[gtk/wip/matthiasc/lottie-stroke: 20/24] Add an interactive test for stroking

[Matthias Clasen <matthiasc src gnome org>]

commit 65ca4bb336fc3031fa7215dbf146d1bc960afa95
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Nov 28 13:30:35 2020 -0500

    Add an interactive test for stroking
    
    Give the curve3 test a full complement of stroke
    parameters to play with.

 tests/curve3.c | 142 ++++++++++++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 131 insertions(+), 11 deletions(-)
---
diff --git a/tests/curve3.c b/tests/curve3.c
index 827927b7fa..b34590db22 100644
--- a/tests/curve3.c
+++ b/tests/curve3.c
@@ -7,9 +7,11 @@ struct _DemoWidget
 {
   GtkWidget parent_instance;
   GskPath *path;
-  GskPathMeasure *measure;
+  GskPathMeasure *stroke_measure;
+  GskPath *stroke_path;
   gboolean inside;
   GskFillRule fill_rule;
+  GskStroke *stroke;
 };
 
 struct _DemoWidgetClass
@@ -27,7 +29,7 @@ motion (GtkEventControllerMotion *controller,
 {
   gboolean inside = TRUE;
 
-  inside = gsk_path_measure_in_fill (self->measure, &GRAPHENE_POINT_INIT (x, y), self->fill_rule);
+  inside = gsk_path_measure_in_fill (self->stroke_measure, &GRAPHENE_POINT_INIT (x, y), self->fill_rule);
   if (self->inside == inside)
     return;
 
@@ -43,6 +45,8 @@ demo_widget_init (DemoWidget *self)
   controller = gtk_event_controller_motion_new ();
   g_signal_connect (controller, "motion", G_CALLBACK (motion), self);
   gtk_widget_add_controller (GTK_WIDGET (self), controller);
+
+  self->stroke = gsk_stroke_new (20.f);
 }
 
 static void
@@ -61,24 +65,32 @@ demo_widget_snapshot (GtkWidget   *widget,
 
   if (self->inside)
     {
-       gtk_snapshot_push_fill (snapshot, self->path, self->fill_rule);
+       gtk_snapshot_push_fill (snapshot, self->stroke_path, self->fill_rule);
 
        gtk_snapshot_append_color (snapshot,
-                                  &(GdkRGBA){ 1, 0, 1, 1},
+                                  &(GdkRGBA){ 1, 0, 1, 0.3},
                                   &GRAPHENE_RECT_INIT (0, 0, width, height ));
 
        gtk_snapshot_pop (snapshot);
     }
 
   stroke = gsk_stroke_new (1.0);
-  gtk_snapshot_push_stroke (snapshot, self->path, stroke);
-  gsk_stroke_free (stroke);
+  gtk_snapshot_push_stroke (snapshot, self->stroke_path, stroke);
 
   gtk_snapshot_append_color (snapshot,
                              &(GdkRGBA){ 0, 0, 0, 1},
                              &GRAPHENE_RECT_INIT (0, 0, width, height ));
 
   gtk_snapshot_pop (snapshot);
+
+  gtk_snapshot_push_stroke (snapshot, self->path, stroke);
+
+  gtk_snapshot_append_color (snapshot,
+                             &(GdkRGBA){ 0, 0, 0, 0.3},
+                             &GRAPHENE_RECT_INIT (0, 0, width, height ));
+
+  gtk_snapshot_pop (snapshot);
+  gsk_stroke_free (stroke);
 }
 
 static void
@@ -87,7 +99,9 @@ demo_widget_dispose (GObject *object)
   DemoWidget *self = DEMO_WIDGET (object);
 
   g_clear_pointer (&self->path, gsk_path_unref);
-  g_clear_pointer (&self->measure, gsk_path_measure_unref);
+  g_clear_pointer (&self->stroke_path, gsk_path_unref);
+  g_clear_pointer (&self->stroke, gsk_stroke_free);
+  g_clear_pointer (&self->stroke_measure, gsk_path_measure_unref);
 
   G_OBJECT_CLASS (demo_widget_parent_class)->dispose (object);
 }
@@ -111,15 +125,25 @@ demo_widget_new (void)
   return g_object_new (DEMO_TYPE_WIDGET, NULL);
 }
 
+static void
+update_stroke_path (DemoWidget *self)
+{
+  g_clear_pointer (&self->stroke_path, gsk_path_unref);
+  g_clear_pointer (&self->stroke_measure, gsk_path_measure_unref);
+
+  self->stroke_path = gsk_path_to_stroke (self->path, self->stroke);
+  self->stroke_measure = gsk_path_measure_new (self->stroke_path);
+
+  gtk_widget_queue_draw (GTK_WIDGET (self));
+}
+
 static void
 demo_widget_set_path (DemoWidget *self,
                       GskPath    *path)
 {
   g_clear_pointer (&self->path, gsk_path_unref);
-  g_clear_pointer (&self->measure, gsk_path_measure_unref);
   self->path = gsk_path_ref (path);
-  self->measure = gsk_path_measure_new (path);
-  gtk_widget_queue_draw (GTK_WIDGET (self));
+  update_stroke_path (self);
 }
 
 static void
@@ -127,9 +151,25 @@ demo_widget_set_fill_rule (DemoWidget  *self,
                            GskFillRule  fill_rule)
 {
   self->fill_rule = fill_rule;
+
   gtk_widget_queue_draw (GTK_WIDGET (self));
 }
 
