feat: add Window.visible and add safety checks to monitor API

examples/balls.zig

@@ -19,12 +19,17 @@ var totalEnergy = capy.Atom(f32).of(0);
 const BALL_DIAMETER = 20;
 const BALL_RADIUS = BALL_DIAMETER / 2;
 
-//var gpa = std.heap.GeneralPurposeAllocator(.{}) {};
-//pub const capy_allocator = gpa.allocator();
+var gpa = std.heap.GeneralPurposeAllocator(.{}){};
+pub const capy_allocator = gpa.allocator();
 
 pub fn main() !void {
+    defer _ = gpa.deinit();
     try capy.init();
+    defer capy.deinit();
+
+    defer totalEnergy.deinit();
     balls = std.ArrayList(Ball).init(capy.internal.lasting_allocator);
+    defer balls.deinit();
 
     // Generate random balls
     var prng = std.Random.DefaultPrng.init(@as(u64, @bitCast(std.time.milliTimestamp())));
@@ -39,6 +44,8 @@ pub fn main() !void {
         });
     }
 
+    // the canvas isn't referenced (canvas.ref()) so it will get deinitialized whenever the window
+    // is deinitialized
     var canvas = capy.canvas(.{
         .preferredSize = capy.Size.init(500, 500),
         .ondraw = @as(*const fn (*anyopaque, *capy.DrawContext) anyerror!void, @ptrCast(&onDraw)),
@@ -51,6 +58,7 @@ pub fn main() !void {
     defer totalEnergyFormat.deinit();
 
     var window = try capy.Window.init();
+    defer window.deinit();
     try window.set(capy.column(.{}, .{
         capy.label(.{ .text = "Balls with attraction and friction" }),
         capy.label(.{})
@@ -129,7 +137,7 @@ fn simulationThread(window: *capy.Window) !void {
     const root = window.getChild().?.as(capy.Container);
     const canvas = root.getChild("ball-canvas").?.as(capy.Canvas);
 
-    while (true) {
+    while (window.visible.get()) {
         const delta = 1.0 / 60.0;
         for (balls.items, 0..) |*ball, i| {
             // Moving

src/backends/gtk/Window.zig

@@ -44,6 +44,7 @@ pub fn create() common.BackendError!Window {
 
     const surface = c.gtk_native_get_surface(@ptrCast(window));
     _ = c.g_signal_connect_data(surface, "layout", @ptrCast(&gtkLayout), window, null, c.G_CONNECT_AFTER);
+    _ = c.g_signal_connect_data(window, "close-request", @as(c.GCallback, @ptrCast(&gtkCloseRequest)), null, null, c.G_CONNECT_AFTER);
     return Window{ .peer = window, .wbin = wbin, .vbox = vbox };
 }
 
@@ -79,6 +80,18 @@ fn gtkLayout(peer: *c.GdkSurface, width: c.gint, height: c.gint, userdata: ?*any
     return 0;
 }
 
+fn gtkCloseRequest(peer: *c.GtkWindow, userdata: ?*anyopaque) callconv(.C) c.gint {
+    _ = userdata;
+    const data = common.getEventUserData(@ptrCast(peer));
+    const value_bool: bool = false;
+    if (data.class.propertyChangeHandler) |handler|
+        handler("visible", &value_bool, data.userdata);
+    if (data.user.propertyChangeHandler) |handler|
+        handler("visible", &value_bool, data.userdata);
+
+    return 0;
+}
+
 pub fn resize(self: *Window, width: c_int, height: c_int) void {
     c.gtk_window_set_default_size(@ptrCast(self.peer), width, height);
 }
@@ -162,6 +175,12 @@ pub fn unfullscreen(self: *Window) void {
 
 pub fn show(self: *Window) void {
     c.gtk_widget_show(self.peer);
+    const data = common.getEventUserData(self.peer);
+    const value_bool: bool = true;
+    if (data.class.propertyChangeHandler) |handler|
+        handler("visible", &value_bool, data.userdata);
+    if (data.user.propertyChangeHandler) |handler|
+        handler("visible", &value_bool, data.userdata);
 }
 
 pub fn registerTickCallback(self: *Window) void {

src/monitor.zig

@@ -6,12 +6,16 @@ const ListAtom = @import("data.zig").ListAtom;
 // TODO: when a monitor is removed, monitor.peer.deinit should be called
 pub const Monitors = struct {
     /// List of all monitors that are connected
-    pub var list = ListAtom(Monitor).init(internal.lasting_allocator);
+    pub var list: ListAtom(Monitor) = undefined;
+    /// Lock used to ensure the backend is initialized only once (at least in debug mode)
+    var initialized: std.debug.SafetyLock = .{};
 
     /// Init the subsystem by filling the monitor list and by listening to events indicating
     /// that a monitor is being added or removed.
     /// This function is called by `capy.init()`, so it doesn't need to be called manually.
     pub fn init() void {
+        initialized.lock();
+        Monitors.list = ListAtom(Monitor).init(internal.lasting_allocator);
         const peer_list = backend.Monitor.getList();
         for (peer_list) |*monitor_peer| {
             list.append(Monitor.init(monitor_peer)) catch @panic("OOM");
@@ -25,6 +29,7 @@ pub const Monitors = struct {
 
     /// This function is called by `capy.deinit()`, so it doesn't need to be called manually.
     pub fn deinit() void {
+        initialized.unlock();
         {
             var iterator = Monitors.list.iterate();
             defer iterator.deinit();
@@ -33,7 +38,6 @@ pub const Monitors = struct {
             }
         }
         Monitors.list.deinit();
-        Monitors.list = ListAtom(Monitor).init(internal.lasting_allocator);
         backend.Monitor.deinitAllPeers();
     }
 };
@@ -129,10 +133,6 @@ pub const Monitor = struct {
         const monitor = Monitors.list.get(0);
         const width, const height = monitor.getSize();
         std.log.info("Monitor pixels: {d} px x {d} px", .{ width, height });
-
-        // Alternate usage to only retrieve the monitor's height
-        _, const h = monitor.getSize();
-        _ = h;
     }
 };
 

src/window.zig

@@ -37,6 +37,7 @@ pub const Window = struct {
     /// This can be used for synchronizing animations to the window's monitor's sync rate.
     on_frame: *EventSource,
     animation_controller: *AnimationController,
+    visible: Atom(bool) = Atom(bool).of(false),
 
     pub const Feature = enum {
         Title,
@@ -68,11 +69,13 @@ pub const Window = struct {
 
     pub fn show(self: *Window) void {
         self.peer.setUserData(self);
-        return self.peer.show();
+        self.peer.show();
+        self.visible.set(true);
     }
 
     pub fn close(self: *Window) void {
-        return self.peer.close();
+        self.peer.close();
+        self.visible.set(false);
     }
 
     /// wrappedContainer can be an error union, a pointer to the container or the container itself.
@@ -129,8 +132,10 @@ pub const Window = struct {
     fn propertyChanged(name: []const u8, value: *const anyopaque, data: usize) void {
         const self: *Window = @ptrFromInt(data);
         if (std.mem.eql(u8, name, "tick_id")) {
-            _ = value;
             self.on_frame.callListeners();
+        } else if (std.mem.eql(u8, name, "visible")) {
+            const bool_ptr: *const bool = @ptrCast(value);
+            self.visible.set(bool_ptr.*);
         }
     }