Add material slot reorder buttons

source/blender/blenkernel/intern/curve.c

@@ -4492,6 +4492,54 @@ int BKE_curve_material_index_validate(Curve *cu)
 	}
 }
 
+void BKE_curve_material_remap(Curve *cu, const unsigned int *remap, unsigned int remap_len)
+{
+	const int curvetype = BKE_curve_type_get(cu);
+	const short remap_len_short = (short)remap_len;
+
+#define MAT_NR_REMAP(n) \
+	if (n < remap_len_short) { \
+		BLI_assert(n >= 0 && remap[n] < remap_len_short); \
+		n = remap[n]; \
+	} ((void)0)
+
+	if (curvetype == OB_FONT) {
+		struct CharInfo *strinfo;
+		int charinfo_len, i;
+
+		if (cu->editfont) {
+			EditFont *ef = cu->editfont;
+			strinfo = ef->textbufinfo;
+			charinfo_len = ef->len;
+		}
+		else {
+			strinfo = cu->strinfo;
+			charinfo_len = cu->len_wchar;
+		}
+
+		for (i = 0; i <= charinfo_len; i++) {
+			if (strinfo[i].mat_nr > 0) {
+				strinfo[i].mat_nr -= 1;
+				MAT_NR_REMAP(strinfo[i].mat_nr);
+				strinfo[i].mat_nr += 1;
+			}
+		}
+	}
+	else {
+		Nurb *nu;
+		ListBase *nurbs = BKE_curve_editNurbs_get(cu);
+
+		if (nurbs) {
+			for (nu = nurbs->first; nu; nu = nu->next) {
+				MAT_NR_REMAP(nu->mat_nr);
+			}
+		}
+	}
+
+#undef MAT_NR_REMAP
+
+}
+
 void BKE_curve_rect_from_textbox(const struct Curve *cu, const struct TextBox *tb, struct rctf *r_rect)
 {
 	r_rect->xmin = cu->xof + tb->x;