Asuka and MyGo

MyGo makes desktop apps in Go, with phones coming soon. Both are Go alone, and both call the desktop without cgo. They differ in where an app runs and, above all, in what shows its interface: MyGo draws it, or shows a web page; Asuka shows the platform's own widgets.

What shows the interface

A MyGo window shows one of two things:

• UI that MyGo draws itself, on the GPU (Metal on the Mac, Direct3D 11 on Windows, OpenGL), in a look of MyGo's theme. Its text comes from the system's text engines, and it builds an accessibility tree of what it draws.
• A web page, in the system's web view (WKWebView, WebView2, WebKitGTK), which calls the app's Go through a TypeScript client MyGo generates.

An Asuka app shows the platform's own widgets. A ui.Button is a UIButton on iOS, a MaterialButton on Android, an NSButton on the Mac, a Win32 BUTTON drawn as Windows 11's on Windows, a GtkButton on Linux and a <button> in a browser; Components has them all. Asuka lays them out, with one layout engine in Go for every platform, and sets their properties; the platform draws them, and they work as its own: its text input and autocorrection, its input methods, its screen readers, its menus, scrolling and focus.

What follows from it:

• The look. An Asuka app that sets no style looks as each platform's apps do, and follows the platform when it changes (a new iOS restyles its buttons, a new libadwaita its switches). A MyGo window looks as MyGo's theme says, drawn the same way on each system.
• Text, input and accessibility. Asuka's are the platform's, done by the platform. MyGo's are MyGo's, made over what it draws.
• What no widget shows. MyGo draws anything as it draws the rest. Asuka has packages for what has no widget, drawing with the platform: asuka/sdk/chart, asuka/sdk/svg, and ui.Shader for shaders.
• Images without a screen. MyGo has a software renderer: it draws on the CPU, in memory, with no window, display or GPU, so a test or a server renders a view to an image on any machine (ui.NewTester, ui.Render). Asuka's widgets are drawn by the platform, so an image of them needs the platform running: a window on the desktop (ASUKA_SNAPSHOT; Xvfb on a Linux server), the simulator, an emulator or a browser. Without one, uitest describes the screen as text: each view's kind, frame and what it shows (Testing).

Where it runs

How a view updates

A MyGo view is a function of the app's state, built again from it for every frame. An Asuka component runs once: it makes its views and wires them to signals, and a signal's change updates only the views that read it, in one batch for the frame (Concepts).

When to use each

Use Asuka when:

• the app is for phones today, or for phones, desktops and the web from one code base;
• it should look and work as each platform's apps do: its controls, its text input, its accessibility, its navigation.

Use MyGo when:

• the app is for the desktop and its interface is a web frontend: existing web code, HTML and CSS, rich documents, what only a browser has;
• it should have one look of its own, drawn the same on every desktop, rather than each platform's: an editor, an inspector, a game;
• its views should render to images headlessly: snapshot tests that compare pixels, or images made on a server.