MODULE snapshot ;

(*
   m2-GTK4 example - a custom GdkPaintable drawn with GtkSnapshot and
   Graphene from Modula-2 (via the shim).

   Build:  make examples
   Run:    ./build/examples/snapshot
*)

FROM Gio IMPORT g_application_run;
FROM GtkApplication IMPORT gtk_application_new;
FROM GtkWindow IMPORT gtk_application_window_new, gtk_window_set_title,
   gtk_window_set_default_size, gtk_window_set_child, gtk_window_present;
FROM GtkPicture IMPORT gtk_picture_new, gtk_picture_set_paintable;
FROM GtkWidget IMPORT gtk_widget_set_size_request;
FROM M2GtkShim IMPORT m2_snapshot_paintable_new;
FROM GtkSnapshot IMPORT gtk_snapshot_append_color,
   gtk_snapshot_append_cairo;
FROM Graphene IMPORT GrapheneRect, graphene_rect_init;
FROM Gdk IMPORT GdkRGBA;
FROM Cairo IMPORT cairo_set_source_rgb, cairo_arc, cairo_fill, cairo_destroy;
FROM GtkClosures IMPORT Connect2;
FROM SYSTEM IMPORT ADDRESS, ADR;
FROM libc IMPORT printf;

CONST
   AppId = "org.example.m2gtk4.Snapshot";

PROCEDURE Draw (snapshot: ADDRESS; width, height: INTEGER; user: ADDRESS);
VAR
   rect: GrapheneRect;
   color: GdkRGBA;
   cr: ADDRESS;
BEGIN
   graphene_rect_init(rect, 0.0, 0.0, VAL(REAL, width), VAL(REAL, height));

   color.red := 0.12;
   color.green := 0.16;
   color.blue := 0.22;
   color.alpha := 1.0;
   gtk_snapshot_append_color(snapshot, color, rect);

   cr := gtk_snapshot_append_cairo(snapshot, rect);
   IF cr # NIL THEN
      cairo_set_source_rgb(cr, 0.20, 0.60, 0.90);
      cairo_arc(cr, VAL(REAL, width) / 2.0, VAL(REAL, height) / 2.0, 60.0,
                0.0, 6.2831853);
      cairo_fill(cr);
      cairo_destroy(cr)
   END
END Draw;

PROCEDURE OnActivate (application: ADDRESS; data: ADDRESS);
VAR
   window, picture, paintable: ADDRESS;
BEGIN
   paintable := m2_snapshot_paintable_new(ADR(Draw), 240, 160, NIL, NIL);
   picture := gtk_picture_new();
   gtk_picture_set_paintable(picture, paintable);
   gtk_widget_set_size_request(picture, 240, 160);

   window := gtk_application_window_new(application);
   gtk_window_set_title(window, "m2-GTK4 Snapshot");
   gtk_window_set_default_size(window, 280, 200);
   gtk_window_set_child(window, picture);
   gtk_window_present(window)
END OnActivate;

VAR
   app: ADDRESS;
BEGIN
   app := gtk_application_new(AppId, 0);
   IF app = NIL THEN
      printf("gtk_application_new failed\n");
      HALT(1)
   END;
   Connect2(app, "activate", OnActivate, NIL);
   g_application_run(app, 0, NIL)
END snapshot.