New Grease Pencil object for 2D animation

This commit merge the full development done in greasepencil-object branch and include mainly the following features.

- New grease pencil object.
- New drawing engine.
- New grease pencil modes Draw/Sculpt/Edit and Weight Paint.
- New brushes for grease pencil.
- New modifiers for grease pencil.
- New shaders FX.
- New material system (replace old palettes and colors).
- Split of annotations (old grease pencil) and new grease pencil object.
- UI adapted to blender 2.8.

You can get more info here:

https://code.blender.org/2017/12/drawing-2d-animation-in-blender-2-8/
https://code.blender.org/2018/07/grease-pencil-status-update/

This is the result of nearly two years of development and I want thanks firstly the other members of the grease pencil team: Daniel M. Lara, Matias Mendiola and Joshua Leung for their support, ideas and to keep working in the project all the time, without them this project had been impossible.

Also, I want thanks other Blender developers for their help, advices and to be there always to help me, and specially to Clément Foucault, Dalai Felinto, Pablo Vázquez and Campbell Barton.

1 files changed, 910 insertions, 352 deletions

diff --git a/source/blender/editors/gpencil/gpencil_utils.c b/source/blender/editors/gpencil/gpencil_utils.c
index 8b65855f7c4..7262c537321 100644
--- a/source/blender/editors/gpencil/gpencil_utils.c
+++ b/source/blender/editors/gpencil/gpencil_utils.c
@@ -40,7 +40,9 @@
 #include "BLT_translation.h"
 #include "BLI_rand.h"
 
+#include "DNA_meshdata_types.h"
 #include "DNA_gpencil_types.h"
+#include "DNA_brush_types.h"
 #include "DNA_object_types.h"
 #include "DNA_scene_types.h"
 #include "DNA_screen_types.h"
@@ -48,9 +50,13 @@
 #include "DNA_view3d_types.h"
 
 #include "BKE_action.h"
+#include "BKE_main.h"
+#include "BKE_brush.h"
 #include "BKE_context.h"
 #include "BKE_gpencil.h"
-#include "BKE_main.h"
+#include "BKE_object.h"
+#include "BKE_paint.h"
+#include "BKE_material.h"
 #include "BKE_tracking.h"
 
 #include "WM_api.h"
@@ -65,8 +71,14 @@
 #include "ED_gpencil.h"
 #include "ED_clip.h"
 #include "ED_view3d.h"
+#include "ED_object.h"
+#include "ED_screen.h"
+
+#include "GPU_immediate.h"
+#include "GPU_immediate_util.h"
 
 #include "DEG_depsgraph.h"
+#include "DEG_depsgraph_query.h"
 
 #include "gpencil_intern.h"
 
@@ -76,7 +88,7 @@
 /* Get pointer to active Grease Pencil datablock, and an RNA-pointer to trace back to whatever owns it,
  * when context info is not available.
  */
-bGPdata **ED_gpencil_data_get_pointers_direct(ID *screen_id, Scene *scene, ScrArea *sa, Object *ob, PointerRNA *ptr)
+bGPdata **ED_gpencil_data_get_pointers_direct(ID *screen_id, ScrArea *sa, Scene *scene, Object *ob, PointerRNA *r_ptr)
 {
 	/* if there's an active area, check if the particular editor may
 	 * have defined any special Grease Pencil context for editing...
@@ -85,26 +97,37 @@ bGPdata **ED_gpencil_data_get_pointers_direct(ID *screen_id, Scene *scene, ScrAr
 		SpaceLink *sl = sa->spacedata.first;
 
 		switch (sa->spacetype) {
-			case SPACE_VIEW3D: /* 3D-View */
+			/* XXX: Should we reduce reliance on context.gpencil_data for these cases? */
+			case SPACE_BUTS: /* properties */
+			case SPACE_INFO: /* header info (needed after workspaces merge) */
 			{
-				BLI_assert(scene && ELEM(scene->toolsettings->gpencil_src,
-				                         GP_TOOL_SOURCE_SCENE, GP_TOOL_SOURCE_OBJECT));
+				if (ob && (ob->type == OB_GPENCIL)) {
+					/* GP Object */
+					if (r_ptr) RNA_id_pointer_create(&ob->id, r_ptr);
+					return (bGPdata **)&ob->data;
+				}
+				else {
+					return NULL;
+				}
 
-				if (scene->toolsettings->gpencil_src == GP_TOOL_SOURCE_OBJECT) {
-					/* legacy behaviour for usage with old addons requiring object-linked to objects */
+				break;
+			}
 
-					/* just in case no active/selected object... */
-					if (ob && (ob->flag & SELECT)) {
-						/* for now, as long as there's an object, default to using that in 3D-View */
-						if (ptr) RNA_id_pointer_create(&ob->id, ptr);
-						return &ob->gpd;
-					}
-					/* else: defaults to scene... */
+			case SPACE_TOPBAR: /* Topbar (needed after topbar merge) */
+			case SPACE_VIEW3D: /* 3D-View */
+			{
+				if (ob && (ob->type == OB_GPENCIL)) {
+					/* GP Object */
+					if (r_ptr) RNA_id_pointer_create(&ob->id, r_ptr);
+					return (bGPdata **)&ob->data;
 				}
 				else {
-					if (ptr) RNA_id_pointer_create(&scene->id, ptr);
+					/* Annotations */
+					/* XXX: */
+					if (r_ptr) RNA_id_pointer_create(&scene->id, r_ptr);
 					return &scene->gpd;
 				}
+
 				break;
 			}
 			case SPACE_NODE: /* Nodes Editor */
@@ -114,7 +137,7 @@ bGPdata **ED_gpencil_data_get_pointers_direct(ID *screen_id, Scene *scene, ScrAr
 				/* return the GP data for the active node block/node */
 				if (snode && snode->nodetree) {
 					/* for now, as long as there's an active node tree, default to using that in the Nodes Editor */
-					if (ptr) RNA_id_pointer_create(&snode->nodetree->id, ptr);
+					if (r_ptr) RNA_id_pointer_create(&snode->nodetree->id, r_ptr);
 					return &snode->nodetree->gpd;
 				}
 
@@ -127,7 +150,7 @@ bGPdata **ED_gpencil_data_get_pointers_direct(ID *screen_id, Scene *scene, ScrAr
 
 				/* for now, Grease Pencil data is associated with the space (actually preview region only) */
 				/* XXX our convention for everything else is to link to data though... */
-				if (ptr) RNA_pointer_create(screen_id, &RNA_SpaceSequenceEditor, sseq, ptr);
+				if (r_ptr) RNA_pointer_create(screen_id, &RNA_SpaceSequenceEditor, sseq, r_ptr);
 				return &sseq->gpd;
 			}
 			case SPACE_IMAGE: /* Image/UV Editor */
@@ -136,7 +159,7 @@ bGPdata **ED_gpencil_data_get_pointers_direct(ID *screen_id, Scene *scene, ScrAr
 
 				/* for now, Grease Pencil data is associated with the space... */
 				/* XXX our convention for everything else is to link to data though... */
-				if (ptr) RNA_pointer_create(screen_id, &RNA_SpaceImageEditor, sima, ptr);
+				if (r_ptr) RNA_pointer_create(screen_id, &RNA_SpaceImageEditor, sima, r_ptr);
 				return &sima->gpd;
 			}
 			case SPACE_CLIP: /* Nodes Editor */
@@ -151,15 +174,11 @@ bGPdata **ED_gpencil_data_get_pointers_direct(ID *screen_id, Scene *scene, ScrAr
 						if (!track)
 							return NULL;
 
-						if (ptr)
-							RNA_pointer_create(&clip->id, &RNA_MovieTrackingTrack, track, ptr);
-
+						if (r_ptr) RNA_pointer_create(&clip->id, &RNA_MovieTrackingTrack, track, r_ptr);
 						return &track->gpd;
 					}
 					else {
-						if (ptr)
-							RNA_id_pointer_create(&clip->id, ptr);
-
+						if (r_ptr) RNA_id_pointer_create(&clip->id, r_ptr);
 						return &clip->gpd;
 					}
 				}
@@ -170,79 +189,102 @@ bGPdata **ED_gpencil_data_get_pointers_direct(ID *screen_id, Scene *scene, ScrAr
 		}
 	}
 
-	/* just fall back on the scene's GP data */
-	if (ptr) RNA_id_pointer_create((ID *)scene, ptr);
-	return (scene) ? &scene->gpd : NULL;
+	return NULL;
 }
 
 /* Get pointer to active Grease Pencil datablock, and an RNA-pointer to trace back to whatever owns it */
-bGPdata **ED_gpencil_data_get_pointers(const bContext *C, PointerRNA *ptr)
+bGPdata **ED_gpencil_data_get_pointers(const bContext *C, PointerRNA *r_ptr)
 {
 	ID *screen_id = (ID *)CTX_wm_screen(C);
 	Scene *scene = CTX_data_scene(C);
 	ScrArea *sa = CTX_wm_area(C);
 	Object *ob = CTX_data_active_object(C);
 
