Manipulator: Python API

Initial support for Python/Manipulator integration
from 'custom-manipulators' branch.

Supports:

- Registering custom manipulators & manipulator-groups.
- Modifying RNA properties, custom values via get/set callbacks,
  or invoking an operator.
- Drawing shape presets for Python defined manipulators (arrow, circle, face-maps)

Limitations:

- Only float properties supported.
- Drawing only supported via shape presets.
  (we'll likely want a way to define custom geometry or draw directly).
- When to refresh, recalculate manipulators will likely need
  integration with notifier system.

Development will be continued in the 2.8 branch

14 files changed, 1979 insertions, 16 deletions

diff --git a/source/blender/makesrna/intern/CMakeLists.txt b/source/blender/makesrna/intern/CMakeLists.txt
index d57fbbbd764..75d127079b9 100644
--- a/source/blender/makesrna/intern/CMakeLists.txt
+++ b/source/blender/makesrna/intern/CMakeLists.txt
@@ -127,6 +127,7 @@ set(APISRC
 	rna_ui_api.c
 	rna_vfont_api.c
 	rna_wm_api.c
+	rna_wm_manipulator_api.c
 )
 
 string(REGEX REPLACE "rna_([a-zA-Z0-9_-]*).c" "${CMAKE_CURRENT_BINARY_DIR}/rna_\\1_gen.c" GENSRC "${DEFSRC}")
diff --git a/source/blender/makesrna/intern/makesrna.c b/source/blender/makesrna/intern/makesrna.c
index 20b3daeb79d..7d2ce4cb3b2 100644
--- a/source/blender/makesrna/intern/makesrna.c
+++ b/source/blender/makesrna/intern/makesrna.c
@@ -3365,7 +3365,7 @@ static RNAProcessItem PROCESS_ITEMS[] = {
 	{"rna_userdef.c", NULL, RNA_def_userdef},
 	{"rna_vfont.c", "rna_vfont_api.c", RNA_def_vfont},
 	{"rna_wm.c", "rna_wm_api.c", RNA_def_wm},
-	{"rna_wm_manipulator.c", NULL, RNA_def_wm_manipulator},
+	{"rna_wm_manipulator.c", "rna_wm_manipulator_api.c", RNA_def_wm_manipulator},
 	{"rna_workspace.c", NULL, RNA_def_workspace},
 	{"rna_world.c", NULL, RNA_def_world},
 	{"rna_movieclip.c", NULL, RNA_def_movieclip},
diff --git a/source/blender/makesrna/intern/rna_wm_api.c b/source/blender/makesrna/intern/rna_wm_api.c
index 677ea92aea1..166b6f96956 100644
--- a/source/blender/makesrna/intern/rna_wm_api.c
+++ b/source/blender/makesrna/intern/rna_wm_api.c
@@ -71,6 +71,8 @@ EnumPropertyItem rna_enum_window_cursor_items[] = {
 #include "UI_interface.h"
 #include "BKE_context.h"
 
+#include "WM_types.h"
+
 static wmKeyMap *rna_keymap_active(wmKeyMap *km, bContext *C)
 {
 	wmWindowManager *wm = CTX_wm_manager(C);
@@ -115,6 +117,37 @@ static void rna_event_timer_remove(struct wmWindowManager *wm, wmTimer *timer)
 	WM_event_remove_timer(wm, timer->win, timer);
 }
 
+
+static wmManipulatorGroupType *wm_manipulatorgrouptype_find_for_add_remove(ReportList *reports, const char *idname)
+{
+	wmManipulatorGroupType *wgt = WM_manipulatorgrouptype_find(idname, true);
+	if (wgt == NULL) {
+		BKE_reportf(reports, RPT_ERROR, "Manipulator group type '%s' not found!", idname);
+		return NULL;
+	}
+	if (wgt->flag & WM_MANIPULATORGROUPTYPE_PERSISTENT) {
+		BKE_reportf(reports, RPT_ERROR, "Manipulator group '%s' has 'PERSISTENT' option set!", idname);
+		return NULL;
+	}
+	return wgt;
+}
+
+static void rna_manipulator_group_type_add(ReportList *reports, const char *idname)
+{
+	wmManipulatorGroupType *wgt = wm_manipulatorgrouptype_find_for_add_remove(reports, idname);
+	if (wgt != NULL) {
+		WM_manipulator_group_add_ptr(wgt);
+	}
+}
+
+static void rna_manipulator_group_type_remove(Main *bmain, ReportList *reports, const char *idname)
+{
+	wmManipulatorGroupType *wgt = wm_manipulatorgrouptype_find_for_add_remove(reports, idname);
+	if (wgt != NULL) {
+		WM_manipulator_group_remove_ptr(bmain, wgt);
+	}
+}
+
 /* placeholder data for final implementation of a true progressbar */
 static struct wmStaticProgress {
 	float min;
@@ -426,6 +459,18 @@ void RNA_api_wm(StructRNA *srna)
 	parm = RNA_def_pointer(func, "timer", "Timer", "", "");
 	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
 
+	func = RNA_def_function(srna, "manipulator_group_type_add", "rna_manipulator_group_type_add");
+	RNA_def_function_ui_description(func, "Activate an existing widget group (when the persistent option isn't set)");
+	RNA_def_function_flag(func, FUNC_NO_SELF | FUNC_USE_REPORTS);
+	parm = RNA_def_string(func, "identifier", NULL, 0, "", "Manipulator group type name");
+	RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
+
+	func = RNA_def_function(srna, "manipulator_group_type_remove", "rna_manipulator_group_type_remove");
+	RNA_def_function_ui_description(func, "De-activate a widget group (when the persistent option isn't set)");
+	RNA_def_function_flag(func, FUNC_NO_SELF | FUNC_USE_MAIN | FUNC_USE_REPORTS);
+	parm = RNA_def_string(func, "identifier", NULL, 0, "", "Manipulator group type name");
+	RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
+
 	/* Progress bar interface */
 	func = RNA_def_function(srna, "progress_begin", "rna_progress_begin");
 	RNA_def_function_ui_description(func, "Start progress report");
diff --git a/source/blender/makesrna/intern/rna_wm_manipulator.c b/source/blender/makesrna/intern/rna_wm_manipulator.c
index 06e31688a8a..030f1a1628c 100644
--- a/source/blender/makesrna/intern/rna_wm_manipulator.c
+++ b/source/blender/makesrna/intern/rna_wm_manipulator.c
@@ -63,6 +63,7 @@
 #include "BKE_global.h"
 #include "BKE_idprop.h"
 #include "BKE_workspace.h"
+#include "BKE_utildefines.h"
 
 #include "MEM_guardedalloc.h"
 
@@ -75,6 +76,171 @@
 /** \name Manipulator API
  * \{ */
 
+static void rna_manipulator_draw_cb(
+        const struct bContext *C, struct wmManipulator *mpr)
+{
+	extern FunctionRNA rna_Manipulator_draw_func;
+	wmManipulatorGroup *mgroup = mpr->parent_mgroup;
+	PointerRNA mpr_ptr;
+	ParameterList list;
+	FunctionRNA *func;
+	RNA_pointer_create(NULL, mpr->type->ext.srna, mpr, &mpr_ptr);
+	/* RNA_struct_find_function(&mpr_ptr, "draw"); */
+	func = &rna_Manipulator_draw_func;
+	RNA_parameter_list_create(&list, &mpr_ptr, func);
+	RNA_parameter_set_lookup(&list, "context", &C);
+	mgroup->type->ext.call((bContext *)C, &mpr_ptr, func, &list);
+	RNA_parameter_list_free(&list);
+}
+
+static void rna_manipulator_draw_select_cb(
+        const struct bContext *C, struct wmManipulator *mpr, int select_id)
+{
+	extern FunctionRNA rna_Manipulator_draw_select_func;
+	wmManipulatorGroup *mgroup = mpr->parent_mgroup;
+	PointerRNA mpr_ptr;
+	ParameterList list;
+	FunctionRNA *func;
+	RNA_pointer_create(NULL, mpr->type->ext.srna, mpr, &mpr_ptr);
+	/* RNA_struct_find_function(&mpr_ptr, "draw_select"); */
+	func = &rna_Manipulator_draw_select_func;
+	RNA_parameter_list_create(&list, &mpr_ptr, func);
+	RNA_parameter_set_lookup(&list, "context", &C);
+	RNA_parameter_set_lookup(&list, "select_id", &select_id);
+	mgroup->type->ext.call((bContext *)C, &mpr_ptr, func, &list);
+	RNA_parameter_list_free(&list);
+}
+
+static int rna_manipulator_test_select_cb(
+        struct bContext *C, struct wmManipulator *mpr, const struct wmEvent *event)
+{
+	extern FunctionRNA rna_Manipulator_test_select_func;
+	wmManipulatorGroup *mgroup = mpr->parent_mgroup;
+	PointerRNA mpr_ptr;
+	ParameterList list;
+	FunctionRNA *func;
+	RNA_pointer_create(NULL, mpr->type->ext.srna, mpr, &mpr_ptr);
+	/* RNA_struct_find_function(&mpr_ptr, "test_select"); */
+	func = &rna_Manipulator_test_select_func;
+	RNA_parameter_list_create(&list, &mpr_ptr, func);
+	RNA_parameter_set_lookup(&list, "context", &C);
+	RNA_parameter_set_lookup(&list, "event", &event);
+	mgroup->type->ext.call((bContext *)C, &mpr_ptr, func, &list);
+
+	void *ret;
+	RNA_parameter_get_lookup(&list, "intersect_id", &ret);
+	int intersect_id = *(int *)ret;
+
+	RNA_parameter_list_free(&list);
+	return intersect_id;
+}
+
+static void rna_manipulator_modal_cb(
+        struct bContext *C, struct wmManipulator *mpr, const struct wmEvent *event, int tweak)
+{
+	extern FunctionRNA rna_Manipulator_modal_func;
+	wmManipulatorGroup *mgroup = mpr->parent_mgroup;
+	PointerRNA mpr_ptr;
+	ParameterList list;
+	FunctionRNA *func;
+	RNA_pointer_create(NULL, mpr->type->ext.srna, mpr, &mpr_ptr);
+	/* RNA_struct_find_function(&mpr_ptr, "modal"); */
+	func = &rna_Manipulator_modal_func;
+	RNA_parameter_list_create(&list, &mpr_ptr, func);
+	RNA_parameter_set_lookup(&list, "context", &C);
+	RNA_parameter_set_lookup(&list, "event", &event);
+	RNA_parameter_set_lookup(&list, "tweak", &tweak);
+	mgroup->type->ext.call((bContext *)C, &mpr_ptr, func, &list);
+	RNA_parameter_list_free(&list);
+}
+
+static void rna_manipulator_setup_cb(
+        struct wmManipulator *mpr)
+{
+	extern FunctionRNA rna_Manipulator_setup_func;
+	wmManipulatorGroup *mgroup = mpr->parent_mgroup;
+	PointerRNA mpr_ptr;
+	ParameterList list;
+	FunctionRNA *func;
+	RNA_pointer_create(NULL, mpr->type->ext.srna, mpr, &mpr_ptr);
+	/* RNA_struct_find_function(&mpr_ptr, "setup"); */
+	func = &rna_Manipulator_setup_func;
+	RNA_parameter_list_create(&list, &mpr_ptr, func);
+	mgroup->type->ext.call((bContext *)NULL, &mpr_ptr, func, &list);
+	RNA_parameter_list_free(&list);
+}
+
+
+static void rna_manipulator_invoke_cb(
+        struct bContext *C, struct wmManipulator *mpr, const struct wmEvent *event)
+{
+	extern FunctionRNA rna_Manipulator_invoke_func;
+	wmManipulatorGroup *mgroup = mpr->parent_mgroup;
+	PointerRNA mpr_ptr;
+	ParameterList list;
+	FunctionRNA *func;
+	RNA_pointer_create(NULL, mpr->type->ext.srna, mpr, &mpr_ptr);
+	/* RNA_struct_find_function(&mpr_ptr, "invoke"); */
+	func = &rna_Manipulator_invoke_func;
+	RNA_parameter_list_create(&list, &mpr_ptr, func);
+	RNA_parameter_set_lookup(&list, "context", &C);
+	RNA_parameter_set_lookup(&list, "event", &event);
+	mgroup->type->ext.call((bContext *)C, &mpr_ptr, func, &list);
+	RNA_parameter_list_free(&list);
+}
+
+static void rna_manipulator_exit_cb(
+        struct bContext *C, struct wmManipulator *mpr, bool cancel)
+{
+	extern FunctionRNA rna_Manipulator_exit_func;
+	wmManipulatorGroup *mgroup = mpr->parent_mgroup;
+	PointerRNA mpr_ptr;
+	ParameterList list;
+	FunctionRNA *func;
+	RNA_pointer_create(NULL, mpr->type->ext.srna, mpr, &mpr_ptr);
+	/* RNA_struct_find_function(&mpr_ptr, "exit"); */
+	func = &rna_Manipulator_exit_func;
+	RNA_parameter_list_create(&list, &mpr_ptr, func);
+	RNA_parameter_set_lookup(&list, "context", &C);
+	{
+		int cancel_i = cancel;
+		RNA_parameter_set_lookup(&list, "cancel", &cancel_i);
+	}
+	mgroup->type->ext.call((bContext *)C, &mpr_ptr, func, &list);
+	RNA_parameter_list_free(&list);
+}
+
+static void rna_manipulator_select_cb(
+        struct bContext *C, struct wmManipulator *mpr, int action)
+{
+	extern FunctionRNA rna_Manipulator_select_func;
+	wmManipulatorGroup *mgroup = mpr->parent_mgroup;
+	PointerRNA mpr_ptr;
+	ParameterList list;
+	FunctionRNA *func;
+	RNA_pointer_create(NULL, mpr->type->ext.srna, mpr, &mpr_ptr);
+	/* RNA_struct_find_function(&mpr_ptr, "select"); */
+	func = &rna_Manipulator_select_func;
+	RNA_parameter_list_create(&list, &mpr_ptr, func);
+	RNA_parameter_set_lookup(&list, "context", &C);
+	RNA_parameter_set_lookup(&list, "action", &action);
+	mgroup->type->ext.call((bContext *)C, &mpr_ptr, func, &list);
+	RNA_parameter_list_free(&list);
+}
+
+/* just to work around 'const char *' warning and to ensure this is a python op */
+static void rna_Manipulator_bl_idname_set(PointerRNA *ptr, const char *value)
+{
+	wmManipulator *data = ptr->data;
+	char *str = (char *)data->type->idname;
+	if (!str[0]) {
+		BLI_strncpy(str, value, MAX_NAME);    /* utf8 already ensured */
+	}
+	else {
+		assert(!"setting the bl_idname on a non-builtin operator");
+	}
+}
+
 static wmManipulator *rna_ManipulatorProperties_find_operator(PointerRNA *ptr)
 {
 #if 0
@@ -83,7 +249,7 @@ static wmManipulator *rna_ManipulatorProperties_find_operator(PointerRNA *ptr)
 
