[gtk/wip/matthiasc/lottie-stroke: 9/10] wip: more subdivision tweakery

[Matthias Clasen <matthiasc src gnome org>]

commit 581a6efeb96de1c537daf60184fb47ffc2813690
Author: Matthias Clasen <mclasen redhat com>
Date:   Mon Nov 30 01:11:56 2020 -0500

    wip: more subdivision tweakery

 gsk/gskpathstroke.c | 44 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 41 insertions(+), 3 deletions(-)
---
diff --git a/gsk/gskpathstroke.c b/gsk/gskpathstroke.c
index 2761d963dd..db94b1ed9b 100644
--- a/gsk/gskpathstroke.c
+++ b/gsk/gskpathstroke.c
@@ -870,7 +870,7 @@ path_op_data_new (GskPathOperation        op,
     d->pts[i] = pts[i];
   d->n_pts = n_pts;
 
-#if 1
+#if 0
   /* detect uninitialized values */
   for (i = 0; i < n_pts; i++)
     d->l[i].x = d->l[i].y = d->r[i].x = d->r[i].y = NAN;
@@ -908,6 +908,7 @@ subdivide_and_add (const graphene_point_t  pts[4],
   GList *l, *pass1 = NULL;
   graphene_point_t p[4];
   graphene_point_t *segment;
+  float t0, t1;
 
   n += get_cubic_extrema (pts[0].x, pts[1].x, pts[2].x, pts[3].x, &pos[n]);
   n += get_cubic_extrema (pts[0].y, pts[1].y, pts[2].y, pts[3].y, &pos[n]);
@@ -921,6 +922,8 @@ subdivide_and_add (const graphene_point_t  pts[4],
 
   pass1 = NULL;
 
+  t0 = 0.1;
+  t1 = 0.9;
   for (i = 0; i < n; i++)
     {
       graphene_point_t left[4];
@@ -928,7 +931,7 @@ subdivide_and_add (const graphene_point_t  pts[4],
       float t;
 
       t = pos[i];
-      if (t < 0.1 || t > 0.9)
+      if (t < t0 || t > t1)
         continue;
 
       split_bezier (p, 4, t, left, right);
@@ -941,7 +944,10 @@ subdivide_and_add (const graphene_point_t  pts[4],
         p[k] = right[k];
 
       for (k = i + 1; k < n; k++)
-        pos[k] = pos[k] / (1 - pos[i]);
+        pos[k] = (pos[k] - pos[i]) / (1 - pos[i]);
+
+      t0 = 0;
+      t1 = (t1 - pos[i]) / (1 - pos[i]);
     }
 
   segment = g_new (graphene_point_t, 4);
@@ -1219,6 +1225,38 @@ gsk_contour_to_stroke (const GskContour *contour,
         }
     }
 
+#if 0
+  /* Subdivide */
+  sops = NULL;
+  for (l = ops; l; l = l->next)
+    {
+      op = l->data;
+
+      switch (op->op)
+        {
+        case GSK_PATH_MOVE:
+          g_assert_not_reached ();
+          break;
+
+        case GSK_PATH_LINE:
+        case GSK_PATH_CLOSE:
+          sops = g_list_prepend (sops, op);
+          break;
+
+        case GSK_PATH_CURVE:
+          subdivide_and_add (op, &sops);
+          g_free (op);
+          break;
+
+        default:
+          g_assert_not_reached ();
+        }
+    }
+
+  g_list_free (ops);
+  ops = g_list_reverse (sops);
+#endif
+
   for (l = ops; l; l = l->next)
     {
       int i;