-	return ED_gpencil_data_get_pointers_direct(screen_id, scene, sa, ob, ptr);
+	return ED_gpencil_data_get_pointers_direct(screen_id, sa, scene, ob, r_ptr);
 }
 
 /* -------------------------------------------------------- */
 
 /* Get the active Grease Pencil datablock, when context is not available */
-bGPdata *ED_gpencil_data_get_active_direct(ID *screen_id, Scene *scene, ScrArea *sa, Object *ob)
+bGPdata *ED_gpencil_data_get_active_direct(ID *screen_id, ScrArea *sa, Scene *scene, Object *ob)
 {
-	bGPdata **gpd_ptr = ED_gpencil_data_get_pointers_direct(screen_id, scene, sa, ob, NULL);
+	bGPdata **gpd_ptr = ED_gpencil_data_get_pointers_direct(screen_id, sa, scene, ob, NULL);
 	return (gpd_ptr) ? *(gpd_ptr) : NULL;
 }
 
-/* Get the active Grease Pencil datablock */
+/**
+ * Get the active Grease Pencil datablock
+ * \note This is the original (bmain) copy of the datablock, stored in files.
+ *       Do not use for reading evaluated copies of GP Objects data
+ */
 bGPdata *ED_gpencil_data_get_active(const bContext *C)
 {
 	bGPdata **gpd_ptr = ED_gpencil_data_get_pointers(C, NULL);
 	return (gpd_ptr) ? *(gpd_ptr) : NULL;
 }
 
+/**
+ * Get the evaluated copy of the active Grease Pencil datablock (where applicable)
+ * - For the 3D View (i.e. "GP Objects"), this gives the evaluated copy of the GP datablock
+ *   (i.e. a copy of the active GP datablock for the active object, where modifiers have been
+ *   applied). This is needed to correctly work with "Copy-on-Write"
+ * - For all other editors (i.e. "GP Annotations"), this just gives the active datablock
+ *   like for ED_gpencil_data_get_active()
+ */
+bGPdata *ED_gpencil_data_get_active_evaluated(const bContext *C)
+{
+	ID *screen_id = (ID *)CTX_wm_screen(C);
+	ScrArea *sa = CTX_wm_area(C);
+
+	const Depsgraph *depsgraph = CTX_data_depsgraph(C);
+	Scene *scene_eval = DEG_get_evaluated_scene(depsgraph);
+	Object *ob = CTX_data_active_object(C);
+	Object *ob_eval = DEG_get_evaluated_object(depsgraph, ob);
+
+	/* if (ob && ob->type == OB_GPENCIL) BLI_assert(ob_eval->data == DEG_get_evaluated_id(ob->data)); */
+	return ED_gpencil_data_get_active_direct(screen_id, sa, scene_eval, ob_eval);
+}
+
+/* -------------------------------------------------------- */
+
+/**
+ * Utility to check whether the r_ptr output of ED_gpencil_data_get_pointers()
+ * is for annotation usage.
+ */
+bool ED_gpencil_data_owner_is_annotation(PointerRNA *owner_ptr)
+{
+	/* Key Assumption: If the pointer is an object, we're dealing with a GP Object's data.
+	 * Otherwise, the GP datablock is being used for annotations (i.e. everywhere else)
+	 */
+	return ((owner_ptr) && (owner_ptr->type != &RNA_Object));
+}
+
 /* -------------------------------------------------------- */
 
 // XXX: this should be removed... We really shouldn't duplicate logic like this!
-bGPdata *ED_gpencil_data_get_active_v3d(Scene *scene, ViewLayer *view_layer)
+bGPdata *ED_gpencil_data_get_active_v3d(ViewLayer *view_layer)
 {
 	Base *base = view_layer->basact;
 	bGPdata *gpd = NULL;
+
 	/* We have to make sure active object is actually visible and selected, else we must use default scene gpd,
 	 * to be consistent with ED_gpencil_data_get_active's behavior.
 	 */
-
 	if (base && TESTBASE(base)) {
-		gpd = base->object->gpd;
+		if (base->object->type == OB_GPENCIL)
+			gpd = base->object->data;
 	}
-	return gpd ? gpd : scene->gpd;
+	return gpd ? gpd : NULL;
 }
 
 /* ******************************************************** */
 /* Keyframe Indicator Checks */
 
 /* Check whether there's an active GP keyframe on the current frame */
-bool ED_gpencil_has_keyframe_v3d(Scene *scene, Object *ob, int cfra)
+bool ED_gpencil_has_keyframe_v3d(Scene *UNUSED(scene), Object *ob, int cfra)
 {
-	/* just check both for now... */
-	// XXX: this could get confusing (e.g. if only on the object, but other places don't show this)
-	if (scene->gpd) {
-		bGPDlayer *gpl = BKE_gpencil_layer_getactive(scene->gpd);
-		if (gpl) {
-			if (gpl->actframe) {
-				// XXX: assumes that frame has been fetched already
-				return (gpl->actframe->framenum == cfra);
-			}
-			else {
-				/* XXX: disabled as could be too much of a penalty */
-				/* return BKE_gpencil_layer_find_frame(gpl, cfra); */
-			}
-		}
-	}
-
-	if (ob && ob->gpd) {
-		bGPDlayer *gpl = BKE_gpencil_layer_getactive(ob->gpd);
+	if (ob && ob->data && (ob->type == OB_GPENCIL)) {
+		bGPDlayer *gpl = BKE_gpencil_layer_getactive(ob->data);
 		if (gpl) {
 			if (gpl->actframe) {
 				// XXX: assumes that frame has been fetched already
@@ -281,28 +323,13 @@ bool gp_active_layer_poll(bContext *C)
 bool gp_active_brush_poll(bContext *C)
 {
 	ToolSettings *ts = CTX_data_tool_settings(C);
-	bGPDbrush *brush = BKE_gpencil_brush_getactive(ts);
-
-	return (brush != NULL);
-}
-
-/* poll callback for checking if there is an active palette */
-bool gp_active_palette_poll(bContext *C)
-{
-	bGPdata *gpd = ED_gpencil_data_get_active(C);
-	bGPDpalette *palette = BKE_gpencil_palette_getactive(gpd);
-
-	return (palette != NULL);
-}
-
-/* poll callback for checking if there is an active palette color */
-bool gp_active_palettecolor_poll(bContext *C)
-{
-	bGPdata *gpd = ED_gpencil_data_get_active(C);
-	bGPDpalette *palette = BKE_gpencil_palette_getactive(gpd);
-	bGPDpalettecolor *palcolor = BKE_gpencil_palettecolor_getactive(palette);
-
-	return (palcolor != NULL);
+	Paint *paint = &ts->gp_paint->paint;
+	if (paint) {
+		return (paint->brush != NULL);
+	}
+	else {
+		return false;
+	}
 }
 
 /* ******************************************************** */
@@ -360,7 +387,7 @@ const EnumPropertyItem *ED_gpencil_layers_with_new_enum_itemf(
 	/* Create new layer */
 	/* TODO: have some way of specifying that we don't want this? */
 	{
-		/* active Keying Set */
+		/* "New Layer" entry */
 		item_tmp.identifier = "__CREATE__";
 		item_tmp.name = "New Layer";
 		item_tmp.value = -1;
@@ -392,7 +419,6 @@ const EnumPropertyItem *ED_gpencil_layers_with_new_enum_itemf(
 }
 
 
-
 /* ******************************************************** */
 /* Brush Tool Core */
 
@@ -426,7 +452,7 @@ bool gp_stroke_inside_circle(const int mval[2], const int UNUSED(mvalo[2]),
 /* Stroke Validity Testing */
 
 /* Check whether given stroke can be edited given the supplied context */
-// XXX: do we need additional flags for screenspace vs dataspace?
+/* TODO: do we need additional flags for screenspace vs dataspace? */
 bool ED_gpencil_stroke_can_use_direct(const ScrArea *sa, const bGPDstroke *gps)
 {
 	/* sanity check */
@@ -436,7 +462,7 @@ bool ED_gpencil_stroke_can_use_direct(const ScrArea *sa, const bGPDstroke *gps)
 	/* filter stroke types by flags + spacetype */
 	if (gps->flag & GP_STROKE_3DSPACE) {
 		/* 3D strokes - only in 3D view */
-		return (sa->spacetype == SPACE_VIEW3D);
+		return ((sa->spacetype == SPACE_VIEW3D) || (sa->spacetype == SPACE_BUTS));
 	}
 	else if (gps->flag & GP_STROKE_2DIMAGE) {
 		/* Special "image" strokes - only in Image Editor */
@@ -460,59 +486,21 @@ bool ED_gpencil_stroke_can_use(const bContext *C, const bGPDstroke *gps)
 }
 
