[gtk/curve-ops] Add gsk_curve_reverse

[Matthias Clasen <matthiasc src gnome org>]

commit ac64f0d63f27db350b71c26ec2b2cbf2c98bbcce
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Dec 13 00:42:53 2020 -0500

    Add gsk_curve_reverse
    
    This will be used in stroking.

 gsk/gskcurve.c        | 57 ++++++++++++++++++++++++++++++++++++++++++++++++---
 gsk/gskcurveprivate.h |  2 ++
 2 files changed, 56 insertions(+), 3 deletions(-)
---
diff --git a/gsk/gskcurve.c b/gsk/gskcurve.c
index fe966aee78..8785ec3806 100644
--- a/gsk/gskcurve.c
+++ b/gsk/gskcurve.c
@@ -70,6 +70,8 @@ struct _GskCurveClass
   void                          (* offset)              (const GskCurve         *curve,
                                                          float                   distance,
                                                          GskCurve               *offset_curve);
+  void                          (* reverse)             (const GskCurve         *curve,
+                                                         GskCurve               *reverse);
 };
 
 static void
@@ -313,6 +315,17 @@ gsk_line_curve_offset (const GskCurve *curve,
   gsk_curve_init (offset_curve, gsk_pathop_encode (GSK_PATH_LINE, p));
 }
 
+static void
+gsk_line_curve_reverse (const GskCurve *curve,
+                        GskCurve       *reverse)
+{
+  const GskLineCurve *self = &curve->line;
+
+  reverse->op = GSK_PATH_LINE;
+  reverse->line.points[0] = self->points[1];
+  reverse->line.points[1] = self->points[0];
+}
+
 static const GskCurveClass GSK_LINE_CURVE_CLASS = {
   gsk_line_curve_init,
   gsk_line_curve_init_foreach,
@@ -329,7 +342,8 @@ static const GskCurveClass GSK_LINE_CURVE_CLASS = {
   gsk_line_curve_get_start_end_tangent,
   gsk_line_curve_get_bounds,
   gsk_line_curve_get_bounds,
-  gsk_line_curve_offset
+  gsk_line_curve_offset,
+  gsk_line_curve_reverse
 };
 
 /** CURVE **/
@@ -676,6 +690,20 @@ gsk_curve_curve_offset (const GskCurve *curve,
   gsk_curve_init (offset_curve, gsk_pathop_encode (GSK_PATH_CURVE, p));
 }
 
+static void
+gsk_curve_curve_reverse (const GskCurve *curve,
+                         GskCurve       *reverse)
+{
+  const GskCurveCurve *self = &curve->curve;
+
+  reverse->op = GSK_PATH_CURVE;
+  reverse->curve.points[0] = self->points[3];
+  reverse->curve.points[1] = self->points[2];
+  reverse->curve.points[2] = self->points[1];
+  reverse->curve.points[3] = self->points[0];
+  reverse->curve.has_coefficients = FALSE;
+}
+
 static const GskCurveClass GSK_CURVE_CURVE_CLASS = {
   gsk_curve_curve_init,
   gsk_curve_curve_init_foreach,
@@ -692,7 +720,8 @@ static const GskCurveClass GSK_CURVE_CURVE_CLASS = {
   gsk_curve_curve_get_end_tangent,
   gsk_curve_curve_get_bounds,
   gsk_curve_curve_get_tight_bounds,
-  gsk_curve_curve_offset
+  gsk_curve_curve_offset,
+  gsk_curve_curve_reverse
 };
 
 /** CONIC **/
@@ -1285,6 +1314,20 @@ gsk_conic_curve_offset (const GskCurve *curve,
   gsk_curve_init (offset_curve, gsk_pathop_encode (GSK_PATH_CONIC, p));
 }
 
+static void
+gsk_conic_curve_reverse (const GskCurve *curve,
+                         GskCurve       *reverse)
+{
+  const GskConicCurve *self = &curve->conic;
+
+  reverse->op = GSK_PATH_CONIC;
+  reverse->conic.points[0] = self->points[3];
+  reverse->conic.points[1] = self->points[1];
+  reverse->conic.points[2] = self->points[2];
+  reverse->conic.points[3] = self->points[0];
+  reverse->conic.has_coefficients = FALSE;
+}
+
 static const GskCurveClass GSK_CONIC_CURVE_CLASS = {
   gsk_conic_curve_init,
   gsk_conic_curve_init_foreach,
@@ -1301,7 +1344,8 @@ static const GskCurveClass GSK_CONIC_CURVE_CLASS = {
   gsk_conic_curve_get_end_tangent,
   gsk_conic_curve_get_bounds,
   gsk_conic_curve_get_tight_bounds,
-  gsk_conic_curve_offset
+  gsk_conic_curve_offset,
+  gsk_conic_curve_reverse
 };
 
 /** API **/
@@ -1450,6 +1494,13 @@ gsk_curve_offset (const GskCurve *curve,
   get_class (curve->op)->offset (curve, distance, offset_curve);
 }
 
+void
+gsk_curve_reverse (const GskCurve *curve,
+                   GskCurve       *reverse)
+{
+  get_class (curve->op)->reverse (curve, reverse);
+}
+
 /** Intersections **/
 
 static int
diff --git a/gsk/gskcurveprivate.h b/gsk/gskcurveprivate.h
index e4705f915b..0f721e2016 100644
--- a/gsk/gskcurveprivate.h
+++ b/gsk/gskcurveprivate.h
@@ -135,6 +135,8 @@ int                     gsk_curve_intersect                     (const GskCurve
 void                    gsk_curve_offset                        (const GskCurve         *curve,
                                                                  float                   distance,
                                                                  GskCurve               *offset_curve);
+void                    gsk_curve_reverse                       (const GskCurve         *curve,
+                                                                 GskCurve               *reverse);
 
 G_END_DECLS