add(renderer/direct): write newline function to align view if necessary

Introduce `.cancel` event that is fired when the user sends EOF
in *non raw mode* renderings. The event `.line` now sends the
entire line (even if larger than the internal buffer) but requires
now an `Allocator`.

.gitea/workflows/release.yaml

@@ -15,9 +15,15 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
       - name: Setup zig installation
-        uses: mlugg/setup-zig@v2
+        uses: https://codeberg.org/mlugg/setup-zig@v2
         with:
-          version: master
+          version: latest
+      - name: Lint check
+        run: zig fmt --check .
+      - name: Spell checking
+        uses: crate-ci/typos@v1.39.0
+        with:
+          config: ./.typos-config
       - name: Run tests
         run: zig build --release=fast
       - name: Release build artifacts

.gitea/workflows/test.yaml

@@ -14,13 +14,13 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
       - name: Setup zig installation
-        uses: mlugg/setup-zig@v2
+        uses: https://codeberg.org/mlugg/setup-zig@v2
         with:
-          version: master
+          version: latest
       - name: Lint check
         run: zig fmt --check --exclude src/test .
       - name: Spell checking
-        uses: crate-ci/typos@v1.25.0
+        uses: crate-ci/typos@v1.39.0
         with:
           config: ./.typos-config
       - name: Run tests

README.md

@@ -2,9 +2,6 @@
 
 `zterm` is a terminal user interface library (*tui*) to implement terminal (fullscreen or inline) applications.
 
-> [!caution]
-> Only builds using the zig master version are tested to work.
-
 ## Demo
 
 Clone this repository and run `zig build --help` to see the available examples. Run a given example as follows:

build.zig

@@ -24,6 +24,8 @@ pub fn build(b: *std.Build) void {
         palette,
         // error handling
         errors,
+        // non alternate screen applications
+        direct,
     };
 
     const example = b.option(Examples, "example", "Example to build and/or run. (default: all)") orelse .all;
@@ -73,6 +75,8 @@ pub fn build(b: *std.Build) void {
                     .palette => "examples/styles/palette.zig",
                     // error handling
                     .errors => "examples/errors.zig",
+                    // non-alternate screen
+                    .direct => "examples/direct.zig",
                     .all => unreachable, // should never happen
                 }),
                 .target = target,

examples/continuous.zig

@@ -87,7 +87,7 @@ const InputField = struct {
         const this: *@This() = @ptrCast(@alignCast(ctx));
         switch (event) {
             .key => |key| {
-                if (key.isAscii()) try this.input.append(this.allocator, key.cp);
+                if (key.isUnicode()) try this.input.append(this.allocator, key.cp);
 
                 if (key.eql(.{ .cp = zterm.input.Enter }) or key.eql(.{ .cp = zterm.input.KpEnter }))
                     this.queue.push(.{ .accept = try this.input.toOwnedSlice(this.allocator) });
@@ -133,7 +133,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -153,7 +153,7 @@ pub fn main() !void {
     defer container.deinit();
 
     try container.append(try App.Container.init(allocator, .{
-        .rectangle = .{ .fill = .light_grey },
+        .rectangle = .{ .fill = .lightgrey },
         .size = .{
             .grow = .horizontal,
             .dim = .{ .y = 10 },
@@ -161,11 +161,11 @@ pub fn main() !void {
     }, input_field.element()));
 
     const nested_container: App.Container = try .init(allocator, .{
-        .rectangle = .{ .fill = .light_grey },
+        .rectangle = .{ .fill = .lightgrey },
     }, spinner.element());
     try container.append(nested_container);
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     var framerate: u64 = 60;
@@ -228,8 +228,8 @@ pub fn main() !void {
             }
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/demo.zig

@@ -1,5 +1,5 @@
 const QuitText = struct {
-    const text = "Press ctrl+c to quit. Press ctrl+n to launch helix.";
+    const text = "Press ctrl+c to quit. Press ctrl+n to launch `vim`.";
 
     pub fn element(this: *@This()) App.Element {
         return .{ .ptr = this, .vtable = &.{ .content = content } };
@@ -27,13 +27,12 @@ const QuitText = struct {
 pub fn main() !void {
     errdefer |err| log.err("Application Error: {any}", .{err});
 
-    // TODO maybe create own allocator as some sort of arena allocator to have consistent memory usage
     var gpa: std.heap.DebugAllocator(.{}) = .init;
     defer if (gpa.deinit() == .leak) log.err("memory leak", .{});
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -57,15 +56,14 @@ pub fn main() !void {
         },
     }, .{});
     try box.append(try App.Container.init(allocator, .{
-        .rectangle = .{ .fill = .light_green },
+        .rectangle = .{ .fill = .lightgreen },
     }, .{}));
     try box.append(try App.Container.init(allocator, .{
-        .rectangle = .{ .fill = .light_green },
+        .rectangle = .{ .fill = .lightgreen },
     }, .{}));
     try box.append(try App.Container.init(allocator, .{
-        .rectangle = .{ .fill = .light_green },
+        .rectangle = .{ .fill = .lightgreen },
     }, .{}));
-    defer box.deinit();
 
     var scrollable: App.Scrollable = .init(box, .disabled);
 
@@ -92,7 +90,7 @@ pub fn main() !void {
             .direction = .vertical,
         },
         .border = .{
-            .color = .light_blue,
+            .color = .lightblue,
             .sides = .all,
         },
     }, .{});
@@ -135,7 +133,7 @@ pub fn main() !void {
     }, .{}));
     defer container.deinit(); // also de-initializes the children
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     // event loop
@@ -151,8 +149,8 @@ pub fn main() !void {
                 if (key.eql(.{ .cp = 'n', .mod = .{ .ctrl = true } })) {
                     try app.interrupt();
                     renderer.size = .{}; // reset size, such that next resize will cause a full re-draw!
-                    defer app.start() catch @panic("could not start app event loop");
-                    var child = std.process.Child.init(&.{"hx"}, allocator);
+                    defer app.start(.full) catch @panic("could not start app event loop");
+                    var child = std.process.Child.init(&.{"vim"}, allocator);
                     _ = child.spawnAndWait() catch |err| app.postEvent(.{
                         .err = .{
                             .err = err,
@@ -181,8 +179,8 @@ pub fn main() !void {
             else => {},
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/direct.zig

