add option to convert grease pencil into poly line directly.

Without this, bezier curves at 12 resolution are very high detail for many tasks when converted from freehand strokes.
so add the option to convert 1:1 grease pencil points to curve polygons.

also add use_handles option to curve conversion which is used when converting beziers to poly lines.

1 files changed, 138 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/curve.c b/source/blender/blenkernel/intern/curve.c
index 5d2c85e5825..5fba308e3df 100644
--- a/source/blender/blenkernel/intern/curve.c
+++ b/source/blender/blenkernel/intern/curve.c
@@ -3393,6 +3393,144 @@ bool BKE_nurb_order_clamp_v(struct Nurb *nu)
 	return change;
 }
 
+bool BKE_nurb_type_convert(Nurb *nu, const short type, const bool use_handles)
+{
+	BezTriple *bezt;
+	BPoint *bp;
+	int a, c, nr;
+
+	if (nu->type == CU_POLY) {
+		if (type == CU_BEZIER) {  /* to Bezier with vecthandles  */
+			nr = nu->pntsu;
+			bezt = (BezTriple *)MEM_callocN(nr * sizeof(BezTriple), "setsplinetype2");
+			nu->bezt = bezt;
+			a = nr;
+			bp = nu->bp;
+			while (a--) {
+				copy_v3_v3(bezt->vec[1], bp->vec);
+				bezt->f1 = bezt->f2 = bezt->f3 = bp->f1;
+				bezt->h1 = bezt->h2 = HD_VECT;
+				bezt->weight = bp->weight;
+				bezt->radius = bp->radius;
+				bp++;
+				bezt++;
+			}
+			MEM_freeN(nu->bp);
+			nu->bp = NULL;
+			nu->pntsu = nr;
+			nu->type = CU_BEZIER;
+			BKE_nurb_handles_calc(nu);
+		}
+		else if (type == CU_NURBS) {
+			nu->type = CU_NURBS;
+			nu->orderu = 4;
+			nu->flagu &= CU_NURB_CYCLIC; /* disable all flags except for cyclic */
+			BKE_nurb_knot_calc_u(nu);
+			a = nu->pntsu * nu->pntsv;
+			bp = nu->bp;
+			while (a--) {
+				bp->vec[3] = 1.0;
+				bp++;
+			}
+		}
+	}
+	else if (nu->type == CU_BEZIER) {   /* Bezier */
+		if (type == CU_POLY || type == CU_NURBS) {
+			nr = use_handles ? (3 * nu->pntsu) : nu->pntsu;
+			nu->bp = MEM_callocN(nr * sizeof(BPoint), "setsplinetype");
+			a = nu->pntsu;
+			bezt = nu->bezt;
+			bp = nu->bp;
+			while (a--) {
+				if ((type == CU_POLY && bezt->h1 == HD_VECT && bezt->h2 == HD_VECT) || (use_handles == false)) {
+					/* vector handle becomes 1 poly vertice */
+					copy_v3_v3(bp->vec, bezt->vec[1]);
+					bp->vec[3] = 1.0;
+					bp->f1 = bezt->f2;
+					if (use_handles) nr -= 2;
+					bp->radius = bezt->radius;
+					bp->weight = bezt->weight;
+					bp++;
+				}
+				else {
+					char *f = &bezt->f1;
+					for (c = 0; c < 3; c++, f++) {
+						copy_v3_v3(bp->vec, bezt->vec[c]);
+						bp->vec[3] = 1.0;
+						bp->f1 = *f;
+						bp->radius = bezt->radius;
+						bp->weight = bezt->weight;
+						bp++;
+					}
+				}
+				bezt++;
+			}
+			MEM_freeN(nu->bezt);
+			nu->bezt = NULL;
+			nu->pntsu = nr;
+			nu->pntsv = 1;
+			nu->orderu = 4;
+			nu->orderv = 1;
+			nu->type = type;
+
+#if 0       /* UNUSED */
+			if (nu->flagu & CU_NURB_CYCLIC) c = nu->orderu - 1;
+			else c = 0;
+#endif
+
+			if (type == CU_NURBS) {
+				nu->flagu &= CU_NURB_CYCLIC; /* disable all flags except for cyclic */
+				nu->flagu |= CU_NURB_BEZIER;
+				BKE_nurb_knot_calc_u(nu);
+			}
+		}
+	}
+	else if (nu->type == CU_NURBS) {
+		if (type == CU_POLY) {
+			nu->type = CU_POLY;
+			if (nu->knotsu) MEM_freeN(nu->knotsu);  /* python created nurbs have a knotsu of zero */
+			nu->knotsu = NULL;
+			if (nu->knotsv) MEM_freeN(nu->knotsv);
+			nu->knotsv = NULL;
+		}
+		else if (type == CU_BEZIER) {     /* to Bezier */
+			nr = nu->pntsu / 3;
+
+			if (nr < 2) {
+				return false;  /* conversion impossible */
+			}
+			else {
+				bezt = MEM_callocN(nr * sizeof(BezTriple), "setsplinetype2");
+				nu->bezt = bezt;
+				a = nr;
+				bp = nu->bp;
+				while (a--) {
+					copy_v3_v3(bezt->vec[0], bp->vec);
+					bezt->f1 = bp->f1;
+					bp++;
+					copy_v3_v3(bezt->vec[1], bp->vec);
+					bezt->f2 = bp->f1;
+					bp++;
+					copy_v3_v3(bezt->vec[2], bp->vec);
+					bezt->f3 = bp->f1;
+					bezt->radius = bp->radius;
+					bezt->weight = bp->weight;
+					bp++;
+					bezt++;
+				}
+				MEM_freeN(nu->bp);
+				nu->bp = NULL;
+				MEM_freeN(nu->knotsu);
+				nu->knotsu = NULL;
+				nu->pntsu = nr;
+				nu->type = CU_BEZIER;
+			}
+		}
+	}
+
+	return true;
+}
+
 /* Get edit nurbs or normal nurbs list */
 ListBase *BKE_curve_nurbs_get(Curve *cu)
 {