[gtk/matthiasc/lottie2] Add a visual test for closest points

[Matthias Clasen <matthiasc src gnome org>]

commit f35172ae45aebf63b6b7a9195692cfb99437cfac
Author: Matthias Clasen <mclasen redhat com>
Date:   Wed Nov 25 19:26:22 2020 -0500

    Add a visual test for closest points
    
    This is fun and a good debugging aid.

 tests/curve2.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)
---
diff --git a/tests/curve2.c b/tests/curve2.c
index 0f594d597f..b5da0fc433 100644
--- a/tests/curve2.c
+++ b/tests/curve2.c
@@ -7,6 +7,8 @@ struct _DemoWidget
 {
   GtkWidget parent_instance;
   GskPath *path;
+  GskPathMeasure *measure;
+  double x, y;
 };
 
 struct _DemoWidgetClass
@@ -16,9 +18,25 @@ struct _DemoWidgetClass
 
 G_DEFINE_TYPE (DemoWidget, demo_widget, GTK_TYPE_WIDGET)
 
+static void
+motion (GtkEventControllerMotion *controller,
+        double                    x,
+        double                    y,
+        DemoWidget               *self)
+{
+  self->x = x;
+  self->y = y;
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
 static void
 demo_widget_init (DemoWidget *self)
 {
+  GtkEventController *controller;
+
+  controller = gtk_event_controller_motion_new ();
+  g_signal_connect (controller, "motion", G_CALLBACK (motion), self);
+  gtk_widget_add_controller (GTK_WIDGET (self), controller);
 }
 
 static void
@@ -28,6 +46,9 @@ demo_widget_snapshot (GtkWidget   *widget,
   DemoWidget *self = DEMO_WIDGET (widget);
   int width, height;
   GskStroke *stroke;
+  graphene_point_t point;
+  GskPathBuilder *builder;
+  GskPath *path;
 
   if (!self->path)
     return;
@@ -44,6 +65,32 @@ demo_widget_snapshot (GtkWidget   *widget,
                              &GRAPHENE_RECT_INIT (0, 0, width, height ));
 
   gtk_snapshot_pop (snapshot);
+
+  gsk_path_measure_get_closest_point (self->measure,
+                                      &GRAPHENE_POINT_INIT (self->x, self->y),
+                                      &point);
+
+  builder = gsk_path_builder_new ();
+  gsk_path_builder_add_circle (builder, &point, 10);
+  path = gsk_path_builder_free_to_path (builder);
+
+  gtk_snapshot_push_fill (snapshot, path, 0);
+  gtk_snapshot_append_color (snapshot,
+                             &(GdkRGBA){ 1, 0, 0, 1},
+                             &GRAPHENE_RECT_INIT (0, 0, width, height ));
+  gtk_snapshot_pop (snapshot);
+
+  stroke = gsk_stroke_new (1.0);
+  gtk_snapshot_push_stroke (snapshot, path, stroke);
+  gsk_stroke_free (stroke);
+
+  gtk_snapshot_append_color (snapshot,
+                             &(GdkRGBA){ 0, 0, 0, 1},
+                             &GRAPHENE_RECT_INIT (0, 0, width, height ));
+
+  gtk_snapshot_pop (snapshot);
+
+  gsk_path_unref (path);
 }
 
 static void
@@ -79,6 +126,10 @@ demo_widget_set_path (DemoWidget *self,
 {
   g_clear_pointer (&self->path, gsk_path_unref);
   self->path = gsk_path_ref (path);
+
+  g_clear_pointer (&self->measure, gsk_path_measure_unref);
+  self->measure = gsk_path_measure_new (self->path);
+
   gtk_widget_queue_draw (GTK_WIDGET (self));
 }