tag: 0.2.0

Correct example to use the actual `zterm.Error` type accordingly.

.gitea/workflows/test.yaml

@@ -18,7 +18,7 @@ jobs:
         with:
           version: master
       - name: Lint check
-        run: zig fmt --check .
+        run: zig fmt --check --exclude src/test .
       - name: Spell checking
         uses: crate-ci/typos@v1.25.0
         with:

README.md

@@ -10,7 +10,7 @@
 Clone this repository and run `zig build --help` to see the available examples. Run a given example as follows:
 
 ```sh
-zig build --release=safe -Dexample=input run
+zig build --release=safe -Dexample=demo run
 ```
 
 > [!TIP]

build.zig

@@ -5,6 +5,7 @@ pub fn build(b: *std.Build) void {
     const optimize = b.standardOptimizeOption(.{});
 
     const Examples = enum {
+        all,
         demo,
         // elements:
         button,
@@ -22,7 +23,7 @@ pub fn build(b: *std.Build) void {
         errors,
     };
 
-    const example = b.option(Examples, "example", "Example to build and/or run. (default: demo)") orelse .demo;
+    const example = b.option(Examples, "example", "Example to build and/or run. (default: all)") orelse .all;
 
     const options = b.addOptions();
     options.addOption(Examples, "example", example);
@@ -153,6 +154,19 @@ pub fn build(b: *std.Build) void {
         .palette => palette,
         // error handling:
         .errors => errors,
+        else => blk: {
+            b.installArtifact(button);
+            b.installArtifact(input);
+            b.installArtifact(scrollable);
+            b.installArtifact(vertical);
+            b.installArtifact(horizontal);
+            b.installArtifact(grid);
+            b.installArtifact(mixed);
+            b.installArtifact(text);
+            b.installArtifact(palette);
+            b.installArtifact(errors);
+            break :blk demo;
+        },
     };
     b.installArtifact(exe);
 

build.zig.zon

@@ -6,16 +6,29 @@
     //
     // It is redundant to include "zig" in this name because it is already
     // within the Zig package namespace.
-    .name = "zterm",
+    .name = .zterm,
+
+    // Together with name, this represents a globally unique package
+    // identifier. This field is generated by the Zig toolchain when the
+    // package is first created, and then *never changes*. This allows
+    // unambiguous detection of one package being an updated version of
+    // another.
+    //
+    // When forking a Zig project, this id should be regenerated (delete the
+    // field and run `zig build`) if the upstream project is still maintained.
+    // Otherwise, the fork is *hostile*, attempting to take control over the
+    // original project's identity. Thus it is recommended to leave the comment
+    // on the following line intact, so that it shows up in code reviews that
+    // modify the field.
+    .fingerprint = 0xf10b37e210a619d7, // Changing this has security and trust implications.
 
     // This is a [Semantic Version](https://semver.org/).
     // In a future version of Zig it will be used for package deduplication.
-    .version = "0.0.0",
+    .version = "0.2.0",
 
-    // This field is optional.
-    // This is currently advisory only; Zig does not yet do anything
-    // with this value.
-    //.minimum_zig_version = "0.11.0",
+    // Tracks the earliest Zig version that the package considers to be a
+    // supported use case.
+    .minimum_zig_version = "0.15.0-dev.56+d0911786c",
 
     // This field is optional.
     // Each dependency must either provide a `url` and `hash`, or a `path`.
@@ -29,11 +42,9 @@
         },
     },
     .paths = .{
+        "LICENSE",
         "build.zig",
         "build.zig.zon",
         "src",
-        // For example...
-        //"LICENSE",
-        //"README.md",
     },
 }

examples/demo.zig

@@ -13,20 +13,20 @@ const QuitText = struct {
         return .{ .ptr = this, .vtable = &.{ .content = content } };
     }
 
-    pub fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
+    pub fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
         _ = ctx;
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
-        const row = 2;
-        const col = size.cols / 2 -| (text.len / 2);
-        const anchor = (row * size.cols) + col;
+        const y = 2;
+        const x = size.x / 2 -| (text.len / 2);
+        const anchor = (y * size.x) + x;
 
         for (text, 0..) |cp, idx| {
             cells[anchor + idx].style.fg = .white;
             cells[anchor + idx].style.bg = .black;
             cells[anchor + idx].cp = cp;
 
-            // NOTE: do not write over the contents of this `Container`'s `Size`
+            // NOTE do not write over the contents of this `Container`'s `Size`
             if (anchor + idx == cells.len - 1) break;
         }
     }
@@ -35,7 +35,7 @@ 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
+    // TODO maybe create own allocator as some sort of arena allocator to have consistent memory usage
     var gpa: std.heap.GeneralPurposeAllocator(.{}) = .init;
     defer if (gpa.deinit() == .leak) log.err("memory leak", .{});
 
@@ -47,15 +47,22 @@ pub fn main() !void {
 
     var quit_text: QuitText = .{};
 
-    // TODO: what should the demo application do?
+    // TODO what should the demo application do?
     // - some sort of chat? -> write messages and have them displayed in a scrollable array at the right hand side?
     // - on the left some buttons?
     var box = try App.Container.init(allocator, .{
+        .border = .{
+            .color = .blue,
+            .sides = .all,
+        },
         .layout = .{
             .gap = 1,
             .padding = .vertical(2),
+            .direction = .vertical,
+        },
+        .size = .{
+            .dim = .{ .y = 90 },
         },
-        .min_size = .{ .cols = 50 },
     }, .{});
     try box.append(try App.Container.init(allocator, .{
         .rectangle = .{ .fill = .light_green },
@@ -68,16 +75,12 @@ pub fn main() !void {
     }, .{}));
     defer box.deinit();
 
-    var scrollable: App.Scrollable = .{
-        .container = box,
-    };
+    var scrollable: App.Scrollable = .{ .container = box };
 
     var container = try App.Container.init(allocator, .{
-        .border = .{
-            .separator = .{ .enabled = true },
-        },
         .layout = .{
             .gap = 2,
+            .separator = .{ .enabled = true },
             .padding = .{ .top = 5, .bottom = 3, .left = 3, .right = 3 },
             .direction = .horizontal,
         },
@@ -89,9 +92,15 @@ pub fn main() !void {
             .color = .light_blue,
             .sides = .all,
         },
+        .size = .{
+            .dim = .{ .x = 100 },
+        },
     }, .{}));
     try container.append(try App.Container.init(allocator, .{
         .rectangle = .{ .fill = .blue },
+        .size = .{
+            .dim = .{ .x = 30 },
+        },
     }, .{}));
     defer container.deinit(); // also de-initializes the children
 
@@ -103,10 +112,8 @@ pub fn main() !void {
         const event = app.nextEvent();
         log.debug("received event: {s}", .{@tagName(event)});
 
+        // pre event handling
         switch (event) {
-            .init => continue,
-            .quit => break,
-            .resize => |size| try renderer.resize(size),
             .key => |key| {
                 if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit();
 
@@ -123,18 +130,28 @@ pub fn main() !void {
                     continue;
                 }
             },
-            // NOTE: errors could be displayed in another container in case one was received, etc. to provide the user with feedback
+            // 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
+        // NOTE returned errors should be propagated back to the application
         container.handle(event) catch |err| app.postEvent(.{
             .err = .{
                 .err = err,
                 .msg = "Container Event handling failed",
             },
         });
+
+        // post event handling
+        switch (event) {
+            .quit => break,
+            else => {},
+        }
+
+        try renderer.resize();
+        container.resize(renderer.size);
+        container.reposition(.{});
         try renderer.render(@TypeOf(container), &container);
         try renderer.flush();
     }

examples/elements/button.zig

@@ -7,10 +7,37 @@ const App = zterm.App(union(enum) {
 
 const log = std.log.scoped(.default);
 
-pub const Clickable = struct {
+const QuitText = struct {
+    const text = "Press ctrl+c to quit.";
+
+    pub fn element(this: *@This()) App.Element {
+        return .{ .ptr = this, .vtable = &.{ .content = content } };
+    }
+
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
+        _ = ctx;
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
+
+        const row = 2;
+        const col = size.x / 2 -| (text.len / 2);
+        const anchor = (row * size.x) + col;
+
+        for (text, 0..) |cp, idx| {
+            cells[anchor + idx].style.fg = .white;
+            cells[anchor + idx].style.bg = .black;
+            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 Clickable = struct {
     const text = "Press me";
 
     queue: *App.Queue,
+    color: zterm.Color = .black,
 
     pub fn element(this: *@This()) App.Element {
         return .{
@@ -25,24 +52,32 @@ pub const Clickable = struct {
     fn handle(ctx: *anyopaque, event: App.Event) !void {
         const this: *@This() = @ptrCast(@alignCast(ctx));
         switch (event) {
-            .mouse => |mouse| this.queue.push(.{ .click = @tagName(mouse.button) }),
+            .mouse => |mouse| if (mouse.button == .left and mouse.kind == .release) {
+                var value = @intFromEnum(this.color);
+                value += 1;
+                value %= 17;
+                if (value == 0) value = 1;
+                this.color = @enumFromInt(value);
+                this.queue.push(.{ .click = @tagName(mouse.button) });
+            },
             else => {},
         }
     }
 
-    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
-        _ = ctx;
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
+        const this: *@This() = @ptrCast(@alignCast(ctx));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
-        const row = size.rows / 2 -| (text.len / 2);
-        const col = size.cols / 2 -| (text.len / 2);
-        const anchor = (row * size.cols) + col;
+        const row = size.y / 2 -| (text.len / 2);
+        const col = size.x / 2 -| (text.len / 2);
+        const anchor = (row * size.x) + col;
 
         for (text, 0..) |cp, idx| {
-            cells[anchor + idx].style.fg = .black;
+            cells[anchor + idx].style.fg = this.color;
+            cells[anchor + idx].style.emphasis = &.{.bold};
             cells[anchor + idx].cp = cp;
 
-            // NOTE: do not write over the contents of this `Container`'s `Size`
+            // NOTE do not write over the contents of this `Container`'s `Size`
             if (anchor + idx == cells.len - 1) break;
         }
     }
@@ -63,10 +98,12 @@ pub fn main() !void {
     var clickable: Clickable = .{ .queue = &app.queue };
     const element = clickable.element();
 
