gskpathop: Introduce a type to represent an aligned graphene_point_t

When we allocate a graphene_point_t on the stack, there's no guarantee
that it will be aligned at an 8-byte boundary, which is an assumption
made by gsk_pathop_encode() (which wants to use the lowest 3 bits to
encode the operation). In the places where it matters, force the
points on the stack and embedded in structs to be nicely aligned.

By using a distinct type for this (a union with a suitable size and
alignment), we ensure that the compiler will warn or error whenever we
can't prove that a particular point is, in fact, suitably aligned.
We can go from a `GskAlignedPoint *` to a `graphene_point_t *`
(which is always valid, because the `GskAlignedPoint` is aligned)
via &aligned_points[0].pt, but we cannot go back the other way
(which is not always valid, because the `graphene_point_t` is not
necessarily aligned nicely) without a cast.

In practice, it seems that a graphene_point_t on x86_64 *is* usually
placed at an 8-byte boundary, but this is not the case on 32-bit
architectures or on s390x.

In many cases we can avoid needing an explicit reference to the more
complicated type by making use of a transparent union. There's already
at least one transparent union in GSK's public API, so it's presumably
portable enough to match GTK's requirements.

Increasing the alignment of GskAlignedPoint also requires adjusting how
a GskStandardContour is allocated and initialized. This data structure
allocates extra memory to hold an array of GskAlignedPoint outside the
bounds of the struct itself, and that array now needs to be aligned
suitably. Previously the array started with at next byte after the
flexible array of gskpathop, but the alignment of a gskpathop is only
4 bytes on 32-bit architectures, so depending on the number of gskpathop
in the trailing flexible array, that pointer might be an unsuitable
location to allocate a GskAlignedPoint.

Resolves: https://gitlab.gnome.org/GNOME/gtk/-/issues/6395
Signed-off-by: Simon McVittie <smcv@debian.org>

gsk/gskcontour.c

@@ -532,7 +532,7 @@ struct _GskStandardContour
 
   gsize n_ops;
   gsize n_points;
-  graphene_point_t *points;
+  GskAlignedPoint *points;
   gskpathop ops[];
 };
 
@@ -540,19 +540,27 @@ static gsize
 gsk_standard_contour_compute_size (gsize n_ops,
                                    gsize n_points)
 {
-  gsize align = MAX (G_ALIGNOF (graphene_point_t),
+  const gsize point_align = G_ALIGNOF (GskAlignedPoint);
-                     MAX (G_ALIGNOF (gpointer),
+  const gsize align = MAX (G_ALIGNOF (GskAlignedPoint),
-                          G_ALIGNOF (GskStandardContour)));
+                           MAX (G_ALIGNOF (gpointer),
-  gsize s = sizeof (GskStandardContour)
+                                G_ALIGNOF (GskStandardContour)));
-          + sizeof (gskpathop) * n_ops
+  gsize s = sizeof (GskStandardContour);
-          + sizeof (graphene_point_t) * n_points;
+
+  s += sizeof (gskpathop) * n_ops;
+
+  /* The array of points needs to be 8-byte aligned, but on 32-bit,
+   * a single entry in ops might only be 4 bytes, so we might need
+   * 4 bytes of padding before starting the array of points */
+  s += (point_align - (s % point_align));
+  s += sizeof (GskAlignedPoint) * n_points;
+
   return s + (align - (s % align));
 }
 
 static void
 gsk_standard_contour_init (GskContour             *contour,
                            GskPathFlags            flags,
-                           const graphene_point_t *points,
+                           const GskAlignedPoint  *points,
                            gsize                   n_points,
                            const gskpathop        *ops,
                            gsize                   n_ops,
@@ -625,8 +633,8 @@ gsk_standard_contour_reverse (const GskContour *contour)
 
   builder = gsk_path_builder_new ();
 