 /* Check whether given stroke can be edited for the current color */
-bool ED_gpencil_stroke_color_use(const bGPDlayer *gpl, const bGPDstroke *gps)
+bool ED_gpencil_stroke_color_use(Object *ob, const bGPDlayer *gpl, const bGPDstroke *gps)
 {
 	/* check if the color is editable */
-	bGPDpalettecolor *palcolor = gps->palcolor;
-	if (palcolor != NULL) {
-		if (palcolor->flag & PC_COLOR_HIDE)
+	MaterialGPencilStyle *gp_style = BKE_material_gpencil_settings_get(ob, gps->mat_nr + 1);
+
+	if (gp_style != NULL) {
+		if (gp_style->flag & GP_STYLE_COLOR_HIDE)
 			return false;
-		if (((gpl->flag & GP_LAYER_UNLOCK_COLOR) == 0) && (palcolor->flag & PC_COLOR_LOCKED))
+		if (((gpl->flag & GP_LAYER_UNLOCK_COLOR) == 0) && (gp_style->flag & GP_STYLE_COLOR_LOCKED))
 			return false;
 	}
 
 	return true;
 }
 
-/* Get palette color or create a new one */
-bGPDpalettecolor *ED_gpencil_stroke_getcolor(bGPdata *gpd, bGPDstroke *gps)
-{
-	bGPDpalette *palette;
-	bGPDpalettecolor *palcolor;
-
-	if ((gps->palcolor != NULL) && ((gps->flag & GP_STROKE_RECALC_COLOR) == 0))
-		return gps->palcolor;
-
-	/* get palette */
-	palette = BKE_gpencil_palette_getactive(gpd);
-	if (palette == NULL) {
-		palette = BKE_gpencil_palette_addnew(gpd, DATA_("GP_Palette"), true);
-	}
-	/* get color */
-	palcolor = BKE_gpencil_palettecolor_getbyname(palette, gps->colorname);
-	if (palcolor == NULL) {
-		if (gps->palcolor == NULL) {
-			palcolor = BKE_gpencil_palettecolor_addnew(palette, DATA_("Color"), true);
-			/* set to a different color */
-			ARRAY_SET_ITEMS(palcolor->color, 1.0f, 0.0f, 1.0f, 0.9f);
-		}
-		else {
-			palcolor = BKE_gpencil_palettecolor_addnew(palette, gps->colorname, true);
-			/* set old color and attributes */
-			bGPDpalettecolor *gpscolor = gps->palcolor;
-			copy_v4_v4(palcolor->color, gpscolor->color);
-			copy_v4_v4(palcolor->fill, gpscolor->fill);
-			palcolor->flag = gpscolor->flag;
-		}
-	}
-
-	/* clear flag and set pointer */
-	gps->flag &= ~GP_STROKE_RECALC_COLOR;
-	gps->palcolor = palcolor;
-
-	return palcolor;
-}
-
 /* ******************************************************** */
 /* Space Conversion */
 
@@ -573,9 +561,9 @@ void gp_point_to_parent_space(bGPDspoint *pt, float diff_mat[4][4], bGPDspoint *
 }
 
 /**
- * Change points position relative to parent object
+ * Change position relative to parent object
  */
-void gp_apply_parent(bGPDlayer *gpl, bGPDstroke *gps)
+void gp_apply_parent(Depsgraph *depsgraph, Object *obact, bGPdata *gpd, bGPDlayer *gpl, bGPDstroke *gps)
 {
 	bGPDspoint *pt;
 	int i;
@@ -585,7 +573,7 @@ void gp_apply_parent(bGPDlayer *gpl, bGPDstroke *gps)
 	float inverse_diff_mat[4][4];
 	float fpt[3];
 
-	ED_gpencil_parent_location(gpl, diff_mat);
+	ED_gpencil_parent_location(depsgraph, obact, gpd, gpl, diff_mat);
 	invert_m4_m4(inverse_diff_mat, diff_mat);
 
 	for (i = 0; i < gps->totpoints; i++) {
@@ -598,14 +586,14 @@ void gp_apply_parent(bGPDlayer *gpl, bGPDstroke *gps)
 /**
  * Change point position relative to parent object
  */
-void gp_apply_parent_point(bGPDlayer *gpl, bGPDspoint *pt)
+void gp_apply_parent_point(Depsgraph *depsgraph, Object *obact, bGPdata *gpd, bGPDlayer *gpl, bGPDspoint *pt)
 {
 	/* undo matrix */
 	float diff_mat[4][4];
 	float inverse_diff_mat[4][4];
 	float fpt[3];
 
-	ED_gpencil_parent_location(gpl, diff_mat);
+	ED_gpencil_parent_location(depsgraph, obact, gpd, gpl, diff_mat);
 	invert_m4_m4(inverse_diff_mat, diff_mat);
 
 	mul_v3_m4v3(fpt, inverse_diff_mat, &pt->x);
@@ -770,194 +758,259 @@ bool gp_point_xy_to_3d(GP_SpaceConversion *gsc, Scene *scene, const float screen
 }
 
 /**
- * Apply smooth to stroke point
- * \param gps              Stroke to smooth
- * \param i                Point index
- * \param inf              Amount of smoothing to apply
- * \param affect_pressure  Apply smoothing to pressure values too?
+ * Convert tGPspoint (temporary 2D/screenspace point data used by GP modal operators)
+ * to 3D coordinates.
+ *
+ * \param point2D: The screenspace 2D point data to convert
+ * \param depth: Depth array (via ED_view3d_autodist_depth())
+ * \param[out] r_out: The resulting 2D point data
  */
-bool gp_smooth_stroke(bGPDstroke *gps, int i, float inf, bool affect_pressure)
+void gp_stroke_convertcoords_tpoint(
+        Scene *scene, ARegion *ar, View3D *v3d,
+        Object *ob, bGPDlayer *gpl,
+        const tGPspoint *point2D, float *depth,
+        float r_out[3])
 {
-	bGPDspoint *pt = &gps->points[i];
-	float pressure = 0.0f;
-	float sco[3] = {0.0f};
-
-	/* Do nothing if not enough points to smooth out */
-	if (gps->totpoints <= 2) {
-		return false;
-	}
+	ToolSettings *ts = scene->toolsettings;
+	const int mval[2] = {point2D->x, point2D->y};
 
-	/* Only affect endpoints by a fraction of the normal strength,
-	 * to prevent the stroke from shrinking too much
-	 */
-	if ((i == 0) || (i == gps->totpoints - 1)) {
-		inf *= 0.1f;
+	if ((depth != NULL) && (ED_view3d_autodist_simple(ar, mval, r_out, 0, depth))) {
+		/* projecting onto 3D-Geometry
+		*	- nothing more needs to be done here, since view_autodist_simple() has already done it
+		*/
 	}
-
-	/* Compute smoothed coordinate by taking the ones nearby */
-	/* XXX: This is potentially slow, and suffers from accumulation error as earlier points are handled before later ones */
-	{
-		// XXX: this is hardcoded to look at 2 points on either side of the current one (i.e. 5 items total)
-		const int   steps = 2;
-		const float average_fac = 1.0f / (float)(steps * 2 + 1);
-		int step;
-
-		/* add the point itself */
-		madd_v3_v3fl(sco, &pt->x, average_fac);
-
-		if (affect_pressure) {
-			pressure += pt->pressure * average_fac;
+	else {
+		float mval_f[2] = {(float)point2D->x, (float)point2D->y};
+		float mval_prj[2];
+		float rvec[3], dvec[3];
+		float zfac;
+
+		/* Current method just converts each point in screen-coordinates to
+		 * 3D-coordinates using the 3D-cursor as reference.
+		 */
+		ED_gp_get_drawing_reference(v3d, scene, ob, gpl, ts->gpencil_v3d_align, rvec);
+		zfac = ED_view3d_calc_zfac(ar->regiondata, rvec, NULL);
+
+		if (ED_view3d_project_float_global(ar, rvec, mval_prj, V3D_PROJ_TEST_NOP) == V3D_PROJ_RET_OK) {
+			sub_v2_v2v2(mval_f, mval_prj, mval_f);
+			ED_view3d_win_to_delta(ar, mval_f, dvec, zfac);
+			sub_v3_v3v3(r_out, rvec, dvec);
 		}
+		else {
+			zero_v3(r_out);
+		}
+	}
+}
 