+    var quit_text: QuitText = .{};
+
     var container = try App.Container.init(allocator, .{
         .rectangle = .{ .fill = .grey },
         .layout = .{ .padding = .all(5) },
-    }, .{});
+    }, quit_text.element());
     defer container.deinit();
 
     try container.append(try App.Container.init(allocator, .{ .rectangle = .{ .fill = .light_grey } }, element));
@@ -79,10 +116,8 @@ pub fn main() !void {
         const event = app.nextEvent();
         log.debug("received event: {s}", .{@tagName(event)});
 
+        // pre event handling
         switch (event) {
-            .init => continue,
-            .quit => break,
-            .resize => |size| try renderer.resize(size),
             .key => |key| if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit(),
             .click => |button| {
                 log.info("Clicked with mouse using Button: {s}", .{button});
@@ -98,6 +133,15 @@ pub fn main() !void {
             },
         });
 
+        // post event handling
+        switch (event) {
+            .quit => break,
+            else => {},
+        }
+
+        try renderer.resize();
+        container.resize(renderer.size);
+        container.reposition(.{});
         try renderer.render(@TypeOf(container), &container);
         try renderer.flush();
     }

examples/elements/input.zig

@@ -7,7 +7,33 @@ const App = zterm.App(union(enum) {
 
 const log = std.log.scoped(.default);
 
-pub const InputField = struct {
+const QuitText = struct {
+    const text = "Press ctrl+c to quit.";
+
+    pub fn element(this: *@This()) App.Element {
+        return .{ .ptr = this, .vtable = &.{ .content = content } };
+    }
+
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
+        _ = ctx;
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
+
+        const row = 2;
+        const col = size.x / 2 -| (text.len / 2);
+        const anchor = (row * size.x) + col;
+
+        for (text, 0..) |cp, idx| {
+            cells[anchor + idx].style.fg = .white;
+            cells[anchor + idx].style.bg = .black;
+            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 InputField = struct {
     input: std.ArrayList(u21),
     queue: *App.Queue,
 
@@ -48,21 +74,21 @@ pub const InputField = struct {
         }
     }
 
-    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
         const this: *@This() = @ptrCast(@alignCast(ctx));
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
         if (this.input.items.len == 0) return;
 
         const row = 1;
         const col = 1;
-        const anchor = (row * size.cols) + col;
+        const anchor = (row * size.x) + col;
 
         for (this.input.items, 0..) |cp, idx| {
             cells[anchor + idx].style.fg = .black;
             cells[anchor + idx].cp = cp;
 
-            // NOTE: do not write over the contents of this `Container`'s `Size`
+            // NOTE do not write over the contents of this `Container`'s `Size`
             if (anchor + idx == cells.len - 1) break;
         }
     }
@@ -83,12 +109,14 @@ pub fn main() !void {
     var input_field: InputField = .init(allocator, &app.queue);
     defer input_field.deinit();
 
+    var quit_text: QuitText = .{};
+
     const element = input_field.element();
 
     var container = try App.Container.init(allocator, .{
         .rectangle = .{ .fill = .grey },
         .layout = .{ .padding = .all(5) },
-    }, .{});
+    }, quit_text.element());
     defer container.deinit();
 
     try container.append(try App.Container.init(allocator, .{ .rectangle = .{ .fill = .light_grey } }, element));
@@ -101,10 +129,8 @@ pub fn main() !void {
         const event = app.nextEvent();
         log.debug("received event: {s}", .{@tagName(event)});
 
+        // pre event handling
         switch (event) {
-            .init => continue,
-            .quit => break,
-            .resize => |size| try renderer.resize(size),
             .key => |key| if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit(),
             .accept => |input| {
                 defer allocator.free(input);
@@ -121,6 +147,15 @@ pub fn main() !void {
             },
         });
 
+        // post event handling
+        switch (event) {
+            .quit => break,
+            else => {},
+        }
+
+        try renderer.resize();
+        container.resize(renderer.size);
+        container.reposition(.{});
         try renderer.render(@TypeOf(container), &container);
         try renderer.flush();
     }

examples/elements/scrollable.zig

@@ -6,7 +6,33 @@ const App = zterm.App(union(enum) {});
 
 const log = std.log.scoped(.default);
 
-pub const HelloWorldText = packed struct {
+const QuitText = struct {
+    const text = "Press ctrl+c to quit.";
+
+    pub fn element(this: *@This()) App.Element {
+        return .{ .ptr = this, .vtable = &.{ .content = content } };
+    }
+
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
+        _ = ctx;
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
+
+        const row = 2;
+        const col = size.x / 2 -| (text.len / 2);
+        const anchor = (row * size.x) + col;
+
+        for (text, 0..) |cp, idx| {
+            cells[anchor + idx].style.fg = .white;
+            cells[anchor + idx].style.bg = .black;
+            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 HelloWorldText = packed struct {
     const text = "Hello World";
 
     pub fn element(this: *@This()) App.Element {
@@ -16,18 +42,21 @@ pub const HelloWorldText = packed struct {
         };
     }
 
-    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
         _ = ctx;
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
-        // NOTE: error should only be returned here in case an in-recoverable exception has occurred
-        const row = size.rows / 2;
-        const col = size.cols / 2 -| (text.len / 2);
-        const anchor = (row * size.cols) + col;
+        const row = size.y / 2;
+        const col = size.x / 2 -| (text.len / 2);
+        const anchor = (row * size.x) + col;
 
-        for (0.., text) |idx, char| {
-            cells[anchor + idx].style.fg = .black;
-            cells[anchor + idx].cp = char;
+        for (text, 0..) |cp, idx| {
+            cells[anchor + idx].style.fg = .white;
+            cells[anchor + idx].style.bg = .black;
+            cells[anchor + idx].cp = cp;
+
+            // NOTE do not write over the contents of this `Container`'s `Size`
+            if (anchor + idx == cells.len - 1) break;
         }
     }
 };
@@ -35,7 +64,7 @@ pub 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
+    // TODO maybe create own allocator as some sort of arena allocator to have consistent memory usage
     var gpa: std.heap.GeneralPurposeAllocator(.{}) = .init;
     defer {
         const deinit_status = gpa.deinit();
@@ -52,34 +81,55 @@ pub fn main() !void {
     var element_wrapper: HelloWorldText = .{};
     const element = element_wrapper.element();
 
+    var quit_text: QuitText = .{};
+
     var top_box = try App.Container.init(allocator, .{
         .rectangle = .{ .fill = .blue },
         .layout = .{
-            .gap = 1,
+            .gap = 2,
+            .separator = .{
+                .enabled = true,
+            },
             .direction = .vertical,
             .padding = .vertical(1),
         },
-        .min_size = .{ .rows = 50 },
     }, .{});
     try top_box.append(try App.Container.init(allocator, .{
         .rectangle = .{ .fill = .light_green },
+        .size = .{
+            .dim = .{ .y = 30 },
+        },
     }, .{}));
     try top_box.append(try App.Container.init(allocator, .{
         .rectangle = .{ .fill = .light_green },
+        .size = .{
+            .dim = .{ .y = 5 },
+        },
     }, element));
     try top_box.append(try App.Container.init(allocator, .{
         .rectangle = .{ .fill = .light_green },
+        .size = .{
+            .dim = .{ .y = 2 },
+        },
     }, .{}));
     defer top_box.deinit();
 
     var bottom_box = try App.Container.init(allocator, .{
-        .border = .{ .separator = .{ .enabled = true } },
-        .rectangle = .{ .fill = .blue },
+        .border = .{
+            .sides = .all,
+            .color = .blue,
+        },
         .layout = .{
+            .separator = .{
+                .enabled = true,
+                .color = .red,
+            },
             .direction = .vertical,
             .padding = .vertical(1),
         },
-        .min_size = .{ .rows = 30 },
+        .size = .{
+            .dim = .{ .y = 30 },
+        },
     }, .{});
     try bottom_box.append(try App.Container.init(allocator, .{
         .rectangle = .{ .fill = .grey },
@@ -93,25 +143,23 @@ pub fn main() !void {
     defer bottom_box.deinit();
 
     var container = try App.Container.init(allocator, .{
-        .border = .{
+        .layout = .{
+            .gap = 2,
             .separator = .{
                 .enabled = true,
                 .line = .double,
             },
-        },
-        .layout = .{
-            .gap = 2,
-            .padding = .all(5),
+            .padding = .{ .top = 5, .bottom = 3, .left = 3, .right = 3 },
             .direction = .vertical,
         },
-    }, .{});
+    }, quit_text.element());
     defer container.deinit();
 
     // place empty container containing the element of the scrollable Container.
-    var scrollable_top: App.Scrollable = .init(top_box);
+    var scrollable_top: App.Scrollable = .{ .container = top_box };
     try container.append(try App.Container.init(allocator, .{}, scrollable_top.element()));
 
-    var scrollable_bottom: App.Scrollable = .init(bottom_box);
+    var scrollable_bottom: App.Scrollable = .{ .container = bottom_box };
     try container.append(try App.Container.init(allocator, .{}, scrollable_bottom.element()));
 
     try app.start();
@@ -122,10 +170,8 @@ pub fn main() !void {
         const event = app.nextEvent();
         log.debug("received event: {s}", .{@tagName(event)});
 
+        // pre event handling
         switch (event) {
-            .init => continue,
-            .quit => break,
-            .resize => |size| try renderer.resize(size),
             .key => |key| if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit(),
             .err => |err| log.err("Received {s} with message: {s}", .{ @errorName(err.err), err.msg }),
             else => {},
@@ -137,6 +183,16 @@ pub fn main() !void {
                 .msg = "Container Event handling failed",
             },
         });
+
+        // post event handling
+        switch (event) {
+            .quit => break,
+            else => {},
+        }
+
+        try renderer.resize();
+        container.resize(renderer.size);
+        container.reposition(.{});
         try renderer.render(@TypeOf(container), &container);
         try renderer.flush();
     }

examples/errors.zig

@@ -12,20 +12,20 @@ const QuitText = struct {
         return .{ .ptr = this, .vtable = &.{ .content = content } };
     }
 
