UI: Grease Pencil Modifier Drag and Drop, Layout Changes

This patch implements the list panel system D7490 for grease pencil
modifiers. It also moves their drawing to a callback in
GpencilModifierTypeInfo in line with the extensible architecture
refactoring goal T75724.

This also adds the "set_error" function for grease pencil modifiers,
which hadn't been copied from mesh modifiers yet.

The implementation is basically exactly the same as for the modifier
patch (9b099c86123fc82).

Thanks to Matias Mendiola (mendio) for providing mockups for many
of the layout changes.

Differential Revision: https://developer.blender.org/D7978

1 files changed, 35 insertions, 127 deletions

diff --git a/source/blender/editors/interface/interface_templates.c b/source/blender/editors/interface/interface_templates.c
index 189441a1f10..56a71970f90 100644
--- a/source/blender/editors/interface/interface_templates.c
+++ b/source/blender/editors/interface/interface_templates.c
@@ -2040,147 +2040,55 @@ void uiTemplateConstraints(uiLayout *UNUSED(layout), bContext *C, bool use_bone_
 /** \name Grease Pencil Modifier Template
  * \{ */
 
-#define ERROR_LIBDATA_MESSAGE TIP_("Can't edit external library data")
-
-static uiLayout *gpencil_draw_modifier(uiLayout *layout, Object *ob, GpencilModifierData *md)
+/**
+ * Function with void * argument for #uiListPanelIDFromDataFunc.
+ */
+static void gpencil_modifier_panel_id(void *md_link, char *r_name)
 {
-  const GpencilModifierTypeInfo *mti = BKE_gpencil_modifier_get_info(md->type);
-  PointerRNA ptr;
-  uiBlock *block;
-  uiLayout *box, *column, *row, *sub;
-  uiLayout *result = NULL;
-
-  /* create RNA pointer */
-  RNA_pointer_create(&ob->id, &RNA_GpencilModifier, md, &ptr);
-
-  column = uiLayoutColumn(layout, true);
-  uiLayoutSetContextPointer(column, "modifier", &ptr);
-
-  /* rounded header ------------------------------------------------------------------- */
-  box = uiLayoutBox(column);
-
-  row = uiLayoutRow(box, false);
-  block = uiLayoutGetBlock(row);
-
-  UI_block_emboss_set(block, UI_EMBOSS_NONE);
-  /* Open/Close .................................  */
-  uiItemR(row, &ptr, "show_expanded", 0, "", ICON_NONE);
-
-  /* modifier-type icon */
-  uiItemL(row, "", RNA_struct_ui_icon(ptr.type));
-  UI_block_emboss_set(block, UI_EMBOSS);
-
-  /* modifier name */
-  if (mti->isDisabled && mti->isDisabled(md, 0)) {
-    uiLayoutSetRedAlert(row, true);
-  }
-  uiItemR(row, &ptr, "name", 0, "", ICON_NONE);
-  uiLayoutSetRedAlert(row, false);
-
-  /* mode enabling buttons */
-  UI_block_align_begin(block);
-  uiItemR(row, &ptr, "show_render", 0, "", ICON_NONE);
-  uiItemR(row, &ptr, "show_viewport", 0, "", ICON_NONE);
-
-  if (mti->flags & eGpencilModifierTypeFlag_SupportsEditmode) {
-    sub = uiLayoutRow(row, true);
-    uiLayoutSetActive(sub, false);
-    uiItemR(sub, &ptr, "show_in_editmode", 0, "", ICON_NONE);
-  }
-
-  UI_block_align_end(block);
-
-  /* Up/Down + Delete ........................... */
-  UI_block_align_begin(block);
-  uiItemO(row, "", ICON_TRIA_UP, "OBJECT_OT_gpencil_modifier_move_up");
-  uiItemO(row, "", ICON_TRIA_DOWN, "OBJECT_OT_gpencil_modifier_move_down");
-  UI_block_align_end(block);
-
-  UI_block_emboss_set(block, UI_EMBOSS_NONE);
-  uiItemO(row, "", ICON_X, "OBJECT_OT_gpencil_modifier_remove");
-  UI_block_emboss_set(block, UI_EMBOSS);
-
-  /* modifier settings (under the header) --------------------------------------------------- */
-  if (md->mode & eGpencilModifierMode_Expanded) {
-    /* apply/convert/copy */
-    box = uiLayoutBox(column);
-    row = uiLayoutRow(box, false);
-
-    /* only here obdata, the rest of modifiers is ob level */
-    UI_block_lock_set(block, BKE_object_obdata_is_libdata(ob), ERROR_LIBDATA_MESSAGE);
-
-    uiLayoutSetOperatorContext(row, WM_OP_INVOKE_DEFAULT);
-
-    sub = uiLayoutRow(row, false);
-    if (mti->flags & eGpencilModifierTypeFlag_NoApply) {
-      uiLayoutSetEnabled(sub, false);
-    }
-    uiItemEnumO(sub,
-                "OBJECT_OT_gpencil_modifier_apply",
-                CTX_IFACE_(BLT_I18NCONTEXT_OPERATOR_DEFAULT, "Apply"),
-                0,
-                "apply_as",
-                MODIFIER_APPLY_DATA);
-
-    UI_block_lock_clear(block);
-    UI_block_lock_set(block, ob && ID_IS_LINKED(ob), ERROR_LIBDATA_MESSAGE);
-
-    uiItemO(row,
-            CTX_IFACE_(BLT_I18NCONTEXT_OPERATOR_DEFAULT, "Copy"),
-            ICON_NONE,
-            "OBJECT_OT_gpencil_modifier_copy");
-
-    /* result is the layout block inside the box,
-     * that we return so that modifier settings can be drawn */
-    result = uiLayoutColumn(box, false);
-    block = uiLayoutAbsoluteBlock(box);
-  }
-
-  /* error messages */
-  if (md->error) {
-    box = uiLayoutBox(column);
-    row = uiLayoutRow(box, false);
-    uiItemL(row, md->error, ICON_ERROR);
-  }
-
-  return result;
+  ModifierData *md = (ModifierData *)md_link;
+  BKE_gpencil_modifierType_panel_id(md->type, r_name);
 }
 