 	/* We could try workaruond this lookup, but not trivial. */
 	for (bScreen *screen = G.main->screen.first; screen; screen = screen->id.next) {
-		IDProperty *properties = (IDProperty *)ptr->data;
+		IDProperty *properties = ptr->data;
 		for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
 			for (ARegion *ar = sa->regionbase.first; ar; ar = ar->next) {
 				if (ar->manipulator_map) {
@@ -127,10 +293,202 @@ static IDProperty *rna_ManipulatorProperties_idprops(PointerRNA *ptr, bool creat
 
 static PointerRNA rna_Manipulator_properties_get(PointerRNA *ptr)
 {
-	wmManipulator *mpr = (wmManipulator *)ptr->data;
+	wmManipulator *mpr = ptr->data;
 	return rna_pointer_inherit_refine(ptr, mpr->type->srna, mpr->properties);
 }
 
+/* wmManipulator.float */
+#define RNA_MANIPULATOR_GENERIC_FLOAT_RW_DEF(func_id, member_id) \
+static float rna_Manipulator_##func_id##_get(PointerRNA *ptr) \
+{ \
+	wmManipulator *mpr = ptr->data; \
+	return mpr->member_id; \
+} \
+static void rna_Manipulator_##func_id##_set(PointerRNA *ptr, float value) \
+{ \
+	wmManipulator *mpr = ptr->data; \
+	mpr->member_id = value; \
+}
+/* wmManipulator.float[len] */
+#define RNA_MANIPULATOR_GENERIC_FLOAT_ARRAY_RW_DEF(func_id, member_id, len) \
+static void rna_Manipulator_##func_id##_get(PointerRNA *ptr, float value[len]) \
+{ \
+	wmManipulator *mpr = ptr->data; \
+	memcpy(value, mpr->member_id, sizeof(float[len])); \
+} \
+static void rna_Manipulator_##func_id##_set(PointerRNA *ptr, const float value[len]) \
+{ \
+	wmManipulator *mpr = ptr->data; \
+	memcpy(mpr->member_id, value, sizeof(float[len])); \
+}
+
+/* wmManipulator.flag */
+#define RNA_MANIPULATOR_GENERIC_FLAG_RW_DEF(func_id, member_id, flag_value) \
+static int rna_Manipulator_##func_id##_get(PointerRNA *ptr) \
+{ \
+	wmManipulator *mpr = ptr->data; \
+	return (mpr->member_id & flag_value) != 0; \
+} \
+static void rna_Manipulator_##func_id##_set(PointerRNA *ptr, int value) \
+{ \
+	wmManipulator *mpr = ptr->data; \
+	BKE_BIT_TEST_SET(mpr->member_id, value, flag_value); \
+}
+
+#define RNA_MANIPULATOR_FLAG_RO_DEF(func_id, member_id, flag_value) \
+static int rna_Manipulator_##func_id##_get(PointerRNA *ptr) \
+{ \
+	wmManipulator *mpr = ptr->data; \
+	return (mpr->member_id & flag_value) != 0; \
+}
+
+RNA_MANIPULATOR_GENERIC_FLOAT_ARRAY_RW_DEF(color, color, 4);
+RNA_MANIPULATOR_GENERIC_FLOAT_ARRAY_RW_DEF(color_hi, color_hi, 4);
+
+RNA_MANIPULATOR_GENERIC_FLOAT_ARRAY_RW_DEF(matrix_basis, matrix_basis, 16);
+RNA_MANIPULATOR_GENERIC_FLOAT_ARRAY_RW_DEF(matrix_offset, matrix_offset, 16);
+
+RNA_MANIPULATOR_GENERIC_FLOAT_RW_DEF(scale_basis, scale_basis);
+RNA_MANIPULATOR_GENERIC_FLOAT_RW_DEF(line_width, line_width);
+
+RNA_MANIPULATOR_GENERIC_FLAG_RW_DEF(flag_use_draw_hover, flag, WM_MANIPULATOR_DRAW_HOVER);
+RNA_MANIPULATOR_GENERIC_FLAG_RW_DEF(flag_use_draw_active, flag, WM_MANIPULATOR_DRAW_ACTIVE);
+RNA_MANIPULATOR_GENERIC_FLAG_RW_DEF(flag_use_draw_value, flag, WM_MANIPULATOR_DRAW_VALUE);
+RNA_MANIPULATOR_GENERIC_FLAG_RW_DEF(flag_hide, flag, WM_MANIPULATOR_HIDDEN);
+
+/* wmManipulator.state */
+RNA_MANIPULATOR_FLAG_RO_DEF(state_is_highlight, state, WM_MANIPULATOR_STATE_HIGHLIGHT);
+RNA_MANIPULATOR_FLAG_RO_DEF(state_is_active, state, WM_MANIPULATOR_STATE_ACTIVE);
+RNA_MANIPULATOR_FLAG_RO_DEF(state_select, state, WM_MANIPULATOR_STATE_SELECT);
+
+static void rna_Manipulator_name_get(PointerRNA *ptr, char *value)
+{
+	wmManipulator *mpr = ptr->data;
+	strcpy(value, mpr->name);
+}
+
+static void rna_Manipulator_name_set(PointerRNA *ptr, const char *value)
+{
+	wmManipulator *mpr = ptr->data;
+	WM_manipulator_name_set(mpr->parent_mgroup, mpr, value);
+}
+
+static int rna_Manipulator_name_length(PointerRNA *ptr)
+{
+	wmManipulator *mpr = ptr->data;
+	return strlen(mpr->name);
+}
+
+#ifdef WITH_PYTHON
+
+static void rna_Manipulator_unregister(struct Main *bmain, StructRNA *type);
+void BPY_RNA_manipulator_wrapper(wmManipulatorType *wgt, void *userdata);
+
+static StructRNA *rna_Manipulator_register(
+        Main *bmain, ReportList *reports, void *data, const char *identifier,
+        StructValidateFunc validate, StructCallbackFunc call, StructFreeFunc free)
+{
+	struct {
+		char idname[MAX_NAME];
+	} temp_buffers;
+
+	wmManipulatorType dummywt = {NULL};
+	wmManipulator dummymnp = {NULL};
+	PointerRNA mnp_ptr;
+
+	/* Two sets of functions. */
+	int have_function[8];
+
+	/* setup dummy manipulator & manipulator type to store static properties in */
+	dummymnp.type = &dummywt;
+	dummywt.idname = temp_buffers.idname;
+	RNA_pointer_create(NULL, &RNA_Manipulator, &dummymnp, &mnp_ptr);
+
+	/* Clear so we can detect if it's left unset. */
+	temp_buffers.idname[0] = '\0';
+
+	/* validate the python class */
+	if (validate(&mnp_ptr, data, have_function) != 0)
+		return NULL;
+
+	if (strlen(identifier) >= sizeof(temp_buffers.idname)) {
+		BKE_reportf(reports, RPT_ERROR, "Registering manipulator class: '%s' is too long, maximum length is %d",
+		            identifier, (int)sizeof(temp_buffers.idname));
+		return NULL;
+	}
+
+	/* check if we have registered this manipulator type before, and remove it */
+	{
+		const wmManipulatorType *wt = WM_manipulatortype_find(dummywt.idname, true);
+		if (wt && wt->ext.srna) {
+			rna_Manipulator_unregister(bmain, wt->ext.srna);
+		}
+	}
+
+	/* create a new manipulator type */
+	dummywt.ext.srna = RNA_def_struct_ptr(&BLENDER_RNA, dummywt.idname, &RNA_Manipulator);
+	/* manipulator properties are registered separately */
+	RNA_def_struct_flag(dummywt.ext.srna, STRUCT_NO_IDPROPERTIES);
+	dummywt.ext.data = data;
+	dummywt.ext.call = call;
+	dummywt.ext.free = free;
+
+	{
+		int i = 0;
+		dummywt.draw = (have_function[i++]) ? rna_manipulator_draw_cb : NULL;
+		dummywt.draw_select = (have_function[i++]) ? rna_manipulator_draw_select_cb : NULL;
+		dummywt.test_select = (have_function[i++]) ? rna_manipulator_test_select_cb : NULL;
+		dummywt.modal = (have_function[i++]) ? rna_manipulator_modal_cb : NULL;
+//		dummywt.property_update = (have_function[i++]) ? rna_manipulator_property_update : NULL;
+//		dummywt.position_get = (have_function[i++]) ? rna_manipulator_position_get : NULL;
+		dummywt.setup = (have_function[i++]) ? rna_manipulator_setup_cb : NULL;
+		dummywt.invoke = (have_function[i++]) ? rna_manipulator_invoke_cb : NULL;
+		dummywt.exit = (have_function[i++]) ? rna_manipulator_exit_cb : NULL;
+		dummywt.select = (have_function[i++]) ? rna_manipulator_select_cb : NULL;
+
+		BLI_assert(i == ARRAY_SIZE(have_function));
+	}
+
+	RNA_def_struct_duplicate_pointers(dummywt.ext.srna);
+
+	/* use duplicated string */
+	dummywt.idname = dummywt.ext.srna->identifier;
+
+	WM_manipulatortype_append_ptr(BPY_RNA_manipulator_wrapper, (void *)&dummywt);
+
+	/* update while blender is running */
+	WM_main_add_notifier(NC_SCREEN | NA_EDITED, NULL);
+
+	return dummywt.ext.srna;
+}
+
+static void rna_Manipulator_unregister(struct Main *UNUSED(bmain), StructRNA *type)
+{
+	wmManipulatorType *wt = RNA_struct_blender_type_get(type);
+
+	/* TODO, remove widgets from interface! */
+
+	if (!wt)
+		return;
+
+	WM_main_add_notifier(NC_SCREEN | NA_EDITED, NULL);
+
+	RNA_struct_free_extension(type, &wt->ext);
+
+	WM_manipulatortype_remove_ptr(wt);
+
+	RNA_struct_free(&BLENDER_RNA, type);
+}
+
+static void **rna_Manipulator_instance(PointerRNA *ptr)
+{
+	wmManipulator *mpr = ptr->data;
+	return &mpr->py_instance;
+}
+
+#endif  /* WITH_PYTHON */
+
+
 static StructRNA *rna_Manipulator_refine(PointerRNA *mnp_ptr)
 {
 	wmManipulator *mpr = mnp_ptr->data;
@@ -142,6 +500,296 @@ static StructRNA *rna_Manipulator_refine(PointerRNA *mnp_ptr)
 /** \name Manipulator Group API
  * \{ */
 