@@ -0,0 +1,192 @@
+const QuitText = struct {
+    const text = "Press ctrl+c to quit.";
+
+    pub fn element(this: *@This()) App.Element {
+        return .{
+            .ptr = this,
+            .vtable = &.{
+                .minSize = minSize,
+                .content = content,
+            },
+        };
+    }
+
+    fn minSize(_: *anyopaque, _: *const App.Model, size: zterm.Point) zterm.Point {
+        return .{ .x = size.x, .y = 10 }; // this includes the border
+    }
+
+    pub fn content(ctx: *anyopaque, _: *const App.Model, cells: []zterm.Cell, size: zterm.Point) !void {
+        _ = ctx;
+        assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
+
+        const y = 0;
+        const x = 2;
+        const anchor = (y * size.x) + x;
+
+        for (text, 0..) |cp, idx| {
+            cells[anchor + idx].style.fg = .white;
+            cells[anchor + idx].style.emphasis = &.{ .bold, .underline };
+            cells[anchor + idx].cp = cp;
+
+            // NOTE do not write over the contents of this `Container`'s `Size`
+            if (anchor + idx == cells.len - 1) break;
+        }
+    }
+};
+
+const Prompt = struct {
+    len: u16 = 3,
+    pub fn element(this: *@This()) App.Element {
+        return .{
+            .ptr = this,
+            .vtable = &.{
+                // .minSize = minSize,
+                .content = content,
+            },
+        };
+    }
+
+    // NOTE size hint is not required as the `.size = .{ .dim = .{..} }` property is set accordingly which denotes the minimal size
+    // fn minSize(ctx: *anyopaque, _: *const App.Model, _: zterm.Point) zterm.Point {
+    //     const this: *@This() = @ptrCast(@alignCast(ctx));
+    //     return .{ .x = this.len, .y = 1 };
+    // }
+
+    pub fn content(ctx: *anyopaque, _: *const App.Model, cells: []zterm.Cell, size: zterm.Point) !void {
+        const this: *@This() = @ptrCast(@alignCast(ctx));
+        assert(cells.len > 2); // expect at least two cells
+        assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
+
+        for (0..this.len) |idx| {
+            cells[idx].style.bg = .blue;
+            cells[idx].style.fg = .black;
+            cells[idx].style.emphasis = &.{.bold};
+        }
+        cells[1].cp = '>';
+        // leave one clear whitespace after the prompt
+        cells[this.len].style.bg = .default;
+        cells[this.len].style.cursor = true; // marks the actual end of the rendering!
+    }
+};
+
+pub fn main() !void {
+    errdefer |err| log.err("Application Error: {any}", .{err});
+
+    var allocator: std.heap.DebugAllocator(.{}) = .init;
+    defer if (allocator.deinit() == .leak) log.err("memory leak", .{});
+
+    const gpa = allocator.allocator();
+
+    var app: App = .init(gpa, .{}, .{});
+    var renderer = zterm.Renderer.Direct.init(gpa);
+    defer renderer.deinit();
+
+    var container: App.Container = try .init(gpa, .{
+        .layout = .{
+            .direction = .vertical,
+            .gap = 1, // show empty line between elements to allow navigation through paragraph jumping
+        },
+        .size = .{
+            .grow = .horizontal_only,
+        },
+    }, .{});
+    defer container.deinit();
+
+    var quit_text: QuitText = .{};
+    var intermediate: App.Container = try .init(gpa, .{
+        .border = .{
+            .sides = .{ .left = true },
+            .color = .grey,
+        },
+        .layout = .{
+            .direction = .horizontal,
+            .padding = .{ .left = 1, .top = 1 },
+        },
+    }, quit_text.element());
+    try intermediate.append(try .init(gpa, .{
+        .rectangle = .{ .fill = .blue },
+    }, .{}));
+
+    try intermediate.append(try .init(gpa, .{
+        .rectangle = .{ .fill = .green },
+    }, .{}));
+
+    var padding_container: App.Container = try .init(gpa, .{
+        .layout = .{
+            .padding = .horizontal(1),
+        },
+    }, .{});
+    try padding_container.append(intermediate);
+    try container.append(padding_container);
+
+    var prompt: Prompt = .{};
+    try container.append(try .init(gpa, .{
+        .rectangle = .{ .fill = .grey },
+        .size = .{
+            .dim = .{ .y = 1 },
+        },
+    }, prompt.element()));
+
+    try app.start(.direct); // needs to become configurable, as what should be enabled / disabled (i.e. show cursor, hide cursor, use alternate screen, etc.)
+    defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
+
+    // event loop
+    event: while (true) {
+        // batch events since last iteration
+        const len = blk: {
+            app.queue.poll();
+            app.queue.lock();
+            defer app.queue.unlock();
+            break :blk app.queue.len();
+        };
+
+        // handle events
+        for (0..len) |_| {
+            const event = app.queue.pop();
+            log.debug("received event: {s}", .{@tagName(event)});
+
+            // pre event handling
+            switch (event) {
+                // NOTE draw the character with the ctrl indication and a newline to make sure the rendering stays consistent
+                .cancel => try renderer.writeCtrlDWithNewline(),
+                .line => |line| {
+                    defer gpa.free(line);
+                    log.debug("{s}", .{line});
+                },
+                // NOTE errors could be displayed in another container in case one was received, etc. to provide the user with feedback
+                .err => |err| log.err("Received {s} with message: {s}", .{ @errorName(err.err), err.msg }),
+                else => {},
+            }
+
+            // NOTE returned errors should be propagated back to the application
+            container.handle(&app.model, event) catch |err| app.postEvent(.{
+                .err = .{
+                    .err = err,
+                    .msg = "Container Event handling failed",
+                },
+            });
+
+            // post event handling
+            switch (event) {
+                .quit => break :event,
+                else => {},
+            }
+        }
+        // if there are more events to process continue handling them otherwise I can render the next frame
+        if (app.queue.len() > 0) continue :event;
+
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
+        try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
+        try renderer.flush();
+    }
+}
+
+pub const panic = App.panic_handler;
+const log = std.log.scoped(.default);
+
+const std = @import("std");
+const assert = std.debug.assert;
+const zterm = @import("zterm");
+const input = zterm.input;
+const App = zterm.App(struct {}, union(enum) {});

examples/elements/alignment.zig

@@ -32,7 +32,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -55,7 +55,7 @@ pub fn main() !void {
     var alignment: App.Alignment = .init(quit_container, .center);
     try container.append(try .init(allocator, .{}, alignment.element()));
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     // event loop
@@ -83,8 +83,8 @@ pub fn main() !void {
             else => {},
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/elements/button.zig

@@ -82,7 +82,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -99,10 +99,10 @@ pub fn main() !void {
     }, quit_text.element());
     defer container.deinit();
 
-    try container.append(try App.Container.init(allocator, .{ .rectangle = .{ .fill = .light_grey } }, element));
+    try container.append(try App.Container.init(allocator, .{ .rectangle = .{ .fill = .lightgrey } }, element));
     try container.append(try App.Container.init(allocator, .{ .rectangle = .{ .fill = .black } }, button.element()));
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     // event loop
@@ -132,8 +132,8 @@ pub fn main() !void {
             else => {},
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/elements/input.zig

@@ -65,13 +65,11 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
-    var input_field: App.Input(.accept) = .init(allocator, &app.queue, .init(.black));
-    defer input_field.deinit();
-
+    var input_field: App.Input(.accept) = .init(allocator, &app.queue, .init(.black, .blue));
     var mouse_draw: MouseDraw = .{};
     var second_mouse_draw: MouseDraw = .{};
     var quit_text: QuitText = .{};
@@ -86,7 +84,7 @@ pub fn main() !void {
     defer container.deinit();
 
     try container.append(try App.Container.init(allocator, .{
-        .rectangle = .{ .fill = .light_grey },
+        .rectangle = .{ .fill = .lightgrey },
         .size = .{
             .grow = .horizontal,
             .dim = .{ .y = 1 },
@@ -98,7 +96,7 @@ pub fn main() !void {
             .sides = .all,
             .color = .black,
         },
-        .rectangle = .{ .fill = .light_grey },
+        .rectangle = .{ .fill = .lightgrey },
         .layout = .{
             .separator = .{
                 .enabled = true,
@@ -107,14 +105,14 @@ pub fn main() !void {
         },
     }, .{});
     try nested_container.append(try .init(allocator, .{
-        .rectangle = .{ .fill = .light_grey },
+        .rectangle = .{ .fill = .lightgrey },
     }, mouse_draw.element()));
     try nested_container.append(try .init(allocator, .{
-        .rectangle = .{ .fill = .light_grey },
+        .rectangle = .{ .fill = .lightgrey },
     }, second_mouse_draw.element()));
     try container.append(nested_container);
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     // event loop
@@ -146,8 +144,8 @@ pub fn main() !void {
             else => {},
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/elements/progress.zig

@@ -32,7 +32,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -85,7 +85,7 @@ pub fn main() !void {
         });
         try container.append(try App.Container.init(allocator, .{}, progress.element()));
     }
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     var framerate: u64 = 60;
@@ -152,8 +152,8 @@ pub fn main() !void {
             }
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/elements/radio-button.zig

@@ -32,7 +32,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -51,7 +51,7 @@ pub fn main() !void {
     try container.append(try .init(allocator, .{}, radiobutton.element()));
     try container.append(try App.Container.init(allocator, .{ .rectangle = .{ .fill = .black } }, button.element()));
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     // event loop
@@ -80,8 +80,8 @@ pub fn main() !void {
             else => {},
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/elements/scrollable.zig

@@ -56,7 +56,6 @@ const HelloWorldText = packed struct {
 pub fn main() !void {
     errdefer |err| log.err("Application Error: {any}", .{err});
 