-    pub fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
         _ = ctx;
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
         const row = 2;
-        const col = size.cols / 2 -| (text.len / 2);
-        const anchor = (row * size.cols) + col;
+        const col = size.x / 2 -| (text.len / 2);
+        const anchor = (row * size.x) + col;
 
         for (text, 0..) |cp, idx| {
             cells[anchor + idx].style.fg = .white;
             cells[anchor + idx].style.bg = .black;
             cells[anchor + idx].cp = cp;
 
-            // NOTE: do not write over the contents of this `Container`'s `Size`
+            // NOTE do not write over the contents of this `Container`'s `Size`
             if (anchor + idx == cells.len - 1) break;
         }
     }
@@ -38,20 +38,20 @@ const InfoText = struct {
         return .{ .ptr = this, .vtable = &.{ .content = content } };
     }
 
-    pub fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
         _ = ctx;
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
         const row = 2;
-        const col = size.cols / 2 -| (text.len / 2);
-        const anchor = (row * size.cols) + col;
+        const col = size.x / 2 -| (text.len / 2);
+        const anchor = (row * size.x) + col;
 
         for (text, 0..) |cp, idx| {
             cells[anchor + idx].style.fg = .white;
             cells[anchor + idx].style.bg = .black;
             cells[anchor + idx].cp = cp;
 
-            // NOTE: do not write over the contents of this `Container`'s `Size`
+            // NOTE do not write over the contents of this `Container`'s `Size`
             if (anchor + idx == cells.len - 1) break;
         }
     }
@@ -64,31 +64,30 @@ const ErrorNotification = struct {
         return .{ .ptr = this, .vtable = &.{ .handle = handle, .content = content } };
     }
 
-    pub fn handle(ctx: *anyopaque, event: App.Event) !void {
+    fn handle(ctx: *anyopaque, event: App.Event) !void {
         const this: *@This() = @ptrCast(@alignCast(ctx));
         switch (event) {
-            .key => |key| if (!key.isAscii()) return error.UnsupportedKey,
-            .resize => |_| {},
+            .key => |key| if (!key.isAscii()) return zterm.Error.TooSmall,
             .err => |err| this.msg = err.msg,
             else => {},
         }
     }
 
-    pub fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
         const this: *@This() = @ptrCast(@alignCast(ctx));
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
         if (this.msg) |msg| {
-            const row = size.rows -| 2;
-            const col = size.cols -| 2 -| msg.len;
-            const anchor = (row * size.cols) + col;
+            const row = size.y -| 2;
+            const col = size.x -| 2 -| msg.len;
+            const anchor = (row * size.x) + col;
 
             for (msg, 0..) |cp, idx| {
                 cells[anchor + idx].style.fg = .white;
                 cells[anchor + idx].style.bg = .black;
                 cells[anchor + idx].cp = cp;
 
-                // NOTE: do not write over the contents of this `Container`'s `Size`
+                // NOTE do not write over the contents of this `Container`'s `Size`
                 if (anchor + idx == cells.len - 1) break;
             }
 
@@ -131,10 +130,8 @@ pub fn main() !void {
         const event = app.nextEvent();
         log.debug("received event: {s}", .{@tagName(event)});
 
+        // pre event handling
         switch (event) {
-            .init => continue,
-            .quit => break,
-            .resize => |size| try renderer.resize(size),
             .key => |key| if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit(),
             .err => |err| log.err("Received {s} with message: {s}", .{ @errorName(err.err), err.msg }),
             else => {},
@@ -146,6 +143,16 @@ pub fn main() !void {
                 .msg = "Container Event handling failed",
             },
         });
+
+        // post event handling
+        switch (event) {
+            .quit => break,
+            else => {},
+        }
+
+        try renderer.resize();
+        container.resize(renderer.size);
+        container.reposition(.{});
         try renderer.render(@TypeOf(container), &container);
         try renderer.flush();
     }

examples/layouts/grid.zig

@@ -15,20 +15,20 @@ const QuitText = struct {
         };
     }
 
-    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
         _ = ctx;
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
         const row = 2;
-        const col = size.cols / 2 -| (text.len / 2);
-        const anchor = (row * size.cols) + col;
+        const col = size.x / 2 -| (text.len / 2);
+        const anchor = (row * size.x) + col;
 
         for (text, 0..) |cp, idx| {
             cells[anchor + idx].style.fg = .white;
             cells[anchor + idx].style.bg = .black;
             cells[anchor + idx].cp = cp;
 
-            // NOTE: do not write over the contents of this `Container`'s `Size`
+            // NOTE do not write over the contents of this `Container`'s `Size`
             if (anchor + idx == cells.len - 1) break;
         }
     }
@@ -50,16 +50,16 @@ pub fn main() !void {
     const element = quit_text.element();
 
     var container = try App.Container.init(allocator, .{
-        .border = .{ .separator = .{ .enabled = true } },
         .layout = .{
+            .separator = .{ .enabled = true },
             .padding = .{ .top = 5, .bottom = 3, .left = 3, .right = 3 },
             .direction = .horizontal,
         },
     }, element);
     for (0..3) |_| {
         var column = try App.Container.init(allocator, .{
-            .border = .{ .separator = .{ .enabled = true } },
             .layout = .{
+                .separator = .{ .enabled = true },
                 .direction = .vertical,
             },
         }, .{});
@@ -84,23 +84,31 @@ pub fn main() !void {
         const event = app.nextEvent();
         log.debug("received event: {s}", .{@tagName(event)});
 
+        // pre event handling
         switch (event) {
-            .init => continue,
-            .quit => break,
-            .resize => |size| try renderer.resize(size),
             .key => |key| if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit(),
-            // NOTE: errors could be displayed in another container in case one was received, etc. to provide the user with feedback
+            // 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
+        // NOTE returned errors should be propagated back to the application
         container.handle(event) catch |err| app.postEvent(.{
             .err = .{
                 .err = err,
                 .msg = "Container Event handling failed",
             },
         });
+
+        // post event handling
+        switch (event) {
+            .quit => break,
+            else => {},
+        }
+
+        try renderer.resize();
+        container.resize(renderer.size);
+        container.reposition(.{});
         try renderer.render(@TypeOf(container), &container);
         try renderer.flush();
     }

examples/layouts/horizontal.zig

@@ -15,20 +15,20 @@ const QuitText = struct {
         };
     }
 
-    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
         _ = ctx;
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
         const row = 2;
-        const col = size.cols / 2 -| (text.len / 2);
-        const anchor = (row * size.cols) + col;
+        const col = size.x / 2 -| (text.len / 2);
+        const anchor = (row * size.x) + col;
 
         for (text, 0..) |cp, idx| {
             cells[anchor + idx].style.fg = .white;
             cells[anchor + idx].style.bg = .black;
             cells[anchor + idx].cp = cp;
 
-            // NOTE: do not write over the contents of this `Container`'s `Size`
+            // NOTE do not write over the contents of this `Container`'s `Size`
             if (anchor + idx == cells.len - 1) break;
         }
     }
@@ -76,23 +76,31 @@ pub fn main() !void {
         const event = app.nextEvent();
         log.debug("received event: {s}", .{@tagName(event)});
 
+        // pre event handling
         switch (event) {
-            .init => continue,
-            .quit => break,
-            .resize => |size| try renderer.resize(size),
             .key => |key| if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit(),
-            // NOTE: errors could be displayed in another container in case one was received, etc. to provide the user with feedback
+            // 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
+        // NOTE returned errors should be propagated back to the application
         container.handle(event) catch |err| app.postEvent(.{
             .err = .{
                 .err = err,
                 .msg = "Container Event handling failed",
             },
         });
+
+        // post event handling
+        switch (event) {
+            .quit => break,
+            else => {},
+        }
+
+        try renderer.resize();
+        container.resize(renderer.size);
+        container.reposition(.{});
         try renderer.render(@TypeOf(container), &container);
         try renderer.flush();
     }

examples/layouts/mixed.zig

@@ -15,20 +15,20 @@ const QuitText = struct {
         };
     }
 
-    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
         _ = ctx;
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
         const row = 2;
-        const col = size.cols / 2 -| (text.len / 2);
-        const anchor = (row * size.cols) + col;
+        const col = size.x / 2 -| (text.len / 2);
+        const anchor = (row * size.x) + col;
 
         for (text, 0..) |cp, idx| {
             cells[anchor + idx].style.fg = .white;
             cells[anchor + idx].style.bg = .black;
             cells[anchor + idx].cp = cp;
 
-            // NOTE: do not write over the contents of this `Container`'s `Size`
+            // NOTE do not write over the contents of this `Container`'s `Size`
             if (anchor + idx == cells.len - 1) break;
         }
     }
@@ -53,13 +53,12 @@ pub fn main() !void {
         .layout = .{
             .gap = 2,
             .padding = .{ .top = 5, .bottom = 3, .left = 3, .right = 3 },
-            .direction = .horizontal,
         },
     }, element);
     for (0..3) |i| {
         var column = try App.Container.init(allocator, .{
-            .border = .{ .separator = .{ .enabled = true } },
             .layout = .{
+                .separator = .{ .enabled = true },
                 .direction = if (i > 0) .vertical else .horizontal,
             },
         }, .{});
@@ -71,7 +70,12 @@ pub fn main() !void {
                 .rectangle = .{ .fill = .yellow },
             }, .{}));
         } else {
-            try column.append(try App.Container.init(allocator, .{}, .{}));
+            try column.append(try App.Container.init(allocator, .{
+                .size = .{
+                    .dim = .{ .y = 4 },
+                    .grow = .horizontal,
+                },
+            }, .{}));
         }
         try column.append(try App.Container.init(allocator, .{
             .rectangle = .{ .fill = .blue },
@@ -88,23 +92,31 @@ pub fn main() !void {
         const event = app.nextEvent();
         log.debug("received event: {s}", .{@tagName(event)});
 