-		/* n-steps before/after current point */
-		// XXX: review how the endpoints are treated by this algorithm
-		// XXX: falloff measures should also introduce some weighting variations, so that further-out points get less weight
-		for (step = 1; step <= steps; step++) {
-			bGPDspoint *pt1, *pt2;
-			int before = i - step;
-			int after = i + step;
-
-			CLAMP_MIN(before, 0);
-			CLAMP_MAX(after, gps->totpoints - 1);
-
-			pt1 = &gps->points[before];
-			pt2 = &gps->points[after];
-
-			/* add both these points to the average-sum (s += p[i]/n) */
-			madd_v3_v3fl(sco, &pt1->x, average_fac);
-			madd_v3_v3fl(sco, &pt2->x, average_fac);
-
-#if 0
-			/* XXX: Disabled because get weird result */
-			/* do pressure too? */
-			if (affect_pressure) {
-				pressure += pt1->pressure * average_fac;
-				pressure += pt2->pressure * average_fac;
+/**
+ * Get drawing reference point for conversion or projection of the stroke
+ * \param[out] r_vec : Reference point found
+ */
+void ED_gp_get_drawing_reference(
+        View3D *v3d, Scene *scene, Object *ob, bGPDlayer *UNUSED(gpl),
+        char align_flag, float r_vec[3])
+{
+	const float *fp = ED_view3d_cursor3d_get(scene, v3d)->location;
+
+	/* if using a gpencil object at cursor mode, can use the location of the object */
+	if (align_flag & GP_PROJECT_VIEWSPACE) {
+		if (ob && (ob->type == OB_GPENCIL)) {
+			/* fallback (no strokes) - use cursor or object location */
+			if (align_flag & GP_PROJECT_CURSOR) {
+				/* use 3D-cursor */
+				copy_v3_v3(r_vec, fp);
+			}
+			else {
+				/* use object location */
+				copy_v3_v3(r_vec, ob->obmat[3]);
 			}
-#endif
 		}
 	}
-
-	/* Based on influence factor, blend between original and optimal smoothed coordinate */
-	interp_v3_v3v3(&pt->x, &pt->x, sco, inf);
-
-#if 0
-	/* XXX: Disabled because get weird result */
-	if (affect_pressure) {
-		pt->pressure = pressure;
+	else {
+		/* use 3D-cursor */
+		copy_v3_v3(r_vec, fp);
 	}
-#endif
-
-	return true;
 }
 
+
 /**
-* Apply smooth for strength to stroke point
-* \param gps              Stroke to smooth
-* \param i                Point index
-* \param inf              Amount of smoothing to apply
-*/
-bool gp_smooth_stroke_strength(bGPDstroke *gps, int i, float inf)
+ * Reproject all points of the stroke to a plane locked to axis to avoid stroke offset
+ */
+void ED_gp_project_stroke_to_plane(Object *ob, RegionView3D *rv3d, bGPDstroke *gps, const float origin[3], const int axis)
 {
-	bGPDspoint *ptb = &gps->points[i];
-
-	/* Do nothing if not enough points */
-	if (gps->totpoints <= 2) {
-		return false;
+	float plane_normal[3];
+	float vn[3];
+
+	float ray[3];
+	float rpoint[3];
+
+	/* normal vector for a plane locked to axis */
+	zero_v3(plane_normal);
+	if (axis < 0) {
+		/* if the axis is not locked, need a vector to the view direction
+		* in order to get the right size of the stroke.
+		*/
+		ED_view3d_global_to_vector(rv3d, origin, plane_normal);
+	}
+	else {
+		plane_normal[axis] = 1.0f;
+		/* if object, apply object rotation */
+		if (ob && (ob->type == OB_GPENCIL)) {
+			mul_mat3_m4_v3(ob->obmat, plane_normal);
+		}
 	}
 
-	/* Compute theoretical optimal value using distances */
-	bGPDspoint *pta, *ptc;
-	int before = i - 1;
-	int after = i + 1;
-
-	CLAMP_MIN(before, 0);
-	CLAMP_MAX(after, gps->totpoints - 1);
-
-	pta = &gps->points[before];
-	ptc = &gps->points[after];
+	/* Reproject the points in the plane */
+	for (int i = 0; i < gps->totpoints; i++) {
+		bGPDspoint *pt = &gps->points[i];
 
-	/* the optimal value is the corresponding to the interpolation of the strength
-	 *  at the distance of point b
-	 */
-	const float fac = line_point_factor_v3(&ptb->x, &pta->x, &ptc->x);
-	const float optimal = (1.0f - fac) * pta->strength + fac * ptc->strength;
+		/* get a vector from the point with the current view direction of the viewport */
+		ED_view3d_global_to_vector(rv3d, &pt->x, vn);
 
-	/* Based on influence factor, blend between original and optimal */
-	ptb->strength = (1.0f - inf) * ptb->strength + inf * optimal;
+		/* calculate line extreme point to create a ray that cross the plane */
+		mul_v3_fl(vn, -50.0f);
+		add_v3_v3v3(ray, &pt->x, vn);
 
-	return true;
+		/* if the line never intersect, the point is not changed */
+		if (isect_line_plane_v3(rpoint, &pt->x, ray, origin, plane_normal)) {
+			copy_v3_v3(&pt->x, rpoint);
+		}
+	}
 }
 
 /**
-* Apply smooth for thickness to stroke point (use pressure)
-* \param gps              Stroke to smooth
-* \param i                Point index
-* \param inf              Amount of smoothing to apply
-*/
-bool gp_smooth_stroke_thickness(bGPDstroke *gps, int i, float inf)
+ * Reproject given point to a plane locked to axis to avoid stroke offset
+ * \param[in, out] pt : Point to affect
+ */
+void ED_gp_project_point_to_plane(Object *ob, RegionView3D *rv3d, const float origin[3], const int axis, bGPDspoint *pt)
 {
-	bGPDspoint *ptb = &gps->points[i];
-
-	/* Do nothing if not enough points */
-	if (gps->totpoints <= 2) {
-		return false;
+	float plane_normal[3];
+	float vn[3];
+
+	float ray[3];
+	float rpoint[3];
+
+	/* normal vector for a plane locked to axis */
+	zero_v3(plane_normal);
+	if (axis < 0) {
+		/* if the axis is not locked, need a vector to the view direction
+		 * in order to get the right size of the stroke.
+		 */
+		ED_view3d_global_to_vector(rv3d, origin, plane_normal);
+	}
+	else {
+		plane_normal[axis] = 1.0f;
+		/* if object, apply object rotation */
+		if (ob && (ob->type == OB_GPENCIL)) {
+			mul_mat3_m4_v3(ob->obmat, plane_normal);
+		}
 	}
 
-	/* Compute theoretical optimal value using distances */
-	bGPDspoint *pta, *ptc;
-	int before = i - 1;
-	int after = i + 1;
-
-	CLAMP_MIN(before, 0);
-	CLAMP_MAX(after, gps->totpoints - 1);
-
-	pta = &gps->points[before];
-	ptc = &gps->points[after];
 
-	/* the optimal value is the corresponding to the interpolation of the pressure
-	 *  at the distance of point b
-	 */
-	float fac = line_point_factor_v3(&ptb->x, &pta->x, &ptc->x);
-	float optimal = (1.0f - fac) * pta->pressure + fac * ptc->pressure;
+	/* Reproject the points in the plane */
+	/* get a vector from the point with the current view direction of the viewport */
+	ED_view3d_global_to_vector(rv3d, &pt->x, vn);
 
-	/* Based on influence factor, blend between original and optimal */
-	ptb->pressure = (1.0f - inf) * ptb->pressure + inf * optimal;
+	/* calculate line extrem point to create a ray that cross the plane */
+	mul_v3_fl(vn, -50.0f);
+	add_v3_v3v3(ray, &pt->x, vn);
 
-	return true;
+	/* if the line never intersect, the point is not changed */
+	if (isect_line_plane_v3(rpoint, &pt->x, ray, origin, plane_normal)) {
+		copy_v3_v3(&pt->x, rpoint);
+	}
 }
 