-    // TODO maybe create own allocator as some sort of arena allocator to have consistent memory usage
     var gpa: std.heap.DebugAllocator(.{}) = .init;
     defer {
         const deinit_status = gpa.deinit();
@@ -66,7 +65,7 @@ pub fn main() !void {
     }
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -87,24 +86,23 @@ pub fn main() !void {
         },
     }, .{});
     try top_box.append(try App.Container.init(allocator, .{
-        .rectangle = .{ .fill = .light_green },
+        .rectangle = .{ .fill = .lightgreen },
         .size = .{
             .dim = .{ .y = 30 },
         },
     }, .{}));
     try top_box.append(try App.Container.init(allocator, .{
-        .rectangle = .{ .fill = .light_green },
+        .rectangle = .{ .fill = .lightgreen },
         .size = .{
             .dim = .{ .y = 5 },
         },
     }, element));
     try top_box.append(try App.Container.init(allocator, .{
-        .rectangle = .{ .fill = .light_green },
+        .rectangle = .{ .fill = .lightgreen },
         .size = .{
             .dim = .{ .y = 2 },
         },
     }, .{}));
-    defer top_box.deinit();
 
     var bottom_box = try App.Container.init(allocator, .{
         .border = .{
@@ -132,7 +130,6 @@ pub fn main() !void {
     try bottom_box.append(try App.Container.init(allocator, .{
         .rectangle = .{ .fill = .grey },
     }, .{}));
-    defer bottom_box.deinit();
 
     var container = try App.Container.init(allocator, .{
         .layout = .{
@@ -148,13 +145,13 @@ pub fn main() !void {
     defer container.deinit();
 
     // place empty container containing the element of the scrollable Container.
-    var scrollable_top: App.Scrollable = .init(top_box, .enabled(.grey));
+    var scrollable_top: App.Scrollable = .init(top_box, .enabled(.default, false));
     try container.append(try App.Container.init(allocator, .{}, scrollable_top.element()));
 
-    var scrollable_bottom: App.Scrollable = .init(bottom_box, .enabled(.white));
+    var scrollable_bottom: App.Scrollable = .init(bottom_box, .enabled(.white, true));
     try container.append(try App.Container.init(allocator, .{}, scrollable_bottom.element()));
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     // event loop
@@ -182,8 +179,8 @@ pub fn main() !void {
             else => {},
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/elements/selection.zig

@@ -32,7 +32,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -52,7 +52,7 @@ pub fn main() !void {
     defer container.deinit();
     try container.append(try .init(allocator, .{}, selection.element()));
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     // event loop
@@ -80,8 +80,8 @@ pub fn main() !void {
             else => {},
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/errors.zig

@@ -97,7 +97,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -116,7 +116,7 @@ pub fn main() !void {
     try container.append(try App.Container.init(allocator, .{}, info_text.element()));
     try container.append(try App.Container.init(allocator, .{}, error_notification.element()));
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     while (true) {
@@ -143,8 +143,8 @@ pub fn main() !void {
             else => {},
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/layouts/grid.zig

@@ -35,7 +35,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -69,7 +69,7 @@ pub fn main() !void {
     }
     defer container.deinit(); // also de-initializes the children
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     // event loop
@@ -99,8 +99,8 @@ pub fn main() !void {
             else => {},
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/layouts/horizontal.zig

@@ -35,7 +35,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -61,7 +61,7 @@ pub fn main() !void {
     }, .{}));
     defer container.deinit(); // also de-initializes the children
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     // event loop
@@ -91,8 +91,8 @@ pub fn main() !void {
             else => {},
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/layouts/mixed.zig

@@ -35,7 +35,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -77,7 +77,7 @@ pub fn main() !void {
     }
     defer container.deinit(); // also de-initializes the children
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     // event loop
@@ -107,8 +107,8 @@ pub fn main() !void {
             else => {},
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/layouts/vertical.zig

@@ -35,7 +35,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -60,7 +60,7 @@ pub fn main() !void {
     }, .{}));
     defer container.deinit(); // also de-initializes the children
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     // event loop
@@ -90,8 +90,8 @@ pub fn main() !void {
             else => {},
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/styles/palette.zig

@@ -32,7 +32,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -50,7 +50,6 @@ pub fn main() !void {
     var box = try App.Container.init(allocator, .{
         .layout = .{ .direction = .horizontal },
     }, .{});
-    defer box.deinit();
 
     inline for (std.meta.fields(zterm.Color)) |field| {
         if (field.value == 0) continue; // zterm.Color.default == 0 -> skip
@@ -59,7 +58,7 @@ pub fn main() !void {
     var scrollable: App.Scrollable = .init(box, .disabled);
     try container.append(try App.Container.init(allocator, .{}, scrollable.element()));
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     while (true) {
@@ -86,8 +85,8 @@ pub fn main() !void {
             else => {},
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

examples/styles/text.zig

@@ -117,7 +117,7 @@ const TextStyles = struct {
         };
     }
 
-    fn minSize(ctx: *anyopaque, size: zterm.Point) zterm.Point {
+    fn minSize(ctx: *anyopaque, _: *const App.Model, size: zterm.Point) zterm.Point {
         _ = ctx;
         _ = size;
         return .{
@@ -178,7 +178,7 @@ pub fn main() !void {
 
     const allocator = gpa.allocator();
 
-    var app: App = .init(.{});
+    var app: App = .init(allocator, .{}, .{});
     var renderer = zterm.Renderer.Buffered.init(allocator);
     defer renderer.deinit();
 
@@ -204,15 +204,12 @@ pub fn main() !void {
         },
     }, table_head.element()));
 
-    var box = try App.Container.init(allocator, .{
+    var scrollable: App.Scrollable = .init(try .init(allocator, .{
         .layout = .{ .direction = .vertical },
-    }, text_styles.element());
-    defer box.deinit();
-
-    var scrollable: App.Scrollable = .init(box, .disabled);
+    }, text_styles.element()), .enabled(.white, true));
     try container.append(try App.Container.init(allocator, .{}, scrollable.element()));
 
-    try app.start();
+    try app.start(.full);
     defer app.stop() catch |err| log.err("Failed to stop application: {any}", .{err});
 
     // event loop
@@ -250,8 +247,8 @@ pub fn main() !void {
             }
         }
 
-        container.resize(try renderer.resize());
-        container.reposition(.{});
+        container.resize(&app.model, try renderer.resize());
+        container.reposition(&app.model, .{});
         try renderer.render(@TypeOf(container), &container, App.Model, &app.model);
         try renderer.flush();
     }

src/app.zig

@@ -16,75 +16,114 @@
 ///       union(enum) {}, // no additional user event's
 ///   );
 ///   // later on create an `App` instance and start the event loop
-///   var app: App = .init(.{}); // provide instance of the model that shall be used
-///   try app.start();
+///   var app: App = .init(io, .{}); // provide instance of the `std.Io` and `App` model that shall be used
+///   try app.start(.full);
 ///   defer app.stop() catch unreachable; // does not clean-up the resources used in the model
 /// ```
 pub fn App(comptime M: type, comptime E: type) type {
     if (!isStruct(M)) @compileError("Provided model `M` for `App(comptime M: type, comptime E: type)` is not of type `struct`");
     if (!isTaggedUnion(E)) @compileError("Provided user event `E` for `App(comptime M: type, comptime E: type)` is not of type `union(enum)`.");
     return struct {
+        gpa: Allocator,
+        io: std.Io,
         model: Model,
         queue: Queue,
         thread: ?Thread = null,
         quit_event: Thread.ResetEvent,
         termios: ?posix.termios = null,
-        winch_registered: bool = false,
+        handler_registered: bool = false,
+        config: TerminalConfiguration,
+
+        pub const TerminalConfiguration = struct {
+            altScreen: bool,
+            saveScreen: bool,
+            rawMode: bool,
+            hideCursor: bool,
+
+            pub const full: @This() = .{
+                .altScreen = true,
+                .saveScreen = true,
+                .rawMode = true,
+                .hideCursor = true,
+            };
+
+            pub const direct: @This() = .{
+                .altScreen = false,
+                .saveScreen = false,
+                .rawMode = false,
+                .hideCursor = false,
+            };
+        };
 