+static wmManipulator *rna_ManipulatorGroup_manipulator_new(
+        wmManipulatorGroup *mgroup, ReportList *reports, const char *idname, const char *name)
+{
+	const wmManipulatorType *wt = WM_manipulatortype_find(idname, true);
+	if (wt == NULL) {
+		BKE_reportf(reports, RPT_ERROR, "ManipulatorType '%s' not known", idname);
+		return NULL;
+	}
+	wmManipulator *mpr = WM_manipulator_new_ptr(wt, mgroup, name, NULL);
+	return mpr;
+}
+
+static void rna_ManipulatorGroup_manipulator_remove(
+        wmManipulatorGroup *mgroup, bContext *C, wmManipulator *mpr)
+{
+	WM_manipulator_free(&mgroup->manipulators, mgroup->parent_mmap, mpr, C);
+}
+
+static void rna_ManipulatorGroup_manipulator_clear(
+        wmManipulatorGroup *mgroup, bContext *C)
+{
+	while (mgroup->manipulators.first) {
+		WM_manipulator_free(&mgroup->manipulators, mgroup->parent_mmap, mgroup->manipulators.first, C);
+	}
+}
+
+static void rna_ManipulatorGroup_name_get(PointerRNA *ptr, char *value)
+{
+	wmManipulatorGroup *mgroup = ptr->data;
+	strcpy(value, mgroup->type->name);
+}
+
+static int rna_ManipulatorGroup_name_length(PointerRNA *ptr)
+{
+	wmManipulatorGroup *mgroup = ptr->data;
+	return strlen(mgroup->type->name);
+}
+
+/* just to work around 'const char *' warning and to ensure this is a python op */
+static void rna_ManipulatorGroup_bl_idname_set(PointerRNA *ptr, const char *value)
+{
+	wmManipulatorGroup *data = ptr->data;
+	char *str = (char *)data->type->idname;
+	if (!str[0])
+		BLI_strncpy(str, value, MAX_NAME);    /* utf8 already ensured */
+	else
+		assert(!"setting the bl_idname on a non-builtin operator");
+}
+
+static void rna_ManipulatorGroup_bl_label_set(PointerRNA *ptr, const char *value)
+{
+	wmManipulatorGroup *data = ptr->data;
+	char *str = (char *)data->type->name;
+	if (!str[0])
+		BLI_strncpy(str, value, MAX_NAME);    /* utf8 already ensured */
+	else
+		assert(!"setting the bl_label on a non-builtin operator");
+}
+
+static int rna_ManipulatorGroup_has_reports_get(PointerRNA *ptr)
+{
+	wmManipulatorGroup *mgroup = ptr->data;
+	return (mgroup->reports && mgroup->reports->list.first);
+}
+
+#ifdef WITH_PYTHON
+
+static bool rna_manipulatorgroup_poll_cb(const bContext *C, wmManipulatorGroupType *wgt)
+{
+
+	extern FunctionRNA rna_ManipulatorGroup_poll_func;
+
+	PointerRNA ptr;
+	ParameterList list;
+	FunctionRNA *func;
+	void *ret;
+	int visible;
+
+	RNA_pointer_create(NULL, wgt->ext.srna, NULL, &ptr); /* dummy */
+	func = &rna_ManipulatorGroup_poll_func; /* RNA_struct_find_function(&ptr, "poll"); */
+
+	RNA_parameter_list_create(&list, &ptr, func);
+	RNA_parameter_set_lookup(&list, "context", &C);
+	wgt->ext.call((bContext *)C, &ptr, func, &list);
+
+	RNA_parameter_get_lookup(&list, "visible", &ret);
+	visible = *(int *)ret;
+
+	RNA_parameter_list_free(&list);
+
+	return visible;
+}
+
+static void rna_manipulatorgroup_setup_cb(const bContext *C, wmManipulatorGroup *mgroup)
+{
+	extern FunctionRNA rna_ManipulatorGroup_setup_func;
+
+	PointerRNA mgroup_ptr;
+	ParameterList list;
+	FunctionRNA *func;
+
+	RNA_pointer_create(NULL, mgroup->type->ext.srna, mgroup, &mgroup_ptr);
+	func = &rna_ManipulatorGroup_setup_func; /* RNA_struct_find_function(&wgroupr, "setup"); */
+
+	RNA_parameter_list_create(&list, &mgroup_ptr, func);
+	RNA_parameter_set_lookup(&list, "context", &C);
+	mgroup->type->ext.call((bContext *)C, &mgroup_ptr, func, &list);
+
+	RNA_parameter_list_free(&list);
+}
+
+static wmKeyMap *rna_manipulatorgroup_setup_keymap_cb(const wmManipulatorGroupType *wgt, wmKeyConfig *config)
+{
+	extern FunctionRNA rna_ManipulatorGroup_setup_keymap_func;
+	const char *wgroupname = wgt->name;
+	void *ret;
+
+	PointerRNA ptr;
+	ParameterList list;
+	FunctionRNA *func;
+
+	RNA_pointer_create(NULL, wgt->ext.srna, NULL, &ptr); /* dummy */
+	func = &rna_ManipulatorGroup_setup_keymap_func; /* RNA_struct_find_function(&wgroupr, "setup_keymap"); */
+
+	RNA_parameter_list_create(&list, &ptr, func);
+	RNA_parameter_set_lookup(&list, "keyconfig", &config);
+	RNA_parameter_set_lookup(&list, "manipulator_group", &wgroupname);
+	wgt->ext.call(NULL, &ptr, func, &list);
+
+	RNA_parameter_get_lookup(&list, "keymap", &ret);
+	wmKeyMap *keymap = *(wmKeyMap **)ret;
+
+	RNA_parameter_list_free(&list);
+
+	return keymap;
+}
+
+static void rna_manipulatorgroup_refresh_cb(const bContext *C, wmManipulatorGroup *mgroup)
+{
+	extern FunctionRNA rna_ManipulatorGroup_refresh_func;
+
+	PointerRNA mgroup_ptr;
+	ParameterList list;
+	FunctionRNA *func;
+
+	RNA_pointer_create(NULL, mgroup->type->ext.srna, mgroup, &mgroup_ptr);
+	func = &rna_ManipulatorGroup_refresh_func; /* RNA_struct_find_function(&wgroupr, "refresh"); */
+
+	RNA_parameter_list_create(&list, &mgroup_ptr, func);
+	RNA_parameter_set_lookup(&list, "context", &C);
+	mgroup->type->ext.call((bContext *)C, &mgroup_ptr, func, &list);
+
+	RNA_parameter_list_free(&list);
+}
+
+static void rna_manipulatorgroup_draw_prepare_cb(const bContext *C, wmManipulatorGroup *mgroup)
+{
+	extern FunctionRNA rna_ManipulatorGroup_draw_prepare_func;
+
+	PointerRNA mgroup_ptr;
+	ParameterList list;
+	FunctionRNA *func;
+
+	RNA_pointer_create(NULL, mgroup->type->ext.srna, mgroup, &mgroup_ptr);
+	func = &rna_ManipulatorGroup_draw_prepare_func; /* RNA_struct_find_function(&wgroupr, "draw_prepare"); */
+
+	RNA_parameter_list_create(&list, &mgroup_ptr, func);
+	RNA_parameter_set_lookup(&list, "context", &C);
+	mgroup->type->ext.call((bContext *)C, &mgroup_ptr, func, &list);
+
+	RNA_parameter_list_free(&list);
+}
+
+void BPY_RNA_manipulatorgroup_wrapper(wmManipulatorGroupType *wgt, void *userdata);
+
+static StructRNA *rna_ManipulatorGroup_register(
+        Main *bmain, ReportList *reports, void *data, const char *identifier,
+        StructValidateFunc validate, StructCallbackFunc call, StructFreeFunc free)
+{
+	struct {
+		char name[MAX_NAME];
+		char idname[MAX_NAME];
+	} temp_buffers;
+
+	wmManipulatorGroupType dummywgt = {NULL};
+	wmManipulatorGroup dummywg = {NULL};
+	PointerRNA wgptr;
+
+	/* Two sets of functions. */
+	int have_function[5];
+
+	/* setup dummy manipulatorgroup & manipulatorgroup type to store static properties in */
+	dummywg.type = &dummywgt;
+	dummywgt.name = temp_buffers.name;
+	dummywgt.idname = temp_buffers.idname;
+
+	RNA_pointer_create(NULL, &RNA_ManipulatorGroup, &dummywg, &wgptr);
+
+	/* Clear so we can detect if it's left unset. */
+	temp_buffers.idname[0] = temp_buffers.name[0] = '\0';
+
+	/* validate the python class */
+	if (validate(&wgptr, data, have_function) != 0)
+		return NULL;
+
+	if (strlen(identifier) >= sizeof(temp_buffers.idname)) {
+		BKE_reportf(reports, RPT_ERROR, "Registering manipulatorgroup class: '%s' is too long, maximum length is %d",
+		            identifier, (int)sizeof(temp_buffers.idname));
+		return NULL;
+	}
+
+	/* check if the area supports widgets */
+	const struct wmManipulatorMapType_Params wmap_params = {
+		.spaceid = dummywgt.mmap_params.spaceid,
+		.regionid = dummywgt.mmap_params.regionid,
+	};
+
+	wmManipulatorMapType *mmap_type = WM_manipulatormaptype_ensure(&wmap_params);
+	if (mmap_type == NULL) {
+		BKE_reportf(reports, RPT_ERROR, "Area type does not support manipulators");
+		return NULL;
+	}
+
+	/* check if we have registered this manipulatorgroup type before, and remove it */
+	{
+		wmManipulatorGroupType *wgt = WM_manipulatorgrouptype_find(dummywgt.idname, true);
+		if (wgt && wgt->ext.srna) {
+			WM_manipulatormaptype_group_unlink(NULL, bmain, mmap_type, wgt);
+			WM_manipulatorgrouptype_remove_ptr(wgt);
+
+			WM_main_add_notifier(NC_SCREEN | NA_EDITED, NULL);
+		}
+	}
+
+	/* create a new manipulatorgroup type */
+	dummywgt.ext.srna = RNA_def_struct_ptr(&BLENDER_RNA, dummywgt.idname, &RNA_ManipulatorGroup);
+	RNA_def_struct_flag(dummywgt.ext.srna, STRUCT_NO_IDPROPERTIES); /* manipulatorgroup properties are registered separately */
+	dummywgt.ext.data = data;
+	dummywgt.ext.call = call;
+	dummywgt.ext.free = free;
+
+	/* We used to register widget group types like this, now we do it similar to
+	 * operator types. Thus we should be able to do the same as operator types now. */
+	dummywgt.poll = (have_function[0]) ? rna_manipulatorgroup_poll_cb : NULL;
+	dummywgt.setup_keymap =     (have_function[1]) ? rna_manipulatorgroup_setup_keymap_cb : NULL;
+	dummywgt.setup =            (have_function[2]) ? rna_manipulatorgroup_setup_cb : NULL;
+	dummywgt.refresh =          (have_function[3]) ? rna_manipulatorgroup_refresh_cb : NULL;
+	dummywgt.draw_prepare =     (have_function[4]) ? rna_manipulatorgroup_draw_prepare_cb : NULL;
+
+	RNA_def_struct_duplicate_pointers(dummywgt.ext.srna);
+	dummywgt.idname = dummywgt.ext.srna->identifier;
+	dummywgt.name = dummywgt.ext.srna->name;
+
+	wmManipulatorGroupType *wgt = WM_manipulatorgrouptype_append_ptr(
+	        BPY_RNA_manipulatorgroup_wrapper, (void *)&dummywgt);
+
+	if (wgt->flag & WM_MANIPULATORGROUPTYPE_PERSISTENT) {
+		WM_manipulator_group_add_ptr_ex(wgt, mmap_type);
+
+		/* update while blender is running */
+		WM_main_add_notifier(NC_SCREEN | NA_EDITED, NULL);
+	}
+
+	return dummywgt.ext.srna;
+}
+
+static void rna_ManipulatorGroup_unregister(struct Main *bmain, StructRNA *type)
+{
+	wmManipulatorGroupType *wgt = RNA_struct_blender_type_get(type);
+
+	if (!wgt)
+		return;
+
+	WM_main_add_notifier(NC_SCREEN | NA_EDITED, NULL);
+
+	RNA_struct_free_extension(type, &wgt->ext);
+
+	WM_manipulator_group_remove_ptr(bmain, wgt);
+
+	RNA_struct_free(&BLENDER_RNA, type);
+}
+
+static void **rna_ManipulatorGroup_instance(PointerRNA *ptr)
+{
+	wmManipulatorGroup *mgroup = ptr->data;
+	return &mgroup->py_instance;
+}
+
+#endif  /* WITH_PYTHON */
+
 static StructRNA *rna_ManipulatorGroup_refine(PointerRNA *mgroup_ptr)
 {
 	wmManipulatorGroup *mgroup = mgroup_ptr->data;
@@ -165,10 +813,32 @@ static void rna_def_manipulators(BlenderRNA *brna, PropertyRNA *cprop)
 {
 	StructRNA *srna;
 