+        // pre event handling
         switch (event) {
-            .init => continue,
-            .quit => break,
-            .resize => |size| try renderer.resize(size),
             .key => |key| if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit(),
-            // NOTE: errors could be displayed in another container in case one was received, etc. to provide the user with feedback
+            // 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
+        // NOTE returned errors should be propagated back to the application
         container.handle(event) catch |err| app.postEvent(.{
             .err = .{
                 .err = err,
                 .msg = "Container Event handling failed",
             },
         });
+
+        // post event handling
+        switch (event) {
+            .quit => break,
+            else => {},
+        }
+
+        try renderer.resize();
+        container.resize(renderer.size);
+        container.reposition(.{});
         try renderer.render(@TypeOf(container), &container);
         try renderer.flush();
     }

examples/layouts/vertical.zig

@@ -15,20 +15,20 @@ const QuitText = struct {
         };
     }
 
-    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
         _ = ctx;
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
         const row = 2;
-        const col = size.cols / 2 -| (text.len / 2);
-        const anchor = (row * size.cols) + col;
+        const col = size.x / 2 -| (text.len / 2);
+        const anchor = (row * size.x) + col;
 
         for (text, 0..) |cp, idx| {
             cells[anchor + idx].style.fg = .white;
             cells[anchor + idx].style.bg = .black;
             cells[anchor + idx].cp = cp;
 
-            // NOTE: do not write over the contents of this `Container`'s `Size`
+            // NOTE do not write over the contents of this `Container`'s `Size`
             if (anchor + idx == cells.len - 1) break;
         }
     }
@@ -75,23 +75,31 @@ pub fn main() !void {
         const event = app.nextEvent();
         log.debug("received event: {s}", .{@tagName(event)});
 
+        // pre event handling
         switch (event) {
-            .init => continue,
-            .quit => break,
-            .resize => |size| try renderer.resize(size),
             .key => |key| if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit(),
-            // NOTE: errors could be displayed in another container in case one was received, etc. to provide the user with feedback
+            // 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
+        // NOTE returned errors should be propagated back to the application
         container.handle(event) catch |err| app.postEvent(.{
             .err = .{
                 .err = err,
                 .msg = "Container Event handling failed",
             },
         });
+
+        // post event handling
+        switch (event) {
+            .quit => break,
+            else => {},
+        }
+
+        try renderer.resize();
+        container.resize(renderer.size);
+        container.reposition(.{});
         try renderer.render(@TypeOf(container), &container);
         try renderer.flush();
     }

examples/styles/palette.zig

@@ -12,20 +12,20 @@ const QuitText = struct {
         return .{ .ptr = this, .vtable = &.{ .content = content } };
     }
 
-    pub fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
         _ = ctx;
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
         const row = 2;
-        const col = size.cols / 2 -| (text.len / 2);
-        const anchor = (row * size.cols) + col;
+        const col = size.x / 2 -| (text.len / 2);
+        const anchor = (row * size.x) + col;
 
         for (text, 0..) |cp, idx| {
             cells[anchor + idx].style.fg = .white;
             cells[anchor + idx].style.bg = .black;
             cells[anchor + idx].cp = cp;
 
-            // NOTE: do not write over the contents of this `Container`'s `Size`
+            // NOTE do not write over the contents of this `Container`'s `Size`
             if (anchor + idx == cells.len - 1) break;
         }
     }
@@ -56,7 +56,6 @@ pub fn main() !void {
 
     var box = try App.Container.init(allocator, .{
         .layout = .{ .direction = .horizontal },
-        .min_size = .{ .cols = 3 * std.meta.fields(zterm.Color).len }, // ensure enough columns to render all colors -> scrollable otherwise
     }, .{});
     defer box.deinit();
 
@@ -64,7 +63,7 @@ pub fn main() !void {
         if (comptime field.value == 0) continue; // zterm.Color.default == 0 -> skip
         try box.append(try App.Container.init(allocator, .{ .rectangle = .{ .fill = @enumFromInt(field.value) } }, .{}));
     }
-    var scrollable: App.Scrollable = .init(box);
+    var scrollable: App.Scrollable = .{ .container = box };
     try container.append(try App.Container.init(allocator, .{}, scrollable.element()));
 
     try app.start();
@@ -74,10 +73,8 @@ pub fn main() !void {
         const event = app.nextEvent();
         log.debug("received event: {s}", .{@tagName(event)});
 
+        // pre event handling
         switch (event) {
-            .init => continue,
-            .quit => break,
-            .resize => |size| try renderer.resize(size),
             .key => |key| if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit(),
             .err => |err| log.err("Received {s} with message: {s}", .{ @errorName(err.err), err.msg }),
             else => {},
@@ -89,6 +86,16 @@ pub fn main() !void {
                 .msg = "Container Event handling failed",
             },
         });
+
+        // post event handling
+        switch (event) {
+            .quit => break,
+            else => {},
+        }
+
+        try renderer.resize();
+        container.resize(renderer.size);
+        container.reposition(.{});
         try renderer.render(@TypeOf(container), &container);
         try renderer.flush();
     }

examples/styles/text.zig

@@ -12,20 +12,20 @@ const QuitText = struct {
         return .{ .ptr = this, .vtable = &.{ .content = content } };
     }
 
-    pub fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
         _ = ctx;
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
         const row = 2;
-        const col = size.cols / 2 -| (text.len / 2);
-        const anchor = (row * size.cols) + col;
+        const col = size.x / 2 -| (text.len / 2);
+        const anchor = (row * size.x) + col;
 
         for (text, 0..) |cp, idx| {
             cells[anchor + idx].style.fg = .white;
             cells[anchor + idx].style.bg = .black;
             cells[anchor + idx].cp = cp;
 
-            // NOTE: do not write over the contents of this `Container`'s `Size`
+            // NOTE do not write over the contents of this `Container`'s `Size`
             if (anchor + idx == cells.len - 1) break;
         }
     }
@@ -38,10 +38,10 @@ const TextStyles = struct {
         return .{ .ptr = this, .vtable = &.{ .content = content } };
     }
 
-    pub fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Size) !void {
+    fn content(ctx: *anyopaque, cells: []zterm.Cell, size: zterm.Point) !void {
         @setEvalBranchQuota(50000);
         _ = ctx;
-        std.debug.assert(cells.len == @as(usize, size.cols) * @as(usize, size.rows));
+        std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
 
         var row: usize = 0;
         var col: usize = 0;
@@ -56,9 +56,9 @@ const TextStyles = struct {
 
                 // witouth any emphasis
                 for (text) |cp| {
-                    cells[(row * size.cols) + col].style.bg = @enumFromInt(bg_field.value);
-                    cells[(row * size.cols) + col].style.fg = @enumFromInt(fg_field.value);
-                    cells[(row * size.cols) + col].cp = cp;
+                    cells[(row * size.x) + col].style.bg = @enumFromInt(bg_field.value);
+                    cells[(row * size.x) + col].style.fg = @enumFromInt(fg_field.value);
+                    cells[(row * size.x) + col].cp = cp;
                     col += 1;
                 }
 
@@ -68,10 +68,10 @@ const TextStyles = struct {
                     const emphasis: zterm.Style.Emphasis = @enumFromInt(emp_field.value);
 
                     for (text) |cp| {
-                        cells[(row * size.cols) + col].style.bg = @enumFromInt(bg_field.value);
-                        cells[(row * size.cols) + col].style.fg = @enumFromInt(fg_field.value);
-                        cells[(row * size.cols) + col].style.emphasis = &.{emphasis};
-                        cells[(row * size.cols) + col].cp = cp;
+                        cells[(row * size.x) + col].style.bg = @enumFromInt(bg_field.value);
+                        cells[(row * size.x) + col].style.fg = @enumFromInt(fg_field.value);
+                        cells[(row * size.x) + col].style.emphasis = &.{emphasis};
+                        cells[(row * size.x) + col].cp = cp;
                         col += 1;
                     }
                 }
@@ -109,14 +109,16 @@ pub fn main() !void {
 
     var box = try App.Container.init(allocator, .{
         .layout = .{ .direction = .vertical },
-        .min_size = .{
-            .rows = (std.meta.fields(zterm.Color).len - 1) * (std.meta.fields(zterm.Color).len - 2),
-            .cols = std.meta.fields(zterm.Style.Emphasis).len * TextStyles.text.len,
-        }, // ensure enough rows and/or columns to render all text styles -> scrollable otherwise
+        .size = .{
+            .dim = .{
+                .x = std.meta.fields(zterm.Style.Emphasis).len * TextStyles.text.len,
+                .y = (std.meta.fields(zterm.Color).len - 1) * (std.meta.fields(zterm.Color).len - 2),
+            },
+        },
     }, text_styles.element());
     defer box.deinit();
 
-    var scrollable: App.Scrollable = .init(box);
+    var scrollable: App.Scrollable = .{ .container = box };
     try container.append(try App.Container.init(allocator, .{}, scrollable.element()));
 
     try app.start();
@@ -126,10 +128,8 @@ pub fn main() !void {
         const event = app.nextEvent();
         log.debug("received event: {s}", .{@tagName(event)});
 
+        // pre event handling
         switch (event) {
-            .init => continue,
-            .quit => break,
-            .resize => |size| try renderer.resize(size),
             .key => |key| if (key.eql(.{ .cp = 'c', .mod = .{ .ctrl = true } })) app.quit(),
             .err => |err| log.err("Received {s} with message: {s}", .{ @errorName(err.err), err.msg }),
             else => {},
@@ -141,6 +141,16 @@ pub fn main() !void {
                 .msg = "Container Event handling failed",
             },
         });
+
+        // post event handling
+        switch (event) {
+            .quit => break,
+            else => {},
+        }
+
+        try renderer.resize();
+        container.resize(renderer.size);
+        container.reposition(.{});
         try renderer.render(@TypeOf(container), &container);
         try renderer.flush();
     }

src/app.zig

@@ -11,7 +11,7 @@ const isTaggedUnion = event.isTaggedUnion;
 
 const Mouse = input.Mouse;
 const Key = input.Key;
-const Size = @import("size.zig").Size;
+const Point = @import("point.zig").Point;
 
 const log = std.log.scoped(.app);
 
