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, 460 insertions, 0 deletions

diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencil_ui_common.c b/source/blender/gpencil_modifiers/intern/MOD_gpencil_ui_common.c
new file mode 100644
index 00000000000..93d6dff4c16
--- /dev/null
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencil_ui_common.c
@@ -0,0 +1,460 @@
+/* This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software  Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+/** \file
+ * \ingroup modifiers
+ */
+
+#include <string.h>
+
+#include "BLI_listbase.h"
+
+#include "MEM_guardedalloc.h"
+
+#include "BKE_context.h"
+#include "BKE_gpencil_modifier.h"
+#include "BKE_material.h"
+#include "BKE_object.h"
+#include "BKE_screen.h"
+
+#include "DNA_object_force_types.h"
+#include "DNA_object_types.h"
+#include "DNA_particle_types.h"
+#include "DNA_scene_types.h"
+#include "DNA_screen_types.h"
+#include "DNA_space_types.h"
+
+#include "ED_object.h"
+
+#include "BLT_translation.h"
+
+#include "UI_interface.h"
+#include "UI_resources.h"
+
+#include "RNA_access.h"
+
+#include "WM_api.h"
+#include "WM_types.h"
+
+#include "MOD_gpencil_ui_common.h" /* Self include */
+
+static Object *get_gpencilmodifier_object(const bContext *C)
+{
+  SpaceProperties *sbuts = CTX_wm_space_properties(C);
+  if (sbuts != NULL && (sbuts->pinid != NULL) && GS(sbuts->pinid->name) == ID_OB) {
+    return (Object *)sbuts->pinid;
+  }
+  else {
+    return CTX_data_active_object(C);
+  }
+}
+
+/**
+ * Poll function so these modifier panels only show for grease pencil objects.
+ */
+static bool gpencil_modifier_ui_poll(const bContext *C, PanelType *UNUSED(pt))
+{
+  Object *ob = get_gpencilmodifier_object(C);
+
+  return (ob != NULL) && (ob->type == OB_GPENCIL);
+}
+
+/* -------------------------------------------------------------------- */
+/** \name Panel Drag and Drop, Expansion Saving
+ * \{ */
+
+/**
+ * Move a modifier to the index it's moved to after a drag and drop.
+ */
+static void gpencil_modifier_reorder(bContext *C, Panel *panel, int new_index)
+{
+  Object *ob = get_gpencilmodifier_object(C);
+
+  GpencilModifierData *md = BLI_findlink(&ob->greasepencil_modifiers, panel->runtime.list_index);
+  PointerRNA props_ptr;
+  wmOperatorType *ot = WM_operatortype_find("OBJECT_OT_gpencil_modifier_move_to_index", false);
+  WM_operator_properties_create_ptr(&props_ptr, ot);
+  RNA_string_set(&props_ptr, "modifier", md->name);
+  RNA_int_set(&props_ptr, "index", new_index);
+  WM_operator_name_call_ptr(C, ot, WM_OP_INVOKE_DEFAULT, &props_ptr);
+  WM_operator_properties_free(&props_ptr);
+}
+
+static short get_gpencil_modifier_expand_flag(const bContext *C, Panel *panel)
+{
+  Object *ob = get_gpencilmodifier_object(C);
+  GpencilModifierData *md = BLI_findlink(&ob->greasepencil_modifiers, panel->runtime.list_index);
+  return md->ui_expand_flag;
+  return 0;
+}
+
+static void set_gpencil_modifier_expand_flag(const bContext *C, Panel *panel, short expand_flag)
+{
+  Object *ob = get_gpencilmodifier_object(C);
+  GpencilModifierData *md = BLI_findlink(&ob->greasepencil_modifiers, panel->runtime.list_index);
+  md->ui_expand_flag = expand_flag;
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Modifier Panel Layouts
+ * \{ */
+
+void gpencil_modifier_masking_panel_draw(const bContext *C,
+                                         Panel *panel,
+                                         bool use_material,
+                                         bool use_vertex)
+{
+  uiLayout *row, *col, *sub;
+  uiLayout *layout = panel->layout;
+
+  PointerRNA ptr;
+  PointerRNA ob_ptr;
+  gpencil_modifier_panel_get_property_pointers(C, panel, &ob_ptr, &ptr);
+
+  PointerRNA obj_data_ptr = RNA_pointer_get(&ob_ptr, "data");