+/* ******************************************************** */
+/* Stroke Operations */
+// XXX: Check if these functions duplicate stuff in blenkernel, and/or whether we should just deduplicate
+
 /**
  * Subdivide a stroke once, by adding a point half way between each pair of existing points
  * \param gps           Stroke data
- * \param new_totpoints Total number of points (after subdividing)
+ * \param subdivide      Number of times to subdivide
  */
-void gp_subdivide_stroke(bGPDstroke *gps, const int new_totpoints)
+void gp_subdivide_stroke(bGPDstroke *gps, const int subdivide)
 {
-	/* Move points towards end of enlarged points array to leave space for new points */
-	int y = 1;
-	for (int i = gps->totpoints - 1; i > 0; i--) {
-		gps->points[new_totpoints - y] = gps->points[i];
-		y += 2;
-	}
+	bGPDspoint *temp_points;
+	int totnewpoints, oldtotpoints;
+	int i2;
+
+	/* loop as many times as levels */
+	for (int s = 0; s < subdivide; s++) {
+		totnewpoints = gps->totpoints - 1;
+		/* duplicate points in a temp area */
+		temp_points = MEM_dupallocN(gps->points);
+		oldtotpoints = gps->totpoints;
+
+		/* resize the points arrys */
+		gps->totpoints += totnewpoints;
+		gps->points = MEM_recallocN(gps->points, sizeof(*gps->points) * gps->totpoints);
+		gps->dvert = MEM_recallocN(gps->dvert, sizeof(*gps->dvert) * gps->totpoints);
+		gps->flag |= GP_STROKE_RECALC_CACHES;
+
+		/* move points from last to first to new place */
+		i2 = gps->totpoints - 1;
+		for (int i = oldtotpoints - 1; i > 0; i--) {
+			bGPDspoint *pt = &temp_points[i];
+			bGPDspoint *pt_final = &gps->points[i2];
+			MDeformVert *dvert = &gps->dvert[i];
+			MDeformVert *dvert_final = &gps->dvert[i2];
+
+			copy_v3_v3(&pt_final->x, &pt->x);
+			pt_final->pressure = pt->pressure;
+			pt_final->strength = pt->strength;
+			pt_final->time = pt->time;
+			pt_final->flag = pt->flag;
+			pt_final->uv_fac = pt->uv_fac;
+			pt_final->uv_rot = pt->uv_rot;
+
+			dvert_final->totweight = dvert->totweight;
+			dvert_final->dw = dvert->dw;
+
+			i2 -= 2;
+		}
+		/* interpolate mid points */
+		i2 = 1;
+		for (int i = 0; i < oldtotpoints - 1; i++) {
+			bGPDspoint *pt = &temp_points[i];
+			bGPDspoint *next = &temp_points[i + 1];
+			bGPDspoint *pt_final = &gps->points[i2];
+			MDeformVert *dvert_final = &gps->dvert[i2];
+
+			/* add a half way point */
+			interp_v3_v3v3(&pt_final->x, &pt->x, &next->x, 0.5f);
+			pt_final->pressure = interpf(pt->pressure, next->pressure, 0.5f);
+			pt_final->strength = interpf(pt->strength, next->strength, 0.5f);
+			CLAMP(pt_final->strength, GPENCIL_STRENGTH_MIN, 1.0f);
+			pt_final->time = interpf(pt->time, next->time, 0.5f);
+			pt_final->uv_fac = interpf(pt->uv_fac, next->uv_fac, 0.5f);
+			pt_final->uv_rot = interpf(pt->uv_rot, next->uv_rot, 0.5f);
+
+			dvert_final->totweight = 0;
+			dvert_final->dw = NULL;
+
+			i2 += 2;
+		}
 
-	/* Create interpolated points */
-	for (int i = 0; i < new_totpoints - 1; i += 2) {
-		bGPDspoint *prev  = &gps->points[i];
-		bGPDspoint *pt    = &gps->points[i + 1];
-		bGPDspoint *next  = &gps->points[i + 2];
+		MEM_SAFE_FREE(temp_points);
 
-		/* Interpolate all values */
-		interp_v3_v3v3(&pt->x, &prev->x, &next->x, 0.5f);
+		/* move points to smooth stroke */
+		/* duplicate points in a temp area with the new subdivide data */
+		temp_points = MEM_dupallocN(gps->points);
 
-		pt->pressure = interpf(prev->pressure, next->pressure, 0.5f);
-		pt->strength = interpf(prev->strength, next->strength, 0.5f);
-		CLAMP(pt->strength, GPENCIL_STRENGTH_MIN, 1.0f);
-		pt->time = interpf(prev->time, next->time, 0.5f);
-	}
+		/* extreme points are not changed */
+		for (int i = 0; i < gps->totpoints - 2; i++) {
+			bGPDspoint *pt = &temp_points[i];
+			bGPDspoint *next = &temp_points[i + 1];
+			bGPDspoint *pt_final = &gps->points[i + 1];
 
-	/* Update to new total number of points */
-	gps->totpoints = new_totpoints;
+			/* move point */
+			interp_v3_v3v3(&pt_final->x, &pt->x, &next->x, 0.5f);
+		}
+		/* free temp memory */
+		MEM_SAFE_FREE(temp_points);
+	}
 }
 
 /**
@@ -965,7 +1018,7 @@ void gp_subdivide_stroke(bGPDstroke *gps, const int new_totpoints)
  * \param gps           Stroke data
  * \param brush         Brush data
  */
-void gp_randomize_stroke(bGPDstroke *gps, bGPDbrush *brush, RNG *rng)
+void gp_randomize_stroke(bGPDstroke *gps, Brush *brush, RNG *rng)
 {
 	bGPDspoint *pt1, *pt2, *pt3;
 	float v1[3];
@@ -995,10 +1048,10 @@ void gp_randomize_stroke(bGPDstroke *gps, bGPDbrush *brush, RNG *rng)
 	normalize_v3(ortho);
 
 	/* Read all points and apply shift vector (first and last point not modified) */
-	for (int i = 1; i < gps->totpoints - 1; ++i) {
+	for (int i = 1; i < gps->totpoints - 1; i++) {
 		bGPDspoint *pt = &gps->points[i];
 		/* get vector with shift (apply a division because random is too sensitive */
-		const float fac = BLI_rng_get_float(rng) * (brush->draw_random_sub / 10.0f);
+		const float fac = BLI_rng_get_float(rng) * (brush->gpencil_settings->draw_random_sub / 10.0f);
 		float svec[3];
 		copy_v3_v3(svec, ortho);
 		if (BLI_rng_get_float(rng) > 0.5f) {
@@ -1011,31 +1064,46 @@ void gp_randomize_stroke(bGPDstroke *gps, bGPDbrush *brush, RNG *rng)
 		/* apply shift */
 		add_v3_v3(&pt->x, svec);
 	}
-
 }
+
+/* ******************************************************** */
+/* Layer Parenting  - Compute Parent Transforms */
+
 /* calculate difference matrix */
-void ED_gpencil_parent_location(bGPDlayer *gpl, float diff_mat[4][4])
+void ED_gpencil_parent_location(
+        const Depsgraph *depsgraph, Object *obact, bGPdata *UNUSED(gpd),
+        bGPDlayer *gpl, float diff_mat[4][4])
 {
-	Object *ob = gpl->parent;
-
-	if (ob == NULL) {
+	Object *ob_eval = depsgraph != NULL ? DEG_get_evaluated_object(depsgraph, obact) : obact;
+	Object *obparent = gpl->parent;
+	Object *obparent_eval = depsgraph != NULL ? DEG_get_evaluated_object(depsgraph, obparent) : obparent;
+
+	/* if not layer parented, try with object parented */
+	if (obparent_eval == NULL) {
+		if (ob_eval != NULL) {
+			if (ob_eval->type == OB_GPENCIL) {
+				copy_m4_m4(diff_mat, ob_eval->obmat);
+				return;
+			}
+		}
+		/* not gpencil object */
 		unit_m4(diff_mat);
 		return;
 	}
 	else {
 		if ((gpl->partype == PAROBJECT) || (gpl->partype == PARSKEL)) {
-			mul_m4_m4m4(diff_mat, ob->obmat, gpl->inverse);
+			mul_m4_m4m4(diff_mat, obparent_eval->obmat, gpl->inverse);
 			return;
 		}
 		else if (gpl->partype == PARBONE) {
-			bPoseChannel *pchan = BKE_pose_channel_find_name(ob->pose, gpl->parsubstr);
+			bPoseChannel *pchan = BKE_pose_channel_find_name(obparent_eval->pose, gpl->parsubstr);
 			if (pchan) {
 				float tmp_mat[4][4];
-				mul_m4_m4m4(tmp_mat, ob->obmat, pchan->pose_mat);
+				mul_m4_m4m4(tmp_mat, obparent_eval->obmat, pchan->pose_mat);
 				mul_m4_m4m4(diff_mat, tmp_mat, gpl->inverse);
 			}
 			else {
-				mul_m4_m4m4(diff_mat, ob->obmat, gpl->inverse); /* if bone not found use object (armature) */
+				mul_m4_m4m4(diff_mat, obparent_eval->obmat, gpl->inverse); /* if bone not found use object (armature) */
 			}
 			return;
 		}
@@ -1046,7 +1114,7 @@ void ED_gpencil_parent_location(bGPDlayer *gpl, float diff_mat[4][4])
 }
 
 /* reset parent matrix for all layers */
-void ED_gpencil_reset_layers_parent(bGPdata *gpd)
+void ED_gpencil_reset_layers_parent(Depsgraph *depsgraph, Object *obact, bGPdata *gpd)
 {
 	bGPDspoint *pt;
 	int i;
@@ -1071,7 +1139,7 @@ void ED_gpencil_reset_layers_parent(bGPdata *gpd)
 			/* only redo if any change */
 			if (!equals_m4m4(gpl->inverse, cur_mat)) {
 				/* first apply current transformation to all strokes */
-				ED_gpencil_parent_location(gpl, diff_mat);
+				ED_gpencil_parent_location(depsgraph, obact, gpd, gpl, diff_mat);
 				for (bGPDframe *gpf = gpl->frames.first; gpf; gpf = gpf->next) {
 					for (bGPDstroke *gps = gpf->strokes.first; gps; gps = gps->next) {
 						for (i = 0, pt = gps->points; i < gps->totpoints; i++, pt++) {
@@ -1086,90 +1154,580 @@ void ED_gpencil_reset_layers_parent(bGPdata *gpd)
 	}
 }
 /* ******************************************************** */
-bool ED_gpencil_stroke_minmax(
-        const bGPDstroke *gps, const bool use_select,
-        float r_min[3], float r_max[3])
+/* GP Object Stuff */
+
+/* Helper function to create new OB_GPENCIL Object */
+Object *ED_add_gpencil_object(bContext *C, Scene *scene, const float loc[3])
 {
-	const bGPDspoint *pt;
-	int i;
-	bool changed = false;
+	float rot[3] = {0.0f};
+
+	Object *ob = ED_object_add_type(C, OB_GPENCIL, NULL, loc, rot, false, scene->lay);
+
+	/* define size */
+	BKE_object_obdata_size_init(ob, GP_OBGPENCIL_DEFAULT_SIZE);
+	/* create default brushes and colors */
+	ED_gpencil_add_defaults(C);
 
