path: Add gsk_path_get_start/end_point

These are useful to have, now that we are
relying more on GskPathPoint in our api.

gsk/gskcontour.c

@@ -66,6 +66,10 @@ struct _GskContourClass
                                                  float                   threshold,
                                                  GskRealPathPoint       *result,
                                                  float                  *out_dist);
+  gboolean              (* get_start_point)     (const GskContour       *contour,
+                                                 GskRealPathPoint       *result);
+  gboolean              (* get_end_point)       (const GskContour       *contour,
+                                                 GskRealPathPoint       *result);
   void                  (* get_position)        (const GskContour       *contour,
                                                  GskRealPathPoint       *point,
                                                  graphene_point_t       *position);
@@ -682,6 +686,28 @@ gsk_standard_contour_get_closest_point (const GskContour       *contour,
   return FALSE;
 }
 
+static gboolean
+gsk_standard_contour_get_start_point (const GskContour *contour,
+                                      GskRealPathPoint *result)
+{
+  result->data.std.idx = 1;
+  result->data.std.t = 0;
+
+  return TRUE;
+}
+
+static gboolean
+gsk_standard_contour_get_end_point (const GskContour *contour,
+                                    GskRealPathPoint *result)
+{
+  GskStandardContour *self = (GskStandardContour *) contour;
+
+  result->data.std.idx = self->n_ops - 1;
+  result->data.std.t = 1;
+
+  return TRUE;
+}
+
 static void
 gsk_standard_contour_get_point (const GskContour *contour,
                                 gpointer          measure_data,
@@ -847,6 +873,8 @@ static const GskContourClass GSK_STANDARD_CONTOUR_CLASS =
   gsk_standard_contour_reverse,
   gsk_standard_contour_get_winding,
   gsk_standard_contour_get_closest_point,
+  gsk_standard_contour_get_start_point,
+  gsk_standard_contour_get_end_point,
   gsk_standard_contour_get_position,
   gsk_standard_contour_get_tangent,
   gsk_standard_contour_get_curvature,
@@ -1035,6 +1063,20 @@ gsk_contour_get_closest_point (const GskContour       *self,
   return self->klass->get_closest_point (self, point, threshold, result, out_dist);
 }
 
+void
+gsk_contour_get_start_point (const GskContour *self,
+                             GskRealPathPoint *result)
+{
+  self->klass->get_start_point (self, result);
+}
+
+void
+gsk_contour_get_end_point (const GskContour *self,
+                           GskRealPathPoint *result)
+{
+  self->klass->get_end_point (self, result);
+}
+
 void
 gsk_contour_get_point (const GskContour *self,
                        gpointer          measure_data,

gsk/gskcontourprivate.h

@@ -94,6 +94,10 @@ void                    gsk_contour_get_point                   (const GskContou
                                                                  gpointer                measure_data,
                                                                  float                   offset,
                                                                  GskRealPathPoint       *result);
+void                    gsk_contour_get_start_point             (const GskContour       *self,
+                                                                 GskRealPathPoint       *result);
+void                    gsk_contour_get_end_point               (const GskContour       *self,
+                                                                 GskRealPathPoint       *result);
 float                   gsk_contour_get_distance                (const GskContour       *self,
                                                                  GskRealPathPoint       *point,
                                                                  gpointer                measure_data);

gsk/gskpath.c

@@ -540,6 +540,74 @@ gsk_path_get_closest_point (GskPath                *self,
   return found;
 }
 
+/**
+ * gsk_path_get_start_point:
+ * @self: a `GskPath`
+ * @result: (out caller-allocates): return location for point
+ *
+ * Gets the start point of the path.
+ *
+ * An empty path has no points, so `FALSE`
+ * is returned in this case.
+ *
+ * Returns: `TRUE` if @result was filled
+ *
+ * Since: 4.14
+ */
+gboolean
+gsk_path_get_start_point (GskPath      *self,
+                          GskPathPoint *result)
+{
+  GskRealPathPoint *res = (GskRealPathPoint *) result;
+
+  g_return_val_if_fail (self != NULL, FALSE);
+  g_return_val_if_fail (result != NULL, FALSE);
+
+  if (self->n_contours == 0)
+    return FALSE;
+
+  gsk_contour_get_start_point (self->contours[0], res);
+
+  res->path = self;
+  res->contour = 0;
+
+  return TRUE;
+}
+
+/**
+ * gsk_path_get_end_point:
+ * @self: a `GskPath`
+ * @result: (out caller-allocates): return location for point
+ *
+ * Gets the end point of the path.
+ *
+ * An empty path has no points, so `FALSE`
+ * is returned in this case.
+ *
+ * Returns: `TRUE` if @result was filled
+ *
+ * Since: 4.14
+ */
+gboolean
+gsk_path_get_end_point (GskPath      *self,
+                        GskPathPoint *result)
+{
+  GskRealPathPoint *res = (GskRealPathPoint *) result;
+
+  g_return_val_if_fail (self != NULL, FALSE);
+  g_return_val_if_fail (result!= NULL, FALSE);
+
+  if (self->n_contours == 0)
+    return FALSE;
+
+  gsk_contour_get_end_point (self->contours[self->n_contours - 1], res);
+
+  res->path = self;
+  res->contour = self->n_contours - 1;
+
+  return TRUE;
+}
+
 /**
  * gsk_path_foreach:
  * @self: a `GskPath`

gsk/gskpath.h

@@ -116,6 +116,13 @@ gboolean                gsk_path_get_closest_point              (GskPath
                                                                  float                   threshold,
                                                                  GskPathPoint           *result);
 
+GDK_AVAILABLE_IN_4_14
+gboolean                gsk_path_get_start_point                (GskPath                *self,
+                                                                 GskPathPoint           *result);
+GDK_AVAILABLE_IN_4_14
+gboolean                gsk_path_get_end_point                  (GskPath                *self,
+                                                                 GskPathPoint           *result);
+
 GDK_AVAILABLE_IN_4_14
 gboolean                gsk_path_foreach                        (GskPath                *self,
                                                                  GskPathForeachFlags     flags,