+	FunctionRNA *func;
+	PropertyRNA *parm;
+
 	RNA_def_property_srna(cprop, "Manipulators");
 	srna = RNA_def_struct(brna, "Manipulators", NULL);
 	RNA_def_struct_sdna(srna, "wmManipulatorGroup");
 	RNA_def_struct_ui_text(srna, "Manipulators", "Collection of manipulators");
+
+	func = RNA_def_function(srna, "new", "rna_ManipulatorGroup_manipulator_new");
+	RNA_def_function_ui_description(func, "Add manipulator");
+	RNA_def_function_flag(func, FUNC_USE_REPORTS);
+	RNA_def_string(func, "type", "Type", 0, "", "Manipulator identifier"); /* optional */
+	RNA_def_string(func, "name", "Name", 0, "", "Manipulator name"); /* optional */
+	parm = RNA_def_pointer(func, "manipulator", "Manipulator", "", "New manipulator");
+	RNA_def_function_return(func, parm);
+
+	func = RNA_def_function(srna, "remove", "rna_ManipulatorGroup_manipulator_remove");
+	RNA_def_function_flag(func, FUNC_USE_CONTEXT);
+	RNA_def_function_ui_description(func, "Delete manipulator");
+	parm = RNA_def_pointer(func, "manipulator", "Manipulator", "", "New manipulator");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+	RNA_def_parameter_clear_flags(parm, PROP_THICK_WRAP, 0);
+
+	func = RNA_def_function(srna, "clear", "rna_ManipulatorGroup_manipulator_clear");
+	RNA_def_function_flag(func, FUNC_USE_CONTEXT);
+	RNA_def_function_ui_description(func, "Delete all manipulators");
 }
 
 
@@ -177,18 +847,222 @@ static void rna_def_manipulator(BlenderRNA *brna, PropertyRNA *cprop)
 	StructRNA *srna;
 	PropertyRNA *prop;
 
+	FunctionRNA *func;
+	PropertyRNA *parm;
+
 	RNA_def_property_srna(cprop, "Manipulator");
 	srna = RNA_def_struct(brna, "Manipulator", NULL);
 	RNA_def_struct_sdna(srna, "wmManipulator");
 	RNA_def_struct_ui_text(srna, "Manipulator", "Collection of manipulators");
 	RNA_def_struct_refine_func(srna, "rna_Manipulator_refine");
 
+#ifdef WITH_PYTHON
+	RNA_def_struct_register_funcs(
+	        srna,
+	        "rna_Manipulator_register",
+	        "rna_Manipulator_unregister",
+	        "rna_Manipulator_instance");
+#endif
+	RNA_def_struct_translation_context(srna, BLT_I18NCONTEXT_OPERATOR_DEFAULT);
+
 	prop = RNA_def_property(srna, "properties", PROP_POINTER, PROP_NONE);
 	RNA_def_property_flag(prop, PROP_NEVER_NULL);
 	RNA_def_property_struct_type(prop, "ManipulatorProperties");
 	RNA_def_property_ui_text(prop, "Properties", "");
 	RNA_def_property_pointer_funcs(prop, "rna_Manipulator_properties_get", NULL, NULL, NULL);
 
+	/* -------------------------------------------------------------------- */
+	/* Registerable Variables */
+
+	RNA_define_verify_sdna(0); /* not in sdna */
+
+	prop = RNA_def_property(srna, "bl_idname", PROP_STRING, PROP_NONE);
+	RNA_def_property_string_sdna(prop, NULL, "type->idname");
+	RNA_def_property_string_maxlength(prop, MAX_NAME);
+	RNA_def_property_string_funcs(prop, NULL, NULL, "rna_Manipulator_bl_idname_set");
+	/* RNA_def_property_clear_flag(prop, PROP_EDITABLE); */
+	RNA_def_property_flag(prop, PROP_REGISTER);
+
+	RNA_define_verify_sdna(1); /* not in sdna */
+
+	/* wmManipulator.draw */
+	func = RNA_def_function(srna, "draw", NULL);
+	RNA_def_function_ui_description(func, "");
+	RNA_def_function_flag(func, FUNC_REGISTER);
+	parm = RNA_def_pointer(func, "context", "Context", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+
+	/* wmManipulator.draw_select */
+	func = RNA_def_function(srna, "draw_select", NULL);
+	RNA_def_function_ui_description(func, "");
+	RNA_def_function_flag(func, FUNC_REGISTER_OPTIONAL);
+	parm = RNA_def_pointer(func, "context", "Context", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+	parm = RNA_def_int(func, "select_id", 0, 0, INT_MAX, "", "", 0, INT_MAX);
+
+	/* wmManipulator.test_select */
+	func = RNA_def_function(srna, "test_select", NULL);
+	RNA_def_function_ui_description(func, "");
+	RNA_def_function_flag(func, FUNC_REGISTER_OPTIONAL);
+	parm = RNA_def_pointer(func, "context", "Context", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+	parm = RNA_def_pointer(func, "event", "Event", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+	parm = RNA_def_int(func, "intersect_id", 0, 0, INT_MAX, "", "", 0, INT_MAX);
+	RNA_def_function_return(func, parm);
+
+	/* wmManipulator.handler */
+	static EnumPropertyItem tweak_actions[] = {
+		{WM_MANIPULATOR_TWEAK_PRECISE, "PRECISE", 0, "Precise", ""},
+		{0, NULL, 0, NULL, NULL}
+	};
+	func = RNA_def_function(srna, "modal", NULL);
+	RNA_def_function_ui_description(func, "");
+	RNA_def_function_flag(func, FUNC_REGISTER_OPTIONAL);
+	parm = RNA_def_pointer(func, "context", "Context", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+	parm = RNA_def_pointer(func, "event", "Event", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+	/* TODO, shuold be a enum-flag */
+	parm = RNA_def_enum(func, "tweak", tweak_actions, 0, "Tweak", "");
+	RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
+	RNA_def_property_flag(parm, PROP_ENUM_FLAG);
+
+	/* wmManipulator.property_update */
+	/* TODO */
+
+	/* wmManipulator.setup */
+	func = RNA_def_function(srna, "setup", NULL);
+	RNA_def_function_ui_description(func, "");
+	RNA_def_function_flag(func, FUNC_REGISTER_OPTIONAL);
+
+	/* wmManipulator.invoke */
+	func = RNA_def_function(srna, "invoke", NULL);
+	RNA_def_function_ui_description(func, "");
+	RNA_def_function_flag(func, FUNC_REGISTER_OPTIONAL);
+	parm = RNA_def_pointer(func, "context", "Context", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+	parm = RNA_def_pointer(func, "event", "Event", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+
+	/* wmManipulator.exit */
+	func = RNA_def_function(srna, "exit", NULL);
+	RNA_def_function_ui_description(func, "");
+	RNA_def_function_flag(func, FUNC_REGISTER_OPTIONAL);
+	parm = RNA_def_pointer(func, "context", "Context", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+	parm = RNA_def_boolean(func, "cancel", 0, "Cancel, otherwise confirm", "");
+	RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
+
+	/* wmManipulator.cursor_get */
+	/* TODO */
+
+	/* wmManipulator.select */
+	/* TODO, de-duplicate! */
+	static EnumPropertyItem select_actions[] = {
+		{SEL_TOGGLE, "TOGGLE", 0, "Toggle", "Toggle selection for all elements"},
+		{SEL_SELECT, "SELECT", 0, "Select", "Select all elements"},
+		{SEL_DESELECT, "DESELECT", 0, "Deselect", "Deselect all elements"},
+		{SEL_INVERT, "INVERT", 0, "Invert", "Invert selection of all elements"},
+		{0, NULL, 0, NULL, NULL}
+	};
+	func = RNA_def_function(srna, "select", NULL);
+	RNA_def_function_ui_description(func, "");
+	RNA_def_function_flag(func, FUNC_REGISTER_OPTIONAL);
+	parm = RNA_def_pointer(func, "context", "Context", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+	parm = RNA_def_enum(func, "action", select_actions, 0, "Action", "Selection action to execute");
+	RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
+
+
+	/* -------------------------------------------------------------------- */
+	/* Instance Variables */
+
+	prop = RNA_def_property(srna, "name", PROP_STRING, PROP_NONE);
+	RNA_def_property_string_funcs(
+	        prop, "rna_Manipulator_name_get", "rna_Manipulator_name_length", "rna_Manipulator_name_set");
+	RNA_def_property_ui_text(prop, "Name", "");
+	RNA_def_struct_name_property(srna, prop);
+	RNA_def_property_update(prop, NC_SCENE | ND_SEQUENCER, NULL);
+
+	prop = RNA_def_property(srna, "color", PROP_FLOAT, PROP_COLOR);
+	RNA_def_property_array(prop, 4);
+	RNA_def_property_float_funcs(prop, "rna_Manipulator_color_get", "rna_Manipulator_color_set", NULL);
+
+	prop = RNA_def_property(srna, "color_highlight", PROP_FLOAT, PROP_COLOR);
+	RNA_def_property_array(prop, 4);
+	RNA_def_property_float_funcs(prop, "rna_Manipulator_color_hi_get", "rna_Manipulator_color_hi_set", NULL);
+	RNA_def_property_ui_text(prop, "Color", "");
+
+	prop = RNA_def_property(srna, "matrix_basis", PROP_FLOAT, PROP_MATRIX);
+	RNA_def_property_multi_array(prop, 2, rna_matrix_dimsize_4x4);
+	RNA_def_property_ui_text(prop, "Basis Matrix", "");
+	RNA_def_property_float_funcs(prop, "rna_Manipulator_matrix_basis_get", "rna_Manipulator_matrix_basis_set", NULL);
+	RNA_def_property_update(prop, NC_SCREEN | NA_EDITED, NULL);
+
+	prop = RNA_def_property(srna, "matrix_offset", PROP_FLOAT, PROP_MATRIX);
+	RNA_def_property_multi_array(prop, 2, rna_matrix_dimsize_4x4);
+	RNA_def_property_ui_text(prop, "Offset Matrix", "");
+	RNA_def_property_float_funcs(prop, "rna_Manipulator_matrix_offset_get", "rna_Manipulator_matrix_offset_set", NULL);
+	RNA_def_property_update(prop, NC_SCREEN | NA_EDITED, NULL);
+
+	prop = RNA_def_property(srna, "scale_basis", PROP_FLOAT, PROP_MATRIX);
+	RNA_def_property_ui_text(prop, "Scale Basis", "");
+	RNA_def_property_float_funcs(prop, "rna_Manipulator_scale_basis_get", "rna_Manipulator_scale_basis_set", NULL);
+	RNA_def_property_range(prop, 0.0f, FLT_MAX);
+	RNA_def_property_update(prop, NC_SCREEN | NA_EDITED, NULL);
+
+	prop = RNA_def_property(srna, "line_width", PROP_FLOAT, PROP_MATRIX);
+	RNA_def_property_ui_text(prop, "Line Width", "");
+	RNA_def_property_float_funcs(prop, "rna_Manipulator_line_width_get", "rna_Manipulator_line_width_set", NULL);
+	RNA_def_property_range(prop, 0.0f, FLT_MAX);
+	RNA_def_property_update(prop, NC_SCREEN | NA_EDITED, NULL);
+
+	/* wmManipulator.flag */
+	/* WM_MANIPULATOR_HIDDEN */
+	prop = RNA_def_property(srna, "hide", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_funcs(
+	        prop, "rna_Manipulator_flag_hide_get", "rna_Manipulator_flag_hide_set");
+	RNA_def_property_ui_text(prop, "Hide", "");
+	RNA_def_property_update(prop, NC_SCREEN | NA_EDITED, NULL);
+	/* WM_MANIPULATOR_DRAW_HOVER */
+	prop = RNA_def_property(srna, "use_draw_hover", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_funcs(
+	        prop, "rna_Manipulator_flag_use_draw_hover_get", "rna_Manipulator_flag_use_draw_hover_set");
+	RNA_def_property_ui_text(prop, "Draw Hover", "");
+	RNA_def_property_update(prop, NC_SCREEN | NA_EDITED, NULL);
+	/* WM_MANIPULATOR_DRAW_ACTIVE */
+	prop = RNA_def_property(srna, "use_draw_active", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_funcs(
+	        prop, "rna_Manipulator_flag_use_draw_active_get", "rna_Manipulator_flag_use_draw_active_set");
+	RNA_def_property_ui_text(prop, "Draw Active", "Draw while dragging");
+	RNA_def_property_update(prop, NC_SCREEN | NA_EDITED, NULL);
+	/* WM_MANIPULATOR_DRAW_VALUE */
+	prop = RNA_def_property(srna, "use_draw_value", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_funcs(
+	        prop, "rna_Manipulator_flag_use_draw_value_get", "rna_Manipulator_flag_use_draw_value_set");
+	RNA_def_property_ui_text(prop, "Draw Value", "Show an indicator for the current value while dragging");
+	RNA_def_property_update(prop, NC_SCREEN | NA_EDITED, NULL);
+
+	/* wmManipulator.state (readonly) */
+	/* WM_MANIPULATOR_STATE_HIGHLIGHT */
+	prop = RNA_def_property(srna, "is_highlight", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_funcs(prop, "rna_Manipulator_state_is_highlight_get", NULL);
+	RNA_def_property_ui_text(prop, "Highlight", "");
+	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+	/* WM_MANIPULATOR_STATE_ACTIVE */
+	prop = RNA_def_property(srna, "is_active", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_funcs(prop, "rna_Manipulator_state_is_active_get", NULL);
+	RNA_def_property_ui_text(prop, "Highlight", "");
+	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+	/* WM_MANIPULATOR_STATE_SELECT */
+	prop = RNA_def_property(srna, "select", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_funcs(prop, "rna_Manipulator_state_select_get", NULL);
+	RNA_def_property_ui_text(prop, "Select", "");
+	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+
+	RNA_api_manipulator(srna);
+
 	srna = RNA_def_struct(brna, "ManipulatorProperties", NULL);
 	RNA_def_struct_ui_text(srna, "Manipulator Properties", "Input properties of an Manipulator");
 	RNA_def_struct_refine_func(srna, "rna_ManipulatorProperties_refine");
@@ -201,10 +1075,137 @@ static void rna_def_manipulatorgroup(BlenderRNA *brna)
 	StructRNA *srna;
 	PropertyRNA *prop;
 