         // global variable for the registered handler for WINCH
         var handler_ctx: *anyopaque = undefined;
         /// registered WINCH handler to report resize events
-        fn handleWinch(_: std.os.linux.SIG) callconv(.c) void {
+        fn handleWinch(_: i32) callconv(.c) void {
+            const this: *@This() = @ptrCast(@alignCast(handler_ctx));
+            // NOTE this does not have to be done if in-band resize events are supported
+            // -> the signal might not work correctly when hosting the application over ssh!
+            this.postEvent(.resize);
+        }
+        /// registered CONT handler to force a complete redraw
+        fn handleCont(_: i32) callconv(.c) void {
             const this: *@This() = @ptrCast(@alignCast(handler_ctx));
             // NOTE this does not have to be done if in-band resize events are supported
             // -> the signal might not work correctly when hosting the application over ssh!
             this.postEvent(.resize);
         }
 
-        pub fn init(model: Model) @This() {
+        pub fn init(gpa: Allocator, io: std.Io, model: Model) @This() {
             return .{
+                .gpa = gpa,
+                .io = io,
                 .model = model,
                 .queue = .{},
-                .quit_event = .unset,
+                .quit_event = .{},
+                .config = undefined,
             };
         }
 
-        pub fn start(this: *@This()) !void {
+        pub fn start(this: *@This(), config: TerminalConfiguration) !void {
+            this.config = config;
             if (this.thread) |_| return;
 
             // post init event (as the very first element to be in the queue - event loop)
             this.postEvent(.init);
 
-            if (!this.winch_registered) {
+            if (!this.handler_registered) {
                 handler_ctx = this;
-                var act = posix.Sigaction{
+                posix.sigaction(posix.SIG.WINCH, &.{
                     .handler = .{ .handler = handleWinch },
                     .mask = posix.sigemptyset(),
                     .flags = 0,
-                };
-                posix.sigaction(posix.SIG.WINCH, &act, null);
-                this.winch_registered = true;
+                }, null);
+                posix.sigaction(posix.SIG.CONT, &.{
+                    .handler = .{ .handler = handleCont },
+                    .mask = posix.sigemptyset(),
+                    .flags = 0,
+                }, null);
+                this.handler_registered = true;
             }
 
             this.quit_event.reset();
             this.thread = try Thread.spawn(.{}, @This().run, .{this});
 
             var termios: posix.termios = undefined;
-            try terminal.enableRawMode(&termios);
+            if (this.config.rawMode) try terminal.enableRawMode(&termios);
             if (this.termios) |_| {} else this.termios = termios;
 
-            try terminal.enterAltScreen();
-            try terminal.saveScreen();
-            try terminal.hideCursor();
-            try terminal.enableMouseSupport();
+            if (this.config.altScreen) try terminal.enterAltScreen();
+            if (this.config.saveScreen) try terminal.saveScreen();
+            if (this.config.hideCursor) try terminal.hideCursor();
+            if (this.config.altScreen and this.config.rawMode) try terminal.enableMouseSupport();
         }
 
         pub fn interrupt(this: *@This()) !void {
             this.quit_event.set();
-            try terminal.disableMouseSupport();
-            try terminal.restoreScreen();
-            try terminal.exitAltScreen();
-            if (this.thread) |thread| {
+            if (this.config.altScreen and this.config.rawMode) try terminal.disableMouseSupport();
+            if (this.config.saveScreen) try terminal.restoreScreen();
+            if (this.config.altScreen) try terminal.exitAltScreen();
+            if (this.thread) |*thread| {
                 thread.join();
                 this.thread = null;
             }
@@ -92,18 +131,16 @@ pub fn App(comptime M: type, comptime E: type) type {
 
         pub fn stop(this: *@This()) !void {
             try this.interrupt();
+            if (this.config.hideCursor) try terminal.showCursor();
+            if (this.config.saveScreen) try terminal.resetCursor();
             if (this.termios) |termios| {
-                try terminal.disableMouseSupport();
-                try terminal.showCursor();
-                try terminal.restoreScreen();
-                try terminal.disableRawMode(&termios);
-                try terminal.exitAltScreen();
+                if (this.config.rawMode) try terminal.disableRawMode(&termios);
+                this.termios = null;
             }
-            this.termios = null;
         }
 
         /// Quit the application loop.
-        /// This will stop the internal input thread and post a **.quit** `Event`.
+        /// This will cancel the internal input thread and post a **.quit** `Event`.
         pub fn quit(this: *@This()) void {
             this.quit_event.set();
             this.postEvent(.quit);
@@ -121,13 +158,52 @@ pub fn App(comptime M: type, comptime E: type) type {
 
         fn run(this: *@This()) !void {
             // thread to read user inputs
-            var buf: [256]u8 = undefined;
+            var buf: [512]u8 = undefined;
+            // NOTE set the `NONBLOCK` option for the stdin file, such that reading is not blocking!
+            if (this.config.rawMode) {
+                // TODO is there a better way to do this through the `std.Io` interface?
+                var fl_flags = posix.fcntl(posix.STDIN_FILENO, posix.F.GETFL, 0) catch |err| switch (err) {
+                    error.FileBusy => unreachable,
+                    error.Locked => unreachable,
+                    error.PermissionDenied => unreachable,
+                    error.DeadLock => unreachable,
+                    error.LockedRegionLimitExceeded => unreachable,
+                    else => |e| return e,
+                };
+                fl_flags |= 1 << @bitOffsetOf(posix.system.O, "NONBLOCK");
+                _ = posix.fcntl(posix.STDIN_FILENO, posix.F.SETFL, fl_flags) catch |err| switch (err) {
+                    error.FileBusy => unreachable,
+                    error.Locked => unreachable,
+                    error.PermissionDenied => unreachable,
+                    error.DeadLock => unreachable,
+                    error.LockedRegionLimitExceeded => unreachable,
+                    else => |e| return e,
+                };
+            }
+
+            var remaining_bytes: usize = 0;
+            var lines: std.ArrayList(u8) = .empty;
+            defer lines.deinit(this.gpa);
+
             while (true) {
-                // FIX I still think that there is a race condition (I'm just waiting 'long' enough)
                 this.quit_event.timedWait(20 * std.time.ns_per_ms) catch {
-                    // FIX in case the queue is full -> the next user input should panic and quit the application? because something seems to clock up the event queue
-                    const read_bytes = try terminal.read(buf[0..]);
-                    // TODO `break` should not terminate the reading of the user inputs, but instead only the received faulty input!
+                    // non-blocking read
+                    const read_bytes = terminal.read(buf[remaining_bytes..]) catch |err| switch (err) {
+                        error.WouldBlock => {
+                            // wait a bit
+                            std.Thread.sleep(20);
+                            continue;
+                        },
+                        else => return err,
+                    } + remaining_bytes;
+                    remaining_bytes = 0;
+
+                    if (read_bytes == 0) {
+                        // received <EOF>
+                        this.postEvent(.cancel);
+                        continue;
+                    }
+
                     // escape key presses
                     if (buf[0] == 0x1b and read_bytes > 1) {
                         switch (buf[1]) {
@@ -154,9 +230,9 @@ pub fn App(comptime M: type, comptime E: type) type {
                                 if (read_bytes < 3) continue;
 
                                 // We start iterating at index 2 to get past the '['
-                                const sequence = for (buf[2..], 2..) |b, i| {
+                                const sequence: []u8 = blk: for (buf[2..], 2..) |b, i| {
                                     switch (b) {
-                                        0x40...0xFF => break buf[0 .. i + 1],
+                                        0x40...0xFF => break :blk buf[0 .. i + 1],
                                         else => continue,
                                     }
                                 } else continue;
@@ -287,18 +363,19 @@ pub fn App(comptime M: type, comptime E: type) type {
                                         // const alt = button_mask & mouse_bits.alt > 0;
                                         // const ctrl = button_mask & mouse_bits.ctrl > 0;
 
