[Bf-blender-cvs] [2d84662a134] greasepencil-object: GPencil: Fix error for wrong Potrace data

[Antonio Vazquez]

Commit: 2d84662a1346d75388613a08ce86da75ff6ec640
Author: Antonio Vazquez
Date:   Wed Sep 9 12:12:32 2020 +0200
Branches: greasepencil-object
https://developer.blender.org/rB2d84662a1346d75388613a08ce86da75ff6ec640

GPencil: Fix error for wrong Potrace data

In some situations, Potrace can produce a wrong data and generate a very long stroke. Now the length is checked and removed if the length is too big.

===================================================================

M	source/blender/editors/gpencil/gpencil_trace_ops.c
M	source/blender/editors/gpencil/gpencil_trace_utils.c

===================================================================

diff --git a/source/blender/editors/gpencil/gpencil_trace_ops.c b/source/blender/editors/gpencil/gpencil_trace_ops.c
index e2a20eee25e..6da198ef144 100644
--- a/source/blender/editors/gpencil/gpencil_trace_ops.c
+++ b/source/blender/editors/gpencil/gpencil_trace_ops.c
@@ -283,12 +283,12 @@ void GPENCIL_OT_trace_image(wmOperatorType *ot)
                 100.0f);
   RNA_def_float(ot->srna,
                 "sample",
-                0.05f,
-                0.001f,
+                0.0f,
+                0.0f,
                 100.0f,
                 "Sample",
-                "Distance to sample points",
-                0.001f,
+                "Distance to sample points, zero to disable",
+                0.0f,
                 100.0f);
   RNA_def_float_factor(ot->srna,
                        "threshold",
diff --git a/source/blender/editors/gpencil/gpencil_trace_utils.c b/source/blender/editors/gpencil/gpencil_trace_utils.c
index efd5314fae9..fe28d21acd3 100644
--- a/source/blender/editors/gpencil/gpencil_trace_utils.c
+++ b/source/blender/editors/gpencil/gpencil_trace_utils.c
@@ -27,6 +27,7 @@
 
 #include "MEM_guardedalloc.h"
 
+#include "BLI_blenlib.h"
 #include "BLI_math.h"
 
 #include "BKE_gpencil.h"
@@ -252,6 +253,7 @@ void ED_gpencil_trace_data_to_strokes(Main *bmain,
                                       const int32_t resolution,
                                       const int32_t thickness)
 {
+#define MAX_LENGTH 100.0f
   /* Find materials and create them if not found.  */
   int32_t mat_fill_idx = BKE_gpencil_material_find_index_by_name_prefix(ob, "Stroke");
   int32_t mat_mask_idx = BKE_gpencil_material_find_index_by_name_prefix(ob, "Mask");
@@ -348,10 +350,26 @@ void ED_gpencil_trace_data_to_strokes(Main *bmain,
           break;
       }
     }
-    /* Resample stroke. Don't need to call to BKE_gpencil_stroke_geometry_update() because
-     * the sample function already call that. */
-    BKE_gpencil_stroke_sample(gps, MAX2(sample, 0.001f), false);
+    /* In some situations, Potrace can produce a wrong data and generate a very
+     * long stroke. Here the length is checked and removed if the length is too big. */
+    float length = BKE_gpencil_stroke_length(gps, true);
+    if (length <= MAX_LENGTH) {
+      if (sample > 0.0f) {
+        /* Resample stroke. Don't need to call to BKE_gpencil_stroke_geometry_update() because
+         * the sample function already call that. */
+        BKE_gpencil_stroke_sample(gps, sample, false);
+      }
+      else {
+        BKE_gpencil_stroke_geometry_update(gps);
+      }
+    }
+    else {
+      /* Remove too long strokes. */
+      BLI_remlink(&gpf->strokes, gps);
+      BKE_gpencil_free_stroke(gps);
+    }
 
     path = path->next;
   }
+#undef MAX_LENGTH
 }