+	FunctionRNA *func;
+	PropertyRNA *parm;
+
 	srna = RNA_def_struct(brna, "ManipulatorGroup", NULL);
 	RNA_def_struct_ui_text(srna, "ManipulatorGroup", "Storage of an operator being executed, or registered after execution");
 	RNA_def_struct_sdna(srna, "wmManipulatorGroup");
 	RNA_def_struct_refine_func(srna, "rna_ManipulatorGroup_refine");
+#ifdef WITH_PYTHON
+	RNA_def_struct_register_funcs(
+	        srna,
+	        "rna_ManipulatorGroup_register",
+	        "rna_ManipulatorGroup_unregister",
+	        "rna_ManipulatorGroup_instance");
+#endif
+	RNA_def_struct_translation_context(srna, BLT_I18NCONTEXT_OPERATOR_DEFAULT);
+
+	/* -------------------------------------------------------------------- */
+	/* Registration */
+
+	RNA_define_verify_sdna(0); /* not in sdna */
+
+	prop = RNA_def_property(srna, "bl_idname", PROP_STRING, PROP_NONE);
+	RNA_def_property_string_sdna(prop, NULL, "type->idname");
+	RNA_def_property_string_maxlength(prop, MAX_NAME);
+	RNA_def_property_string_funcs(prop, NULL, NULL, "rna_ManipulatorGroup_bl_idname_set");
+	RNA_def_property_flag(prop, PROP_REGISTER);
+	RNA_def_struct_name_property(srna, prop);
+
+	prop = RNA_def_property(srna, "bl_label", PROP_STRING, PROP_NONE);
+	RNA_def_property_string_sdna(prop, NULL, "type->name");
+	RNA_def_property_string_maxlength(prop, MAX_NAME); /* else it uses the pointer size! */
+	RNA_def_property_string_funcs(prop, NULL, NULL, "rna_ManipulatorGroup_bl_label_set");
+	/* RNA_def_property_clear_flag(prop, PROP_EDITABLE); */
+	RNA_def_property_flag(prop, PROP_REGISTER);
+
+	prop = RNA_def_property(srna, "bl_space_type", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "type->mmap_params.spaceid");
+	RNA_def_property_enum_items(prop, rna_enum_space_type_items);
+	RNA_def_property_flag(prop, PROP_REGISTER);
+	RNA_def_property_ui_text(prop, "Space type", "The space where the panel is going to be used in");
+
+	prop = RNA_def_property(srna, "bl_region_type", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "type->mmap_params.regionid");
+	RNA_def_property_enum_items(prop, rna_enum_region_type_items);
+	RNA_def_property_flag(prop, PROP_REGISTER);
+	RNA_def_property_ui_text(prop, "Region Type", "The region where the panel is going to be used in");
+
+	/* bl_options */
+	static EnumPropertyItem manipulatorgroup_flag_items[] = {
+		{WM_MANIPULATORGROUPTYPE_3D, "3D", 0, "3D",
+		 "Use in 3D viewport"},
+		{WM_MANIPULATORGROUPTYPE_SCALE, "SCALE", 0, "Scale",
+		 "Scale to respect zoom (otherwise zoom independent draw size)"},
+		{WM_MANIPULATORGROUPTYPE_DEPTH_3D, "DEPTH_3D", 0, "Depth 3D",
+		 "Supports culled depth by other objects in the view"},
+		{WM_MANIPULATORGROUPTYPE_SELECT, "SELECT", 0, "Select",
+		 "Supports selection"},
+		{WM_MANIPULATORGROUPTYPE_PERSISTENT, "PERSISTENT", 0, "Persistent",
+		 ""},
+		{0, NULL, 0, NULL, NULL}
+	};
+	prop = RNA_def_property(srna, "bl_options", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "type->flag");
+	RNA_def_property_enum_items(prop, manipulatorgroup_flag_items);
+	RNA_def_property_flag(prop, PROP_REGISTER_OPTIONAL | PROP_ENUM_FLAG);
+	RNA_def_property_ui_text(prop, "Options",  "Options for this operator type");
+
+	RNA_define_verify_sdna(1); /* not in sdna */
+
+
+	/* Functions */
+
+	/* poll */
+	func = RNA_def_function(srna, "poll", NULL);
+	RNA_def_function_ui_description(func, "Test if the manipulator group can be called or not");
+	RNA_def_function_flag(func, FUNC_NO_SELF | FUNC_REGISTER_OPTIONAL);
+	RNA_def_function_return(func, RNA_def_boolean(func, "visible", 1, "", ""));
+	parm = RNA_def_pointer(func, "context", "Context", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+
+	/* keymap_init */
+	func = RNA_def_function(srna, "setup_keymap", NULL);
+	RNA_def_function_ui_description(
+	        func,
+	        "Initialize keymaps for this manipulator group, use fallback keymap when not present");
+	RNA_def_function_flag(func, FUNC_NO_SELF | FUNC_REGISTER_OPTIONAL);
+	parm = RNA_def_pointer(func, "keyconf", "KeyConfig", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+	parm = RNA_def_property(func, "manipulator_group", PROP_STRING, PROP_NONE);
+	RNA_def_property_ui_text(parm, "Manipulator Group", "Manipulator Group ID");
+	// RNA_def_property_string_default(parm, "");
+	RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
+	/* return */
+	parm = RNA_def_pointer(func, "keymap", "KeyMap", "", "");
+	RNA_def_property_flag(parm, PROP_NEVER_NULL);
+	RNA_def_function_return(func, parm);
+
+	/* setup */
+	func = RNA_def_function(srna, "setup", NULL);
+	RNA_def_function_ui_description(func, "Create manipulators function for the manipulator group");
+	RNA_def_function_flag(func, FUNC_REGISTER);
+	parm = RNA_def_pointer(func, "context", "Context", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+
+	/* refresh */
+	func = RNA_def_function(srna, "refresh", NULL);
+	RNA_def_function_ui_description(func, "Refresh data (called on common state changes such as selection)");
+	RNA_def_function_flag(func, FUNC_REGISTER_OPTIONAL);
+	parm = RNA_def_pointer(func, "context", "Context", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+
+	func = RNA_def_function(srna, "draw_prepare", NULL);
+	RNA_def_function_ui_description(func, "Run before each redraw");
+	RNA_def_function_flag(func, FUNC_REGISTER_OPTIONAL);
+	parm = RNA_def_pointer(func, "context", "Context", "", "");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+
+	/* -------------------------------------------------------------------- */
+	/* Instance Variables */
+
+	prop = RNA_def_property(srna, "name", PROP_STRING, PROP_NONE);
+	RNA_def_property_clear_flag(prop, PROP_EDITABLE);
+	RNA_def_property_string_funcs(prop, "rna_ManipulatorGroup_name_get", "rna_ManipulatorGroup_name_length", NULL);
+	RNA_def_property_ui_text(prop, "Name", "");
+
+	prop = RNA_def_property(srna, "has_reports", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_clear_flag(prop, PROP_EDITABLE); /* this is 'virtual' property */
+	RNA_def_property_boolean_funcs(prop, "rna_ManipulatorGroup_has_reports_get", NULL);
+	RNA_def_property_ui_text(prop, "Has Reports",
+	                         "ManipulatorGroup has a set of reports (warnings and errors) from last execution");
+
 
 	RNA_define_verify_sdna(0); /* not in sdna */
 
@@ -221,6 +1222,8 @@ static void rna_def_manipulatorgroup(BlenderRNA *brna)
 	rna_def_manipulators(brna, prop);
 
 	RNA_define_verify_sdna(1); /* not in sdna */
+
+	RNA_api_manipulatorgroup(srna);
 }
 
