ash-windows

ash-windows

Windows and a widget toolkit for Ash, on X11, written in Ash itself: it speaks the X protocol over a unix socket with the raw_* builtins, draws into a software framebuffer (anti-aliased shapes, TrueType text) and uploads it with PutImage. No native library, no C. Linux + a running X server (Xorg, Xwayland, Xephyr).

apm add github:lennoxrose/ash-windows

import ash_windows.ui.*;

public class Hello {
    public static void main(String[] args) {
        Theme? theme = Theme.create(true);              // true: dark, false: light; null: no TrueType font
        if (theme == null) return;
        Theme.set(theme);
        App? app = App.open("Hello", 360, 200);         // opens on $DISPLAY; null: no X server
        if (app == null) return;
        app.root().padding(20);
        Box col = Box.column().gap(12);
        col.add(new Label("Hello from Ash").title());
        col.add(new Button("Quit", () -> System.exit(0)).primary());
        app.root().add(col);
        app.run();
    }
}

Layers (each file under 100 lines)

Package	What
ash_windows.x11	X11: one window, putImage, waitEvent(timeout), keyboard translation, clipboard (copy / paste). Its parts: Wire, Setup, Auth, Keyboard, Props, Windows, Clipboard, Selection; Events and Keys hold constants
ash_windows.gfx	Canvas (framebuffer + clip), Shapes (round rects, circles, lines, shadows, gradients), Font (TrueType loader and rasteriser with GPOS kerning; Fonts finds a system one), Image with Png and Bmp loaders (own DEFLATE in Inflate)
ash_windows.ui	App (window + event loop), Root, Router, Focus, Theme, and the widgets below

Widgets: Box (row / column / card), Label, Button, Checkbox, Slider, Progress, TextField (selection, Ctrl+A/C/X/V), Select (dropdown), ListView, ScrollView (wheel + draggable thumb), ImageView, MenuBar, Separator, Spacer. Menu.popup(...) opens a context menu anywhere; Dialogs.message / Dialogs.confirm and Overlay give modal dialogs. Widgets that react to input extend Control; the rest extend Widget.

Window frames and shapes

By default the window manager draws the frame (title bar, border, buttons) and decides how it looks. To own it:

App? app = App.openBorderless("My app", 520, 360);   // asks the window manager to draw no frame at all
app.setShape(WindowShapes.rounded(14));              // cut the window to any outline
app.setResizeBorder(6);                              // resize by dragging within 6 px of the edges
app.root().add(new TitleBar("My app", true));        // or build your own frame from widgets

• TitleBar(title, buttonsLeft): title, close / minimise / maximize buttons (round on the left, flat on the right), drag to move, double-click to maximize. DragArea is an invisible move handle; any widget can drive the window through chrome(): close(), minimize(), toggleMaximize(), beginMove(), beginResize(edges), setCursor(...).
• WindowShape is (x, y, w, h) -> bool: which pixels belong to the window. WindowShapes.rounded(r), .ellipse(), .fromImage(image) (whatever is opaque), or your own lambda. The outline is recomputed when the window is resized. It is cut with the X Shape extension: edges are hard (one pixel in or out, no anti-aliasing), the cut-away parts are not drawn and clicks fall through them. Orb.ash is a circular window dragged by its body.
• examples/Frameless.ash: rounded corners, own title bar, resizable from its edges.
• Every window sets a cursor (the arrow; I-beam over text fields, a hand over buttons, resize arrows at the edges): under Xwayland a window with no cursor makes the pointer vanish.

Only the damaged rectangles are repainted and uploaded. A widget that changes calls invalidate() (the built-in ones do); one that changes size calls relayout(). add / remove / removeAll relayout by themselves.

Things to know

• Native is the way to ship: kiln app.ash -o app. ashvm run app.ash also works for small programs, but the bytecode VM stops a bigger one with this function has more than 256 different constants (examples/Gallery is over that line, examples/Demo is not).
• Keep widgets you need later in fields, not locals: with memory-safety: on, a local is moved into the tree by add(...) and cannot be used afterwards (status.setText(...) from a callback is fine on a field).
• Test on a nested server so a bug cannot touch your desktop: Xephyr :9 -screen 800x600 &, then DISPLAY=:9 ./app. $DISPLAY must be of the form :n (or :n.s); there is no TCP / ssh -X transport.
• Tested on Xephyr (no window manager) and, for window-manager behaviour, on GNOME / mutter under Xwayland (maximize, restore, move and resize were checked there; minimise, _MOTIF_WM_HINTS handling by other window managers and tiling window managers were not), with the US keyboard layout. Keysyms come from the server's own table, so other layouts should work; AltGr / dead keys are not handled.
• Clipboard is text only, up to 16 KB, no selection (middle-click) buffer. Png reads 8-bit non-interlaced images, Bmp 24/32-bit uncompressed; ImageView scales down, never up.
• Not there: smooth (anti-aliased / translucent) window edges (would need a 32-bit visual and a compositor), a native Wayland client, HiDPI scaling, IME / complex-script shaping, text wrapping in labels, tabs / trees / tables.

Tests (run from the project root, native or ashvm run): tests/CoreTest.ash (DEFLATE, UTF-8, text editing, damage), tests/ImageTest.ash (PNG / BMP against known pixels), tests/FontTest.ash (kerning), tests/RouterTest.ash (clicks, Tab, typing, slider through the real input router), tests/FrameTest.ash (window shapes, edge hit-testing). Examples: examples/Demo.ash (basic widgets), examples/Gallery.ash (menus, list, scroll, dropdown, dialogs), examples/Frameless.ash and examples/Orb.ash (own frames and shapes).