+  bool has_layer = RNA_string_length(&ptr, "layer") != 0;
+
+  uiLayoutSetPropSep(layout, true);
+
+  col = uiLayoutColumn(layout, true);
+  row = uiLayoutRow(col, true);
+  uiItemPointerR(row, &ptr, "layer", &obj_data_ptr, "layers", NULL, ICON_GREASEPENCIL);
+  sub = uiLayoutRow(row, true);
+  uiLayoutSetActive(sub, has_layer);
+  uiLayoutSetPropDecorate(sub, false);
+  uiItemR(sub, &ptr, "invert_layers", 0, "", ICON_ARROW_LEFTRIGHT);
+
+  row = uiLayoutRow(col, true);
+  uiItemR(row, &ptr, "layer_pass", 0, NULL, ICON_NONE);
+  sub = uiLayoutRow(row, true);
+  uiLayoutSetActive(sub, RNA_int_get(&ptr, "layer_pass") != 0);
+  uiLayoutSetPropDecorate(sub, false);
+  uiItemR(sub, &ptr, "invert_layer_pass", 0, "", ICON_ARROW_LEFTRIGHT);
+
+  if (use_material) {
+    PointerRNA material_ptr = RNA_pointer_get(&ptr, "material");
+    bool has_material = !RNA_pointer_is_null(&material_ptr);
+
+    /* Because the Gpencil modifier material property used to be a string in an earlier version of
+     * Blender, we need to check if the material is valid and display it differently if so. */
+    bool valid = false;
+    {
+      if (!has_material) {
+        valid = true;
+      }
+      else {
+        Material *current_material = material_ptr.data;
+        Object *ob = ob_ptr.data;
+        for (int i = 0; i <= ob->totcol; i++) {
+          Material *mat = BKE_object_material_get(ob, i);
+          if (mat == current_material) {
+            valid = true;
+            break;
+          }
+        }
+      }
+    }
+
+    col = uiLayoutColumn(layout, true);
+    row = uiLayoutRow(col, true);
+    uiLayoutSetRedAlert(row, !valid);
+    uiItemPointerR(row,
+                   &ptr,
+                   "material",
+                   &obj_data_ptr,
+                   "materials",
+                   NULL,
+                   valid ? ICON_SHADING_TEXTURE : ICON_ERROR);
+    sub = uiLayoutRow(row, true);
+    uiLayoutSetActive(sub, has_material);
+    uiLayoutSetPropDecorate(sub, false);
+    uiItemR(sub, &ptr, "invert_materials", 0, "", ICON_ARROW_LEFTRIGHT);
+
+    row = uiLayoutRow(col, true);
+    uiItemR(row, &ptr, "pass_index", 0, NULL, ICON_NONE);
+    sub = uiLayoutRow(row, true);
+    uiLayoutSetActive(sub, RNA_int_get(&ptr, "pass_index") != 0);
+    uiLayoutSetPropDecorate(sub, false);
+    uiItemR(sub, &ptr, "invert_material_pass", 0, "", ICON_ARROW_LEFTRIGHT);
+  }
+
+  if (use_vertex) {
+    bool has_vertex_group = RNA_string_length(&ptr, "vertex_group") != 0;
+
+    row = uiLayoutRow(layout, true);
+    uiItemPointerR(row, &ptr, "vertex_group", &ob_ptr, "vertex_groups", NULL, ICON_NONE);
+    sub = uiLayoutRow(row, true);
+    uiLayoutSetActive(sub, has_vertex_group);
+    uiLayoutSetPropDecorate(sub, false);
+    uiItemR(sub, &ptr, "invert_vertex", 0, "", ICON_ARROW_LEFTRIGHT);
+  }
+}
+
+void gpencil_modifier_curve_header_draw(const bContext *C, Panel *panel)
+{
+  uiLayout *layout = panel->layout;
+
+  PointerRNA ptr;
+  gpencil_modifier_panel_get_property_pointers(C, panel, NULL, &ptr);
+
+  uiItemR(layout, &ptr, "use_custom_curve", 0, NULL, ICON_NONE);
+}
+
+void gpencil_modifier_curve_panel_draw(const bContext *C, Panel *panel)
+{
+  uiLayout *layout = panel->layout;
+
+  PointerRNA ptr;
+  gpencil_modifier_panel_get_property_pointers(C, panel, NULL, &ptr);
+
+  uiTemplateCurveMapping(layout, &ptr, "curve", 0, false, false, false, false);
+}
+
+/**
+ * Draw modifier error message.
+ */
+void gpencil_modifier_panel_end(uiLayout *layout, PointerRNA *ptr)
+{
+  GpencilModifierData *md = ptr->data;
+  if (md->error) {
+    uiLayout *row = uiLayoutRow(layout, false);
+    uiItemL(row, IFACE_(md->error), ICON_ERROR);
+  }
+}
+
+/**
+ * Gets RNA pointers for the active object and the panel's modifier data.