 void RNA_def_wm_manipulator(BlenderRNA *brna)
diff --git a/source/blender/makesrna/intern/rna_wm_manipulator_api.c b/source/blender/makesrna/intern/rna_wm_manipulator_api.c
new file mode 100644
index 00000000000..9f011ad7b7d
--- /dev/null
+++ b/source/blender/makesrna/intern/rna_wm_manipulator_api.c
@@ -0,0 +1,254 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * 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.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/makesrna/intern/rna_wm_manipulator_api.c
+ *  \ingroup RNA
+ */
+
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#include "BLI_utildefines.h"
+
+#include "BKE_report.h"
+
+#include "RNA_define.h"
+#include "RNA_enum_types.h"
+
+#include "DNA_windowmanager_types.h"
+
+#include "WM_api.h"
+
+#include "rna_internal.h"  /* own include */
+
+#ifdef RNA_RUNTIME
+
+#include "UI_interface.h"
+#include "BKE_context.h"
+
+#include "ED_manipulator_library.h"
+
+static void rna_manipulator_draw_preset_box(
+        wmManipulator *mpr, float matrix[16], int select_id)
+{
+	ED_manipulator_draw_preset_box(mpr, (float (*)[4])matrix, select_id);
+}
+
+static void rna_manipulator_draw_preset_arrow(
+        wmManipulator *mpr, float matrix[16], int axis, int select_id)
+{
+	ED_manipulator_draw_preset_arrow(mpr, (float (*)[4])matrix, axis, select_id);
+}
+
+static void rna_manipulator_draw_preset_circle(
+        wmManipulator *mpr, float matrix[16], int axis, int select_id)
+{
+	ED_manipulator_draw_preset_circle(mpr, (float (*)[4])matrix, axis, select_id);
+}
+
+static void rna_manipulator_draw_preset_facemap(
+        wmManipulator *mpr, struct bContext *C, struct Object *ob, int facemap, int select_id)
+{
+	struct Scene *scene = CTX_data_scene(C);
+	ED_manipulator_draw_preset_facemap(mpr, scene, ob, facemap, select_id);
+}
+
+static void rna_manipulator_target_set_prop(
+        wmManipulator *mpr, ReportList *reports, const char *target_propname,
+        PointerRNA *ptr, const char *propname, int index)
+{
+	const wmManipulatorPropertyType *mpr_prop_type =
+	        WM_manipulatortype_target_property_find(mpr->type, target_propname);
+	if (mpr_prop_type == NULL) {
+		BKE_reportf(reports, RPT_ERROR, "Manipulator target property '%s.%s' not found",
+		            mpr->type->idname, target_propname);
+		return;
+	}
+
+	PropertyRNA *prop = RNA_struct_find_property(ptr, propname);
+	if (prop == NULL) {
+		BKE_reportf(reports, RPT_ERROR, "Property '%s.%s' not found",
+		            RNA_struct_identifier(ptr->type), target_propname);
+		return;
+	}
+
+	if (mpr_prop_type->data_type != RNA_property_type(prop)) {
+		const int manipulator_type_index = RNA_enum_from_value(rna_enum_property_type_items, mpr_prop_type->data_type);
+		const int prop_type_index = RNA_enum_from_value(rna_enum_property_type_items, RNA_property_type(prop));
+		BLI_assert((manipulator_type_index != -1) && (prop_type_index == -1));
+
+		BKE_reportf(reports, RPT_ERROR, "Manipulator target '%s.%s' expects '%s', '%s.%s' is '%s'",
+		            mpr->type->idname, target_propname,
+		            rna_enum_property_type_items[manipulator_type_index].identifier,
+		            RNA_struct_identifier(ptr->type), propname,
+		            rna_enum_property_type_items[prop_type_index].identifier);
+		return;
+	}
+
+	if (RNA_property_array_check(prop)) {
+		if (index == -1) {
+			const int prop_array_length = RNA_property_array_length(ptr, prop);
+			if (mpr_prop_type->array_length != prop_array_length) {
+				BKE_reportf(reports, RPT_ERROR,
+				            "Manipulator target property '%s.%s' expects an array of length %d, found %d",
+				            mpr->type->idname, target_propname,
+				            mpr_prop_type->array_length,
+				            prop_array_length);
+				return;
+			}
+		}
+	}
+	else {
+		if (mpr_prop_type->array_length != 1) {
+			BKE_reportf(reports, RPT_ERROR,
+			            "Manipulator target property '%s.%s' expects an array of length %d",
+			            mpr->type->idname, target_propname,
+			            mpr_prop_type->array_length);
+			return;
+		}
+	}
+
+	if (index >= mpr_prop_type->array_length) {
+		BKE_reportf(reports, RPT_ERROR, "Manipulator target property '%s.%s', index %d must be below %d",
+		            mpr->type->idname, target_propname, index, mpr_prop_type->array_length);
+		return;
+	}
+
+	WM_manipulator_target_property_def_rna_ptr(mpr, mpr_prop_type, ptr, prop, index);
+}
+
+static PointerRNA rna_manipulator_target_set_operator(
+        wmManipulator *mpr, ReportList *reports, const char *opname)
+{
+	wmOperatorType *ot;
+
+	ot = WM_operatortype_find(opname, 0); /* print error next */
+	if (!ot || !ot->srna) {
+		BKE_reportf(reports, RPT_ERROR, "%s '%s'", ot ? "unknown operator" : "operator missing srna", opname);
+		return PointerRNA_NULL;
+	}
+
+	/* For the return value to be usable, we need 'PointerRNA.data' to be set. */
+	IDProperty *properties;
+	{
+		IDPropertyTemplate val = {0};
+		properties = IDP_New(IDP_GROUP, &val, "wmManipulatorProperties");
+	}
+
+	WM_manipulator_set_operator(mpr, ot, properties);
+
+	return mpr->op_data.ptr;
+}
+
+#else
+
+void RNA_api_manipulator(StructRNA *srna)
+{
+	/* Utility draw functions, since we don't expose new OpenGL drawing wrappers via Python yet.
+	 * exactly how these should be exposed isn't totally clear.
+	 * However it's probably good to have some high level API's for this anyway.
+	 * Just note that this could be re-worked once tests are done.
+	 */
+
+	FunctionRNA *func;
+	PropertyRNA *parm;
+
+	/* -------------------------------------------------------------------- */
+	/* Primitive Shapes */
+
+	/* draw_preset_box */
+	func = RNA_def_function(srna, "draw_preset_box", "rna_manipulator_draw_preset_box");
+	RNA_def_function_ui_description(func, "Draw a box");
+	parm = RNA_def_property(func, "matrix", PROP_FLOAT, PROP_MATRIX);
+	RNA_def_property_flag(parm, PARM_REQUIRED);
+	RNA_def_property_multi_array(parm, 2, rna_matrix_dimsize_4x4);
+	RNA_def_property_ui_text(parm, "", "The matrix to transform");
+	RNA_def_int(func, "select_id", -1, -1, INT_MAX, "Zero when not selecting", "", -1, INT_MAX);
+
+	/* draw_preset_box */
+	func = RNA_def_function(srna, "draw_preset_arrow", "rna_manipulator_draw_preset_arrow");
+	RNA_def_function_ui_description(func, "Draw a box");
+	parm = RNA_def_property(func, "matrix", PROP_FLOAT, PROP_MATRIX);
+	RNA_def_property_flag(parm, PARM_REQUIRED);
+	RNA_def_property_multi_array(parm, 2, rna_matrix_dimsize_4x4);
+	RNA_def_property_ui_text(parm, "", "The matrix to transform");
+	RNA_def_enum(func, "axis", rna_enum_object_axis_items, 2, "", "Arrow Orientation");
+	RNA_def_int(func, "select_id", -1, -1, INT_MAX, "Zero when not selecting", "", -1, INT_MAX);
+
+	func = RNA_def_function(srna, "draw_preset_circle", "rna_manipulator_draw_preset_circle");
+	RNA_def_function_ui_description(func, "Draw a box");
+	parm = RNA_def_property(func, "matrix", PROP_FLOAT, PROP_MATRIX);
+	RNA_def_property_flag(parm, PARM_REQUIRED);
+	RNA_def_property_multi_array(parm, 2, rna_matrix_dimsize_4x4);
+	RNA_def_property_ui_text(parm, "", "The matrix to transform");
+	RNA_def_enum(func, "axis", rna_enum_object_axis_items, 2, "", "Arrow Orientation");
+	RNA_def_int(func, "select_id", -1, -1, INT_MAX, "Zero when not selecting", "", -1, INT_MAX);
+
+	/* -------------------------------------------------------------------- */
+	/* Other Shapes */
+
+	/* draw_preset_facemap */
+	func = RNA_def_function(srna, "draw_preset_facemap", "rna_manipulator_draw_preset_facemap");
+	RNA_def_function_ui_description(func, "Draw the face-map of a mesh object");
+	RNA_def_function_flag(func, FUNC_USE_CONTEXT);
+	parm = RNA_def_pointer(func, "object", "Object", "", "Object");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED);
+	RNA_def_int(func, "facemap", 0, 0, INT_MAX, "Face map index", "", 0, INT_MAX);
+	RNA_def_int(func, "select_id", -1, -1, INT_MAX, "Zero when not selecting", "", -1, INT_MAX);
+
+
+	/* -------------------------------------------------------------------- */
+	/* Property API */
+
+	/* note, 'target_set_handler' is defined in 'bpy_rna_manipulator.c' */
+	func = RNA_def_function(srna, "target_set_prop", "rna_manipulator_target_set_prop");
+	RNA_def_function_flag(func, FUNC_USE_REPORTS);
+	RNA_def_function_ui_description(func, "");
+	parm = RNA_def_string(func, "target", NULL, 0, "", "Target property");
+	RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
+	/* similar to UILayout.prop */
+	parm = RNA_def_pointer(func, "data", "AnyType", "", "Data from which to take property");
+	RNA_def_parameter_flags(parm, PROP_NEVER_NULL, PARM_REQUIRED | PARM_RNAPTR);
+	parm = RNA_def_string(func, "property", NULL, 0, "", "Identifier of property in data");
+	RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
+	RNA_def_int(func, "index", -1, -1, INT_MAX, "", "", -1, INT_MAX); /* RNA_NO_INDEX == -1 */
+
+	func = RNA_def_function(srna, "target_set_operator", "rna_manipulator_target_set_operator");
+	RNA_def_function_flag(func, FUNC_USE_REPORTS);
+	RNA_def_function_ui_description(
+	        func,"Operator to run when activating the manipulator "
+	        "(overrides property targets)");
+	parm = RNA_def_string(func, "operator", NULL, 0, "", "Target operator");
+	RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
+	/* similar to UILayout.operator */
+	parm = RNA_def_pointer(func, "properties", "OperatorProperties", "", "Operator properties to fill in");
+	RNA_def_parameter_flags(parm, 0, PARM_REQUIRED | PARM_RNAPTR);
+	RNA_def_function_return(func, parm);
+
+}
+
+
+void RNA_api_manipulatorgroup(StructRNA *UNUSED(srna))
+{
+	/* nothing yet */
+}
+
+#endif
diff --git a/source/blender/python/intern/CMakeLists.txt b/source/blender/python/intern/CMakeLists.txt
index be4db6477fe..967e90d22cb 100644
--- a/source/blender/python/intern/CMakeLists.txt
+++ b/source/blender/python/intern/CMakeLists.txt
@@ -65,6 +65,7 @@ set(SRC
 	bpy_intern_string.c
 	bpy_library_load.c
 	bpy_library_write.c
+	bpy_manipulator_wrap.c
 	bpy_operator.c
 	bpy_operator_wrap.c
 	bpy_path.c
@@ -75,6 +76,7 @@ set(SRC
 	bpy_rna_callback.c
 	bpy_rna_driver.c
 	bpy_rna_id_collection.c
+	bpy_rna_manipulator.c
 	bpy_traceback.c
 	bpy_util.c
 	bpy_utils_previews.c
@@ -97,6 +99,7 @@ set(SRC
 	bpy_driver.h
 	bpy_intern_string.h
 	bpy_library.h
+	bpy_manipulator_wrap.h
 	bpy_operator.h
 	bpy_operator_wrap.h
 	bpy_path.h
@@ -106,6 +109,7 @@ set(SRC
 	bpy_rna_callback.h
 	bpy_rna_driver.h
 	bpy_rna_id_collection.h
+	bpy_rna_manipulator.h
 	bpy_traceback.h
 	bpy_util.h
 	bpy_utils_previews.h
diff --git a/source/blender/python/intern/bpy.c b/source/blender/python/intern/bpy.c
index 5bbfb4912e6..4a29d4f8da1 100644
--- a/source/blender/python/intern/bpy.c
+++ b/source/blender/python/intern/bpy.c
@@ -46,6 +46,7 @@
 #include "bpy_rna.h"
 #include "bpy_app.h"
 #include "bpy_rna_id_collection.h"
+#include "bpy_rna_manipulator.h"
 #include "bpy_props.h"
 #include "bpy_library.h"
 #include "bpy_operator.h"
@@ -327,6 +328,8 @@ void BPy_init_modules(void)
 
 	BPY_rna_id_collection_module(mod);
 
+	BPY_rna_manipulator_module(mod);
+
 	bpy_import_test("bpy_types");
 	PyModule_AddObject(mod, "data", BPY_rna_module()); /* imports bpy_types by running this */
 	bpy_import_test("bpy_types");
diff --git a/source/blender/python/intern/bpy_intern_string.c b/source/blender/python/intern/bpy_intern_string.c
index e9d84b2099b..6911e985e93 100644
--- a/source/blender/python/intern/bpy_intern_string.c
+++ b/source/blender/python/intern/bpy_intern_string.c
@@ -34,7 +34,7 @@
 
 #include "BLI_utildefines.h"
 
-static PyObject *bpy_intern_str_arr[15];
+static PyObject *bpy_intern_str_arr[16];
 