-  gsk_path_builder_move_to (builder, self->points[self->n_points - 1].x,
+  gsk_path_builder_move_to (builder, self->points[self->n_points - 1].pt.x,
-                                     self->points[self->n_points - 1].y);
+                                     self->points[self->n_points - 1].pt.y);
 
   for (int i = self->n_ops - 1; i >= 0; i--)
     gsk_pathop_foreach (self->ops[i], add_reverse, builder);
@@ -714,8 +722,8 @@ gsk_standard_contour_get_winding (const GskContour       *contour,
       GskCurve c;
 
       gsk_curve_init (&c, gsk_pathop_encode (GSK_PATH_CLOSE,
-                                             (const graphene_point_t[]) { self->points[self->n_points - 1],
+                                             (const GskAlignedPoint[]) { self->points[self->n_points - 1],
-                                                                          self->points[0] }));
+                                                                         self->points[0] }));
 
       winding += gsk_curve_get_crossing (&c, point);
     }
@@ -748,7 +756,7 @@ gsk_standard_contour_get_closest_point (const GskContour       *contour,
     {
       float dist;
 
-      dist = graphene_point_distance (point, &self->points[0], NULL, NULL);
+      dist = graphene_point_distance (point, &self->points[0].pt, NULL, NULL);
       if (dist <= threshold)
         {
           *out_dist = dist;
@@ -799,7 +807,7 @@ gsk_standard_contour_get_position (const GskContour   *contour,
 
   if (G_UNLIKELY (point->idx == 0))
     {
-      *position = self->points[0];
+      *position = self->points[0].pt;
       return;
     }
 
@@ -1288,36 +1296,43 @@ static const GskContourClass GSK_STANDARD_CONTOUR_CLASS =
 static void
 gsk_standard_contour_init (GskContour             *contour,
                            GskPathFlags            flags,
-                           const graphene_point_t *points,
+                           const GskAlignedPoint  *points,
                            gsize                   n_points,
                            const gskpathop        *ops,
                            gsize                   n_ops,
                            gssize                  offset)
 
 {
+  const gsize align = G_ALIGNOF (GskAlignedPoint);
   GskStandardContour *self = (GskStandardContour *) contour;
+  guint8 *points_addr;
 
   self->contour.klass = &GSK_STANDARD_CONTOUR_CLASS;
 
   self->flags = flags;
   self->n_ops = n_ops;
   self->n_points = n_points;
-  self->points = (graphene_point_t *) &self->ops[n_ops];
+  points_addr = (guint8 *) &self->ops[n_ops];
+  /* The array of points needs to be 8-byte aligned, but on 32-bit,
+   * a single entry in ops might only be 4 bytes, so we might need
+   * 4 bytes of padding before starting the array of points. */
+  points_addr += align - (((gsize) points_addr) % align);
+  self->points = (GskAlignedPoint *) points_addr;
   memcpy (self->points, points, sizeof (graphene_point_t) * n_points);
 
   offset += self->points - points;
   for (gsize i = 0; i < n_ops; i++)
     self->ops[i] = gsk_pathop_encode (gsk_pathop_op (ops[i]),
-                                      gsk_pathop_points (ops[i]) + offset);
+                                      gsk_pathop_aligned_points (ops[i]) + offset);
 
-  gsk_bounding_box_init (&self->bounds,  &self->points[0], &self->points[0]);
+  gsk_bounding_box_init (&self->bounds,  &self->points[0].pt, &self->points[0].pt);
   for (gsize i = 1; i < self->n_points; i ++)
-    gsk_bounding_box_expand (&self->bounds, &self->points[i]);
+    gsk_bounding_box_expand (&self->bounds, &self->points[i].pt);
 }
 
 GskContour *
 gsk_standard_contour_new (GskPathFlags            flags,
-                          const graphene_point_t *points,
+                          const GskAlignedPoint  *points,
                           gsize                   n_points,
                           const gskpathop        *ops,
                           gsize                   n_ops,

gsk/gskcontourprivate.h

@@ -28,7 +28,7 @@
 G_BEGIN_DECLS
 
 GskContour *            gsk_standard_contour_new                (GskPathFlags            flags,
-                                                                 const graphene_point_t *points,
+                                                                 const GskAlignedPoint  *points,
                                                                  gsize                   n_points,
                                                                  const gskpathop        *ops,
                                                                  gsize                   n_ops,

gsk/gskcurve.c

@@ -157,30 +157,30 @@ gsk_curve_elevate (const GskCurve *curve,
 {
   if (curve->op == GSK_PATH_LINE)
     {
-      graphene_point_t p[3];
+      GskAlignedPoint p[3];
 