@@ -51,7 +51,6 @@ pub fn App(comptime E: type) type {
         quit_event: std.Thread.ResetEvent,
         termios: ?std.posix.termios = null,
         attached_handler: bool = false,
-        prev_size: Size,
 
         pub const SignalHandler = struct {
             context: *anyopaque,
@@ -64,7 +63,6 @@ pub fn App(comptime E: type) type {
             .quit_event = .{},
             .termios = null,
             .attached_handler = false,
-            .prev_size = .{},
         };
 
         pub fn start(this: *@This()) !void {
@@ -99,11 +97,6 @@ pub fn App(comptime E: type) type {
             try terminal.enterAltScreen();
             try terminal.hideCursor();
             try terminal.enableMouseSupport();
-
-            // send initial size afterwards
-            const size = terminal.getTerminalSize();
-            this.postEvent(.{ .resize = size });
-            this.prev_size = size;
         }
 
         pub fn interrupt(this: *@This()) !void {
@@ -148,11 +141,8 @@ pub fn App(comptime E: type) type {
 
         fn winsizeCallback(ptr: *anyopaque) void {
             const this: *@This() = @ptrCast(@alignCast(ptr));
-            const size = terminal.getTerminalSize();
-            if (size.cols != this.prev_size.cols or size.rows != this.prev_size.rows) {
-                this.postEvent(.{ .resize = size });
-                this.prev_size = size;
-            }
+            _ = this;
+            // this.postEvent(.{ .size = terminal.getTerminalSize() });
         }
 
         var winch_handler: ?SignalHandler = null;
@@ -174,11 +164,11 @@ pub fn App(comptime E: type) type {
             // thread to read user inputs
             var buf: [256]u8 = undefined;
             while (true) {
-                // FIX: I still think that there is a race condition (I'm just waiting 'long' enough)
+                // 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
+                    // 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!
+                    // TODO `break` should not terminate the reading of the user inputs, but instead only the received faulty input!
                     // escape key presses
                     if (buf[0] == 0x1b and read_bytes > 1) {
                         switch (buf[1]) {
@@ -273,7 +263,7 @@ pub fn App(comptime E: type) type {
                                         };
                                         this.postEvent(.{ .key = key });
                                     },
-                                    // TODO: focus usage? should this even be in the default event system?
+                                    // TODO focus usage? should this even be in the default event system?
                                     'I' => this.postEvent(.{ .focus = true }),
                                     'O' => this.postEvent(.{ .focus = false }),
                                     'M', 'm' => {
@@ -302,8 +292,8 @@ pub fn App(comptime E: type) type {
 
                                         const mouse: Mouse = .{
                                             .button = button,
-                                            .col = px -| 1,
-                                            .row = py -| 1,
+                                            .x = px -| 1,
+                                            .y = py -| 1,
                                             .kind = blk: {
                                                 if (motion and button != Mouse.Button.none) {
                                                     break :blk .drag;
@@ -334,19 +324,15 @@ pub fn App(comptime E: type) type {
                                         if (std.mem.eql(u8, "48", ps)) {
                                             // in band window resize
                                             // CSI 48 ; height ; width ; height_pix ; width_pix t
-                                            const height_char = iter.next() orelse break;
                                             const width_char = iter.next() orelse break;
+                                            const height_char = iter.next() orelse break;
 
-                                            // TODO: only post the event if the size has changed?
-                                            // because there might be too many resize events (which force a re-draw of the entire screen)
-                                            const size: Size = .{
-                                                .rows = std.fmt.parseUnsigned(u16, height_char, 10) catch break,
-                                                .cols = std.fmt.parseUnsigned(u16, width_char, 10) catch break,
-                                            };
-                                            if (size.cols != this.prev_size.cols or size.rows != this.prev_size.rows) {
-                                                this.postEvent(.{ .resize = size });
-                                                this.prev_size = size;
-                                            }
+                                            _ = width_char;
+                                            _ = height_char;
+                                            // this.postEvent(.{ .size = .{
+                                            //     .x = std.fmt.parseUnsigned(u16, width_char, 10) catch break,
+                                            //     .y = std.fmt.parseUnsigned(u16, height_char, 10) catch break,
+                                            // } });
                                         }
                                     },
                                     'u' => {
@@ -361,7 +347,7 @@ pub fn App(comptime E: type) type {
                                     else => {},
                                 }
                             },
-                            // TODO: parse corresponding codes
+                            // TODO parse corresponding codes
                             // 0x5B => parseCsi(input, &self.buf), // CSI see https://github.com/rockorager/libvaxis/blob/main/src/Parser.zig
                             else => {},
                         }

src/cell.zig

@@ -4,7 +4,7 @@ const Style = @import("style.zig");
 pub const Cell = @This();
 
 style: Style = .{ .emphasis = &.{} },
-// TODO: embrace `zg` dependency more due to utf-8 encoding
+// TODO embrace `zg` dependency more due to utf-8 encoding
 cp: u21 = ' ',
 
 pub fn eql(this: Cell, other: Cell) bool {

src/color.zig

@@ -18,7 +18,7 @@ pub const Color = enum(u8) {
     magenta,
     cyan,
     white,
-    // TODO: add further colors as described in https://gist.github.com/ConnerWill/d4b6c776b509add763e17f9f113fd25b # Color / Graphics Mode - 256 Colors
+    // TODO add further colors as described in https://gist.github.com/ConnerWill/d4b6c776b509add763e17f9f113fd25b # Color / Graphics Mode - 256 Colors
 
     pub inline fn write(this: Color, writer: anytype, comptime coloring: enum { fg, bg, ul }) !void {
         if (this == .default) {

src/ctlseqs.zig

@@ -92,7 +92,7 @@ pub const bg_rgb_legacy = "\x1b[48;2;{d};{d};{d}m";
 pub const ul_rgb_legacy = "\x1b[58;2;{d};{d};{d}m";
 
 // Underlines
-pub const ul_off = "\x1b[24m"; // NOTE: this could be \x1b[4:0m but is not as widely supported
+pub const ul_off = "\x1b[24m"; // NOTE this could be \x1b[4:0m but is not as widely supported
 pub const ul_single = "\x1b[4m";
 pub const ul_double = "\x1b[4:2m";
 pub const ul_curly = "\x1b[4:3m";

src/element.zig

@@ -1,13 +1,11 @@
 //! Interface for Element's which describe the contents of a `Container`.
 const std = @import("std");
-const s = @import("size.zig");
 const input = @import("input.zig");
 
 const Container = @import("container.zig").Container;
 const Cell = @import("cell.zig");
 const Mouse = input.Mouse;
-const Position = s.Position;
-const Size = s.Size;
+const Point = @import("point.zig").Point;
 
 pub fn Element(Event: type) type {
     return struct {
@@ -15,12 +13,26 @@ pub fn Element(Event: type) type {
         vtable: *const VTable = &.{},
 
         pub const VTable = struct {
+            resize: ?*const fn (ctx: *anyopaque, size: Point) void = null,
+            reposition: ?*const fn (ctx: *anyopaque, origin: Point) void = null,
             handle: ?*const fn (ctx: *anyopaque, event: Event) anyerror!void = null,
-            content: ?*const fn (ctx: *anyopaque, cells: []Cell, size: Size) anyerror!void = null,
+            content: ?*const fn (ctx: *anyopaque, cells: []Cell, size: Point) anyerror!void = null,
         };
 
+        /// Resize the corresponding `Element` with the given *size*.
+        pub inline fn resize(this: @This(), size: Point) void {
+            if (this.vtable.resize) |resize_fn|
+                resize_fn(this.ptr, size);
+        }
+
+        /// Reposition the corresponding `Element` with the given *origin*.
+        pub inline fn reposition(this: @This(), origin: Point) void {
+            if (this.vtable.reposition) |reposition_fn|
+                reposition_fn(this.ptr, origin);
+        }
+
         /// Handle the received event. The event is one of the user provided
-        /// events or a system event, with the exception of the `.resize`
+        /// events or a system event, with the exception of the `.size`
         /// `Event` as every `Container` already handles that event.
         ///
         /// In case of user errors this function should return an error. This
@@ -32,14 +44,21 @@ pub fn Element(Event: type) type {
         }
 
         /// Write content into the `cells` of the `Container`. The associated
-        /// `cells` slice has the size of (`size.cols * size.rows`). The
+        /// `cells` slice has the size of (`size.x * size.y`). The
         /// renderer will know where to place the contents on the screen.
         ///
-        /// This function should only fail with an error if the error is
-        /// non-recoverable (i.e. an allocation error, system error, etc.).
-        /// Otherwise user specific errors should be caught using the `handle`
-        /// function before the rendering of the `Container` happens.
-        pub inline fn content(this: @This(), cells: []Cell, size: Size) !void {
+        /// # Note
+        ///
+        /// - Caller owns `cells` slice and ensures that the size usually by assertion:
+        ///   ```zig
+        ///   std.debug.assert(cells.len == @as(usize, size.x) * @as(usize, size.y));
+        ///   ```
+        ///
+        /// - This function should only fail with an error if the error is
+        ///   non-recoverable (i.e. an allocation error, system error, etc.).
+        ///   Otherwise user specific errors should be caught using the `handle`
+        ///   function before the rendering of the `Container` happens.
+        pub inline fn content(this: @This(), cells: []Cell, size: Point) !void {
             if (this.vtable.content) |content_fn|
                 try content_fn(this.ptr, cells, size);
         }
@@ -50,63 +69,64 @@ pub fn Scrollable(Event: type) type {
     return struct {
         /// `Size` of the actual contents where the anchor and the size is
         /// representing the size and location on screen.
-        size: Size = .{},
+        size: Point = .{},
         /// `Size` of the `Container` content that is scrollable and mapped to
         /// the *size* of the `Scrollable` `Element`.
-        container_size: Size = .{},
+        container_size: Point = .{},
         /// Anchor of the viewport of the scrollable `Container`.
-        anchor: Position = .{},
-        /// The actual container, that is scrollable.
+        anchor: Point = .{},
+        /// The actual `Container`, that is scrollable.
         container: Container(Event),
 
         pub fn element(this: *@This()) Element(Event) {
             return .{
                 .ptr = this,
                 .vtable = &.{
+                    .resize = resize,
+                    .reposition = reposition,
                     .handle = handle,
                     .content = content,
                 },
             };
         }
 