 PyObject *bpy_intern_str___doc__;
 PyObject *bpy_intern_str___main__;
@@ -44,6 +44,7 @@ PyObject *bpy_intern_str___slots__;
 PyObject *bpy_intern_str_attr;
 PyObject *bpy_intern_str_bl_property;
 PyObject *bpy_intern_str_bl_rna;
+PyObject *bpy_intern_str_bl_target_properties;
 PyObject *bpy_intern_str_bpy_types;
 PyObject *bpy_intern_str_frame;
 PyObject *bpy_intern_str_order;
@@ -67,6 +68,7 @@ void bpy_intern_string_init(void)
 	BPY_INTERN_STR(bpy_intern_str_attr, "attr");
 	BPY_INTERN_STR(bpy_intern_str_bl_property, "bl_property");
 	BPY_INTERN_STR(bpy_intern_str_bl_rna, "bl_rna");
+	BPY_INTERN_STR(bpy_intern_str_bl_target_properties, "bl_target_properties");
 	BPY_INTERN_STR(bpy_intern_str_bpy_types, "bpy.types");
 	BPY_INTERN_STR(bpy_intern_str_frame, "frame");
 	BPY_INTERN_STR(bpy_intern_str_order, "order");
diff --git a/source/blender/python/intern/bpy_intern_string.h b/source/blender/python/intern/bpy_intern_string.h
index 66c469f70bc..998c312c321 100644
--- a/source/blender/python/intern/bpy_intern_string.h
+++ b/source/blender/python/intern/bpy_intern_string.h
@@ -38,6 +38,7 @@ extern PyObject *bpy_intern_str___slots__;
 extern PyObject *bpy_intern_str_attr;
 extern PyObject *bpy_intern_str_bl_property;
 extern PyObject *bpy_intern_str_bl_rna;
+extern PyObject *bpy_intern_str_bl_target_properties;
 extern PyObject *bpy_intern_str_bpy_types;
 extern PyObject *bpy_intern_str_frame;
 extern PyObject *bpy_intern_str_order;
diff --git a/source/blender/python/intern/bpy_manipulator_wrap.c b/source/blender/python/intern/bpy_manipulator_wrap.c
new file mode 100644
index 00000000000..53b6285e880
--- /dev/null
+++ b/source/blender/python/intern/bpy_manipulator_wrap.c
@@ -0,0 +1,231 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * 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.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/python/intern/bpy_manipulator_wrap.c
+ *  \ingroup pythonintern
+ *
+ * This file is so Python can define widget-group's that C can call into.
+ * The generic callback functions for Python widget-group are defines in
+ * 'rna_wm.c', some calling into functions here to do python specific
+ * functionality.
+ *
+ * \note This follows 'bpy_operator_wrap.c' very closely.
+ * Keep in sync unless there is good reason not to!
+ */
+
+#include <Python.h>
+
+#include "BLI_utildefines.h"
+
+#include "WM_api.h"
+#include "WM_types.h"
+
+#include "RNA_access.h"
+#include "RNA_define.h"
+#include "RNA_enum_types.h"
+
+#include "bpy_rna.h"
+#include "bpy_intern_string.h"
+#include "bpy_manipulator_wrap.h"  /* own include */
+
+/* we may want to add, but not now */
+
+/* -------------------------------------------------------------------- */
+
+/** \name Manipulator
+ * \{ */
+
+
+static bool bpy_manipulatortype_target_property_def(
+        wmManipulatorType *wt, PyObject *item)
+{
+	/* Note: names based on 'rna_rna.c' */
+	PyObject *empty_tuple = PyTuple_New(0);
+	static const char * const _keywords[] = {"id", "type", "array_length", NULL};
+	static _PyArg_Parser _parser = {"|$ssi:register_class", _keywords, 0};
+
+	struct {
+		char *id;
+		char *type_id; int type;
+		int array_length;
+	} params = {
+		.id = NULL, /* not optional */
+		.type = PROP_FLOAT,
+		.type_id = NULL,
+		.array_length = 1,
+	};
+
+	if (!_PyArg_ParseTupleAndKeywordsFast(
+	        empty_tuple, item,
+	        &_parser,
+	        &params.id,
+	        &params.type_id,
+	        &params.array_length))
+	{
+		goto fail;
+	}
+
+	if (params.id == NULL) {
+		PyErr_SetString(PyExc_ValueError, "'id' argument not given");
+		goto fail;
+	}
+
+	if ((params.type_id != NULL) &&
+	    pyrna_enum_value_from_id(
+	        rna_enum_property_type_items, params.type_id, &params.type, "'type' enum value") == -1)
+	{
+		goto fail;
+	}
+	else {
+		params.type = rna_enum_property_type_items[params.type].value;
+	}
+
+	if ((params.array_length < 1 || params.array_length > RNA_MAX_ARRAY_LENGTH)) {
+		PyErr_SetString(PyExc_ValueError, "'array_length' out of range");
+		goto fail;
+	}
+
+	WM_manipulatortype_target_property_def(wt, params.id, params.type, params.array_length);
+	Py_DECREF(empty_tuple);
+	return true;
+
+fail:
+	Py_DECREF(empty_tuple);
+	return false;
+}
+
+static void manipulator_properties_init(wmManipulatorType *wt)
+{
+	PyTypeObject *py_class = wt->ext.data;
+	RNA_struct_blender_type_set(wt->ext.srna, wt);
+
+	/* only call this so pyrna_deferred_register_class gives a useful error
+	 * WM_operatortype_append_ptr will call RNA_def_struct_identifier
+	 * later */
+	RNA_def_struct_identifier(wt->srna, wt->idname);
+
+	if (pyrna_deferred_register_class(wt->srna, py_class) != 0) {
+		PyErr_Print(); /* failed to register operator props */
+		PyErr_Clear();
+	}
+
+	/* Extract target property definitions from 'bl_target_properties' */
+	{
+		/* picky developers will notice that 'bl_targets' won't work with inheritance
+		 * get direct from the dict to avoid raising a load of attribute errors (yes this isnt ideal) - campbell */
+		PyObject *py_class_dict = py_class->tp_dict;
+		PyObject *bl_target_properties = PyDict_GetItem(py_class_dict, bpy_intern_str_bl_target_properties);
+		PyObject *bl_target_properties_fast;
+
+		if (!(bl_target_properties_fast = PySequence_Fast(bl_target_properties, "bl_target_properties sequence"))) {
+			/* PySequence_Fast sets the error */
+			PyErr_Print();
+			PyErr_Clear();
+			return;
+		}
+
+		const uint items_len = PySequence_Fast_GET_SIZE(bl_target_properties_fast);
+		PyObject **items = PySequence_Fast_ITEMS(bl_target_properties_fast);
+
+		for (uint i = 0; i < items_len; i++) {
+			if (!bpy_manipulatortype_target_property_def(wt, items[i])) {
+				PyErr_Print();
+				PyErr_Clear();
+				break;
+			}
+		}
+
+		Py_DECREF(bl_target_properties_fast);
+	}
+}
+
+void BPY_RNA_manipulator_wrapper(wmManipulatorType *wt, void *userdata)
+{
+	/* take care not to overwrite anything set in
+	 * WM_manipulatormaptype_group_link_ptr before opfunc() is called */
+	StructRNA *srna = wt->srna;
+	*wt = *((wmManipulatorType *)userdata);
+	wt->srna = srna; /* restore */
+
+	/* don't do translations here yet */
+#if 0
+	/* Use i18n context from ext.srna if possible (py manipulatorgroups). */
+	if (wt->ext.srna) {
+		RNA_def_struct_translation_context(wt->srna, RNA_struct_translation_context(wt->ext.srna));
+	}
+#endif
+
+	wt->struct_size = sizeof(wmManipulator);
+
+	manipulator_properties_init(wt);
+}
+
+/** \} */
+
+
+/* -------------------------------------------------------------------- */
+
+/** \name Manipulator Group
+ * \{ */
+
+static void manipulatorgroup_properties_init(wmManipulatorGroupType *wgt)
+{
+#ifdef USE_SRNA
+	PyTypeObject *py_class = wgt->ext.data;
+#endif
+	RNA_struct_blender_type_set(wgt->ext.srna, wgt);
+
+#ifdef USE_SRNA
+	/* only call this so pyrna_deferred_register_class gives a useful error
+	 * WM_operatortype_append_ptr will call RNA_def_struct_identifier
+	 * later */
+	RNA_def_struct_identifier(wgt->srna, wgt->idname);
+
+	if (pyrna_deferred_register_class(wgt->srna, py_class) != 0) {
+		PyErr_Print(); /* failed to register operator props */
+		PyErr_Clear();
+	}
+#endif
+}
+
+void BPY_RNA_manipulatorgroup_wrapper(wmManipulatorGroupType *wgt, void *userdata)
+{
+	/* take care not to overwrite anything set in
+	 * WM_manipulatormaptype_group_link_ptr before opfunc() is called */
+#ifdef USE_SRNA
+	StructRNA *srna = wgt->srna;
+#endif
+	*wgt = *((wmManipulatorGroupType *)userdata);
+#ifdef USE_SRNA
+	wgt->srna = srna; /* restore */
+#endif
+
+#ifdef USE_SRNA
+	/* Use i18n context from ext.srna if possible (py manipulatorgroups). */
+	if (wgt->ext.srna) {
+		RNA_def_struct_translation_context(wgt->srna, RNA_struct_translation_context(wgt->ext.srna));
+	}
+#endif
+
+	manipulatorgroup_properties_init(wgt);
+}
+
+/** \} */
+
diff --git a/source/blender/python/intern/bpy_manipulator_wrap.h b/source/blender/python/intern/bpy_manipulator_wrap.h
new file mode 100644
index 00000000000..3f739e26059
--- /dev/null
+++ b/source/blender/python/intern/bpy_manipulator_wrap.h
@@ -0,0 +1,36 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * 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.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/python/intern/bpy_manipulator_wrap.h
+ *  \ingroup pythonintern
+ */
+
+#ifndef __BPY_MANIPULATOR_WRAP_H__
+#define __BPY_MANIPULATOR_WRAP_H__
+
+struct wmManipulatorType;
+struct wmManipulatorGroupType;
+
+/* exposed to rna/wm api */
+void BPY_RNA_manipulator_wrapper(struct wmManipulatorType *wt, void *userdata);
+void BPY_RNA_manipulatorgroup_wrapper(struct wmManipulatorGroupType *wgt, void *userdata);
+
+#endif  /* __BPY_MANIPULATOR_WRAP_H__ */
+
diff --git a/source/blender/python/intern/bpy_rna.c b/source/blender/python/intern/bpy_rna.c
index 6f3d0145d87..51e179fb317 100644
--- a/source/blender/python/intern/bpy_rna.c
+++ b/source/blender/python/intern/bpy_rna.c
@@ -1839,19 +1839,28 @@ static int pyrna_py_to_prop(
 				 * class mixing if this causes problems in the future it should be removed.
 				 */
 				if ((ptr_type == &RNA_AnyType) &&
-				    (BPy_StructRNA_Check(value)) &&
-				    (RNA_struct_is_a(((BPy_StructRNA *)value)->ptr.type, &RNA_Operator)))
+				    (BPy_StructRNA_Check(value)))
 				{
-					value = PyObject_GetAttr(value, bpy_intern_str_properties);
-					value_new = value;
+					const StructRNA *base_type =
+					        RNA_struct_base_child_of(((const BPy_StructRNA *)value)->ptr.type, NULL);
+					if (ELEM(base_type, &RNA_Operator, &RNA_Manipulator)) {
+						value = PyObject_GetAttr(value, bpy_intern_str_properties);
+						value_new = value;
+					}
 				}
 
-
-				/* if property is an OperatorProperties pointer and value is a map,
+				/* if property is an OperatorProperties/ManipulatorProperties pointer and value is a map,
 				 * forward back to pyrna_pydict_to_props */
-				if (RNA_struct_is_a(ptr_type, &RNA_OperatorProperties) && PyDict_Check(value)) {
-					PointerRNA opptr = RNA_property_pointer_get(ptr, prop);
-					return pyrna_pydict_to_props(&opptr, value, false, error_prefix);
+				if (PyDict_Check(value)) {
+					const StructRNA *base_type = RNA_struct_base_child_of(ptr_type, NULL);
+					if (base_type == &RNA_OperatorProperties) {
+						PointerRNA opptr = RNA_property_pointer_get(ptr, prop);
+						return pyrna_pydict_to_props(&opptr, value, false, error_prefix);
+					}
+					else if (base_type == &RNA_ManipulatorProperties) {
+						PointerRNA opptr = RNA_property_pointer_get(ptr, prop);
+						return pyrna_pydict_to_props(&opptr, value, false, error_prefix);
+					}
 				}
 
 				/* another exception, allow to pass a collection as an RNA property */
@@ -6926,7 +6935,7 @@ static PyObject *pyrna_basetype_dir(BPy_BaseTypeRNA *self)
 		StructRNA *srna = itemptr.data;
 		StructRNA *srna_base = RNA_struct_base(itemptr.data);
 		/* skip own operators, these double up [#29666] */
-		if (srna_base == &RNA_Operator) {
+		if (ELEM(srna_base, &RNA_Operator, &RNA_Manipulator)) {
 			/* do nothing */
 		}
 		else {
@@ -7456,7 +7465,8 @@ static int bpy_class_call(bContext *C, PointerRNA *ptr, FunctionRNA *func, Param
 	PyGILState_STATE gilstate;
 
 #ifdef USE_PEDANTIC_WRITE
-	const bool is_operator = RNA_struct_is_a(ptr->type, &RNA_Operator);
+	const bool is_readonly_init = !(RNA_struct_is_a(ptr->type, &RNA_Operator) ||
+	                                RNA_struct_is_a(ptr->type, &RNA_Manipulator));
 	// const char *func_id = RNA_function_identifier(func);  /* UNUSED */
 	/* testing, for correctness, not operator and not draw function */
 	const bool is_readonly = !(RNA_function_flag(func) & FUNC_ALLOW_WRITE);
@@ -7521,7 +7531,7 @@ static int bpy_class_call(bContext *C, PointerRNA *ptr, FunctionRNA *func, Param
 			if (py_class->tp_init) {
 #ifdef USE_PEDANTIC_WRITE
 				const int prev_write = rna_disallow_writes;
-				rna_disallow_writes = is_operator ? false : true;  /* only operators can write on __init__ */
+				rna_disallow_writes = is_readonly_init ? false : true;  /* only operators can write on __init__ */
 #endif
 