-                                        const mouse: Mouse = .{
-                                            .button = button,
-                                            .x = px -| 1,
-                                            .y = py -| 1,
-                                            .kind = blk: {
-                                                if (motion and button != Mouse.Button.none) break :blk .drag;
-                                                if (motion and button == Mouse.Button.none) break :blk .motion;
-                                                if (sequence[sequence.len - 1] == 'm') break :blk .release;
-                                                break :blk .press;
+                                        this.postEvent(.{
+                                            .mouse = .{
+                                                .button = button,
+                                                .x = px -| 1,
+                                                .y = py -| 1,
+                                                .kind = blk: {
+                                                    if (motion and button != Mouse.Button.none) break :blk .drag;
+                                                    if (motion and button == Mouse.Button.none) break :blk .motion;
+                                                    if (sequence[sequence.len - 1] == 'm') break :blk .release;
+                                                    break :blk .press;
+                                                },
                                             },
-                                        };
-                                        this.postEvent(.{ .mouse = mouse });
+                                        });
                                     },
                                     'c' => {
                                         // Primary DA (CSI ? Pm c)
@@ -366,26 +443,49 @@ pub fn App(comptime M: type, comptime E: type) type {
                             },
                         }
                     } else {
-                        const b = buf[0];
-                        const key: Key = switch (b) {
-                            0x00 => .{ .cp = '@', .mod = .{ .ctrl = true } },
-                            0x08 => .{ .cp = input.Backspace },
-                            0x09 => .{ .cp = input.Tab },
-                            0x0a => .{ .cp = 'j', .mod = .{ .ctrl = true } },
-                            0x0d => .{ .cp = input.Enter },
-                            0x01...0x07, 0x0b...0x0c, 0x0e...0x1a => .{ .cp = b + 0x60, .mod = .{ .ctrl = true } },
-                            0x1b => escape: {
-                                assert(read_bytes == 1);
-                                break :escape .{ .cp = input.Escape };
-                            },
-                            0x7f => .{ .cp = input.Backspace },
-                            else => {
-                                var iter: std.unicode.Utf8Iterator = .{ .bytes = buf[0..read_bytes], .i = 0 };
-                                while (iter.nextCodepoint()) |cp| this.postEvent(.{ .key = .{ .cp = cp } });
-                                continue;
-                            },
-                        };
-                        this.postEvent(.{ .key = key });
+                        if (this.config.rawMode) {
+                            const b = buf[0];
+                            const key: Key = switch (b) {
+                                0x00 => .{ .cp = '@', .mod = .{ .ctrl = true } },
+                                0x08 => .{ .cp = input.Backspace },
+                                0x09 => .{ .cp = input.Tab },
+                                0x0a => .{ .cp = 'j', .mod = .{ .ctrl = true } },
+                                0x0d => .{ .cp = input.Enter },
+                                0x01...0x07, 0x0b...0x0c, 0x0e...0x1a => .{ .cp = b + 0x60, .mod = .{ .ctrl = true } },
+                                0x1b => escape: {
+                                    assert(read_bytes == 1);
+                                    break :escape .{ .cp = input.Escape };
+                                },
+                                0x7f => .{ .cp = input.Backspace },
+                                else => {
+                                    var len = read_bytes;
+                                    while (!std.unicode.utf8ValidateSlice(buf[0..len])) len -= 1;
+                                    remaining_bytes = read_bytes - len;
+                                    var iter: std.unicode.Utf8Iterator = .{ .bytes = buf[0..len], .i = 0 };
+                                    while (iter.nextCodepoint()) |cp| this.postEvent(.{ .key = .{ .cp = cp } });
+                                    if (remaining_bytes > 0) {
+                                        @memmove(buf[0..remaining_bytes], buf[len .. len + remaining_bytes]);
+                                    }
+                                    continue; // this switch block does not return a `Key` we continue with loop
+                                },
+                            };
+                            this.postEvent(.{ .key = key });
+                        } else {
+                            var len = read_bytes;
+                            while (!std.unicode.utf8ValidateSlice(buf[0..len])) len -= 1;
+                            remaining_bytes = read_bytes - len;
+                            try lines.appendSlice(this.gpa, buf[0..len]);
+                            if (remaining_bytes > 0) {
+                                @memmove(buf[0..remaining_bytes], buf[len .. len + remaining_bytes]);
+                            } else {
+                                if (read_bytes != 512 and buf[len - 1] == '\n') this.postEvent(.{ .line = try lines.toOwnedSlice(this.gpa) });
+                                // NOTE line did not end with `\n` but with EOF, meaning the user canceled
+                                if (read_bytes != 512 and buf[len - 1] != '\n') {
+                                    lines.clearRetainingCapacity();
+                                    this.postEvent(.cancel);
+                                }
+                            }
+                        }
                     }
                     continue;
                 };
@@ -396,6 +496,7 @@ pub fn App(comptime M: type, comptime E: type) type {
         pub fn panic_handler(msg: []const u8, _: ?*std.builtin.StackTrace, ret_addr: ?usize) noreturn {
             terminal.disableMouseSupport() catch {};
             terminal.showCursor() catch {};
+            terminal.resetCursor() catch {};
             terminal.restoreScreen() catch {};
             terminal.disableRawMode(&.{
                 .iflag = .{},
@@ -418,12 +519,13 @@ pub fn App(comptime M: type, comptime E: type) type {
         pub const Element = element.Element(Model, Event);
         pub const Alignment = element.Alignment(Model, Event);
         pub const Button = element.Button(Model, Event, Queue);
+        pub const TextField = element.TextField(Model, Event);
         pub const Input = element.Input(Model, Event, Queue);
         pub const Progress = element.Progress(Model, Event, Queue);
         pub const RadioButton = element.RadioButton(Model, Event);
         pub const Scrollable = element.Scrollable(Model, Event);
         pub const Selection = element.Selection(Model, Event);
-        pub const Queue = queue.Queue(Event, 256);
+        pub const Queue = queue.Queue(Event, 512);
     };
 }
 
@@ -434,6 +536,7 @@ const mem = std.mem;
 const fmt = std.fmt;
 const posix = std.posix;
 const Thread = std.Thread;
+const Allocator = mem.Allocator;
 const assert = std.debug.assert;
 const event = @import("event.zig");
 const input = @import("input.zig");

src/cell.zig

@@ -1,6 +1,5 @@
 //! Cell type containing content and formatting for each character in the terminal screen.
 
-// TODO embrace `zg` dependency more due to utf-8 encoding
 cp: u21 = ' ',
 style: Style = .{ .emphasis = &.{} },
 
@@ -26,7 +25,7 @@ test "ascii styled text" {
         .{ .cp = 'Y', .style = .{ .fg = .green, .bg = .grey, .emphasis = &.{} } },
         .{ .cp = 'v', .style = .{ .emphasis = &.{ .bold, .underline } } },
         .{ .cp = 'e', .style = .{ .emphasis = &.{.italic} } },
-        .{ .cp = 's', .style = .{ .fg = .light_green, .bg = .black, .emphasis = &.{.underline} } },
+        .{ .cp = 's', .style = .{ .fg = .lightgreen, .bg = .black, .emphasis = &.{.underline} } },
     };
 
     var writer = std.Io.Writer.Allocating.init(std.testing.allocator);
@@ -46,7 +45,7 @@ test "utf-8 styled text" {
         .{ .cp = '╭', .style = .{ .fg = .green, .bg = .grey, .emphasis = &.{} } },
         .{ .cp = '─', .style = .{ .emphasis = &.{} } },
         .{ .cp = '┄', .style = .{ .emphasis = &.{} } },
-        .{ .cp = '┘', .style = .{ .fg = .light_green, .bg = .black, .emphasis = &.{.underline} } },
+        .{ .cp = '┘', .style = .{ .fg = .lightgreen, .bg = .black, .emphasis = &.{.underline} } },
     };
 
     var writer = std.Io.Writer.Allocating.init(std.testing.allocator);

src/color.zig

@@ -1,13 +1,13 @@
 pub const Color = enum(u8) {
     default = 0,
     black = 16,
-    light_red = 1,
-    light_green,
-    light_yellow,
-    light_blue,
-    light_magenta,
-    light_cyan,
-    light_grey,
+    lightred = 1,
+    lightgreen,
+    lightyellow,
+    lightblue,
+    lightmagenta,
+    lightcyan,
+    lightgrey,
     grey,
     red,
     green,
@@ -18,8 +18,6 @@ pub const Color = enum(u8) {
     white,
     // TODO add further colors as described in https://gist.github.com/ConnerWill/d4b6c776b509add763e17f9f113fd25b # Color / Graphics Mode - 256 Colors
 