-      p[0] = curve->line.points[0];
+      p[0].pt = curve->line.points[0];
       graphene_point_interpolate (&curve->line.points[0],
                                   &curve->line.points[1],
                                   0.5,
-                                  &p[1]);
+                                  &p[1].pt);
-      p[2] = curve->line.points[1];
+      p[2].pt = curve->line.points[1];
       gsk_curve_init (elevated, gsk_pathop_encode (GSK_PATH_QUAD, p));
     }
   else if (curve->op == GSK_PATH_QUAD)
     {
-      graphene_point_t p[4];
+      GskAlignedPoint p[4];
 
-      p[0] = curve->quad.points[0];
+      p[0].pt = curve->quad.points[0];
       graphene_point_interpolate (&curve->quad.points[0],
                                   &curve->quad.points[1],
                                   2/3.,
-                                  &p[1]);
+                                  &p[1].pt);
       graphene_point_interpolate (&curve->quad.points[2],
                                   &curve->quad.points[1],
                                   2/3.,
-                                  &p[2]);
+                                  &p[2].pt);
-      p[3] = curve->quad.points[2];
+      p[3].pt = curve->quad.points[2];
       gsk_curve_init (elevated, gsk_pathop_encode (GSK_PATH_CUBIC, p));
     }
   else
@@ -300,7 +300,7 @@ gsk_line_curve_pathop (const GskCurve *curve)
 {
   const GskLineCurve *self = &curve->line;
 
-  return gsk_pathop_encode (self->op, self->points);
+  return gsk_pathop_encode (self->op, self->aligned_points);
 }
 
 static const graphene_point_t *
@@ -576,7 +576,7 @@ gsk_quad_curve_pathop (const GskCurve *curve)
 {
   const GskQuadCurve *self = &curve->quad;
 
-  return gsk_pathop_encode (self->op, self->points);
+  return gsk_pathop_encode (self->op, self->aligned_points);
 }
 
 static const graphene_point_t *
@@ -1003,7 +1003,7 @@ gsk_cubic_curve_pathop (const GskCurve *curve)
 {
   const GskCubicCurve *self = &curve->cubic;
 
-  return gsk_pathop_encode (self->op, self->points);
+  return gsk_pathop_encode (self->op, self->aligned_points);
 }
 
 static const graphene_point_t *
@@ -1499,7 +1499,7 @@ gsk_conic_curve_pathop (const GskCurve *curve)
 {
   const GskConicCurve *self = &curve->conic;
 
-  return gsk_pathop_encode (self->op, self->points);
+  return gsk_pathop_encode (self->op, self->aligned_points);
 }
 
 static const graphene_point_t *
@@ -1726,7 +1726,7 @@ gsk_conic_curve_split (const GskCurve   *curve,
   const GskConicCurve *self = &curve->conic;
   graphene_point3d_t p[3];
   graphene_point3d_t l[3], r[3];
-  graphene_point_t left[4], right[4];
+  GskAlignedPoint left[4], right[4];
   float w;
 
   /* do de Casteljau in homogeneous coordinates... */
@@ -1738,13 +1738,13 @@ gsk_conic_curve_split (const GskCurve   *curve,
   split_bezier3d (p, 3, progress, l, r);
 
   /* then project the control points down */
-  left[0] = GRAPHENE_POINT_INIT (l[0].x / l[0].z, l[0].y / l[0].z);
+  left[0].pt = GRAPHENE_POINT_INIT (l[0].x / l[0].z, l[0].y / l[0].z);
-  left[1] = GRAPHENE_POINT_INIT (l[1].x / l[1].z, l[1].y / l[1].z);
+  left[1].pt = GRAPHENE_POINT_INIT (l[1].x / l[1].z, l[1].y / l[1].z);
-  left[3] = GRAPHENE_POINT_INIT (l[2].x / l[2].z, l[2].y / l[2].z);
+  left[3].pt = GRAPHENE_POINT_INIT (l[2].x / l[2].z, l[2].y / l[2].z);
 
-  right[0] = GRAPHENE_POINT_INIT (r[0].x / r[0].z, r[0].y / r[0].z);
+  right[0].pt = GRAPHENE_POINT_INIT (r[0].x / r[0].z, r[0].y / r[0].z);
-  right[1] = GRAPHENE_POINT_INIT (r[1].x / r[1].z, r[1].y / r[1].z);
+  right[1].pt = GRAPHENE_POINT_INIT (r[1].x / r[1].z, r[1].y / r[1].z);
-  right[3] = GRAPHENE_POINT_INIT (r[2].x / r[2].z, r[2].y / r[2].z);
+  right[3].pt = GRAPHENE_POINT_INIT (r[2].x / r[2].z, r[2].y / r[2].z);
 