-	for (i = 0, pt = gps->points; i < gps->totpoints; i++, pt++) {
-		if ((use_select == false) || (pt->flag & GP_SPOINT_SELECT)) {;
-			minmax_v3v3_v3(r_min, r_max, &pt->x);
-			changed = true;
+	return ob;
+}
+
+/* Helper function to create default colors and drawing brushes */
+void ED_gpencil_add_defaults(bContext *C)
+{
+	Main *bmain = CTX_data_main(C);
+	Object *ob = CTX_data_active_object(C);
+	ToolSettings *ts = CTX_data_tool_settings(C);
+
+	/* first try to reuse default material */
+	if (ob->actcol > 0) {
+		Material *ma = give_current_material(ob, ob->actcol);
+		if ((ma) && (ma->gp_style == NULL)) {
+			BKE_material_init_gpencil_settings(ma);
 		}
 	}
-	return changed;
+
+	/* ensure color exist */
+	BKE_gpencil_material_ensure(bmain, ob);
+
+	Paint *paint = BKE_brush_get_gpencil_paint(ts);
+	/* if not exist, create a new one */
+	if (paint->brush == NULL) {
+		/* create new brushes */
+		BKE_brush_gpencil_presets(C);
+	}
+
 }
 
-/* Dynamic Enums of GP Brushes */
-const EnumPropertyItem *ED_gpencil_brushes_enum_itemf(
-        bContext *C, PointerRNA *UNUSED(ptr), PropertyRNA *UNUSED(prop),
-        bool *r_free)
+/* ******************************************************** */
+/* Vertex Groups */
+
+/* assign points to vertex group */
+void ED_gpencil_vgroup_assign(bContext *C, Object *ob, float weight)
 {
-	ToolSettings *ts = CTX_data_tool_settings(C);
-	bGPDbrush *brush;
-	EnumPropertyItem *item = NULL, item_tmp = { 0 };
-	int totitem = 0;
-	int i = 0;
+	const int def_nr = ob->actdef - 1;
+	if (!BLI_findlink(&ob->defbase, def_nr))
+		return;
 
-	if (ELEM(NULL, C, ts)) {
-		return DummyRNA_DEFAULT_items;
+	CTX_DATA_BEGIN(C, bGPDstroke *, gps, editable_gpencil_strokes)
+	{
+		if (gps->flag & GP_STROKE_SELECT) {
+			for (int i = 0; i < gps->totpoints; i++) {
+				bGPDspoint *pt = &gps->points[i];
+				MDeformVert *dvert = &gps->dvert[i];
+				if (pt->flag & GP_SPOINT_SELECT) {
+					BKE_gpencil_vgroup_add_point_weight(dvert, def_nr, weight);
+				}
+			}
+		}
 	}
+	CTX_DATA_END;
+}
 
-	/* Existing brushes */
-	for (brush = ts->gp_brushes.first; brush; brush = brush->next, i++) {
-		item_tmp.identifier = brush->info;
-		item_tmp.name = brush->info;
-		item_tmp.value = i;
+/* remove points from vertex group */
+void ED_gpencil_vgroup_remove(bContext *C, Object *ob)
+{
+	const int def_nr = ob->actdef - 1;
+	if (!BLI_findlink(&ob->defbase, def_nr))
+		return;
 
-		if (brush->flag & GP_BRUSH_ACTIVE)
-			item_tmp.icon = ICON_BRUSH_DATA;
-		else
-			item_tmp.icon = ICON_NONE;
+	CTX_DATA_BEGIN(C, bGPDstroke *, gps, editable_gpencil_strokes)
+	{
+		for (int i = 0; i < gps->totpoints; i++) {
+			bGPDspoint *pt = &gps->points[i];
+			MDeformVert *dvert = &gps->dvert[i];
 
-		RNA_enum_item_add(&item, &totitem, &item_tmp);
+			if ((pt->flag & GP_SPOINT_SELECT) && (dvert->totweight > 0)) {
+				BKE_gpencil_vgroup_remove_point_weight(dvert, def_nr);
+			}
+		}
 	}
+	CTX_DATA_END;
+}
 
-	RNA_enum_item_end(&item, &totitem);
-	*r_free = true;
+/* select points of vertex group */
+void ED_gpencil_vgroup_select(bContext *C, Object *ob)
+{
+	const int def_nr = ob->actdef - 1;
+	if (!BLI_findlink(&ob->defbase, def_nr))
+		return;
 
-	return item;
+	CTX_DATA_BEGIN(C, bGPDstroke *, gps, editable_gpencil_strokes)
+	{
+		for (int i = 0; i < gps->totpoints; i++) {
+			bGPDspoint *pt = &gps->points[i];
+			MDeformVert *dvert = &gps->dvert[i];
+
+			if (BKE_gpencil_vgroup_use_index(dvert, def_nr) > -1.0f) {
+				pt->flag |= GP_SPOINT_SELECT;
+				gps->flag |= GP_STROKE_SELECT;
+			}
+		}
+	}
+	CTX_DATA_END;
 }
 
-/* Dynamic Enums of GP Palettes */
-const EnumPropertyItem *ED_gpencil_palettes_enum_itemf(
-        bContext *C, PointerRNA *UNUSED(ptr), PropertyRNA *UNUSED(prop),
-        bool *r_free)
+/* unselect points of vertex group */
+void ED_gpencil_vgroup_deselect(bContext *C, Object *ob)
 {
-	bGPdata *gpd = CTX_data_gpencil_data(C);
-	bGPDpalette *palette;
-	EnumPropertyItem *item = NULL, item_tmp = { 0 };
-	int totitem = 0;
-	int i = 0;
+	const int def_nr = ob->actdef - 1;
+	if (!BLI_findlink(&ob->defbase, def_nr))
+		return;
 
-	if (ELEM(NULL, C, gpd)) {
-		return DummyRNA_DEFAULT_items;
+	CTX_DATA_BEGIN(C, bGPDstroke *, gps, editable_gpencil_strokes)
+	{
+		for (int i = 0; i < gps->totpoints; i++) {
+			bGPDspoint *pt = &gps->points[i];
+			MDeformVert *dvert = &gps->dvert[i];
+
+			if (BKE_gpencil_vgroup_use_index(dvert, def_nr) > -1.0f) {
+				pt->flag &= ~GP_SPOINT_SELECT;
+				gps->flag |= GP_STROKE_SELECT;
+			}
+		}
 	}
+	CTX_DATA_END;
+}
 
-	/* Existing palettes */
-	for (palette = gpd->palettes.first; palette; palette = palette->next, i++) {
-		item_tmp.identifier = palette->info;
-		item_tmp.name = palette->info;
-		item_tmp.value = i;
+/* ******************************************************** */
+/* Cursor drawing */
 
-		if (palette->flag & PL_PALETTE_ACTIVE)
-			item_tmp.icon = ICON_COLOR;
-		else
-			item_tmp.icon = ICON_NONE;
+/* check if cursor is in drawing region */
+static bool gp_check_cursor_region(bContext *C, int mval[2])
+{
+	ARegion *ar = CTX_wm_region(C);
+	ScrArea *sa = CTX_wm_area(C);
+	/* TODO: add more spacetypes */
+	if (!ELEM(sa->spacetype, SPACE_VIEW3D)) {
+		return false;
+	}
+	if ((ar) && (ar->regiontype != RGN_TYPE_WINDOW)) {
+		return false;
+	}
+	else if (ar) {
+		rcti region_rect;
 
-		RNA_enum_item_add(&item, &totitem, &item_tmp);
+		/* Perform bounds check using  */
+		ED_region_visible_rect(ar, &region_rect);
+		return BLI_rcti_isect_pt_v(&region_rect, mval);
+	}
+	else {
+		return false;
 	}
+}
 
-	RNA_enum_item_end(&item, &totitem);
-	*r_free = true;
+/* draw eraser cursor */
+void ED_gpencil_brush_draw_eraser(Brush *brush, int x, int y)
+{
+	short radius = (short)brush->size;
 