 				/* true in most cases even when the class its self doesn't define an __init__ function. */
diff --git a/source/blender/python/intern/bpy_rna_manipulator.c b/source/blender/python/intern/bpy_rna_manipulator.c
new file mode 100644
index 00000000000..245735f679e
--- /dev/null
+++ b/source/blender/python/intern/bpy_rna_manipulator.c
@@ -0,0 +1,341 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * 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.
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/python/intern/bpy_rna_manipulator.c
+ *  \ingroup pythonintern
+ *
+ * .
+ */
+
+#include <Python.h>
+#include <stddef.h>
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_utildefines.h"
+
+#include "BKE_main.h"
+
+#include "WM_api.h"
+#include "WM_types.h"
+
+#include "bpy_util.h"
+#include "bpy_rna_manipulator.h"
+
+#include "../generic/py_capi_utils.h"
+#include "../generic/python_utildefines.h"
+
+#include "RNA_access.h"
+#include "RNA_types.h"
+#include "RNA_enum_types.h"
+
+#include "bpy_rna.h"
+
+enum {
+	BPY_MANIPULATOR_FN_SLOT_GET = 0,
+	BPY_MANIPULATOR_FN_SLOT_SET,
+	BPY_MANIPULATOR_FN_SLOT_RANGE_GET,
+};
+#define BPY_MANIPULATOR_FN_SLOT_LEN (BPY_MANIPULATOR_FN_SLOT_RANGE_GET + 1)
+
+struct BPyManipulatorHandlerUserData {
+
+	PyObject *fn_slots[BPY_MANIPULATOR_FN_SLOT_LEN];
+};
+
+static void py_rna_manipulator_handler_get_cb(
+        const wmManipulator *UNUSED(mpr), wmManipulatorProperty *mpr_prop,
+        void *value_p)
+{
+	PyGILState_STATE gilstate = PyGILState_Ensure();
+
+	struct BPyManipulatorHandlerUserData *data = mpr_prop->custom_func.user_data;
+	PyObject *ret = PyObject_CallObject(data->fn_slots[BPY_MANIPULATOR_FN_SLOT_GET], NULL);
+	if (ret == NULL) {
+		goto fail;
+	}
+
+	if (mpr_prop->type->data_type == PROP_FLOAT) {
+		float *value = value_p;
+		if (mpr_prop->type->array_length == 1) {
+			if (((*value = PyFloat_AsDouble(ret)) == -1.0f && PyErr_Occurred()) == 0) {
+				goto fail;
+			}
+		}
+		else {
+			if (PyC_AsArray(value, ret, mpr_prop->type->array_length, &PyFloat_Type, false,
+			                "Manipulator get callback: ") == -1)
+			{
+				goto fail;
+			}
+		}
+	}
+	else {
+		PyErr_SetString(PyExc_AttributeError, "internal error, unsupported type");
+		goto fail;
+	}
+
+	Py_DECREF(ret);
+
+	PyGILState_Release(gilstate);
+	return;
+
+fail:
+	PyErr_Print();
+	PyErr_Clear();
+
+	PyGILState_Release(gilstate);
+}
+
+static void py_rna_manipulator_handler_set_cb(
+        const wmManipulator *UNUSED(mpr), wmManipulatorProperty *mpr_prop,
+        const void *value_p)
+{
+	PyGILState_STATE gilstate = PyGILState_Ensure();
+
+	struct BPyManipulatorHandlerUserData *data = mpr_prop->custom_func.user_data;
+
+	PyObject *args = PyTuple_New(1);
+
+	if (mpr_prop->type->data_type == PROP_FLOAT) {
+		const float *value = value_p;
+		PyObject *py_value;
+		if (mpr_prop->type->array_length == 1) {
+			py_value = PyFloat_FromDouble(*value);
+		}
+		else {
+			py_value =  PyC_FromArray((void *)value, mpr_prop->type->array_length, &PyFloat_Type, false,
+			                          "Manipulator set callback: ");
+		}
+		if (py_value == NULL) {
+			goto fail;
+		}
+		PyTuple_SET_ITEM(args, 0, py_value);
+	}
+	else {
+		PyErr_SetString(PyExc_AttributeError, "internal error, unsupported type");
+		goto fail;
+	}
+
+	PyObject *ret = PyObject_CallObject(data->fn_slots[BPY_MANIPULATOR_FN_SLOT_SET], args);
+	if (ret == NULL) {
+		goto fail;
+	}
+	Py_DECREF(ret);
+
+	PyGILState_Release(gilstate);
+	return;
+
+fail:
+	PyErr_Print();
+	PyErr_Clear();
+
+	Py_DECREF(args);
+
+	PyGILState_Release(gilstate);
+}
+
+static void py_rna_manipulator_handler_range_get_cb(
+        const wmManipulator *UNUSED(mpr), wmManipulatorProperty *mpr_prop,
+        void *value_p)
+{
+	struct BPyManipulatorHandlerUserData *data = mpr_prop->custom_func.user_data;
+
+	PyGILState_STATE gilstate = PyGILState_Ensure();
+
+	PyObject *ret = PyObject_CallObject(data->fn_slots[BPY_MANIPULATOR_FN_SLOT_RANGE_GET], NULL);
+	if (ret == NULL) {
+		goto fail;
+	}
+
+	if (!PyTuple_Check(ret)) {
+		PyErr_Format(PyExc_TypeError,
+		             "Expected a tuple, not %.200s",
+		             Py_TYPE(ret)->tp_name);
+		goto fail;
+	}
+
+	if (PyTuple_GET_SIZE(ret) != 2) {
+		PyErr_Format(PyExc_TypeError,
+		             "Expected a tuple of size 2, not %d",
+		             PyTuple_GET_SIZE(ret));
+		goto fail;
+	}
+
+	if (mpr_prop->type->data_type == PROP_FLOAT) {
+		float range[2];
+		for (int i = 0; i < 2; i++) {
+			if (((range[i] = PyFloat_AsDouble(PyTuple_GET_ITEM(ret, i))) == -1.0f && PyErr_Occurred()) == 0) {
+				/* pass */
+			}
+			else {
+				goto fail;
+			}
+		}
+		memcpy(value_p, range, sizeof(range));
+	}
+	else {
+		PyErr_SetString(PyExc_AttributeError, "internal error, unsupported type");
+		goto fail;
+	}
+
+	Py_DECREF(ret);
+	PyGILState_Release(gilstate);
+	return;
+
+fail:
+	Py_XDECREF(ret);
+
+	PyErr_Print();
+	PyErr_Clear();
+
+	PyGILState_Release(gilstate);
+}
+
+static void py_rna_manipulator_handler_free_cb(
+        const wmManipulator *UNUSED(mpr), wmManipulatorProperty *mpr_prop)
+{
+	struct BPyManipulatorHandlerUserData *data = mpr_prop->custom_func.user_data;
+
+	PyGILState_STATE gilstate = PyGILState_Ensure();
+	for (int i = 0; i < BPY_MANIPULATOR_FN_SLOT_LEN; i++) {
+		Py_XDECREF(data->fn_slots[i]);
+	}
+	PyGILState_Release(gilstate);
+
+	MEM_freeN(data);
+
+}
+
+PyDoc_STRVAR(bpy_manipulator_target_set_handler_doc,
+".. method:: target_set_handler(target, get, set, range=None):\n"
+"\n"
+"   Assigns callbacks to a manipulators property.\n"
+"\n"
+"   :arg get: Function that returns the value for this property (single value or sequence).\n"
+"   :type get: callable\n"
+"   :arg set: Function that takes a single value argument and applies it.\n"
+"   :type set: callable\n"
+"   :arg range: Function that returns a (min, max) tuple for manipulators that use a range.\n"
+"   :type range: callable\n"
+);
+static PyObject *bpy_manipulator_target_set_handler(PyObject *UNUSED(self), PyObject *args, PyObject *kwds)
+{
+	/* Note: this is a counter-part to functions:
+	 * 'Manipulator.target_set_prop & target_set_operator'
+	 * (see: rna_wm_manipulator_api.c). conventions should match. */
+	static const char * const _keywords[] = {"self", "target", "get", "set", "range", NULL};
+	static _PyArg_Parser _parser = {"Os|$OOO:target_set_handler", _keywords, 0};
+
+	PyGILState_STATE gilstate = PyGILState_Ensure();
+
+	struct {
+		PyObject *self;
+		char *target;
+		PyObject *py_fn_slots[BPY_MANIPULATOR_FN_SLOT_LEN];
+	} params = {
+		.self = NULL,
+		.target = NULL,
+		.py_fn_slots = {NULL},
+	};
+
+	if (!_PyArg_ParseTupleAndKeywordsFast(
+	        args, kwds,
+	        &_parser,
+	        &params.self,
+	        &params.target,
+	        &params.py_fn_slots[BPY_MANIPULATOR_FN_SLOT_GET],
+	        &params.py_fn_slots[BPY_MANIPULATOR_FN_SLOT_SET],
+	        &params.py_fn_slots[BPY_MANIPULATOR_FN_SLOT_RANGE_GET]))
+	{
+		goto fail;
+	}
+
+	wmManipulator *mpr = ((BPy_StructRNA *)params.self)->ptr.data;
+
+	const wmManipulatorPropertyType *mpr_prop_type =
+	        WM_manipulatortype_target_property_find(mpr->type, params.target);
+	if (mpr_prop_type == NULL) {
+		PyErr_Format(PyExc_ValueError,
+		             "Manipulator target property '%s.%s' not found",
+		             mpr->type->idname, params.target);
+		goto fail;
+	}
+
+	{
+		const int slots_required = 2;
+		const int slots_start = 2;
+		for (int i = 0; i < BPY_MANIPULATOR_FN_SLOT_LEN; i++) {
+			if (params.py_fn_slots[i] == NULL) {
+				if (i < slots_required) {
+					PyErr_Format(PyExc_ValueError, "Argument '%s' not given", _keywords[slots_start + i]);
+					goto fail;
+				}
+			}
+			else if (!PyCallable_Check(params.py_fn_slots[i])) {
+				PyErr_Format(PyExc_ValueError, "Argument '%s' not callable", _keywords[slots_start + i]);
+				goto fail;
+			}
+		}
+	}
+
+	struct BPyManipulatorHandlerUserData *data = MEM_callocN(sizeof(*data), __func__);
+
+	for (int i = 0; i < BPY_MANIPULATOR_FN_SLOT_LEN; i++) {
+		data->fn_slots[i] = params.py_fn_slots[i];
+		Py_XINCREF(params.py_fn_slots[i]);
+	}
+
+	WM_manipulator_target_property_def_func_ptr(
+	        mpr, mpr_prop_type,
+	        &(const struct wmManipulatorPropertyFnParams) {
+	            .value_get_fn = py_rna_manipulator_handler_get_cb,
+	            .value_set_fn = py_rna_manipulator_handler_set_cb,
+	            .range_get_fn = py_rna_manipulator_handler_range_get_cb,
+	            .free_fn = py_rna_manipulator_handler_free_cb,
+	            .user_data = data,
+	        });
+
+	PyGILState_Release(gilstate);
+
+	Py_RETURN_NONE;
+
+fail:
+	PyGILState_Release(gilstate);
+	return NULL;
+}
+
+int BPY_rna_manipulator_module(PyObject *mod_par)
+{
+	static PyMethodDef method_def = {
+	    "target_set_handler", (PyCFunction)bpy_manipulator_target_set_handler, METH_VARARGS | METH_KEYWORDS,
+	    bpy_manipulator_target_set_handler_doc};
+
+	PyObject *func = PyCFunction_New(&method_def, NULL);
+	PyObject *func_inst = PyInstanceMethod_New(func);
+
+
+	/* TODO, return a type that binds nearly to a method. */
+	PyModule_AddObject(mod_par, "_rna_manipulator_target_set_handler", func_inst);
+
+	return 0;
+}
+
+
diff --git a/source/blender/python/intern/bpy_rna_manipulator.h b/source/blender/python/intern/bpy_rna_manipulator.h
new file mode 100644
index 00000000000..b6f3a2e651d
--- /dev/null
+++ b/source/blender/python/intern/bpy_rna_manipulator.h
@@ -0,0 +1,32 @@
+/*
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * 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.
+ *
+ * Contributor(s): Bastien Montagne
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+/** \file blender/python/intern/bpy_rna_manipulator.h
+ *  \ingroup pythonintern
+ */
+
+#ifndef __BPY_RNA_MANIPULATOR_H__
+#define __BPY_RNA_MANIPULATOR_H__
+
+int BPY_rna_manipulator_module(PyObject *);
+
+#endif  /* __BPY_RNA_MANIPULATOR_H__ */