   /* normalize the outer weights to be 1 by using
    * the fact that weights w_i and c*w_i are equivalent
@@ -1760,8 +1760,8 @@ gsk_conic_curve_split (const GskCurve   *curve,
    * the fact that w_0*w_2/w_1^2 is a constant for
    * all equivalent weights.
    */
-  left[2] = GRAPHENE_POINT_INIT (l[1].z / sqrt (l[2].z), 0);
+  left[2].pt = GRAPHENE_POINT_INIT (l[1].z / sqrt (l[2].z), 0);
-  right[2] = GRAPHENE_POINT_INIT (r[1].z / sqrt (r[0].z), 0);
+  right[2].pt = GRAPHENE_POINT_INIT (r[1].z / sqrt (r[0].z), 0);
 
   if (start)
     gsk_curve_init (start, gsk_pathop_encode (GSK_PATH_CONIC, left));
@@ -1899,17 +1899,17 @@ cubic_approximation (const GskCurve *curve,
                      GskCurve       *cubic)
 {
   const GskConicCurve *self = &curve->conic;
-  graphene_point_t p[4];
+  GskAlignedPoint p[4];
   float w = self->points[2].x;
   float w2 = w*w;
   float lambda;
 
   lambda = 2 * (6*w2 + 1 - sqrt (3*w2 + 1)) / (12*w2 + 3);
 
-  p[0] = self->points[0];
+  p[0].pt = self->points[0];
-  p[3] = self->points[3];
+  p[3].pt = self->points[3];
-  graphene_point_interpolate (&self->points[0], &self->points[1], lambda, &p[1]);
+  graphene_point_interpolate (&self->points[0], &self->points[1], lambda, &p[1].pt);
-  graphene_point_interpolate (&self->points[3], &self->points[1], lambda, &p[2]);
+  graphene_point_interpolate (&self->points[3], &self->points[1], lambda, &p[2].pt);
 
   gsk_curve_init (cubic, gsk_pathop_encode (GSK_PATH_CUBIC, p));
 }

gsk/gskcurveprivate.h

@@ -41,7 +41,10 @@ struct _GskLineCurve
 
   gboolean padding;
 
-  graphene_point_t points[2];
+  union {
+    graphene_point_t points[2];
+    GskAlignedPoint aligned_points[2];
+  };
 };
 
 struct _GskQuadCurve
@@ -50,7 +53,10 @@ struct _GskQuadCurve
 
   gboolean has_coefficients;
 
-  graphene_point_t points[3];
+  union {
+    graphene_point_t points[3];
+    GskAlignedPoint aligned_points[3];
+  };
 
   graphene_point_t coeffs[3];
 };
@@ -61,7 +67,10 @@ struct _GskCubicCurve
 
   gboolean has_coefficients;
 
-  graphene_point_t points[4];
+  union {
+    graphene_point_t points[4];
+    GskAlignedPoint aligned_points[4];
+  };
 
   graphene_point_t coeffs[4];
 };
@@ -75,7 +84,10 @@ struct _GskConicCurve
   /* points[0], points[1], points[3] are the control points,
    * points[2].x is the weight
    */
-  graphene_point_t points[4];
+  union {
+    graphene_point_t points[4];
+    GskAlignedPoint aligned_points[4];
+  };
 
   graphene_point_t num[3];
   graphene_point_t denom[3];

gsk/gskpath.c

@@ -701,6 +701,13 @@ gsk_path_foreach_trampoline (GskPathOperation        op,
                              gpointer                data)
 {
   GskPathForeachTrampoline *trampoline = data;
+  GskAlignedPoint *aligned = g_alloca (sizeof (graphene_point_t) * n_pts);
+
+  /* We can't necessarily guarantee that pts is 8-byte aligned
+   * (probably it is, but we've been through too many layers of
+   * indirection to be sure) so copy it into a buffer that is
+   * definitely suitably-aligned. */
+  memcpy (aligned, pts, sizeof (graphene_point_t) * n_pts);
 
   switch (op)
     {
@@ -731,7 +738,7 @@ gsk_path_foreach_trampoline (GskPathOperation        op,
                                      trampoline->user_data);
           }
 