-    // TODO might be useful to use the std.ascii stuff!
-
     pub inline fn write(this: Color, writer: *std.Io.Writer, comptime coloring: enum { fg, bg, ul }) !void {
         if (this == .default) {
             switch (coloring) {

src/container.zig

@@ -599,9 +599,11 @@ pub const Layout = packed struct {
 /// Sizing options which should be used by the `Container`
 pub const Size = packed struct {
     dim: Point = .{},
-    grow: enum(u2) {
+    grow: enum(u3) {
         both,
         fixed,
+        vertical_only,
+        horizontal_only,
         vertical,
         horizontal,
     } = .both,
@@ -648,16 +650,17 @@ pub fn Container(Model: type, Event: type) type {
         pub fn deinit(this: *@This()) void {
             for (this.elements.items) |*element| element.deinit();
             this.elements.deinit(this.allocator);
+            this.element.deinit();
         }
 
         pub fn append(this: *@This(), element: @This()) !void {
             try this.elements.append(this.allocator, element);
         }
 
-        pub fn reposition(this: *@This(), origin: Point) void {
+        pub fn reposition(this: *@This(), model: *const Model, origin: Point) void {
             const layout = this.properties.layout;
             this.origin = origin;
-            this.element.reposition(origin);
+            this.element.reposition(model, origin);
 
             var offset = origin.add(.{
                 .x = Layout.getAbsolutePadding(layout.padding.left, this.size.x),
@@ -669,7 +672,7 @@ pub fn Container(Model: type, Event: type) type {
             if (sides.top) offset.y += 1;
 
             for (this.elements.items) |*child| {
-                child.reposition(offset);
+                child.reposition(model, offset);
 
                 switch (layout.direction) {
                     .horizontal => offset.x += child.size.x + layout.gap,
@@ -684,7 +687,7 @@ pub fn Container(Model: type, Event: type) type {
         }
 
         /// Resize all fit sized `Containers` to the necessary size required by its child elements.
-        fn fit_resize(this: *@This()) Point {
+        fn fit_resize(this: *@This(), model: *const Model) Point {
             // NOTE this is supposed to be a simple and easy to understand algorithm, there are currently no optimizations done
             const layout = this.properties.layout;
             var size: Point = switch (layout.direction) {
@@ -709,7 +712,7 @@ pub fn Container(Model: type, Event: type) type {
             };
 
             for (this.elements.items) |*child| {
-                const child_size = child.fit_resize();
+                const child_size = child.fit_resize(model);
                 switch (layout.direction) {
                     .horizontal => {
                         size.x += child_size.x;
@@ -722,24 +725,29 @@ pub fn Container(Model: type, Event: type) type {
                 }
             }
 
+            size = this.minSize(model, size);
             // assign currently calculated size
             this.size = switch (this.properties.size.grow) {
-                .both => Point.max(size, this.properties.size.dim),
-                .fixed => this.properties.size.dim,
-                .horizontal => .{
-                    .x = @max(size.x, this.properties.size.dim.x),
-                    .y = this.properties.size.dim.y,
+                .both => .max(size, this.properties.size.dim),
+                .fixed => blk: {
+                    assert(this.properties.size.dim.x > 0 or size.x > 0);
+                    assert(this.properties.size.dim.y > 0 or size.y > 0);
+                    break :blk .max(size, this.properties.size.dim);
                 },
-                .vertical => .{
-                    .x = this.properties.size.dim.x,
-                    .y = @max(size.y, this.properties.size.dim.y),
+                .horizontal, .horizontal_only => blk: {
+                    assert(this.properties.size.dim.y > 0 or size.y > 0);
+                    break :blk .max(size, this.properties.size.dim);
+                },
+                .vertical, .vertical_only => blk: {
+                    assert(this.properties.size.dim.x > 0 or size.x > 0);
+                    break :blk .max(size, this.properties.size.dim);
                 },
             };
             return this.size;
         }
 
         /// growable implicitly requires the root `Container` to have a set a size property to the size of the available terminal screen
-        fn grow_resize(this: *@This(), max_size: Point) void {
+        fn grow_resize(this: *@This(), model: *const Model, max_size: Point) void {
             const layout = this.properties.layout;
             var remainder = switch (layout.direction) {
                 .horizontal => max_size.x -| (Layout.getAbsolutePadding(layout.padding.left, this.size.x) + Layout.getAbsolutePadding(layout.padding.right, this.size.x)),
@@ -756,23 +764,31 @@ pub fn Container(Model: type, Event: type) type {
 
             const sides = this.properties.border.sides;
             switch (layout.direction) {
-                .horizontal => {
+                .vertical => {
                     if (sides.top) {
-                        available -|= 1;
                         remainder -|= 1;
                     }
                     if (sides.bottom) {
-                        available -|= 1;
                         remainder -|= 1;
                     }
-                },
-                .vertical => {
                     if (sides.left) {
                         available -|= 1;
-                        remainder -|= 1;
                     }
                     if (sides.right) {
                         available -|= 1;
+                    }
+                },
+                .horizontal => {
+                    if (sides.top) {
+                        available -|= 1;
+                    }
+                    if (sides.bottom) {
+                        available -|= 1;
+                    }
+                    if (sides.left) {
+                        remainder -|= 1;
+                    }
+                    if (sides.right) {
                         remainder -|= 1;
                     }
                 },
@@ -793,21 +809,21 @@ pub fn Container(Model: type, Event: type) type {
                         if (growable_children == 0) first_growable_child = child;
                         growable_children += 1;
                     },
-                    .horizontal => if (layout.direction == .horizontal) {
+                    .horizontal, .horizontal_only => if (layout.direction == .horizontal) {
                         if (growable_children == 0) first_growable_child = child;
                         growable_children += 1;
                     },
-                    .vertical => if (layout.direction == .vertical) {
+                    .vertical, .vertical_only => if (layout.direction == .vertical) {
                         if (growable_children == 0) first_growable_child = child;
                         growable_children += 1;
                     },
                 }
                 // non layout direction side growth
                 switch (layout.direction) {
-                    .horizontal => if (child.properties.size.grow == .vertical or child.properties.size.grow == .both) {
+                    .horizontal => if (child.properties.size.grow == .vertical or child.properties.size.grow == .vertical_only or child.properties.size.grow == .both) {
                         child.size.y = available;
                     },
-                    .vertical => if (child.properties.size.grow == .horizontal or child.properties.size.grow == .both) {
+                    .vertical => if (child.properties.size.grow == .horizontal or child.properties.size.grow == .horizontal_only or child.properties.size.grow == .both) {
                         child.size.x = available;
                     },
                 }
@@ -825,8 +841,8 @@ pub fn Container(Model: type, Event: type) type {
                     if (child.properties.size.grow == .fixed) continue;
 
                     switch (layout.direction) {
-                        .horizontal => if (child.properties.size.grow == .vertical) continue,
-                        .vertical => if (child.properties.size.grow == .horizontal) continue,
+                        .horizontal => if (child.properties.size.grow == .vertical or child.properties.size.grow == .vertical_only) continue,
+                        .vertical => if (child.properties.size.grow == .horizontal or child.properties.size.grow == .horizontal_only) continue,
                     }
 
                     const size = switch (layout.direction) {
@@ -854,23 +870,23 @@ pub fn Container(Model: type, Event: type) type {
                     };
                     if (child.properties.size.grow != .fixed and child_size == smallest_size) {
                         switch (layout.direction) {
-                            .horizontal => if (child.properties.size.grow != .vertical) {
+                            .horizontal => if (child.properties.size.grow != .vertical and child.properties.size.grow != .vertical_only) {
                                 child.size.x += size_to_correct;
                                 remainder -|= size_to_correct;
                             },
-                            .vertical => if (child.properties.size.grow != .horizontal) {
+                            .vertical => if (child.properties.size.grow != .horizontal and child.properties.size.grow != .horizontal_only) {
                                 child.size.y += size_to_correct;
                                 remainder -|= size_to_correct;
                             },
                         }
                         if (overflow > 0) {
                             switch (layout.direction) {
-                                .horizontal => if (child.properties.size.grow != .vertical) {
+                                .horizontal => if (child.properties.size.grow != .vertical and child.properties.size.grow != .vertical_only) {
                                     child.size.x += 1;
                                     overflow -|= 1;
                                     remainder -|= 1;
                                 },
-                                .vertical => if (child.properties.size.grow != .horizontal) {
+                                .vertical => if (child.properties.size.grow != .horizontal and child.properties.size.grow != .horizontal_only) {
                                     child.size.y += 1;
                                     overflow -|= 1;
                                     remainder -|= 1;
@@ -881,28 +897,54 @@ pub fn Container(Model: type, Event: type) type {
                 }
             }
 
