[gtk/wip/matthiasc/lottie-stroke: 51/55] wip: pathstroke port to curve

[Matthias Clasen <matthiasc src gnome org>]

commit ad497d82c83c15ab34dabd2b994066f89f1841b9
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Dec 10 18:20:11 2020 -0500

    wip: pathstroke port to curve

 gsk/gskpathstroke.c | 45 ++++++++++++++++++++++++++++++++++++---------
 1 file changed, 36 insertions(+), 9 deletions(-)
---
diff --git a/gsk/gskpathstroke.c b/gsk/gskpathstroke.c
index 66aa22b144..2108d21aaa 100644
--- a/gsk/gskpathstroke.c
+++ b/gsk/gskpathstroke.c
@@ -996,10 +996,7 @@ curve_intersection (Curve            *c1,
 
 typedef struct
 {
-  GskPathOperation op;
-  int n_pts;
-  graphene_point_t pts[4]; /* points of the curve */
-  float w;
+  GskCurve curve;
 
   graphene_point_t r[4]; /* offset to the right */
   graphene_point_t l[4]; /* offset to the left */
@@ -1008,6 +1005,37 @@ typedef struct
   float angle[2]; /* angles between tangents at the both ends */
 } PathOpData;
 
+/* Compute the curve that results from offsetting the control points */
+static void
+offset_curve (const GskCurve *c,
+              float           distance,
+              GskCurve       *o)
+{
+  graphene_vec2_t n;
+  graphene_point_t p[4];
+
+  switch (c->op)
+    {
+    case GSK_PATH_LINE:
+      normal_vector (&c->line.points[0], &c->line.points[1], &n);
+      scale_point (&c->line.points[0], &n, distance, &p[0]);
+      scale_point (&c->line.points[1], &n, distance, &p[1]);
+      gsk_curve_initialize (o, gsk_patho_encode (GSK_PATH_LINE, p);
+      break;
+    case GSK_PATH_CURVE:
+      normal_vector (&c->curve.points[0], &c->curve.points[1], &n1);
+      scale_point (&c->curve.points[0], &n, distance, &p[0]);
+      scale_point (&c->curve.points[1], &n, distance, &p[1]);
+      break;
+    case GSK_PATH_CONIC:
+      break;
+    case GSK_PATH_CLOSE:
+    case GSK_PATH_MOVE:
+    default:
+      g_assert_not_reached ();
+    }
+}
+
 static void
 compute_offsets (PathOpData *op,
                  float       d)
@@ -1198,11 +1226,10 @@ path_op_data_new (GskPathOperation        op,
   int i;
 
   d = g_new0 (PathOpData, 1);
-  d->op = op;
-  for (i = 0; i < n_pts; i++)
-    d->pts[i] = pts[i];
-  d->n_pts = n_pts;
-  d->w = w;
+  if (op == GSK_PATH_CONIC)
+    gsk_curve_init (&d->curve, gsk_pathop_encode (op, { pts[0], pts[1], { w,}, pts[2] }));
+  else
+    gsk_curve_init (&d->curve, gsk_pathop_encode (op, pts));
 
 #if STROKE_DEBUG
   /* detect uninitialized values */