-        gsk_curve_init (&curve, gsk_pathop_encode (GSK_PATH_QUAD, pts));
+        gsk_curve_init (&curve, gsk_pathop_encode (GSK_PATH_QUAD, aligned));
         return gsk_curve_decompose (&curve,
                                     trampoline->tolerance,
                                     gsk_path_foreach_trampoline_add_line,
@@ -745,7 +752,7 @@ gsk_path_foreach_trampoline (GskPathOperation        op,
         if (trampoline->flags & GSK_PATH_FOREACH_ALLOW_CUBIC)
           return trampoline->func (op, pts, n_pts, weight, trampoline->user_data);
 
-        gsk_curve_init (&curve, gsk_pathop_encode (GSK_PATH_CUBIC, pts));
+        gsk_curve_init (&curve, gsk_pathop_encode (GSK_PATH_CUBIC, aligned));
         if (trampoline->flags & (GSK_PATH_FOREACH_ALLOW_QUAD|GSK_PATH_FOREACH_ALLOW_CONIC))
           return gsk_curve_decompose_curve (&curve,
                                             trampoline->flags,
@@ -766,7 +773,7 @@ gsk_path_foreach_trampoline (GskPathOperation        op,
         if (trampoline->flags & GSK_PATH_FOREACH_ALLOW_CONIC)
           return trampoline->func (op, pts, n_pts, weight, trampoline->user_data);
 
-        gsk_curve_init (&curve, gsk_pathop_encode (GSK_PATH_CONIC, (graphene_point_t[4]) { pts[0], pts[1], { weight, 0.f }, pts[2] } ));
+        gsk_curve_init (&curve, gsk_pathop_encode (GSK_PATH_CONIC, (GskAlignedPoint[4]) { { pts[0] }, { pts[1] }, { { weight, 0.f } }, { pts[2] } } ));
         if (trampoline->flags & (GSK_PATH_FOREACH_ALLOW_QUAD|GSK_PATH_FOREACH_ALLOW_CUBIC))
           return gsk_curve_decompose_curve (&curve,
                                             trampoline->flags,

gsk/gskpathbuilder.c

@@ -156,7 +156,7 @@ static inline gskpathop
 gsk_pathop_encode_index (GskPathOperation op,
                          gsize            index)
 {
-  return gsk_pathop_encode (op, ((graphene_point_t *) NULL) + index);
+  return gsk_pathop_encode (op, ((GskAlignedPoint *) NULL) + index);
 }
 
 static void
@@ -193,7 +193,7 @@ gsk_path_builder_end_current (GskPathBuilder *self)
    return;
 
   contour = gsk_standard_contour_new (self->flags,
-                                      (graphene_point_t *) self->points->data,
+                                      (GskAlignedPoint *) self->points->data,
                                       self->points->len,
                                       (gskpathop *) self->ops->data,
                                       self->ops->len,

gsk/gskpathopprivate.h

@@ -25,11 +25,52 @@
 
 G_BEGIN_DECLS
 
+/* We assume that arrays of graphene_point_t are aligned on an 8-byte
+ * boundary, which means we can use the lowest 3 bits to represent up
+ * to 8 distinct path operations. */
+#define GSK_PATHOP_OPERATION_MASK (0x7)
+
+/* graphene_point_t is a struct containing two floats, so an array of
+ * graphene_point_t on the stack is not necessarily 8-byte aligned
+ * unless we force it to be.
+ *
+ * Using a union for this means the compiler will warn or error if we
+ * have not handled these correctly: for example we can go from a
+ * GskAlignedPoint * to a graphene_point_t * (which is always OK) with:
+ *
+ * GskAlignedPoint *gap = ...;
+ * graphene_point_t *gpt;
+ * gpt = &gap[0].pt;
+ *
+ * but going back the other way is not possible without a cast or a
+ * compiler warning. */
+typedef union
+{
+  graphene_point_t pt;
+
+  /* On many platforms this will be enough to force the correct alignment. */
+  guint64 alignment;
+
+  /* Unfortunately not all platforms require guint64 to be naturally-aligned
+   * (for example on i386, only 4-byte alignment is required) so we have to
+   * try harder. */
+#ifdef __GNUC__
+  __attribute__((aligned(8))) guint64 really_aligned;
+#elif defined(_MSC_VER)
+  __declspec(align(8)) guint64 really_aligned;
+#endif
+} GskAlignedPoint;
+
+G_STATIC_ASSERT (sizeof (GskAlignedPoint) == sizeof (graphene_point_t));
+G_STATIC_ASSERT (G_ALIGNOF (GskAlignedPoint) >= GSK_PATHOP_OPERATION_MASK + 1);
+
 typedef gpointer gskpathop;
 