-        pub fn init(container: Container(Event)) @This() {
-            return .{ .container = container };
+        fn resize(ctx: *anyopaque, size: Point) void {
+            const this: *@This() = @ptrCast(@alignCast(ctx));
+            this.size = size;
+
+            // TODO scrollbar space - depending on configuration and only if necessary?
+            this.container.resize(this.size);
+            this.container_size = this.container.size;
+        }
+
+        fn reposition(ctx: *anyopaque, _: Point) void {
+            const this: *@This() = @ptrCast(@alignCast(ctx));
+            this.container.reposition(.{});
         }
 
         fn handle(ctx: *anyopaque, event: Event) !void {
             const this: *@This() = @ptrCast(@alignCast(ctx));
             switch (event) {
-                .resize => |size| {
-                    this.size = size;
-                    // TODO: scrollbar space - depending on configuration and only if necessary?
-                    const min_size = this.container.minSize();
-                    this.container_size = .{
-                        .anchor = size.anchor,
-                        .cols = @max(min_size.cols, size.cols),
-                        .rows = @max(min_size.rows, size.rows),
-                    };
-                    try this.container.handle(.{ .resize = this.container_size });
-                },
-                // TODO: other means to scroll except with the mouse? (i.e. Ctrl-u/d, k/j, etc.?)
+                // TODO other means to scroll except with the mouse? (i.e. Ctrl-u/d, k/j, etc.?)
                 .mouse => |mouse| switch (mouse.button) {
-                    Mouse.Button.wheel_up => if (this.container_size.rows > this.size.rows) {
-                        this.anchor.row -|= 1;
+                    Mouse.Button.wheel_up => if (this.container_size.y > this.size.y) {
+                        this.anchor.y -|= 1;
                     },
-                    Mouse.Button.wheel_down => if (this.container_size.rows > this.size.rows) {
-                        const max_anchor_row = this.container_size.rows -| this.size.rows;
-                        this.anchor.row = @min(this.anchor.row + 1, max_anchor_row);
+                    Mouse.Button.wheel_down => if (this.container_size.y > this.size.y) {
+                        const max_origin_y = this.container_size.y -| this.size.y;
+                        this.anchor.y = @min(this.anchor.y + 1, max_origin_y);
                     },
-                    Mouse.Button.wheel_left => if (this.container_size.cols > this.size.cols) {
-                        this.anchor.col -|= 1;
+                    Mouse.Button.wheel_left => if (this.container_size.x > this.size.x) {
+                        this.anchor.x -|= 1;
                     },
-                    Mouse.Button.wheel_right => if (this.container_size.cols > this.size.cols) {
-                        const max_anchor_col = this.container_size.cols -| this.size.cols;
-                        this.anchor.col = @min(this.anchor.col + 1, max_anchor_col);
+                    Mouse.Button.wheel_right => if (this.container_size.x > this.size.x) {
+                        const max_anchor_x = this.container_size.x -| this.size.x;
+                        this.anchor.x = @min(this.anchor.x + 1, max_anchor_x);
                     },
                     else => try this.container.handle(.{
                         .mouse = .{
-                            .col = mouse.col + this.anchor.col,
-                            .row = mouse.row + this.anchor.row,
+                            .x = mouse.x + this.anchor.x,
+                            .y = mouse.y + this.anchor.y,
                             .button = mouse.button,
                             .kind = mouse.kind,
                         },
@@ -116,48 +136,209 @@ pub fn Scrollable(Event: type) type {
             }
         }
 
-        fn content(ctx: *anyopaque, cells: []Cell, size: Size) !void {
-            const this: *@This() = @ptrCast(@alignCast(ctx));
-            std.debug.assert(cells.len == @as(usize, this.size.cols) * @as(usize, this.size.rows));
+        fn render_container(container: Container(Event), cells: []Cell, container_size: Point) !void {
+            const size = container.size;
+            const origin = container.origin;
+            const contents = try container.content();
+            defer container.allocator.free(contents);
 
-            const container_size = this.container.size;
-            const container_cells = try this.container.allocator.alloc(Cell, @as(usize, container_size.cols) * @as(usize, container_size.rows));
-            {
-                const container_cells_const = try this.container.contents();
-                defer this.container.allocator.free(container_cells_const);
-                std.debug.assert(container_cells_const.len == @as(usize, container_size.cols) * @as(usize, container_size.rows));
-                @memcpy(container_cells, container_cells_const);
-            }
+            const anchor = (@as(usize, origin.y) * @as(usize, container_size.x)) + @as(usize, origin.x);
 
-            for (this.container.elements.items) |*e| {
-                const e_size = e.size;
-                const element_cells = try e.contents();
-                defer e.allocator.free(element_cells);
+            var idx: usize = 0;
+            blk: for (0..size.y) |row| {
+                for (0..size.x) |col| {
+                    cells[anchor + (row * container_size.x) + col] = contents[idx];
+                    idx += 1;
 
-                const anchor = (@as(usize, e_size.anchor.row -| container_size.anchor.row) * @as(usize, container_size.cols)) +
-                    @as(usize, e_size.anchor.col -| container_size.anchor.col);
-
-                var idx: usize = 0;
-                blk: for (0..e_size.rows) |row| {
-                    for (0..e_size.cols) |col| {
-                        const cell = element_cells[idx];
-                        idx += 1;
-
-                        container_cells[anchor + (row * container_size.cols) + col] = cell;
-
-                        if (element_cells.len == idx) break :blk;
-                    }
+                    if (contents.len == idx) break :blk;
                 }
             }
 
-            const anchor = (@as(usize, this.anchor.row) * @as(usize, container_size.cols)) + @as(usize, this.anchor.col);
-            // TODO: render scrollbar according to configuration!
-            for (0..size.rows) |row| {
-                for (0..size.cols) |col| {
-                    cells[(row * size.cols) + col] = container_cells[anchor + (row * container_size.cols) + col];
+            for (container.elements.items) |child| try render_container(child, cells, size);
+        }
+
+        fn content(ctx: *anyopaque, cells: []Cell, size: Point) !void {
+            const this: *@This() = @ptrCast(@alignCast(ctx));
+            std.debug.assert(cells.len == @as(usize, this.size.x) * @as(usize, this.size.y));
+
+            const container_size = this.container.size;
+            const container_cells = try this.container.allocator.alloc(Cell, @as(usize, container_size.x) * @as(usize, container_size.y));
+            {
+                const container_cells_const = try this.container.content();
+                defer this.container.allocator.free(container_cells_const);
+                std.debug.assert(container_cells_const.len == @as(usize, container_size.x) * @as(usize, container_size.y));
+                @memcpy(container_cells, container_cells_const);
+            }
+
+            for (this.container.elements.items) |child| try render_container(child, container_cells, container_size);
+
+            const anchor = (@as(usize, this.anchor.y) * @as(usize, container_size.x)) + @as(usize, this.anchor.x);
+            // TODO render scrollbar according to configuration!
+            for (0..size.y) |row| {
+                for (0..size.x) |col| {
+                    cells[(row * size.x) + col] = container_cells[anchor + (row * container_size.x) + col];
                 }
             }
             this.container.allocator.free(container_cells);
         }
     };
 }
+
+// TODO nested scrollable `Container`s?'
+// TODO reaction only for when the event is actually pushed to the corresponding `Container` rendered container
+
+test "scrollable vertical" {
+    const event = @import("event.zig");
+    const testing = @import("testing.zig");
+
+    const allocator = std.testing.allocator;
+    const size: Point = .{
+        .x = 30,
+        .y = 20,
+    };
+
+    var box: Container(event.SystemEvent) = try .init(allocator, .{
+        .border = .{
+            .sides = .all,
+            .color = .red,
+        },
+        .layout = .{
+            .separator = .{
+                .enabled = true,
+                .color = .red,
+            },
+            .direction = .vertical,
+            .padding = .all(1),
+        },
+        .size = .{
+            .dim = .{ .y = size.y + 15 },
+        },
+    }, .{});
+    try box.append(try .init(allocator, .{
+        .rectangle = .{ .fill = .grey },
+    }, .{}));
+    try box.append(try .init(allocator, .{
+        .rectangle = .{ .fill = .grey },
+    }, .{}));
+    defer box.deinit();
+
+    var scrollable: Scrollable(event.SystemEvent) = .{ .container = box };
+
+    var container: Container(event.SystemEvent) = try .init(allocator, .{
+        .border = .{
+            .color = .green,
+            .sides = .vertical,
+        },
+    }, scrollable.element());
+    defer container.deinit();
+
+    var renderer: testing.Renderer = .init(allocator, size);
+    defer renderer.deinit();
+
+    container.resize(size);
+    container.reposition(.{});
+    try renderer.render(Container(event.SystemEvent), &container);
+    try testing.expectEqualCells(.{}, renderer.size, @import("test/element/scrollable.vertical.top.zon"), renderer.screen);
+
+    // scroll down 15 times (exactly to the end)
+    for (0..15) |_| try container.handle(.{
+        .mouse = .{
+            .button = .wheel_down,
+            .kind = .press,
+            .x = 5,
+            .y = 5,
+        },
+    });
+    try renderer.render(Container(event.SystemEvent), &container);
+    try testing.expectEqualCells(.{}, renderer.size, @import("test/element/scrollable.vertical.bottom.zon"), renderer.screen);
+
+    // further scrolling down will not change anything
+    try container.handle(.{
+        .mouse = .{
+            .button = .wheel_down,
+            .kind = .press,
+            .x = 5,
+            .y = 5,
+        },
+    });
+    try renderer.render(Container(event.SystemEvent), &container);
+    try testing.expectEqualCells(.{}, renderer.size, @import("test/element/scrollable.vertical.bottom.zon"), renderer.screen);
+}
+
+test "scrollable horizontal" {
+    const event = @import("event.zig");
+    const testing = @import("testing.zig");
+
+    const allocator = std.testing.allocator;
+    const size: Point = .{
+        .x = 30,
+        .y = 20,
+    };
+
+    var box: Container(event.SystemEvent) = try .init(allocator, .{
+        .border = .{
+            .sides = .all,
+            .color = .red,
+        },
+        .layout = .{
+            .separator = .{
+                .enabled = true,
+                .color = .red,
+            },
+            .direction = .horizontal,
+            .padding = .all(1),
+        },
+        .size = .{
+            .dim = .{ .x = size.x + 15 },
+        },
+    }, .{});
+    try box.append(try .init(allocator, .{
+        .rectangle = .{ .fill = .grey },
+    }, .{}));
+    try box.append(try .init(allocator, .{
+        .rectangle = .{ .fill = .grey },
+    }, .{}));
+    defer box.deinit();
+
+    var scrollable: Scrollable(event.SystemEvent) = .{ .container = box };
+
+    var container: Container(event.SystemEvent) = try .init(allocator, .{
+        .border = .{
+            .color = .green,
+            .sides = .horizontal,
+        },
+    }, scrollable.element());
+    defer container.deinit();
+
+    var renderer: testing.Renderer = .init(allocator, size);
+    defer renderer.deinit();
+
+    container.resize(size);
+    container.reposition(.{});
+    try renderer.render(Container(event.SystemEvent), &container);
+    try testing.expectEqualCells(.{}, renderer.size, @import("test/element/scrollable.horizontal.left.zon"), renderer.screen);
+
+    // scroll right 15 times (exactly to the end)
+    for (0..15) |_| try container.handle(.{
+        .mouse = .{
+            .button = .wheel_right,
+            .kind = .press,
+            .x = 5,
+            .y = 5,
+        },
+    });
+    try renderer.render(Container(event.SystemEvent), &container);
+    try testing.expectEqualCells(.{}, renderer.size, @import("test/element/scrollable.horizontal.right.zon"), renderer.screen);
+
+    // further scrolling right will not change anything
+    try container.handle(.{
+        .mouse = .{
+            .button = .wheel_right,
+            .kind = .press,
+            .x = 5,
+            .y = 5,
+        },
+    });
+    try renderer.render(Container(event.SystemEvent), &container);
+    try testing.expectEqualCells(.{}, renderer.size, @import("test/element/scrollable.horizontal.right.zon"), renderer.screen);
+}

