[Bf-blender-cvs] [487ca29e61a] greasepencil-object: GPencil: Fixed crash in trace with number of points

[Antonio Vazquez]

Commit: 487ca29e61aed4850f7f0380f20b4947bb58d65f
Author: Antonio Vazquez
Date:   Wed Apr 8 17:20:44 2020 +0200
Branches: greasepencil-object
https://developer.blender.org/rB487ca29e61aed4850f7f0380f20b4947bb58d65f

GPencil: Fixed crash in trace with number of points

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

M	source/blender/editors/gpencil/gpencil_trace.h
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.h b/source/blender/editors/gpencil/gpencil_trace.h
index 126a8926bff..e5008a0df9a 100644
--- a/source/blender/editors/gpencil/gpencil_trace.h
+++ b/source/blender/editors/gpencil/gpencil_trace.h
@@ -62,6 +62,9 @@ void ED_gpencil_trace_bm_free(const potrace_bitmap_t *bm);
 void ED_gpencil_trace_bm_invert(const potrace_bitmap_t *bm);
 
 void ED_gpencil_trace_image_to_bm(struct ImBuf *ibuf, const potrace_bitmap_t *bm);
-void ED_gpencil_trace_data_to_gp(potrace_state_t *st, struct Object *ob, struct bGPDframe *gpf);
+void ED_gpencil_trace_data_to_gp(potrace_state_t *st,
+                                 struct Object *ob,
+                                 struct bGPDframe *gpf,
+                                 int offset[2]);
 
 #endif /* __GPENCIL_TRACE_H__ */
diff --git a/source/blender/editors/gpencil/gpencil_trace_ops.c b/source/blender/editors/gpencil/gpencil_trace_ops.c
index 39770be2232..0f2caa4dff1 100644
--- a/source/blender/editors/gpencil/gpencil_trace_ops.c
+++ b/source/blender/editors/gpencil/gpencil_trace_ops.c
@@ -157,7 +157,10 @@ static int gp_trace_image_exec(bContext *C, wmOperator *op)
   ED_gpencil_trace_bm_free(bm);
 
   /* Convert the trace to strokes. */
-  ED_gpencil_trace_data_to_gp(st, ob_gpencil, gpf);
+  int offset[2];
+  offset[0] = ibuf->x / 2;
+  offset[1] = ibuf->y / 2;
+  ED_gpencil_trace_data_to_gp(st, ob_gpencil, gpf, offset);
 
   /* Free memory. */
   potrace_state_free(st);
diff --git a/source/blender/editors/gpencil/gpencil_trace_utils.c b/source/blender/editors/gpencil/gpencil_trace_utils.c
index 04a010c87a7..62dc5332514 100644
--- a/source/blender/editors/gpencil/gpencil_trace_utils.c
+++ b/source/blender/editors/gpencil/gpencil_trace_utils.c
@@ -181,13 +181,18 @@ static void write_line(FILE *fptr, char *line)
   fprintf(fptr, "%s\n", line);
 }
 
-static void add_point(bGPDstroke *gps, int idx, float scale, float x, float y)
+static void add_point(bGPDstroke *gps, int idx, float scale, int offset[2], float x, float y)
 {
-  gps->points = MEM_recallocN(gps->points, sizeof(bGPDspoint) * gps->totpoints + 1);
+  if (gps->totpoints == 0) {
+    gps->points = MEM_callocN(sizeof(bGPDspoint), "gp_stroke_points");
+  }
+  else {
+    gps->points = MEM_recallocN(gps->points, sizeof(bGPDspoint) * (gps->totpoints + 1));
+  }
   bGPDspoint *pt = &gps->points[idx];
-  pt->x = x * scale;
+  pt->x = (x - offset[0]) * scale;
   pt->y = 0;
-  pt->z = y * scale;
+  pt->z = (y - offset[1]) * scale;
   pt->pressure = 1.0f;
   pt->strength = 1.0f;
 
@@ -199,8 +204,9 @@ static void add_point(bGPDstroke *gps, int idx, float scale, float x, float y)
  * \param st: Data with traced data
  * \param ob: Target grease pencil object
  * \param gpf: Currect grease pencil frame
+ * \param offset: Offset to center
  */
-void ED_gpencil_trace_data_to_gp(potrace_state_t *st, Object *ob, bGPDframe *gpf)
+void ED_gpencil_trace_data_to_gp(potrace_state_t *st, Object *ob, bGPDframe *gpf, int offset[2])
 {
   potrace_path_t *path = st->plist;
   int n, *tag;
@@ -217,18 +223,18 @@ void ED_gpencil_trace_data_to_gp(potrace_state_t *st, Object *ob, bGPDframe *gpf
     tag = path->curve.tag;
     c = path->curve.c;
     /* Create a new stroke. */
-    bGPDstroke *gps = BKE_gpencil_stroke_add(gpf, 0, 1, 10, false);
+    bGPDstroke *gps = BKE_gpencil_stroke_add(gpf, 0, 0, 10, false);
     int pt_idx = 0;
     /* Move to last point that is equals to start point. */
-    add_point(gps, pt_idx, scale, c[n - 1][2].x, c[n - 1][2].y);
+    add_point(gps, pt_idx, scale, offset, c[n - 1][2].x, c[n - 1][2].y);
     pt_idx++;
     for (int i = 0; i < n; i++) {
       switch (tag[i]) {
         case POTRACE_CORNER:
-          add_point(gps, pt_idx, scale, c[i][1].x, c[i][1].y);
+          add_point(gps, pt_idx, scale, offset, c[i][1].x, c[i][1].y);
           pt_idx++;
 
-          add_point(gps, pt_idx, scale, c[i][2].x, c[i][2].y);
+          add_point(gps, pt_idx, scale, offset, c[i][2].x, c[i][2].y);
           pt_idx++;
           break;
         case POTRACE_CURVETO: