable)

[mont29, 2012-12-14 18:01:48]

Pff… stupid codereview! Here's the log:

This commit refactors how template_list works.

It introduces a new (py-extendable and registrable) RNA type, UIList, which
currently contains only "standard" list's scroll pos and size (but may be
expended to include e.g. some filtering data, etc.), which now makes lists
completely independent from Panels!

This UIList has a draw_item callback which allows to customize items' drawing
from python, which all addons can now use.

To make all this work, other changes were also necessary:

* Now all buttons (uiBut struct) have a 'custom_data' void pointer, used
currently to store the uiList struct associated with a given uiLayoutListBox.

* DynamicPaintSurface now exposes a new bool, use_color_preview (readonly),
saying whether that surface has some 3D view preview data or not.

* UILayout class has now four new functions, to get the actual icon of any RNA
object (important e.g. with materials or textures), and to get an enum item's UI
name, description and icon.
  NOTE: Is UILayout the best place for these funcs??? Probably not, but where
then? WindowManager? Or even Context itself?

* UILayout's label() func now takes an optional 'icon_value' integer parameter,
which if not zero will override the 'icon' one (mandatory to use "custom" icons
as generated for material/texture/... previews).
  NOTE: not sure whether we should add that one to all UILayout's prop funcs?

[ideasman42, 2012-12-26 11:37:00]

generally LGTM, added some comments.

https://codereview.appspot.com/6854125/diff/16001/release/scripts/startup/bl_...
File release/scripts/startup/bl_ui/properties_data_mesh.py (right):

https://codereview.appspot.com/6854125/diff/16001/release/scripts/startup/bl_...
release/scripts/startup/bl_ui/properties_data_mesh.py:73: if not
isinstance(item, bpy.types.ShapeKey):
why would the item not be a shapekey? - if theres a good reason should add here
as a comment.

https://codereview.appspot.com/6854125/diff/16001/release/scripts/startup/bl_...
File release/scripts/startup/bl_ui/properties_mask_common.py (right):

https://codereview.appspot.com/6854125/diff/16001/release/scripts/startup/bl_...
release/scripts/startup/bl_ui/properties_mask_common.py:30: if not
isinstance(item, bpy.types.MaskLayer):
again, why wouldnt the item be a mask layer?

https://codereview.appspot.com/6854125/diff/16001/source/blender/editors/inte...
File source/blender/editors/interface/interface_templates.c (right):

https://codereview.appspot.com/6854125/diff/16001/source/blender/editors/inte...
source/blender/editors/interface/interface_templates.c:2386: 
*picky* - personally not a fan of this style of declarations; can just be int at
the start of each line and end with ';'

https://codereview.appspot.com/6854125/diff/16001/source/blender/makesrna/int...
File source/blender/makesrna/intern/rna_ui_api.c (right):

https://codereview.appspot.com/6854125/diff/16001/source/blender/makesrna/int...
source/blender/makesrna/intern/rna_ui_api.c:85: 
All these functions can be classmethods, eg:
  bpy.types.UILayout.enum_name(...)
rather then 
  layout.enum_name(...)

https://codereview.appspot.com/6854125/diff/16001/source/blender/makesrna/int...
source/blender/makesrna/intern/rna_ui_api.c:167:
RNA_property_enum_items_gettexted(C, ptr, prop, &items, NULL, &free);
why _gettexted( version of this function?

[mont29, 2012-12-27 15:10:39]

Hi Campbo,

and many thanks for the review! :)

I addressed your remarks, so think it’s ready to go in trunk… Will probably
commit tomorrow, unless you get some last-moment suggestions ;)

Merry Christmas and happy new year!

Bastien

https://codereview.appspot.com/6854125/diff/16001/release/scripts/startup/bl_...
File release/scripts/startup/bl_ui/properties_data_mesh.py (right):

https://codereview.appspot.com/6854125/diff/16001/release/scripts/startup/bl_...
release/scripts/startup/bl_ui/properties_data_mesh.py:73: if not
isinstance(item, bpy.types.ShapeKey):
On 2012/12/26 11:37:00, ideasman42 wrote:
> why would the item not be a shapekey? - if theres a good reason should add
here
> as a comment.

Well, it’s only the fact that once this class is registered, anybody can (try
to) use it with any collection property… So it’s just a security check, to avoid
"crashing" the whole UI in case something is wrong.

If you think it’s over-paranoid, I’m fine with removing those checks.

https://codereview.appspot.com/6854125/diff/16001/source/blender/editors/inte...
File source/blender/editors/interface/interface_templates.c (right):

https://codereview.appspot.com/6854125/diff/16001/source/blender/editors/inte...
source/blender/editors/interface/interface_templates.c:2386: 
On 2012/12/26 11:37:00, ideasman42 wrote:
> *picky* - personally not a fan of this style of declarations; can just be int
at
> the start of each line and end with ';'

Done.

https://codereview.appspot.com/6854125/diff/16001/source/blender/makesrna/int...
File source/blender/makesrna/intern/rna_ui_api.c (right):

https://codereview.appspot.com/6854125/diff/16001/source/blender/makesrna/int...
source/blender/makesrna/intern/rna_ui_api.c:85: 
On 2012/12/26 11:37:00, ideasman42 wrote:
> All these functions can be classmethods, eg:
>   bpy.types.UILayout.enum_name(...)
> rather then 
>   layout.enum_name(...)

Done (actually, made them "static methods" ;) ).

https://codereview.appspot.com/6854125/diff/16001/source/blender/makesrna/int...
source/blender/makesrna/intern/rna_ui_api.c:167:
RNA_property_enum_items_gettexted(C, ptr, prop, &items, NULL, &free);
On 2012/12/26 11:37:00, ideasman42 wrote:
> why _gettexted( version of this function?

Absolutely no reason! Probably a copy/paste glitch. ;)