src/error.zig

@@ -0,0 +1,4 @@
+pub const Error = error{
+    /// Thrown when a `Container` is too small to be rendered in the current screen part.
+    TooSmall,
+};

src/event.zig

@@ -6,12 +6,12 @@ const terminal = @import("terminal.zig");
 
 const Key = input.Key;
 const Mouse = input.Mouse;
-const Size = @import("size.zig").Size;
+const Point = @import("point.zig").Point;
 
 /// System events available to every `zterm.App`
 pub const SystemEvent = union(enum) {
     /// Initialize event, which is send once at the beginning of the event loop and before the first render loop
-    /// TODO: not sure if this is necessary or if there is an actual usecase for this - for now it will remain
+    /// TODO not sure if this is necessary or if there is an actual usecase for this - for now it will remain
     init,
     /// Quit event to signify the end of the event loop (rendering should stop afterwards)
     quit,
@@ -21,14 +21,12 @@ pub const SystemEvent = union(enum) {
         /// associated error message
         msg: []const u8,
     },
-    /// Resize event emitted by the terminal to derive the `Size` of the current terminal the application is rendered in
-    resize: Size,
     /// Input key event received from the user
     key: Key,
     /// Mouse input event
     mouse: Mouse,
     /// Focus event for mouse interaction
-    /// TODO: this should instead be a union with a `Size` to derive which container / element the focus meant for
+    /// TODO this should instead be a union with a `Size` to derive which container / element the focus meant for
     focus: bool,
 };
 

src/input.zig

@@ -1,11 +1,11 @@
 //! Input module for `zterm`. Contains structs to represent key events and mouse events.
 const std = @import("std");
 
-const Size = @import("size.zig").Size;
+const Point = @import("point.zig").Point;
 
 pub const Mouse = packed struct {
-    col: u16,
-    row: u16,
+    x: u16,
+    y: u16,
     button: Button,
     kind: Kind,
 
@@ -35,9 +35,9 @@ pub const Mouse = packed struct {
         return std.meta.eql(this, other);
     }
 
-    pub fn in(this: @This(), size: Size) bool {
-        return this.col >= size.anchor.col and this.col <= size.cols + size.anchor.col and
-            this.row >= size.anchor.row and this.row <= size.rows + size.anchor.row;
+    pub fn in(this: @This(), origin: Point, size: Point) bool {
+        return this.x >= origin.x and this.x < size.x + origin.x and
+            this.y >= origin.y and this.y < size.y + origin.y;
     }
 };
 

src/point.zig

@@ -0,0 +1,60 @@
+pub const Point = packed struct {
+    x: u16 = 0,
+    y: u16 = 0,
+
+    pub fn add(a: @This(), b: @This()) @This() {
+        return .{
+            .x = a.x + b.x,
+            .y = a.y + b.y,
+        };
+    }
+
+    pub fn max(a: @This(), b: @This()) @This() {
+        return .{
+            .x = @max(a.x, b.x),
+            .y = @max(a.y, b.y),
+        };
+    }
+
+    test "adding" {
+        const testing = @import("std").testing;
+
+        const a: @This() = .{
+            .x = 10,
+            .y = 20,
+        };
+
+        const b: @This() = .{
+            .x = 20,
+            .y = 10,
+        };
+
+        try testing.expectEqual(@This(){
+            .x = 30,
+            .y = 30,
+        }, a.add(b));
+    }
+
+    test "maximum" {
+        const testing = @import("std").testing;
+
+        const a: @This() = .{
+            .x = 10,
+            .y = 20,
+        };
+
+        const b: @This() = .{
+            .x = 20,
+            .y = 10,
+        };
+
+        try testing.expectEqual(@This(){
+            .x = 20,
+            .y = 20,
+        }, a.max(b));
+    }
+};
+
+test {
+    _ = Point;
+}

src/render.zig

@@ -2,14 +2,13 @@ const std = @import("std");
 const terminal = @import("terminal.zig");
 
 const Cell = @import("cell.zig");
-const Position = @import("size.zig").Position;
-const Size = @import("size.zig").Size;
+const Point = @import("point.zig").Point;
 
 /// Double-buffered intermediate rendering pipeline
 pub const Buffered = struct {
     allocator: std.mem.Allocator,
     created: bool,
-    size: Size,
+    size: Point,
     screen: []Cell,
     virtual_screen: []Cell,
 
@@ -30,9 +29,12 @@ pub const Buffered = struct {
         }
     }
 
-    pub fn resize(this: *@This(), size: Size) !void {
+    pub fn resize(this: *@This()) !void {
+        const size = terminal.getTerminalSize();
+        if (std.meta.eql(this.size, size)) return;
+
         this.size = size;
-        const n = @as(usize, size.cols) * @as(usize, size.rows);
+        const n = @as(usize, this.size.x) * @as(usize, this.size.y);
 
         if (!this.created) {
             this.screen = this.allocator.alloc(Cell, n) catch @panic("render.zig: Out of memory.");
@@ -60,23 +62,21 @@ pub const Buffered = struct {
 
     /// Render provided cells at size (anchor and dimension) into the *virtual screen*.
     pub fn render(this: *@This(), comptime T: type, container: *T) !void {
-        const size: Size = container.size;
-        const cells: []const Cell = try container.contents();
+        const size: Point = container.size;
+        const origin: Point = container.origin;
+        const cells: []const Cell = try container.content();
 
         if (cells.len == 0) return;
 
         var idx: usize = 0;
         var vs = this.virtual_screen;
-        const anchor: usize = (@as(usize, size.anchor.row) * @as(usize, this.size.cols)) + @as(usize, size.anchor.col);
+        const anchor: usize = (@as(usize, origin.y) * @as(usize, this.size.x)) + @as(usize, origin.x);
 
-        blk: for (0..size.rows) |row| {
-            for (0..size.cols) |col| {
-                const cell = cells[idx];
+        blk: for (0..size.y) |row| {
+            for (0..size.x) |col| {
+                vs[anchor + (row * this.size.x) + col] = cells[idx];
                 idx += 1;
 
-                vs[anchor + (row * this.size.cols) + col].style = cell.style;
-                vs[anchor + (row * this.size.cols) + col].cp = cell.cp;
-
                 if (cells.len == idx) break :blk;
             }
         }
@@ -88,19 +88,19 @@ pub const Buffered = struct {
 
     /// Write *virtual screen* to alternate screen (should be called once and last during each render loop iteration in the main loop).
     pub fn flush(this: *@This()) !void {
-        // TODO: measure timings of rendered frames?
+        // TODO measure timings of rendered frames?
         const writer = terminal.writer();
         const s = this.screen;
         const vs = this.virtual_screen;
-        for (0..this.size.rows) |row| {
-            for (0..this.size.cols) |col| {
-                const idx = (row * this.size.cols) + col;
+        for (0..this.size.y) |row| {
+            for (0..this.size.x) |col| {
+                const idx = (row * this.size.x) + col;
                 const cs = s[idx];
                 const cvs = vs[idx];
                 if (cs.eql(cvs)) continue;
 
                 // render differences found in virtual screen
-                try terminal.setCursorPosition(.{ .row = @truncate(row + 1), .col = @truncate(col + 1) });
+                try terminal.setCursorPosition(.{ .y = @truncate(row + 1), .x = @truncate(col + 1) });
                 try cvs.value(writer);
                 // update screen to be the virtual screen for the next frame
                 s[idx] = vs[idx];

src/size.zig

@@ -1,17 +0,0 @@
-pub const Size = packed struct {
-    anchor: Position = .{},
-    cols: u16 = 0,
-    rows: u16 = 0,
-
-    pub fn merge(this: @This(), other: @This()) Size {
-        return .{
-            .cols = this.cols + other.cols,
-            .rows = this.rows + other.rows,
-        };
-    }
-};
-
-pub const Position = packed struct {
-    col: u16 = 0,
-    row: u16 = 0,
-};

src/style.zig

@@ -56,7 +56,7 @@ pub fn value(this: Style, writer: anytype, cp: u21) !void {
     try std.fmt.format(writer, ";", .{});
     try this.bg.write(writer, .bg);
     // underline
-    // FIX: assert that if the underline property is set that the ul style and the attribute for underlining is available
+    // FIX assert that if the underline property is set that the ul style and the attribute for underlining is available
     try std.fmt.format(writer, ";", .{});
     try this.ul.write(writer, .ul);
     // append styles (aka attributes like bold, italic, strikethrough, etc.)
@@ -67,6 +67,6 @@ pub fn value(this: Style, writer: anytype, cp: u21) !void {
     try std.fmt.format(writer, "\x1b[0m", .{});
 }
 
-// TODO: implement helper functions for terminal capabilities:
+// TODO implement helper functions for terminal capabilities:
 // - links / url display (osc 8)
 // - show / hide cursor?