-            this.element.resize(this.size);
-            for (this.elements.items) |*child| child.grow_resize(child.size);
+            this.element.resize(model, this.size);
+            for (this.elements.items) |*child| child.grow_resize(model, child.size);
         }
 
-        pub fn resize(this: *@This(), size: Point) void {
+        pub fn resize(this: *@This(), model: *const Model, size: Point) void {
             // NOTE assume that this function is only called for the root `Container`
             this.size = size;
-            const fit_size = this.fit_resize();
-            // if (fit_size.y > size.y or fit_size.x > size.x) @panic("error: cannot render in available space");
-            switch (this.properties.size.grow) {
-                .both => this.size = Point.max(size, fit_size),
-                .fixed => {},
-                .horizontal => this.size = .{
+            const fit_size = this.fit_resize(model);
+            this.size = switch (this.properties.size.grow) {
+                .both => .max(size, fit_size),
+                .fixed => fit_size,
+                .horizontal_only => .{
+                    .x = size.x,
+                    .y = fit_size.y,
+                },
+                .vertical_only => .{
+                    .x = fit_size.x,
+                    .y = size.y,
+                },
+                .horizontal => .{
                     .x = @max(size.x, fit_size.x),
                     .y = size.y,
                 },
-                .vertical => this.size = .{
+                .vertical => .{
                     .x = size.x,
                     .y = @max(size.y, fit_size.y),
                 },
+            };
+            this.grow_resize(model, this.size);
+        }
+
+        pub fn minSize(this: *const @This(), model: *const Model, size: Point) Point {
+            var min_size: Point = .{};
+            for (this.elements.items) |*child| {
+                const child_size = child.minSize(model, child.properties.size.dim);
+                min_size = switch (this.properties.layout.direction) {
+                    .horizontal => .{
+                        .x = child_size.x + min_size.x,
+                        .y = @max(child_size.y, min_size.y),
+                    },
+                    .vertical => .{
+                        .x = @max(child_size.x, min_size.x),
+                        .y = child_size.y + min_size.y,
+                    },
+                };
             }
-            this.grow_resize(this.size);
+            const element_size = this.element.minSize(model, size);
+            return .max(element_size, min_size);
         }
 
         pub fn handle(this: *const @This(), model: *Model, event: Event) !void {
@@ -915,6 +957,11 @@ pub fn Container(Model: type, Event: type) type {
                     relative_mouse.y -= this.origin.y;
                     try this.element.handle(model, .{ .mouse = relative_mouse });
                 },
+                .bell => {
+                    // ring the terminal bell and do not propagate the event any further
+                    _ = try terminal.ringBell();
+                    return;
+                },
                 else => try this.element.handle(model, event),
             }
             for (this.elements.items) |*element| try element.handle(model, event);
@@ -961,6 +1008,7 @@ const assert = std.debug.assert;
 const Allocator = std.mem.Allocator;
 const build_options = @import("build_options");
 const input = @import("input.zig");
+const terminal = @import("terminal.zig");
 const isTaggedUnion = @import("event.zig").isTaggedUnion;
 const Cell = @import("cell.zig");
 const Color = @import("color.zig").Color;

src/ctlseqs.zig

@@ -50,6 +50,7 @@ pub const home = "\x1b[H";
 pub const cup = "\x1b[{d};{d}H";
 pub const hide_cursor = "\x1b[?25l";
 pub const show_cursor = "\x1b[?25h";
+pub const reset_cursor_shape = "\x1b[0 q";
 pub const cursor_shape = "\x1b[{d} q";
 pub const ri = "\x1bM";
 pub const ind = "\n";
@@ -139,5 +140,6 @@ pub const osc10_reset = "\x1b]110\x1b\\"; // reset fg to terminal default
 pub const osc11_query = "\x1b]11;?\x1b\\"; // bg
 pub const osc11_set = "\x1b]11;rgb:{x:0>2}{x:0>2}/{x:0>2}{x:0>2}/{x:0>2}{x:0>2}\x1b\\"; // set default terminal bg
 pub const osc11_reset = "\x1b]111\x1b\\"; // reset bg to terminal default
+pub const osc12_set = "\x1b]12;{s}\x1b\\"; // set the cursor color through the name of the 8 base colors!
 pub const osc12_query = "\x1b]12;?\x1b\\"; // cursor color
 pub const osc12_reset = "\x1b]112\x1b\\"; // reset cursor to terminal default

src/event.zig

@@ -8,8 +8,19 @@ pub const SystemEvent = union(enum) {
     init,
     /// Quit event to signify the end of the event loop (rendering should stop afterwards)
     quit,
+    /// Cancel event to signify that the user provided an EOF
+    ///
+    /// Usually this event is only triggered by the system in *non raw mode*
+    /// renderings otherwise the corresponding `.key` event would be fired instead.
+    cancel,
     /// Resize event to signify that the application should re-draw to resize
+    ///
+    /// Usually no `Container` nor `Element` should act on that event, as it
+    /// only serves for event based loops to force a re-draw with a new `Event`.
     resize,
+    /// Ring the terminal bell to notify the user. This `Event` is handled by
+    /// every `Container` and will not be passed through the container tree.
+    bell,
     /// Error event to notify other containers about a recoverable error
     err: struct {
         /// actual error
@@ -17,6 +28,11 @@ pub const SystemEvent = union(enum) {
         /// associated error message
         msg: []const u8,
     },
+    /// Input line event received in *non raw mode* (instead of individual `key` events)
+    ///
+    /// This event contains the entire line until the ending newline character
+    /// (which is included in the payload of this event).
+    line: []const u8,
     /// Input key event received from the user
     key: Key,
     /// Mouse input event
@@ -110,7 +126,7 @@ pub fn isTaggedUnion(comptime T: type) bool {
 /// Determine whether the provided type `T` is a `struct`.
 pub fn isStruct(comptime T: type) bool {
     return switch (@typeInfo(T)) {
-        .@"struct" => |_| true,
+        .@"struct" => true,
         else => false,
     };
 }

src/input.zig

@@ -65,7 +65,30 @@ pub const Key = packed struct {
         return meta.eql(this, other);
     }
 
-    // TODO might be useful to use the std.ascii stuff!
+    /// Determine if the `Key` is an unicode character that can be printed to
+    /// the screen. This means that the code point of the `Key` is an ascii
+    /// character between 32 - 255 (with the exception of 127 = Delete) and no
+    /// modifiers (alt and/or ctrl) are used.
+    ///
+    /// # Example
+    ///
+    /// Get user input's from the .key event from the application event loop:
+    ///
+    /// ```zig
+    /// switch (event) {
+    ///   .key => |key| if (key.isUnicode()) try this.input.append(key.cp),
+    ///   else => {},
+    /// }
+    /// ```
+    pub fn isUnicode(this: @This()) bool {
+        return this.mod.alt == false and this.mod.ctrl == false and // no modifier keys
+            (this.cp >= 32 and this.cp <= 126 or // ascii printable characters (except for input.Delete)
+                this.cp >= 128 and this.cp <= 255) or // extended ascii codes
+            ((this.cp >= 0x0080 and this.cp <= 0x07FF) or
+                (this.cp >= 0x0800 and this.cp <= 0xFFFF) or
+                (this.cp >= 0x100000 and this.cp <= 0x10FFFF)) and // allowed unicode character ranges (2 - 4 byte characters)
+                (this.cp < 57348 or this.cp > 57454); // no other predefined meanings (i.e. arrow keys, etc.)
+    }
 
     /// Determine if the `Key` is an ascii character that can be printed to
     /// the screen. This means that the code point of the `Key` is an ascii

src/queue.zig

@@ -1,7 +1,7 @@
 // taken from https://github.com/rockorager/libvaxis/blob/main/src/queue.zig (MIT-License)
 // with slight modifications
 