 static inline
 gskpathop               gsk_pathop_encode                       (GskPathOperation        op,
-                                                                 const graphene_point_t *pts);
+                                                                 const GskAlignedPoint  *pts);
+static inline
+const GskAlignedPoint  *gsk_pathop_aligned_points               (gskpathop               pop);
 static inline
 const graphene_point_t *gsk_pathop_points                       (gskpathop               pop);
 static inline
@@ -57,11 +98,9 @@ void                    gsk_path_builder_pathop_reverse_to      (GskPathBuilder
  * operations overlapping, so we can't put the weight at the end.
  */
 
-#define GSK_PATHOP_OPERATION_MASK (0x7)
-
 static inline gskpathop
 gsk_pathop_encode (GskPathOperation        op,
-                   const graphene_point_t *pts)
+                   const GskAlignedPoint  *pts)
 {
   /* g_assert (op & GSK_PATHOP_OPERATION_MASK == op); */
   g_assert ((GPOINTER_TO_SIZE (pts) & GSK_PATHOP_OPERATION_MASK) == 0);
@@ -69,10 +108,16 @@ gsk_pathop_encode (GskPathOperation        op,
   return GSIZE_TO_POINTER (GPOINTER_TO_SIZE (pts) | op);
 }
 
+static inline const GskAlignedPoint *
+gsk_pathop_aligned_points (gskpathop pop)
+{
+  return GSIZE_TO_POINTER (GPOINTER_TO_SIZE (pop) & ~GSK_PATHOP_OPERATION_MASK);
+}
+
 static inline const graphene_point_t *
 gsk_pathop_points (gskpathop pop)
 {
-  return GSIZE_TO_POINTER (GPOINTER_TO_SIZE (pop) & ~GSK_PATHOP_OPERATION_MASK);
+  return &(gsk_pathop_aligned_points (pop)->pt);
 }
 
 static inline

testsuite/gsk/curve-special-cases.c

@@ -25,11 +25,11 @@ static void
 test_curve_tangents (void)
 {
   GskCurve c;
-  graphene_point_t p[4];
+  GskAlignedPoint p[4];
   graphene_vec2_t t;
 
-  graphene_point_init (&p[0], 0, 0);
+  graphene_point_init (&p[0].pt, 0, 0);
-  graphene_point_init (&p[1], 100, 0);
+  graphene_point_init (&p[1].pt, 100, 0);
   gsk_curve_init (&c, gsk_pathop_encode (GSK_PATH_LINE, p));
 
   gsk_curve_get_start_tangent (&c, &t);
@@ -37,8 +37,8 @@ test_curve_tangents (void)
   gsk_curve_get_end_tangent (&c, &t);
   g_assert_true (graphene_vec2_near (&t, graphene_vec2_x_axis (), 0.0001));
 
-  graphene_point_init (&p[0], 0, 0);
+  graphene_point_init (&p[0].pt, 0, 0);
-  graphene_point_init (&p[1], 0, 100);
+  graphene_point_init (&p[1].pt, 0, 100);
   gsk_curve_init (&c, gsk_pathop_encode (GSK_PATH_LINE, p));
 
   gsk_curve_get_start_tangent (&c, &t);
@@ -46,10 +46,10 @@ test_curve_tangents (void)
   gsk_curve_get_end_tangent (&c, &t);
   g_assert_true (graphene_vec2_near (&t, graphene_vec2_y_axis (), 0.0001));
 