+ */
+#define ERROR_LIBDATA_MESSAGE TIP_("External library data")
+void gpencil_modifier_panel_get_property_pointers(const bContext *C,
+                                                  Panel *panel,
+                                                  PointerRNA *r_ob_ptr,
+                                                  PointerRNA *r_md_ptr)
+{
+  Object *ob = get_gpencilmodifier_object(C);
+  GpencilModifierData *md = BLI_findlink(&ob->greasepencil_modifiers, panel->runtime.list_index);
+
+  RNA_pointer_create(&ob->id, &RNA_GpencilModifier, md, r_md_ptr);
+
+  if (r_ob_ptr != NULL) {
+    RNA_pointer_create(&ob->id, &RNA_Object, ob, r_ob_ptr);
+  }
+
+  uiBlock *block = uiLayoutGetBlock(panel->layout);
+  UI_block_lock_clear(block);
+  UI_block_lock_set(block, ob && ID_IS_LINKED(ob), ERROR_LIBDATA_MESSAGE);
+
+  uiLayoutSetContextPointer(panel->layout, "modifier", r_md_ptr);
+}
+
+static void gpencil_modifier_ops_extra_draw(bContext *C, uiLayout *layout, void *md_v)
+{
+  PointerRNA op_ptr;
+  uiLayout *row;
+  GpencilModifierData *md = (GpencilModifierData *)md_v;
+  const GpencilModifierTypeInfo *mti = BKE_gpencil_modifier_get_info(md->type);
+
+  PointerRNA ptr;
+  Object *ob = get_gpencilmodifier_object(C);
+  RNA_pointer_create(&ob->id, &RNA_GpencilModifier, md, &ptr);
+  uiLayoutSetContextPointer(layout, "modifier", &ptr);
+  uiLayoutSetOperatorContext(layout, WM_OP_INVOKE_DEFAULT);
+
+  uiLayoutSetUnitsX(layout, 4.0f);
+
+  /* Apply. */
+  if (!(mti->flags & eGpencilModifierTypeFlag_NoApply)) {
+    uiItemEnumO(layout,
+                "OBJECT_OT_gpencil_modifier_apply",
+                CTX_IFACE_(BLT_I18NCONTEXT_OPERATOR_DEFAULT, "Apply"),
+                ICON_CHECKMARK,
+                "apply_as",
+                MODIFIER_APPLY_DATA);
+  }
+
+  /* Duplicate. */
+  uiItemO(layout,
+          CTX_IFACE_(BLT_I18NCONTEXT_OPERATOR_DEFAULT, "Duplicate"),
+          ICON_DUPLICATE,
+          "OBJECT_OT_gpencil_modifier_copy");
+
+  uiItemS(layout);
+
+  /* Move to first. */
+  row = uiLayoutColumn(layout, false);
+  uiItemFullO(row,
+              "OBJECT_OT_gpencil_modifier_move_to_index",
+              IFACE_("Move to First"),
+              ICON_TRIA_UP,
+              NULL,
+              WM_OP_INVOKE_DEFAULT,
+              0,
+              &op_ptr);
+  RNA_int_set(&op_ptr, "index", 0);
+  if (!md->prev) {
+    uiLayoutSetEnabled(row, false);
+  }
+
+  /* Move to last. */
+  row = uiLayoutColumn(layout, false);
+  uiItemFullO(row,
+              "OBJECT_OT_gpencil_modifier_move_to_index",
+              IFACE_("Move to Last"),
+              ICON_TRIA_DOWN,
+              NULL,
+              WM_OP_INVOKE_DEFAULT,
+              0,
+              &op_ptr);
+  RNA_int_set(&op_ptr, "index", BLI_listbase_count(&ob->greasepencil_modifiers) - 1);
+  if (!md->next) {
+    uiLayoutSetEnabled(row, false);
+  }
+}
+
+static void gpencil_modifier_panel_header(const bContext *C, Panel *panel)
+{
+  uiLayout *row, *sub;
+  uiLayout *layout = panel->layout;
+
+  Object *ob = get_gpencilmodifier_object(C);
+  GpencilModifierData *md = BLI_findlink(&ob->greasepencil_modifiers, panel->runtime.list_index);
+  PointerRNA ptr;
+  RNA_pointer_create(&ob->id, &RNA_GpencilModifier, md, &ptr);
+  uiLayoutSetContextPointer(panel->layout, "modifier", &ptr);
+
+  const GpencilModifierTypeInfo *mti = BKE_gpencil_modifier_get_info(md->type);
+  bool narrow_panel = (panel->sizex < UI_UNIT_X * 9 && panel->sizex != 0);
+
+  /* Modifier Icon. */
+  row = uiLayoutRow(layout, false);
+  if (mti->isDisabled && mti->isDisabled(md, 0)) {
+    uiLayoutSetRedAlert(row, true);
+  }
+  uiItemL(row, "", RNA_struct_ui_icon(ptr.type));
+
+  /* Modifier name. */
+  row = uiLayoutRow(layout, true);
+  if (!narrow_panel) {