+static const GskStroke *
+demo_widget_get_stroke (DemoWidget *self)
+{
+  return self->stroke;
+}
+
+static void
+demo_widget_set_stroke (DemoWidget *self,
+                        GskStroke  *stroke)
+{
+  gsk_stroke_free (self->stroke);
+  self->stroke = gsk_stroke_copy (stroke);
+  update_stroke_path (self);
+}
+
 static void
 init_demo (DemoWidget *demo)
 {
@@ -137,11 +177,36 @@ init_demo (DemoWidget *demo)
   GskPath *path;
 
   builder = gsk_path_builder_new ();
-  gsk_path_builder_add_circle (builder, &GRAPHENE_POINT_INIT (150, 150), 100);
+
   gsk_path_builder_add_rect (builder, &GRAPHENE_RECT_INIT (100, 100, 100, 100));
   gsk_path_builder_move_to (builder, 300, 150);
   gsk_path_builder_curve_to (builder, 300, 50, 400, 50, 400, 150);
   gsk_path_builder_curve_to (builder, 400, 250, 500, 250, 500, 150);
+
+#if 0
+  gsk_path_builder_move_to (builder, 50, 50);
+  gsk_path_builder_line_to (builder, 100, 100);
+  gsk_path_builder_line_to (builder, 150, 50);
+  gsk_path_builder_line_to (builder, 200, 100);
+  gsk_path_builder_line_to (builder, 250, 50);
+
+#elif 0
+  gsk_path_builder_move_to (builder, 300, 300);
+  gsk_path_builder_curve_to (builder, 300, 400, 400, 400, 400, 300);
+  gsk_path_builder_curve_to (builder, 400, 200, 500, 200, 500, 300);
+
+  gsk_path_builder_add_rect (builder, 100, 300, 100, 100);
+#elif 0
+  gsk_path_builder_add_rect (builder, 100, 100, 300, 200);
+#elif 0
+  gsk_path_builder_add_circle (builder, &GRAPHENE_POINT_INIT (200, 200), 100);
+#elif 0
+  gsk_path_builder_move_to (builder, 100, 100);
+  gsk_path_builder_line_to (builder, 150, 150);
+  gsk_path_builder_line_to (builder, 200, 100);
+  gsk_path_builder_curve_to (builder, 250, 50, 300, 50, 350, 100);
+#endif
+
   path = gsk_path_builder_free_to_path (builder);
 
   demo_widget_set_path (demo, path);
@@ -158,12 +223,51 @@ fill_rule_changed (GtkDropDown *combo,
   gtk_widget_queue_draw (GTK_WIDGET (self));
 }
 
+static void
+cap_changed (GtkDropDown *combo,
+             GParamSpec  *pspec,
+             DemoWidget  *self)
+{
+  GskStroke *stroke;
+
+  stroke = gsk_stroke_copy (demo_widget_get_stroke (self));
+  gsk_stroke_set_line_cap (stroke, (GskLineCap)gtk_drop_down_get_selected (combo));
+  demo_widget_set_stroke (self, stroke);
+  gsk_stroke_free (stroke);
+}
+
+static void
+join_changed (GtkDropDown *combo,
+              GParamSpec  *pspec,
+              DemoWidget  *self)
+{
+  GskStroke *stroke;
+
+  stroke = gsk_stroke_copy (demo_widget_get_stroke (self));
+  gsk_stroke_set_line_join (stroke, (GskLineJoin)gtk_drop_down_get_selected (combo));
+  demo_widget_set_stroke (self, stroke);
+  gsk_stroke_free (stroke);
+}
+
+static void
+limit_changed (GtkSpinButton *spin,
+               DemoWidget    *self)
+{
+  GskStroke *stroke;
+
+  stroke = gsk_stroke_copy (demo_widget_get_stroke (self));
+  gsk_stroke_set_miter_limit (stroke, gtk_spin_button_get_value (spin));
+  demo_widget_set_stroke (self, stroke);
+  gsk_stroke_free (stroke);
+}
+
 int
 main (int argc, char *argv[])
 {
   GtkWidget *window, *box, *demo;
   GtkWidget *popover, *button, *grid;
   GtkWidget *header, *combo;
+  GtkWidget *spin;
 
   gtk_init ();
 
@@ -199,6 +303,22 @@ main (int argc, char *argv[])
 
   init_demo (DEMO_WIDGET (demo));
 
+  gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Line cap:"), 0, 1, 1, 1);
+  combo = gtk_drop_down_new_from_strings ((const char *[]){"Butt", "Round", "Square", NULL});
+  g_signal_connect (combo, "notify::selected", G_CALLBACK (cap_changed), demo);
+  gtk_grid_attach (GTK_GRID (grid), combo, 1, 1, 1, 1);
+
+  gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Line join:"), 0, 2, 1, 1);
+  combo = gtk_drop_down_new_from_strings ((const char *[]){"Miter", "Miter-clip", "Round", "Bevel", NULL});
+  g_signal_connect (combo, "notify::selected", G_CALLBACK (join_changed), demo);
+  gtk_grid_attach (GTK_GRID (grid), combo, 1, 2, 1, 1);
+
+  gtk_grid_attach (GTK_GRID (grid), gtk_label_new ("Miter limit:"), 0, 3, 1, 1);
+  spin = gtk_spin_button_new_with_range (0, 10, 1);
+  gtk_spin_button_set_value (GTK_SPIN_BUTTON (spin), 4);
+  g_signal_connect (spin, "value-changed", G_CALLBACK (limit_changed), demo);
+  gtk_grid_attach (GTK_GRID (grid), spin, 1, 3, 1, 1);
+
   gtk_window_present (GTK_WINDOW (window));
 
   while (g_list_model_get_n_items (gtk_window_get_toplevels ()) > 0)