-  graphene_point_init (&p[0], 0, 0);
+  graphene_point_init (&p[0].pt, 0, 0);
-  graphene_point_init (&p[1], 50, 0);
+  graphene_point_init (&p[1].pt, 50, 0);
-  graphene_point_init (&p[2], 100, 50);
+  graphene_point_init (&p[2].pt, 100, 50);
-  graphene_point_init (&p[3], 100, 100);
+  graphene_point_init (&p[3].pt, 100, 100);
   gsk_curve_init (&c, gsk_pathop_encode (GSK_PATH_CUBIC, p));
 
   gsk_curve_get_start_tangent (&c, &t);
@@ -62,13 +62,13 @@ static void
 test_curve_degenerate_tangents (void)
 {
   GskCurve c;
-  graphene_point_t p[4];
+  GskAlignedPoint p[4];
   graphene_vec2_t t;
 
-  graphene_point_init (&p[0], 0, 0);
+  graphene_point_init (&p[0].pt, 0, 0);
-  graphene_point_init (&p[1], 0, 0);
+  graphene_point_init (&p[1].pt, 0, 0);
-  graphene_point_init (&p[2], 100, 0);
+  graphene_point_init (&p[2].pt, 100, 0);
-  graphene_point_init (&p[3], 100, 0);
+  graphene_point_init (&p[3].pt, 100, 0);
   gsk_curve_init (&c, gsk_pathop_encode (GSK_PATH_CUBIC, p));
 
   gsk_curve_get_start_tangent (&c, &t);
@@ -76,10 +76,10 @@ test_curve_degenerate_tangents (void)
   gsk_curve_get_end_tangent (&c, &t);
   g_assert_true (graphene_vec2_near (&t, graphene_vec2_x_axis (), 0.0001));
 
-  graphene_point_init (&p[0], 0, 0);
+  graphene_point_init (&p[0].pt, 0, 0);
-  graphene_point_init (&p[1], 50, 0);
+  graphene_point_init (&p[1].pt, 50, 0);
-  graphene_point_init (&p[2], 50, 0);
+  graphene_point_init (&p[2].pt, 50, 0);
-  graphene_point_init (&p[3], 100, 0);
+  graphene_point_init (&p[3].pt, 100, 0);
   gsk_curve_init (&c, gsk_pathop_encode (GSK_PATH_CUBIC, p));
 
   gsk_curve_get_start_tangent (&c, &t);

testsuite/gsk/curve.c

@@ -17,46 +17,46 @@ init_random_curve_with_op (GskCurve         *curve,
     {
     case GSK_PATH_LINE:
       {
-        graphene_point_t p[2];
+        GskAlignedPoint p[2];
 
-        init_random_point (&p[0]);
+        init_random_point (&p[0].pt);
-        init_random_point (&p[1]);
+        init_random_point (&p[1].pt);
         gsk_curve_init (curve, gsk_pathop_encode (GSK_PATH_LINE, p));
       }
       break;
 
     case GSK_PATH_QUAD:
       {
-        graphene_point_t p[3];
+        GskAlignedPoint p[3];
 
-        init_random_point (&p[0]);
+        init_random_point (&p[0].pt);
-        init_random_point (&p[1]);
+        init_random_point (&p[1].pt);
-        init_random_point (&p[2]);
+        init_random_point (&p[2].pt);
         gsk_curve_init (curve, gsk_pathop_encode (GSK_PATH_QUAD, p));
       }
     break;
 
     case GSK_PATH_CUBIC:
       {
-        graphene_point_t p[4];
+        GskAlignedPoint p[4];
 
-        init_random_point (&p[0]);
+        init_random_point (&p[0].pt);
-        init_random_point (&p[1]);
+        init_random_point (&p[1].pt);
-        init_random_point (&p[2]);
+        init_random_point (&p[2].pt);
-        init_random_point (&p[3]);
+        init_random_point (&p[3].pt);
         gsk_curve_init (curve, gsk_pathop_encode (GSK_PATH_CUBIC, p));
       }
     break;
 
     case GSK_PATH_CONIC:
       {
-        graphene_point_t p[4];
+        GskAlignedPoint p[4];
 
-        init_random_point (&p[0]);
+        init_random_point (&p[0].pt);
-        init_random_point (&p[1]);
+        init_random_point (&p[1].pt);
-        p[2].x = g_test_rand_double_range (0.2, 20);
+        p[2].pt.x = g_test_rand_double_range (0.2, 20);
-        p[2].y = 0.f;
+        p[2].pt.y = 0.f;
-        init_random_point (&p[3]);
+        init_random_point (&p[3].pt);
         gsk_curve_init (curve, gsk_pathop_encode (GSK_PATH_CONIC, p));
       }
     break;