[gtk/path-stroke: 98/103] Add gsk_path_stroke

[Matthias Clasen <matthiasc src gnome org>]

commit c9f81c7e36e29485217d155e2ca0876c4170b4f0
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Dec 5 13:37:53 2020 -0500

    Add gsk_path_stroke
    
    Add the plumbing that will let us do special-case stroking
    for rectangles, circles and other special contours. There
    is no implementation yet.

 gsk/gskcontour.c        | 41 ++++++++++++++++++++++++++++++++++++++---
 gsk/gskcontourprivate.h |  6 ++++++
 gsk/gskpath.c           | 25 +++++++++++++++++++++++++
 gsk/gskpath.h           |  5 +++++
 4 files changed, 74 insertions(+), 3 deletions(-)
---
diff --git a/gsk/gskcontour.c b/gsk/gskcontour.c
index 32bd98ec96..5d7bb699f4 100644
--- a/gsk/gskcontour.c
+++ b/gsk/gskcontour.c
@@ -86,6 +86,9 @@ struct _GskContourClass
   gboolean              (* get_stroke_bounds)   (const GskContour       *contour,
                                                  const GskStroke        *stroke,
                                                  graphene_rect_t        *bounds);
+  void                  (* add_stroke)          (const GskContour       *contour,
+                                                 GskPathBuilder         *builder,
+                                                 GskStroke              *stroke);
 };
 
 static gsize
@@ -487,6 +490,13 @@ gsk_rect_contour_get_stroke_bounds (const GskContour       *contour,
   return TRUE;
 }
 
+static void
+gsk_rect_contour_add_stroke (const GskContour *contour,
+                             GskPathBuilder   *builder,
+                             GskStroke        *stroke)
+{
+}
+
 static const GskContourClass GSK_RECT_CONTOUR_CLASS =
 {
   sizeof (GskRectContour),
@@ -504,7 +514,8 @@ static const GskContourClass GSK_RECT_CONTOUR_CLASS =
   gsk_rect_contour_copy,
   gsk_rect_contour_add_segment,
   gsk_rect_contour_get_winding,
-  gsk_rect_contour_get_stroke_bounds
+  gsk_rect_contour_get_stroke_bounds,
+  gsk_rect_contour_add_stroke
 };
 
 GskContour *
@@ -857,6 +868,13 @@ gsk_circle_contour_get_stroke_bounds (const GskContour       *contour,
   return TRUE;
 }
 
+static void
+gsk_circle_contour_add_stroke (const GskContour *contour,
+                               GskPathBuilder   *builder,
+                               GskStroke        *stroke)
+{
+}
+
 static const GskContourClass GSK_CIRCLE_CONTOUR_CLASS =
 {
   sizeof (GskCircleContour),
@@ -874,7 +892,8 @@ static const GskContourClass GSK_CIRCLE_CONTOUR_CLASS =
   gsk_circle_contour_copy,
   gsk_circle_contour_add_segment,
   gsk_circle_contour_get_winding,
-  gsk_circle_contour_get_stroke_bounds
+  gsk_circle_contour_get_stroke_bounds,
+  gsk_circle_contour_add_stroke
 };
 
 GskContour *
@@ -1561,6 +1580,13 @@ gsk_standard_contour_get_stroke_bounds (const GskContour *contour,
   return TRUE;
 }
 
+static void
+gsk_standard_contour_add_stroke (const GskContour *contour,
+                                 GskPathBuilder   *builder,
+                                 GskStroke        *stroke)
+{
+}
+
 static const GskContourClass GSK_STANDARD_CONTOUR_CLASS =
 {
   sizeof (GskStandardContour),
@@ -1578,7 +1604,8 @@ static const GskContourClass GSK_STANDARD_CONTOUR_CLASS =
   gsk_standard_contour_copy,
   gsk_standard_contour_add_segment,
   gsk_standard_contour_get_winding,
-  gsk_standard_contour_get_stroke_bounds
+  gsk_standard_contour_get_stroke_bounds,
+  gsk_standard_contour_add_stroke
 };
 
 /* You must ensure the contour has enough size allocated,
@@ -1750,6 +1777,14 @@ gsk_contour_get_stroke_bounds (const GskContour *self,
   return self->klass->get_stroke_bounds (self, stroke, bounds);
 }
 
+void
+gsk_contour_add_stroke (const GskContour *self,
+                        GskPathBuilder   *builder,
+                        GskStroke        *stroke)
+{
+  self->klass->add_stroke (self, builder, stroke);
+}
+
 void
 gsk_contour_copy (GskContour       *dest,
                   const GskContour *src)
diff --git a/gsk/gskcontourprivate.h b/gsk/gskcontourprivate.h
index 927205fdac..a8cea1eb95 100644
--- a/gsk/gskcontourprivate.h
+++ b/gsk/gskcontourprivate.h
@@ -96,6 +96,12 @@ void                    gsk_contour_add_segment                 (const GskContou
 gboolean                gsk_contour_get_stroke_bounds           (const GskContour       *self,
                                                                  const GskStroke        *stroke,
                                                                  graphene_rect_t        *bounds);
+void                    gsk_contour_add_stroke                  (const GskContour       *contour,
+                                                                 GskPathBuilder         *builder,
+                                                                 GskStroke              *stroke);
+void                    gsk_contour_default_add_stroke          (const GskContour       *contour,
+                                                                 GskPathBuilder         *builder,
+                                                                 GskStroke              *stroke);
 
 G_END_DECLS
 
diff --git a/gsk/gskpath.c b/gsk/gskpath.c
index d67fb763d9..ec4fe8e71f 100644
--- a/gsk/gskpath.c
+++ b/gsk/gskpath.c
@@ -1235,3 +1235,28 @@ gsk_path_get_stroke_bounds (GskPath         *self,
 
   return TRUE;
 }
+
+/**
+ * gsk_path_stroke:
+ * @self: a #GskPath
+ * @stroke: stroke parameters
+ *
+ * Create a new path that follows the outline of the area
+ * that would be affected by stroking along @self with
+ * the given stroke parameters.
+ *
+ * Returns: a new #GskPath
+ */
+GskPath *
+gsk_path_stroke (GskPath   *self,
+                 GskStroke *stroke)
+{
+  GskPathBuilder *builder;
+
+  builder = gsk_path_builder_new ();
+
+  for (int i = 0; i < self->n_contours; i++)
+    gsk_contour_add_stroke (gsk_path_get_contour (self, i), builder, stroke);
+
+  return gsk_path_builder_free_to_path (builder);
+}
diff --git a/gsk/gskpath.h b/gsk/gskpath.h
index 6df9250a33..d9ad6e4cb5 100644
--- a/gsk/gskpath.h
+++ b/gsk/gskpath.h
@@ -110,6 +110,11 @@ gboolean                gsk_path_foreach                        (GskPath
                                                                  GskPathForeachFunc    func,
                                                                  gpointer              user_data);
 
+GDK_AVAILABLE_IN_ALL
+GskPath *               gsk_path_stroke                         (GskPath              *path,
+                                                                 GskStroke            *stroke);
+
+
 G_END_DECLS
 
 #endif /* __GSK_PATH_H__ */