-	return item;
+	GPUVertFormat *format = immVertexFormat();
+	const uint shdr_pos = GPU_vertformat_attr_add(format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
+	immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);
+
+	glEnable(GL_LINE_SMOOTH);
+	glEnable(GL_BLEND);
+	glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
+
+	immUniformColor4ub(255, 100, 100, 20);
+	imm_draw_circle_fill_2d(shdr_pos, x, y, radius, 40);
+
+	immUnbindProgram();
+
+	immBindBuiltinProgram(GPU_SHADER_2D_LINE_DASHED_UNIFORM_COLOR);
+
+	float viewport_size[4];
+	glGetFloatv(GL_VIEWPORT, viewport_size);
+	immUniform2f("viewport_size", viewport_size[2], viewport_size[3]);
+
+	immUniformColor4f(1.0f, 0.39f, 0.39f, 0.78f);
+	immUniform1i("colors_len", 0);  /* "simple" mode */
+	immUniform1f("dash_width", 12.0f);
+	immUniform1f("dash_factor", 0.5f);
+
+	imm_draw_circle_wire_2d(shdr_pos, x, y, radius,
+		/* XXX Dashed shader gives bad results with sets of small segments currently,
+		*     temp hack around the issue. :( */
+		max_ii(8, radius / 2));  /* was fixed 40 */
+
+	immUnbindProgram();
+
+	glDisable(GL_BLEND);
+	glDisable(GL_LINE_SMOOTH);
+}
+
+/* Helper callback for drawing the cursor itself */
+static void gp_brush_drawcursor(bContext *C, int x, int y, void *customdata)
+{
+	Main *bmain = CTX_data_main(C);
+	Scene *scene = CTX_data_scene(C);
+	Object *ob = CTX_data_active_object(C);
+	ARegion *ar = CTX_wm_region(C);
+
+	GP_BrushEdit_Settings *gset = &scene->toolsettings->gp_sculpt;
+	bGPdata *gpd = ED_gpencil_data_get_active(C);
+	GP_EditBrush_Data *brush = NULL;
+	Brush *paintbrush = NULL;
+	Material *ma = NULL;
+	MaterialGPencilStyle *gp_style = NULL;
+	int *last_mouse_position = customdata;
+
+	if ((gpd) && (gpd->flag & GP_DATA_STROKE_WEIGHTMODE)) {
+		brush = &gset->brush[gset->weighttype];
+	}
+	else {
+		brush = &gset->brush[gset->brushtype];
+	}
+
+	/* default radius and color */
+	float color[3] = {1.0f, 1.0f, 1.0f};
+	float darkcolor[3];
+	float radius = 3.0f;
+
+	int mval[2] = {x, y};
+	/* check if cursor is in drawing region and has valid datablock */
+	if ((!gp_check_cursor_region(C, mval)) || (gpd == NULL)) {
+		return;
+	}
+
+	/* for paint use paint brush size and color */
+	if (gpd->flag & GP_DATA_STROKE_PAINTMODE) {
+		paintbrush = BKE_brush_getactive_gpencil(scene->toolsettings);
+		/* while drawing hide */
+		if ((gpd->runtime.sbuffer_size > 0) &&
+		    (paintbrush) && ((paintbrush->gpencil_settings->flag & GP_BRUSH_STABILIZE_MOUSE) == 0) &&
+		    ((paintbrush->gpencil_settings->flag & GP_BRUSH_STABILIZE_MOUSE_TEMP) == 0))
+		{
+			return;
+		}
+
+		if (paintbrush) {
+			if ((paintbrush->gpencil_settings->flag & GP_BRUSH_ENABLE_CURSOR) == 0) {
+				return;
+			}
+
+			/* eraser has special shape and use a different shader program */
+			if (paintbrush->gpencil_settings->brush_type == GP_BRUSH_TYPE_ERASE) {
+				ED_gpencil_brush_draw_eraser(paintbrush, x, y);
+				return;
+			}
+
+			/* get current drawing color */
+			ma = BKE_gpencil_get_material_from_brush(paintbrush);
+			if (ma == NULL) {
+				BKE_gpencil_material_ensure(bmain, ob);
+				/* assign the first material to the brush */
+				ma = give_current_material(ob, 1);
+				paintbrush->gpencil_settings->material = ma;
+			}
+			gp_style = ma->gp_style;
+
+			/* after some testing, display the size of the brush is not practical because
+			 * is too disruptive and the size of cursor does not change with zoom factor.
+			 * The decision was to use a fix size, instead of paintbrush->thickness value.
+			 */
+			if ((gp_style) && (GPENCIL_PAINT_MODE(gpd)) &&
+				((paintbrush->gpencil_settings->flag & GP_BRUSH_STABILIZE_MOUSE) == 0) &&
+				((paintbrush->gpencil_settings->flag & GP_BRUSH_STABILIZE_MOUSE_TEMP) == 0) &&
+				(paintbrush->gpencil_settings->brush_type == GP_BRUSH_TYPE_DRAW))
+			{
+				radius = 2.0f;
+				copy_v3_v3(color, gp_style->stroke_rgba);
+			}
+			else {
+				radius = 5.0f;
+				copy_v3_v3(color, paintbrush->add_col);
+			}
+		}
+		else {
+			return;
+		}
+	}
+
+	/* for sculpt use sculpt brush size */
+	if (GPENCIL_SCULPT_OR_WEIGHT_MODE(gpd)) {
+		if (brush) {
+			if ((brush->flag & GP_EDITBRUSH_FLAG_ENABLE_CURSOR) == 0) {
+				return;
+			}
+
+			radius = brush->size;
+			if (brush->flag & (GP_EDITBRUSH_FLAG_INVERT | GP_EDITBRUSH_FLAG_TMP_INVERT)) {
+				copy_v3_v3(color, brush->curcolor_sub);
+			}
+			else {
+				copy_v3_v3(color, brush->curcolor_add);
+			}
+		}
+	}
+
+	/* draw icon */
+	GPUVertFormat *format = immVertexFormat();
+	uint pos = GPU_vertformat_attr_add(format, "pos", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
+	immBindBuiltinProgram(GPU_SHADER_2D_UNIFORM_COLOR);
+
+	glEnable(GL_LINE_SMOOTH);
+	glEnable(GL_BLEND);
+
+	/* Inner Ring: Color from UI panel */
+	immUniformColor4f(color[0], color[1], color[2], 0.8f);
+	if ((gp_style) && (GPENCIL_PAINT_MODE(gpd)) &&
+	    ((paintbrush->gpencil_settings->flag & GP_BRUSH_STABILIZE_MOUSE) == 0) &&
+	    ((paintbrush->gpencil_settings->flag & GP_BRUSH_STABILIZE_MOUSE_TEMP) == 0) &&
+	    (paintbrush->gpencil_settings->brush_type == GP_BRUSH_TYPE_DRAW))
+	{
+		imm_draw_circle_fill_2d(pos, x, y, radius, 40);
+	}
+	else {
+		imm_draw_circle_wire_2d(pos, x, y, radius, 40);
+	}
+
+	/* Outer Ring: Dark color for contrast on light backgrounds (e.g. gray on white) */
+	mul_v3_v3fl(darkcolor, color, 0.40f);
+	immUniformColor4f(darkcolor[0], darkcolor[1], darkcolor[2], 0.8f);
+	imm_draw_circle_wire_2d(pos, x, y, radius + 1, 40);
+
+	glDisable(GL_BLEND);
+	glDisable(GL_LINE_SMOOTH);
+
+	/* Draw line for lazy mouse */
+	if ((last_mouse_position) &&
+		(paintbrush->gpencil_settings->flag & GP_BRUSH_STABILIZE_MOUSE_TEMP))
+	{
+		glEnable(GL_LINE_SMOOTH);
+		glEnable(GL_BLEND);
+
+		copy_v3_v3(color, paintbrush->add_col);
+		immUniformColor4f(color[0], color[1], color[2], 0.8f);
+
+		immBegin(GPU_PRIM_LINES, 2);
+		immVertex2f(pos, x, y);
+		immVertex2f(pos, last_mouse_position[0] + ar->winrct.xmin,
+						 last_mouse_position[1] + ar->winrct.ymin);
+		immEnd();
+
+		glDisable(GL_BLEND);
+		glDisable(GL_LINE_SMOOTH);
+	}
+
+	immUnbindProgram();
+}
+
+/* Turn brush cursor in on/off */
+void ED_gpencil_toggle_brush_cursor(bContext *C, bool enable, void *customdata)
+{
+	Scene *scene = CTX_data_scene(C);
+	GP_BrushEdit_Settings *gset = &scene->toolsettings->gp_sculpt;
+	int *lastpost = customdata;
