GPencil: Apply Brush Size to Outline thickness while drawing

The new factor allows to apply the current brush size to the
external stroke perimeter conversion done in draw mode.

3 files changed, 17 insertions, 1 deletions

diff --git a/source/blender/editors/gpencil/gpencil_paint.c b/source/blender/editors/gpencil/gpencil_paint.c
index b196fcae51c..cbc88b57c65 100644
--- a/source/blender/editors/gpencil/gpencil_paint.c
+++ b/source/blender/editors/gpencil/gpencil_paint.c
@@ -943,8 +943,9 @@ static bGPDstroke *gpencil_stroke_to_outline(tGPsdata *p, bGPDstroke *gps)
   /* Stroke. */
   float diff_mat[4][4];
   unit_m4(diff_mat);
+  const float outline_thickness = (float)brush->size * gpencil_settings->outline_fac * 0.5f;
   bGPDstroke *gps_perimeter = BKE_gpencil_stroke_perimeter_from_view(
-      rv3d, p->gpd, gpl, gps_duplicate, 3, diff_mat, 0.0f);
+      rv3d, p->gpd, gpl, gps_duplicate, 3, diff_mat, outline_thickness);
   /* Assign material. */
   if (gpencil_settings->material_alt == NULL) {
     gps_perimeter->mat_nr = gps->mat_nr;
@@ -961,6 +962,8 @@ static bGPDstroke *gpencil_stroke_to_outline(tGPsdata *p, bGPDstroke *gps)
   }
 
   /* Set pressure constant. */
+  gps_perimeter->thickness = max_ii((int)outline_thickness, 1);
+
   bGPDspoint *pt;
   for (int i = 0; i < gps_perimeter->totpoints; i++) {
     pt = &gps_perimeter->points[i];
diff --git a/source/blender/makesdna/DNA_brush_types.h b/source/blender/makesdna/DNA_brush_types.h
index 174ec614238..33f5d8eea12 100644
--- a/source/blender/makesdna/DNA_brush_types.h
+++ b/source/blender/makesdna/DNA_brush_types.h
@@ -132,6 +132,10 @@ typedef struct BrushGpencilSettings {
   struct CurveMapping *curve_rand_saturation;
   struct CurveMapping *curve_rand_value;
 
+  /** Factor for external line thickness conversion to outline. */
+  float outline_fac;
+  char _pad1[4];
+
   /* optional link of material to replace default in context */
   /** Material. */
   struct Material *material;
diff --git a/source/blender/makesrna/intern/rna_brush.c b/source/blender/makesrna/intern/rna_brush.c
index 989b0654104..2aa0a1bba01 100644
--- a/source/blender/makesrna/intern/rna_brush.c
+++ b/source/blender/makesrna/intern/rna_brush.c
@@ -1654,6 +1654,15 @@ static void rna_def_gpencil_options(BlenderRNA *brna)
   RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
   RNA_def_property_update(prop, NC_GPENCIL | ND_DATA, NULL);
 
+  /* Factor to determine outline external perimeter thickness. */
+  prop = RNA_def_property(srna, "outline_thickness_factor", PROP_FLOAT, PROP_FACTOR);
+  RNA_def_property_float_sdna(prop, NULL, "outline_fac");
+  RNA_def_property_range(prop, 0.0f, 1.0f);
+  RNA_def_property_float_default(prop, 0.0f);
+  RNA_def_property_ui_text(
+      prop, "Thickness", "Thickness of the outline stroke relative to current brush thickness");
+  RNA_def_parameter_clear_flags(prop, PROP_ANIMATABLE, 0);
+
   /* Flags */
   prop = RNA_def_property(srna, "use_pressure", PROP_BOOLEAN, PROP_NONE);
   RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_BRUSH_USE_PRESSURE);