+    uiItemR(row, &ptr, "name", 0, "", ICON_NONE);
+  }
+  else {
+    uiLayoutSetAlignment(row, UI_LAYOUT_ALIGN_RIGHT);
+  }
+
+  /* Display mode buttons. */
+  if (mti->flags & eGpencilModifierTypeFlag_SupportsEditmode) {
+    sub = uiLayoutRow(row, true);
+    uiItemR(sub, &ptr, "show_in_editmode", 0, "", ICON_NONE);
+  }
+  uiItemR(row, &ptr, "show_viewport", 0, "", ICON_NONE);
+  uiItemR(row, &ptr, "show_render", 0, "", ICON_NONE);
+
+  /* Extra operators. */
+  // row = uiLayoutRow(layout, true);
+  uiItemMenuF(row, "", ICON_DOWNARROW_HLT, gpencil_modifier_ops_extra_draw, md);
+
+  /* Remove button. */
+  sub = uiLayoutRow(row, true);
+  uiLayoutSetEmboss(sub, UI_EMBOSS_NONE);
+  uiItemO(sub, "", ICON_X, "OBJECT_OT_gpencil_modifier_remove");
+
+  /* Extra padding. */
+  uiItemS(layout);
+}
+
+/** \} */
+
+/* -------------------------------------------------------------------- */
+/** \name Modifier Registration Helpers
+ * \{ */
+
+/**
+ * Create a panel in the context's region
+ */
+PanelType *gpencil_modifier_panel_register(ARegionType *region_type,
+                                           GpencilModifierType type,
+                                           PanelDrawFn draw)
+{
+
+  /* Get the name for the modifier's panel. */
+  char panel_idname[BKE_ST_MAXNAME];
+  BKE_gpencil_modifierType_panel_id(type, panel_idname);
+
+  PanelType *panel_type = MEM_callocN(sizeof(PanelType), panel_idname);
+
+  strcpy(panel_type->idname, panel_idname);
+  strcpy(panel_type->label, "");
+  strcpy(panel_type->context, "modifier");
+  strcpy(panel_type->translation_context, BLT_I18NCONTEXT_DEFAULT_BPYRNA);
+
+  panel_type->draw_header = gpencil_modifier_panel_header;
+  panel_type->draw = draw;
+  panel_type->poll = gpencil_modifier_ui_poll;
+
+  /* Give the panel the special flag that says it was built here and corresponds to a
+   * modifer rather than a PanelType. */
+  panel_type->flag = PNL_LAYOUT_HEADER_EXPAND | PNL_DRAW_BOX | PNL_INSTANCED;
+  panel_type->reorder = gpencil_modifier_reorder;
+  panel_type->get_list_data_expand_flag = get_gpencil_modifier_expand_flag;
+  panel_type->set_list_data_expand_flag = set_gpencil_modifier_expand_flag;
+
+  BLI_addtail(&region_type->paneltypes, panel_type);
+
+  return panel_type;
+}
+
+/**
+ * Add a child panel to the parent.
+ *
+ * \note To create the panel type's idname, it appends the \a name argument to the \a parent's
+ * idname.
+ */
+PanelType *gpencil_modifier_subpanel_register(ARegionType *region_type,
+                                              const char *name,
+                                              const char *label,
+                                              PanelDrawFn draw_header,
+                                              PanelDrawFn draw,
+                                              PanelType *parent)
+{
+  /* Create the subpanel's ID name. */
+  char panel_idname[BKE_ST_MAXNAME];
+  strcpy(panel_idname, parent->idname);
+  strcat(panel_idname, "_");
+  strcat(panel_idname, name);
+
+  PanelType *panel_type = MEM_callocN(sizeof(PanelType), panel_idname);
+
+  strcpy(panel_type->idname, panel_idname);
+  strcpy(panel_type->label, label);
+  strcpy(panel_type->context, "modifier");
+  strcpy(panel_type->translation_context, BLT_I18NCONTEXT_DEFAULT_BPYRNA);
+
+  panel_type->draw_header = draw_header;
+  panel_type->draw = draw;
+  panel_type->poll = gpencil_modifier_ui_poll;
+  panel_type->flag = (PNL_DEFAULT_CLOSED | PNL_DRAW_BOX);
+
+  BLI_assert(parent != NULL);
+  strcpy(panel_type->parent_id, parent->idname);
+  panel_type->parent = parent;
+  BLI_addtail(&parent->children, BLI_genericNodeN(panel_type));
+  BLI_addtail(&region_type->paneltypes, panel_type);
+
+  return panel_type;
+}
+
+/** \} */
\ No newline at end of file