-uiLayout *uiTemplateGpencilModifier(uiLayout *layout, bContext *UNUSED(C), PointerRNA *ptr)
+void uiTemplateGpencilModifiers(uiLayout *UNUSED(layout), bContext *C)
 {
-  Object *ob;
-  GpencilModifierData *md, *vmd;
-  int i;
+  ScrArea *sa = CTX_wm_area(C);
+  ARegion *region = CTX_wm_region(C);
+  Object *ob = get_context_object(C);
+  ListBase *modifiers = &ob->greasepencil_modifiers;
 
-  /* verify we have valid data */
-  if (!RNA_struct_is_a(ptr->type, &RNA_GpencilModifier)) {
-    RNA_warning("Expected modifier on object");
-    return NULL;
-  }
+  bool panels_match = UI_panel_list_matches_data(region, modifiers, gpencil_modifier_panel_id);
 
-  ob = (Object *)ptr->owner_id;
-  md = ptr->data;
+  if (!panels_match) {
+    UI_panels_free_instanced(C, region);
+    GpencilModifierData *md = modifiers->first;
+    for (int i = 0; md; i++, md = md->next) {
+      const GpencilModifierTypeInfo *mti = BKE_gpencil_modifier_get_info(md->type);
+      if (mti->panelRegister) {
+        char panel_idname[MAX_NAME];
+        gpencil_modifier_panel_id(md, panel_idname);
 
-  if (!ob || !(GS(ob->id.name) == ID_OB)) {
-    RNA_warning("Expected modifier on object");
-    return NULL;
+        Panel *new_panel = UI_panel_add_instanced(sa, region, &region->panels, panel_idname, i);
+        if (new_panel != NULL) {
+          UI_panel_set_expand_from_list_data(C, new_panel);
+        }
+      }
+    }
   }
-
-  UI_block_lock_set(uiLayoutGetBlock(layout), (ob && ID_IS_LINKED(ob)), ERROR_LIBDATA_MESSAGE);
-
-  /* find modifier and draw it */
-  vmd = ob->greasepencil_modifiers.first;
-  for (i = 0; vmd; i++, vmd = vmd->next) {
-    if (md == vmd) {
-      return gpencil_draw_modifier(layout, ob, md);
+  else {
+    /* The expansion might have been changed elsewhere, so we still need to set it. */
+    LISTBASE_FOREACH (Panel *, panel, &region->panels) {
+      if ((panel->type != NULL) && (panel->type->flag & PNL_INSTANCED))
+        UI_panel_set_expand_from_list_data(C, panel);
     }
   }
-
-  return NULL;
 }
 
 /** \} */
 
+/** \} */
+
+#define ERROR_LIBDATA_MESSAGE TIP_("Can't edit external library data")
+
 /* -------------------------------------------------------------------- */
 /** \name Grease Pencil Shader FX Template
  * \{ */