+
+	if (gset->paintcursor && !enable) {
+		/* clear cursor */
+		WM_paint_cursor_end(CTX_wm_manager(C), gset->paintcursor);
+		gset->paintcursor = NULL;
+	}
+	else if (enable) {
+		/* in some situations cursor could be duplicated, so it is better disable first if exist */
+		if (gset->paintcursor) {
+			/* clear cursor */
+			WM_paint_cursor_end(CTX_wm_manager(C), gset->paintcursor);
+			gset->paintcursor = NULL;
+		}
+		/* enable cursor */
+		gset->paintcursor = WM_paint_cursor_activate(CTX_wm_manager(C),
+		                                             NULL,
+		                                             gp_brush_drawcursor,
+		                                             (lastpost) ? customdata : NULL);
+	}
+}
+
+/* verify if is using the right brush */
+static void gpencil_verify_brush_type(bContext *C, int newmode)
+{
+	ToolSettings *ts = CTX_data_tool_settings(C);
+	GP_BrushEdit_Settings *gset = &ts->gp_sculpt;
+
+	switch (newmode) {
+		case OB_MODE_GPENCIL_SCULPT:
+			gset->flag &= ~GP_BRUSHEDIT_FLAG_WEIGHT_MODE;
+			if ((gset->brushtype < 0) || (gset->brushtype >= GP_EDITBRUSH_TYPE_WEIGHT)) {
+				gset->brushtype = GP_EDITBRUSH_TYPE_PUSH;
+			}
+			break;
+		case OB_MODE_GPENCIL_WEIGHT:
+			gset->flag |= GP_BRUSHEDIT_FLAG_WEIGHT_MODE;
+			if ((gset->weighttype < GP_EDITBRUSH_TYPE_WEIGHT) || (gset->weighttype >= TOT_GP_EDITBRUSH_TYPES)) {
+				gset->weighttype = GP_EDITBRUSH_TYPE_WEIGHT;
+			}
+			break;
+		default:
+			break;
+	}
+}
+
+/* set object modes */
+void ED_gpencil_setup_modes(bContext *C, bGPdata *gpd, int newmode)
+{
+	if (!gpd) {
+		return;
+	}
+
+	switch (newmode) {
+		case OB_MODE_GPENCIL_EDIT:
+			gpd->flag |= GP_DATA_STROKE_EDITMODE;
+			gpd->flag &= ~GP_DATA_STROKE_PAINTMODE;
+			gpd->flag &= ~GP_DATA_STROKE_SCULPTMODE;
+			gpd->flag &= ~GP_DATA_STROKE_WEIGHTMODE;
+			ED_gpencil_toggle_brush_cursor(C, false, NULL);
+			break;
+		case OB_MODE_GPENCIL_PAINT:
+			gpd->flag &= ~GP_DATA_STROKE_EDITMODE;
+			gpd->flag |= GP_DATA_STROKE_PAINTMODE;
+			gpd->flag &= ~GP_DATA_STROKE_SCULPTMODE;
+			gpd->flag &= ~GP_DATA_STROKE_WEIGHTMODE;
+			ED_gpencil_toggle_brush_cursor(C, true, NULL);
+			break;
+		case OB_MODE_GPENCIL_SCULPT:
+			gpd->flag &= ~GP_DATA_STROKE_EDITMODE;
+			gpd->flag &= ~GP_DATA_STROKE_PAINTMODE;
+			gpd->flag |= GP_DATA_STROKE_SCULPTMODE;
+			gpd->flag &= ~GP_DATA_STROKE_WEIGHTMODE;
+			gpencil_verify_brush_type(C, OB_MODE_GPENCIL_SCULPT);
+			ED_gpencil_toggle_brush_cursor(C, true, NULL);
+			break;
+		case OB_MODE_GPENCIL_WEIGHT:
+			gpd->flag &= ~GP_DATA_STROKE_EDITMODE;
+			gpd->flag &= ~GP_DATA_STROKE_PAINTMODE;
+			gpd->flag &= ~GP_DATA_STROKE_SCULPTMODE;
+			gpd->flag |= GP_DATA_STROKE_WEIGHTMODE;
+			gpencil_verify_brush_type(C, OB_MODE_GPENCIL_WEIGHT);
+			ED_gpencil_toggle_brush_cursor(C, true, NULL);
+			break;
+		default:
+			gpd->flag &= ~GP_DATA_STROKE_EDITMODE;
+			gpd->flag &= ~GP_DATA_STROKE_PAINTMODE;
+			gpd->flag &= ~GP_DATA_STROKE_SCULPTMODE;
+			gpd->flag &= ~GP_DATA_STROKE_WEIGHTMODE;
+			ED_gpencil_toggle_brush_cursor(C, false, NULL);
+			break;
+	}
+}
+
+/* helper to convert 2d to 3d for simple drawing buffer */
+static void gpencil_stroke_convertcoords(ARegion *ar, const tGPspoint *point2D, float origin[3], float out[3])
+{
+	float mval_f[2] = { (float)point2D->x, (float)point2D->y };
+	float mval_prj[2];
+	float rvec[3], dvec[3];
+	float zfac;
+
+	copy_v3_v3(rvec, origin);
+
+	zfac = ED_view3d_calc_zfac(ar->regiondata, rvec, NULL);
+
+	if (ED_view3d_project_float_global(ar, rvec, mval_prj, V3D_PROJ_TEST_NOP) == V3D_PROJ_RET_OK) {
+		sub_v2_v2v2(mval_f, mval_prj, mval_f);
+		ED_view3d_win_to_delta(ar, mval_f, dvec, zfac);
+		sub_v3_v3v3(out, rvec, dvec);
+	}
+	else {
+		zero_v3(out);
+	}
+}
+
+/* convert 2d tGPspoint to 3d bGPDspoint */
+void ED_gpencil_tpoint_to_point(ARegion *ar, float origin[3], const tGPspoint *tpt, bGPDspoint *pt)
+{
+	float p3d[3];
+	/* conversion to 3d format */
+	gpencil_stroke_convertcoords(ar, tpt, origin, p3d);
+	copy_v3_v3(&pt->x, p3d);
+
+	pt->pressure = tpt->pressure;
+	pt->strength = tpt->strength;
+	pt->uv_fac = tpt->uv_fac;
+	pt->uv_rot = tpt->uv_rot;
+}
+
+/* texture coordinate utilities */
+void ED_gpencil_calc_stroke_uv(Object *ob, bGPDstroke *gps)
+{
+	if (gps == NULL) {
+		return;
+	}
+	MaterialGPencilStyle *gp_style = BKE_material_gpencil_settings_get(ob, gps->mat_nr + 1);
+	float pixsize;
+	if (gp_style) {
+		pixsize = gp_style->texture_pixsize / 1000000.0f;
+	}
+	else {
+		/* use this value by default */
+		pixsize = 0.000100f;
+	}
+	pixsize = MAX2(pixsize, 0.0000001f);
+
+	bGPDspoint *pt = NULL;
+	bGPDspoint *ptb = NULL;
+	int i;
+	float totlen = 0;
+
+	/* first read all points and calc distance */
+	for (i = 0; i < gps->totpoints; i++) {
+		pt = &gps->points[i];
+		/* first point */
+		if (i == 0) {
+			pt->uv_fac = 0.0f;
+			continue;
+		}
+
+		ptb = &gps->points[i - 1];
+		totlen += len_v3v3(&pt->x, &ptb->x) / pixsize;
+		pt->uv_fac = totlen;
+	}
+	/* normalize the distance using a factor */
+	float factor;
+	/* if image, use texture width */
+	if ((gp_style) && (gp_style->sima)) {
+		factor = gp_style->sima->gen_x;
+	}
+	else {
+		factor = totlen;
+	}
+	for (i = 0; i < gps->totpoints; i++) {
+		pt = &gps->points[i];
+		pt->uv_fac /= factor;
+	}
+}
+
+/* recalc uv for any stroke using the material */
+void ED_gpencil_update_color_uv(Main *bmain, Material *mat)
+{
+	Material *gps_ma = NULL;
+	/* read all strokes  */
+	for (Object *ob = bmain->object.first; ob; ob = ob->id.next) {
+		if (ob->type == OB_GPENCIL) {
+			bGPdata *gpd = ob->data;
+			if (gpd == NULL) {
+				continue;
+			}
+
+			for (bGPDlayer *gpl = gpd->layers.first; gpl; gpl = gpl->next) {
+				/* only editable and visible layers are considered */
+				if (gpencil_layer_is_editable(gpl)) {
+					for (bGPDframe *gpf = gpl->frames.first; gpf; gpf = gpf->next) {
+						for (bGPDstroke *gps = gpf->strokes.first; gps; gps = gps->next) {
+							/* check if it is editable */
+							if (ED_gpencil_stroke_color_use(ob, gpl, gps) == false) {
+								continue;
+							}
+							gps_ma = give_current_material(ob, gps->mat_nr + 1);
+							/* update */
+							if ((gps_ma) && (gps_ma == mat)) {
+								ED_gpencil_calc_stroke_uv(ob, gps);
+							}
+						}
+					}
+				}
+			}
+		}
+	}
 }
 /* ******************************************************** */