GPencil: New Simplify modifier mode Sample and operator

This mode simplify the stroke doing a resampling of the points and generate new geometry at the distance defined.

Sample function developed by @NicksBest

New Resample Stroke operator

This operator recreates the stroke geometry with a predefined length between points.

The operator uses the same code used in Simplify modifier.

Reviewers: @mendio

3 files changed, 50 insertions, 0 deletions

diff --git a/source/blender/editors/gpencil/gpencil_edit.c b/source/blender/editors/gpencil/gpencil_edit.c
index f7c90d44d95..01b62dce3c2 100644
--- a/source/blender/editors/gpencil/gpencil_edit.c
+++ b/source/blender/editors/gpencil/gpencil_edit.c
@@ -3847,6 +3847,54 @@ void GPENCIL_OT_stroke_simplify_fixed(wmOperatorType *ot)
   RNA_def_property_flag(prop, PROP_SKIP_SAVE);
 }
 
+/* ** Resample stroke *** */
+static int gp_stroke_sample_exec(bContext *C, wmOperator *op)
+{
+  bGPdata *gpd = ED_gpencil_data_get_active(C);
+  const float length = RNA_float_get(op->ptr, "length");
+
+  /* sanity checks */
+  if (ELEM(NULL, gpd)) {
+    return OPERATOR_CANCELLED;
+  }
+
+  /* Go through each editable + selected stroke */
+  GP_EDITABLE_STROKES_BEGIN (gpstroke_iter, C, gpl, gps) {
+    if (gps->flag & GP_STROKE_SELECT) {
+      BKE_gpencil_sample_stroke(gps, length, true);
+    }
+  }
+  GP_EDITABLE_STROKES_END(gpstroke_iter);
+
+  /* notifiers */
+  DEG_id_tag_update(&gpd->id, ID_RECALC_TRANSFORM | ID_RECALC_GEOMETRY);
+  WM_event_add_notifier(C, NC_GPENCIL | ND_DATA | NA_EDITED, NULL);
+
+  return OPERATOR_FINISHED;
+}
+
+void GPENCIL_OT_stroke_sample(wmOperatorType *ot)
+{
+  PropertyRNA *prop;
+
+  /* identifiers */
+  ot->name = "Sample Stroke";
+  ot->idname = "GPENCIL_OT_stroke_sample";
+  ot->description = "Sample stroke points to predefined segment length";
+
+  /* api callbacks */
+  ot->exec = gp_stroke_sample_exec;
+  ot->poll = gp_active_layer_poll;
+
+  /* flags */
+  ot->flag = OPTYPE_REGISTER | OPTYPE_UNDO;
+
+  /* properties */
+  prop = RNA_def_float(ot->srna, "length", 0.1f, 0.0f, 100.0f, "Length", "", 0.0f, 100.0f);
+  /* avoid re-using last var */
+  RNA_def_property_flag(prop, PROP_SKIP_SAVE);
+}
+
 /* ******************* Stroke trim ************************** */
 static int gp_stroke_trim_exec(bContext *C, wmOperator *UNUSED(op))
 {
diff --git a/source/blender/editors/gpencil/gpencil_intern.h b/source/blender/editors/gpencil/gpencil_intern.h
index 3776dd09eb5..2a608d44a0b 100644
--- a/source/blender/editors/gpencil/gpencil_intern.h
+++ b/source/blender/editors/gpencil/gpencil_intern.h
@@ -486,6 +486,7 @@ void GPENCIL_OT_stroke_simplify_fixed(struct wmOperatorType *ot);
 void GPENCIL_OT_stroke_separate(struct wmOperatorType *ot);
 void GPENCIL_OT_stroke_split(struct wmOperatorType *ot);
 void GPENCIL_OT_stroke_smooth(struct wmOperatorType *ot);
+void GPENCIL_OT_stroke_sample(struct wmOperatorType *ot);
 void GPENCIL_OT_stroke_merge(struct wmOperatorType *ot);
 void GPENCIL_OT_stroke_cutter(struct wmOperatorType *ot);
 void GPENCIL_OT_stroke_trim(struct wmOperatorType *ot);
diff --git a/source/blender/editors/gpencil/gpencil_ops.c b/source/blender/editors/gpencil/gpencil_ops.c
index 54e99802c54..acdf5c2be4f 100644
--- a/source/blender/editors/gpencil/gpencil_ops.c
+++ b/source/blender/editors/gpencil/gpencil_ops.c
@@ -314,6 +314,7 @@ void ED_operatortypes_gpencil(void)
   WM_operatortype_append(GPENCIL_OT_stroke_separate);
   WM_operatortype_append(GPENCIL_OT_stroke_split);
   WM_operatortype_append(GPENCIL_OT_stroke_smooth);
+  WM_operatortype_append(GPENCIL_OT_stroke_sample);
   WM_operatortype_append(GPENCIL_OT_stroke_merge);
   WM_operatortype_append(GPENCIL_OT_stroke_cutter);
   WM_operatortype_append(GPENCIL_OT_stroke_trim);