src/terminal.zig

@@ -4,8 +4,8 @@ const ctlseqs = @import("ctlseqs.zig");
 const input = @import("input.zig");
 
 const Key = input.Key;
-const Position = @import("size.zig").Position;
-const Size = @import("size.zig").Size;
+const Point = @import("point.zig").Point;
+const Size = @import("point.zig").Point;
 const Cell = @import("cell.zig");
 
 const log = std.log.scoped(.terminal);
@@ -23,7 +23,7 @@ pub const ReportMode = enum {
 pub fn getTerminalSize() Size {
     var ws: std.posix.winsize = undefined;
     _ = std.posix.system.ioctl(std.posix.STDIN_FILENO, std.posix.T.IOCGWINSZ, @intFromPtr(&ws));
-    return .{ .cols = ws.col, .rows = ws.row };
+    return .{ .x = ws.col, .y = ws.row };
 }
 
 pub fn saveScreen() !void {
@@ -89,9 +89,9 @@ pub fn writer() Writer {
     return .{ .context = .{} };
 }
 
-pub fn setCursorPosition(pos: Position) !void {
+pub fn setCursorPosition(pos: Point) !void {
     var buf: [64]u8 = undefined;
-    const value = try std.fmt.bufPrint(&buf, "\x1b[{d};{d}H", .{ pos.row, pos.col });
+    const value = try std.fmt.bufPrint(&buf, "\x1b[{d};{d}H", .{ pos.y, pos.x });
     _ = try std.posix.write(std.posix.STDIN_FILENO, value);
 }
 
@@ -137,8 +137,8 @@ pub fn getCursorPosition() !Size.Position {
     }
 
     return .{
-        .row = try std.fmt.parseInt(u16, row[0..ridx], 10) - 1,
-        .col = try std.fmt.parseInt(u16, col[0..cidx], 10) - 1,
+        .x = try std.fmt.parseInt(u16, col[0..cidx], 10) - 1,
+        .y = try std.fmt.parseInt(u16, row[0..ridx], 10) - 1,
     };
 }
 

src/testing.zig

@@ -5,21 +5,20 @@ const Container = @import("container.zig").Container;
 
 const Cell = @import("cell.zig");
 const DisplayWidth = @import("DisplayWidth");
-const Position = @import("size.zig").Position;
-const Size = @import("size.zig").Size;
+const Point = @import("point.zig").Point;
 
-// TODO: how would I describe the expected screens?
+// TODO how would I describe the expected screens?
 // - including styling?
 // - compare generated strings instead? -> how would this be generated for the user?
 
 /// Single-buffer test rendering pipeline for testing purposes.
 pub const Renderer = struct {
     allocator: std.mem.Allocator,
-    size: Size,
+    size: Point,
     screen: []Cell,
 
-    pub fn init(allocator: std.mem.Allocator, size: Size) @This() {
-        const screen = allocator.alloc(Cell, @as(usize, size.cols) * @as(usize, size.rows)) catch @panic("testing.zig: Out of memory.");
+    pub fn init(allocator: std.mem.Allocator, size: Point) @This() {
+        const screen = allocator.alloc(Cell, @as(usize, size.x) * @as(usize, size.y)) catch @panic("testing.zig: Out of memory.");
         @memset(screen, .{});
 
         return .{
@@ -33,9 +32,9 @@ pub const Renderer = struct {
         this.allocator.free(this.screen);
     }
 
-    pub fn resize(this: *@This(), size: Size) !void {
+    pub fn resize(this: *@This(), size: Point) !void {
         this.size = size;
-        const n = @as(usize, size.cols) * @as(usize, size.rows);
+        const n = @as(usize, size.x) * @as(usize, size.y);
 
         this.allocator.free(this.screen);
         this.screen = this.allocator.alloc(Cell, n) catch @panic("testing.zig: Out of memory.");
@@ -47,21 +46,22 @@ pub const Renderer = struct {
     }
 
     pub fn render(this: *@This(), comptime T: type, container: *const T) !void {
-        const size: Size = container.size;
-        const cells: []const Cell = try container.contents();
+        const size: Point = container.size;
+        const origin: Point = container.origin;
+        const cells: []const Cell = try container.content();
 
         if (cells.len == 0) return;
 
         var idx: usize = 0;
-        const anchor = (@as(usize, size.anchor.row) * @as(usize, this.size.cols)) + @as(usize, size.anchor.col);
+        const anchor = (@as(usize, origin.y) * @as(usize, this.size.x)) + @as(usize, origin.x);
 
-        blk: for (0..size.rows) |row| {
-            for (0..size.cols) |col| {
+        blk: for (0..size.y) |row| {
+            for (0..size.x) |col| {
                 const cell = cells[idx];
                 idx += 1;
 
-                this.screen[anchor + (row * this.size.cols) + col].style = cell.style;
-                this.screen[anchor + (row * this.size.cols) + col].cp = cell.cp;
+                this.screen[anchor + (row * this.size.x) + col].style = cell.style;
+                this.screen[anchor + (row * this.size.x) + col].cp = cell.cp;
 
                 if (cells.len == idx) break :blk;
             }
@@ -92,7 +92,7 @@ pub const Renderer = struct {
 /// var renderer: testing.Renderer = .init(allocator, size);
 /// defer renderer.deinit();
 ///
-/// try container.handle(.{ .resize = size });
+/// try container.handle(.{ .size = size });
 /// try renderer.render(Container(event.SystemEvent), &container);
 /// try renderer.save(file.writer());
 /// ```
@@ -115,34 +115,36 @@ pub const Renderer = struct {
 ///     .cols = 30,
 /// }, &container, @import("test/container/border.all.zon"));
 /// ```
-pub fn expectContainerScreen(size: Size, container: *Container(event.SystemEvent), expected: []const Cell) !void {
+pub fn expectContainerScreen(size: Point, container: *Container(event.SystemEvent), expected: []const Cell) !void {
     const allocator = std.testing.allocator;
     var renderer: Renderer = .init(allocator, size);
     defer renderer.deinit();
 
-    try container.handle(.{ .resize = size });
+    try renderer.resize(size);
+    container.resize(size);
+    container.reposition(.{});
     try renderer.render(Container(event.SystemEvent), container);
 
-    try expectEqualCells(renderer.size, expected, renderer.screen);
+    try expectEqualCells(.{}, renderer.size, expected, renderer.screen);
 }
 
 /// This function is intended to be used only in tests. Test if the two
 /// provided cell arrays are identical. Usually the `Cell` slices are
 /// the contents of a given screen from the `zterm.testing.Renderer`. See
 /// `zterm.testing.expectContainerScreen` for an example usage.
-pub fn expectEqualCells(size: Size, expected: []const Cell, actual: []const Cell) !void {
+pub fn expectEqualCells(origin: Point, size: Point, expected: []const Cell, actual: []const Cell) !void {
     const allocator = std.testing.allocator;
 
     try std.testing.expectEqual(expected.len, actual.len);
-    try std.testing.expectEqual(expected.len, @as(usize, size.rows) * @as(usize, size.cols));
+    try std.testing.expectEqual(expected.len, @as(usize, size.y) * @as(usize, size.x));
 
-    var expected_cps = try std.ArrayList(Cell).initCapacity(allocator, size.cols -| size.anchor.col);
+    var expected_cps = try std.ArrayList(Cell).initCapacity(allocator, size.x);
     defer expected_cps.deinit();
 
-    var actual_cps = try std.ArrayList(Cell).initCapacity(allocator, size.cols -| size.anchor.col);
+    var actual_cps = try std.ArrayList(Cell).initCapacity(allocator, size.x);
     defer actual_cps.deinit();
 
-    var output = try std.ArrayList(u8).initCapacity(allocator, expected_cps.capacity * actual_cps.capacity + 5 * size.rows);
+    var output = try std.ArrayList(u8).initCapacity(allocator, expected_cps.capacity * actual_cps.capacity + 5 * size.y);
     defer output.deinit();
 
     var buffer = std.io.bufferedWriter(output.writer());
@@ -155,23 +157,22 @@ pub fn expectEqualCells(size: Size, expected: []const Cell, actual: []const Cell
     defer dwd.deinit();
     const dw: DisplayWidth = .{ .data = &dwd };
 
-    const expected_centered = try dw.center(allocator, "Expected Screen", size.cols, " ");
+    const expected_centered = try dw.center(allocator, "Expected Screen", size.x, " ");
     defer allocator.free(expected_centered);
 
-    const actual_centered = try dw.center(allocator, "Actual Screen", size.cols, " ");
+    const actual_centered = try dw.center(allocator, "Actual Screen", size.x, " ");
     defer allocator.free(actual_centered);
 
     try writer.print("Screens are not equivalent.\n{s} ┆ {s}\n", .{ expected_centered, actual_centered });
 
-    const anchor = (size.anchor.row * size.cols) + size.anchor.col;
-    for (size.anchor.row..size.rows) |row| {
+    for (origin.y..size.y) |row| {
         defer {
             expected_cps.clearRetainingCapacity();
             actual_cps.clearRetainingCapacity();
         }
-        for (size.anchor.col..size.cols) |col| {
-            const expected_cell = expected[anchor + (row * size.cols) + col];
-            const actual_cell = actual[anchor + (row * size.cols) + col];
+        for (origin.x..size.x) |col| {
+            const expected_cell = expected[(row * size.x) + col];
+            const actual_cell = actual[(row * size.x) + col];
 
             if (!expected_cell.eql(actual_cell)) differ = true;
 

src/zterm.zig

@@ -1,13 +1,14 @@
 // private imports
 const container = @import("container.zig");
 const color = @import("color.zig");
-const size = @import("size.zig");
+const size = @import("point.zig");
 
 // public exports
 pub const input = @import("input.zig");
 pub const testing = @import("testing.zig");
 
 pub const App = @import("app.zig").App;
+pub const Error = @import("error.zig").Error;
 // App also exports further types once initialized with the user events at compile time:
 // `App.Container`
 // `App.Element`
@@ -23,17 +24,17 @@ pub const Cell = @import("cell.zig");
 pub const Color = color.Color;
 pub const Key = input.Key;
 pub const Mouse = input.Mouse;
-pub const Position = size.Position;
-pub const Size = size.Size;
+pub const Point = @import("point.zig").Point;
 pub const Style = @import("style.zig");
 
 test {
     _ = @import("terminal.zig");
     _ = @import("container.zig");
     _ = @import("queue.zig");
+    _ = @import("error.zig");
+    _ = @import("point.zig");
 
     _ = color;
-    _ = size;
 
     _ = Cell;
     _ = Key;