update example

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>

examples/text_input.zig

@@ -5,6 +5,17 @@ const TextInput = vaxis.widgets.TextInput;
 const border = vaxis.widgets.border;
 
 const log = std.log.scoped(.main);
+
+// Our EventType. This can contain internal events as well as Vaxis events.
+// Internal events can be posted into the same queue as vaxis events to allow
+// for a single event loop with exhaustive switching. Booya
+const Event = union(enum) {
+    key_press: vaxis.Key,
+    winsize: vaxis.Winsize,
+    focus_in,
+    foo: u8,
+};
+
 pub fn main() !void {
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
     defer {
@@ -16,14 +27,16 @@ pub fn main() !void {
     }
     const alloc = gpa.allocator();
 
-    // Initialize Vaxis
+    // Initialize Vaxis with our event type
     var vx = try vaxis.init(Event, .{});
+    // deinit takes an optional allocator. If your program is exiting, you can
+    // choose to pass a null allocator to save some exit time.
     defer vx.deinit(alloc);
 
     // Start the read loop. This puts the terminal in raw mode and begins
     // reading user input
-    try vx.start();
-    defer vx.stop();
+    try vx.startReadThread();
+    defer vx.stopReadThread();
 
     // Optionally enter the alternate screen
     try vx.enterAltScreen();
@@ -31,9 +44,13 @@ pub fn main() !void {
     // We'll adjust the color index every keypress for the border
     var color_idx: u8 = 0;
 
+    // init our text input widget. The text input widget needs an allocator to
+    // store the contents of the input
     var text_input = TextInput.init(alloc);
     defer text_input.deinit();
 
+    // Sends queries to terminal to detect certain features. This should
+    // _always_ be called, but is left to the application to decide when
     try vx.queryTerminal();
 
     // The main event loop. Vaxis provides a thread safe, blocking, buffered
@@ -59,9 +76,22 @@ pub fn main() !void {
                 }
             },
 
-            .winsize => |ws| {
-                try vx.resize(alloc, ws);
-            },
+            // winsize events are sent to the application to ensure that all
+            // resizes occur in the main thread. This lets us avoid expensive
+            // locks on the screen. All applications must handle this event
+            // unless they aren't using a screen (IE only detecting features)
+            //
+            // This is the only call that the core of Vaxis needs an allocator
+            // for. The allocations are because we keep a copy of each cell to
+            // optimize renders. When resize is called, we allocated two slices:
+            // one for the screen, and one for our buffered screen. Each cell in
+            // the buffered screen contains an ArrayList(u8) to be able to store
+            // the grapheme for that cell Each cell is initialized with a size
+            // of 1, which is sufficient for all of ASCII. Anything requiring
+            // more than one byte will incur an allocation on the first render
+            // after it is drawn. Thereafter, it will not allocate unless the
+            // screen is resized
+            .winsize => |ws| try vx.resize(alloc, ws),
             else => {},
         }
 
@@ -69,6 +99,7 @@ pub fn main() !void {
         // terminal and can spawn child windows as logical areas. Child windows
         // cannot draw outside of their bounds
         const win = vx.window();
+
         // Clear the entire space because we are drawing in immediate mode.
         // vaxis double buffers the screen. This new frame will be compared to
         // the old and only updated cells will be drawn
@@ -89,13 +120,3 @@ pub fn main() !void {
         try vx.render();
     }
 }
-
-// Our EventType. This can contain internal events as well as Vaxis events.
-// Internal events can be posted into the same queue as vaxis events to allow
-// for a single event loop with exhaustive switching. Booya
-const Event = union(enum) {
-    key_press: vaxis.Key,
-    winsize: vaxis.Winsize,
-    focus_in,
-    foo: u8,
-};

src/vaxis.zig

@@ -109,7 +109,7 @@ pub fn Vaxis(comptime T: type) type {
         }
 
         /// spawns the input thread to start listening to the tty for input
-        pub fn start(self: *Self) !void {
+        pub fn startReadThread(self: *Self) !void {
             self.tty = try Tty.init();
             // run our tty read loop in it's own thread
             const read_thread = try std.Thread.spawn(.{}, Tty.run, .{ &self.tty.?, T, self });
@@ -117,7 +117,7 @@ pub fn Vaxis(comptime T: type) type {
         }
 
         /// stops reading from the tty
-        pub fn stop(self: *Self) void {
+        pub fn stopReadThread(self: *Self) void {
             if (self.tty) |_| {
                 var tty = &self.tty.?;
                 tty.stop();