-/// Queue implementation. Thread safe. Fixed size. Blocking push and pop. Polling through tryPop and tryPush.
+/// Queue implementation. Thread safe. Fixed size. _Blocking_ `push` and `pop`. _Polling_ through `tryPop` and `tryPush`.
 pub fn Queue(comptime T: type, comptime size: usize) type {
     return struct {
         buf: [size]T = undefined,

src/render.zig

@@ -91,6 +91,7 @@ pub const Buffered = struct {
         var writer = terminal.writer();
         const s = this.screen;
         const vs = this.virtual_screen;
+
         for (0..this.size.y) |row| {
             for (0..this.size.x) |col| {
                 const idx = (row * this.size.x) + col;
@@ -104,6 +105,7 @@ pub const Buffered = struct {
                         .x = @truncate(col),
                         .y = @truncate(row),
                     };
+                    try cvs.style.set_cursor_style(&writer);
                 }
 
                 if (cs.eql(cvs)) continue;
@@ -122,6 +124,95 @@ pub const Buffered = struct {
     }
 };
 
+pub const Direct = struct {
+    gpa: Allocator,
+    size: Point,
+    resized: bool,
+    screen: []Cell,
+
+    pub fn init(gpa: Allocator) @This() {
+        return .{
+            .gpa = gpa,
+            .size = .{},
+            .resized = true,
+            .screen = undefined,
+        };
+    }
+
+    pub fn deinit(this: *@This()) void {
+        this.gpa.free(this.screen);
+    }
+
+    pub fn resize(this: *@This()) !Point {
+        this.size = .{};
+        if (!this.resized) {
+            this.gpa.free(this.screen);
+            this.screen = undefined;
+        }
+        this.resized = true;
+        return terminal.getTerminalSize();
+    }
+
+    pub fn clear(this: *@This()) !void {
+        _ = this;
+        try terminal.clearScreen();
+    }
+
+    pub fn writeCtrlDWithNewline(this: *@This()) !void {
+        _ = this;
+        _ = try terminal.write("^D\n");
+    }
+
+    pub fn writeNewline(this: *@This()) !void {
+        _ = this;
+        _ = try terminal.write("\n");
+    }
+
+    /// Render provided cells at size (anchor and dimension) into the *screen*.
+    pub fn render(this: *@This(), comptime Container: type, container: *Container, comptime Model: type, model: *const Model) !void {
+        const size: Point = container.size;
+        const origin: Point = container.origin;
+
+        if (this.resized) {
+            this.size = size;
+            const n = @as(usize, this.size.x) * @as(usize, this.size.y);
+            this.screen = try this.gpa.alloc(Cell, n);
+            @memset(this.screen, .{});
+            this.resized = false;
+        }
+
+        const cells: []const Cell = try container.content(model);
+
+        var idx: usize = 0;
+        var vs = this.screen;
+        const anchor: usize = (@as(usize, origin.y) * @as(usize, this.size.x)) + @as(usize, origin.x);
+
+        blk: for (0..size.y) |row| {
+            for (0..size.x) |col| {
+                vs[anchor + (row * this.size.x) + col] = cells[idx];
+                idx += 1;
+
+                if (cells.len == idx) break :blk;
+            }
+        }
+        // free immediately
+        container.allocator.free(cells);
+        for (container.elements.items) |*element| try this.render(Container, element, Model, model);
+    }
+
+    pub fn flush(this: *@This()) !void {
+        var writer = terminal.writer();
+        for (0..this.size.y) |row| {
+            for (0..this.size.x) |col| {
+                const idx = (row * this.size.x) + col;
+                const cvs = this.screen[idx];
+                try cvs.value(&writer);
+                if (cvs.style.cursor) return; // that's where the cursor should be left!
+            }
+        }
+    }
+};
+
 const std = @import("std");
 const meta = std.meta;
 const assert = std.debug.assert;

src/style.zig

@@ -12,6 +12,8 @@ fg: Color = .default,
 bg: Color = .default,
 ul: Color = .default,
 cursor: bool = false,
+cursor_color: Color = .default,
+cursor_shape: CursorShape = .default,
 ul_style: Underline = .off,
 emphasis: []const Emphasis,
 
@@ -36,11 +38,29 @@ pub const Emphasis = enum(u8) {
     strikethrough,
 };
 
+pub const CursorShape = enum(u4) {
+    default = 0,
+    block_blinking = 1,
+    block_steady,
+    underline_blinking,
+    underline_steady,
+    bar_blinking,
+    bar_steady,
+};
+
 pub fn eql(this: Style, other: Style) bool {
+    // TODO should there be a compare for every field?
     return meta.eql(this, other);
 }
 
-// TODO might be useful to use the std.ascii stuff!
+pub fn set_cursor_style(this: Style, writer: *std.Io.Writer) !void {
+    if (!this.cursor) return;
+    switch (this.cursor_color) {
+        .default => try writer.print(ctlseqs.osc12_reset, .{}),
+        else => try writer.print(ctlseqs.osc12_set, .{@tagName(this.cursor_color)}),
+    }
+    try writer.print(ctlseqs.cursor_shape, .{@intFromEnum(this.cursor_shape)});
+}
 
 pub fn value(this: Style, writer: *std.Io.Writer, cp: u21) !void {
     var buffer: [4]u8 = undefined;
@@ -74,4 +94,5 @@ const unicode = std.unicode;
 const meta = std.meta;
 const assert = std.debug.assert;
 const Color = @import("color.zig").Color;
+const ctlseqs = @import("ctlseqs.zig");
 const Style = @This();

src/terminal.zig

@@ -42,6 +42,11 @@ pub fn showCursor() !void {
     _ = try posix.write(posix.STDIN_FILENO, ctlseqs.show_cursor);
 }
 
+pub fn resetCursor() !void {
+    _ = try posix.write(posix.STDIN_FILENO, ctlseqs.reset_cursor_shape);
+    _ = try posix.write(posix.STDIN_FILENO, ctlseqs.osc12_reset);
+}
+
 pub fn setCursorPositionHome() !void {
     _ = try posix.write(posix.STDIN_FILENO, ctlseqs.home);
 }
@@ -54,6 +59,10 @@ pub fn disableMouseSupport() !void {
     _ = try posix.write(posix.STDIN_FILENO, ctlseqs.mouse_reset);
 }
 
+pub fn ringBell() !void {
+    _ = try posix.write(posix.STDIN_FILENO, &.{7});
+}
+
 pub fn read(buf: []u8) !usize {
     return try posix.read(posix.STDIN_FILENO, buf);
 }
@@ -89,7 +98,7 @@ pub fn setCursorPosition(pos: Point) !void {
     _ = try posix.write(posix.STDIN_FILENO, value);
 }
 
-pub fn getCursorPosition() !Size.Position {
+pub fn getCursorPosition() !Size {
     // Needs Raw mode (no wait for \n) to work properly cause
     // control sequence will not be written without it.
     _ = try posix.write(posix.STDIN_FILENO, "\x1b[6n");

src/testing.zig

@@ -112,9 +112,11 @@ pub fn expectContainerScreen(size: Point, comptime T: type, container: *T, compt
     var renderer: Renderer = .init(allocator, size);
     defer renderer.deinit();
 
-    container.resize(size);
-    container.reposition(.{});
-    try renderer.render(T, container, Model, &.{});
+    const model: Model = .{};
+
+    container.resize(&model, size);
+    container.reposition(&model, .{});
+    try renderer.render(T, container, Model, &model);
 
     try expectEqualCells(.{}, renderer.size, expected, renderer.screen);
 }
@@ -209,14 +211,16 @@ pub fn expectEqualCells(origin: Point, size: Point, expected: []const Cell, actu
     if (!differ) return;
 
     // test failed
-    debug.lockStdErr();
-    defer debug.unlockStdErr();
+    var buf: [1024]u8 = undefined;
+
+    std.debug.lockStdErr();
+    defer std.debug.unlockStdErr();
+
+    var buffer = std.fs.File.stderr().writer(&buf);
+    var error_writer = &buffer.interface;
+    try error_writer.writeAll(writer.buffer[0..writer.end]);
+    try error_writer.flush();
 
-    var stdout_buffer: [1024]u8 = undefined;
-    var stdout = std.fs.File.stdout().writer(&stdout_buffer);
-    const stdout_writer = &stdout.interface;
-    try stdout_writer.writeAll(writer.buffer[0..writer.end]);
-    try stdout_writer.flush();
     return error.TestExpectEqualCells;
 }