| 1 | import { openUrl } from "@tauri-apps/plugin-opener"; |
| 2 | |
| 3 | /** |
| 4 | * Native-shell hardening for the system WebView. |
| 5 | * |
| 6 | * Tauri renders the UI in WKWebView (macOS/iOS) or the Android WebView, both of |
| 7 | * which ship with browser affordances that immediately read as "this is a web |
| 8 | * page" inside a shipped app: pinch-to-zoom, ⌘+/− zoom, the browser context |
| 9 | * menu, dragging text out of the window, and links navigating the app frame |
| 10 | * away from the UI. |
| 11 | * |
| 12 | * App.css handles everything expressible as a passive style (callouts, tap |
| 13 | * highlights, double-tap zoom, overscroll). The gestures below can only be |
| 14 | * suppressed with live listeners, because the WebView acts on them before the |
| 15 | * page sees a scroll or a click. |
| 16 | * |
| 17 | * Returns a teardown function; the listeners live for the lifetime of the app, |
| 18 | * so nothing calls it outside of React's StrictMode double-invoke in dev. |
| 19 | */ |
| 20 | export function installNativeShellBehaviour(): () => void { |
| 21 | const offs: Array<() => void> = []; |
| 22 | |
| 23 | const on = ( |
| 24 | target: EventTarget, |
| 25 | type: string, |
| 26 | handler: (e: never) => void, |
| 27 | opts?: AddEventListenerOptions |
| 28 | ) => { |
| 29 | target.addEventListener(type, handler as EventListener, opts); |
| 30 | offs.push(() => target.removeEventListener(type, handler as EventListener, opts)); |
| 31 | }; |
| 32 | |
| 33 | const swallow = (e: Event) => e.preventDefault(); |
| 34 | |
| 35 | // ── Pinch zoom ──────────────────────────────────────────────────────────── |
| 36 | // WebKit reports trackpad and touch pinches as non-standard `gesture*` |
| 37 | // events; they bypass `touch-action` and the viewport's `user-scalable=no`, |
| 38 | // so a two-finger pinch on a Mac (or an iPad trackpad) still scales the UI |
| 39 | // unless each one is cancelled. Must be non-passive to be cancellable. |
| 40 | for (const type of ["gesturestart", "gesturechange", "gestureend"]) { |
| 41 | on(document, type, swallow, { passive: false }); |
| 42 | } |
| 43 | |
| 44 | // Chromium (Android WebView, and Linux/Windows desktop) maps a trackpad |
| 45 | // pinch and ctrl+scroll onto a wheel event with `ctrlKey` set. |
| 46 | on( |
| 47 | window, |
| 48 | "wheel", |
| 49 | (e: WheelEvent) => { |
| 50 | if (e.ctrlKey || e.metaKey) e.preventDefault(); |
| 51 | }, |
| 52 | { passive: false } |
| 53 | ); |
| 54 | |
| 55 | // ── Keyboard zoom ───────────────────────────────────────────────────────── |
| 56 | // `zoomHotkeysEnabled` is off in tauri.conf.json, but the WebView still |
| 57 | // honours ⌘/Ctrl with +, -, and 0 on some platforms. Only the zoom keys are |
| 58 | // intercepted — ⌘A/⌘C/⌘V and friends must keep working. |
| 59 | on(window, "keydown", (e: KeyboardEvent) => { |
| 60 | if (!(e.metaKey || e.ctrlKey)) return; |
| 61 | if (["+", "=", "-", "_", "0"].includes(e.key)) e.preventDefault(); |
| 62 | }); |
| 63 | |
| 64 | // ── Browser chrome ──────────────────────────────────────────────────────── |
| 65 | // Suppress the WebView context menu except where it does something a native |
| 66 | // app would also offer: editing a text field, or copying a selection. Left |
| 67 | // intact during `pnpm dev` so "Inspect Element" stays reachable. |
| 68 | if (!import.meta.env.DEV) { |
| 69 | on(window, "contextmenu", (e: MouseEvent) => { |
| 70 | const el = e.target as HTMLElement | null; |
| 71 | const editable = |
| 72 | el?.closest("input, textarea, [contenteditable='true']") != null; |
| 73 | const selection = document.getSelection(); |
| 74 | const hasSelection = selection != null && !selection.isCollapsed; |
| 75 | if (!editable && !hasSelection) e.preventDefault(); |
| 76 | }); |
| 77 | } |
| 78 | |
| 79 | // Nothing in the app is draggable, and a dropped file would otherwise |
| 80 | // navigate the WebView away from the UI with no way back. |
| 81 | on(window, "dragstart", swallow); |
| 82 | on(window, "dragover", swallow); |
| 83 | on(window, "drop", swallow); |
| 84 | |
| 85 | // ── External links ──────────────────────────────────────────────────────── |
| 86 | // A link that navigates the app frame is unrecoverable — there is no back |
| 87 | // button. Route anything external to the system browser instead. Components |
| 88 | // that already handle their own links (Settings) call `preventDefault`, so |
| 89 | // check for that first to avoid opening the URL twice. |
| 90 | on(window, "click", (e: MouseEvent) => { |
| 91 | if (e.defaultPrevented) return; |
| 92 | const anchor = (e.target as HTMLElement | null)?.closest("a"); |
| 93 | const href = anchor?.getAttribute("href"); |
| 94 | if (!href || !/^(https?|mailto):/i.test(href)) return; |
| 95 | e.preventDefault(); |
| 96 | void openUrl(href); |
| 97 | }); |
| 98 | |
| 99 | offs.push(installKeyboardInset()); |
| 100 | return () => offs.forEach((off) => off()); |
| 101 | } |
| 102 | |
| 103 | /** |
| 104 | * Keep the composer above the on-screen keyboard. |
| 105 | * |
| 106 | * iOS does not resize the WKWebView when the keyboard appears — it only shrinks |
| 107 | * the visual viewport — so `100dvh` keeps reporting the full screen height and |
| 108 | * the input ends up underneath the keyboard. Publishing the covered height as |
| 109 | * `--keyboard-inset` lets App.css shrink the app frame the way a native view |
| 110 | * controller would. Android WebView resizes the window itself, in which case |
| 111 | * the measured inset stays 0 and this is a no-op. |
| 112 | */ |
| 113 | function installKeyboardInset(): () => void { |
| 114 | const vv = window.visualViewport; |
| 115 | if (!vv) return () => {}; |
| 116 | |
| 117 | const root = document.documentElement; |
| 118 | |
| 119 | const sync = () => { |
| 120 | // Height of the screen the keyboard (or any other overlay) covers. |
| 121 | const covered = window.innerHeight - vv.height - vv.offsetTop; |
| 122 | root.style.setProperty("--keyboard-inset", `${Math.max(0, Math.round(covered))}px`); |
| 123 | // Focusing an input makes WebKit scroll the (non-scrollable) document to |
| 124 | // reveal it, leaving the fixed layout shifted under the status bar. |
| 125 | window.scrollTo(0, 0); |
| 126 | }; |
| 127 | |
| 128 | vv.addEventListener("resize", sync); |
| 129 | vv.addEventListener("scroll", sync); |
| 130 | sync(); |
| 131 | |
| 132 | return () => { |
| 133 | vv.removeEventListener("resize", sync); |
| 134 | vv.removeEventListener("scroll", sync); |
| 135 | root.style.removeProperty("--keyboard-inset"); |
| 136 | }; |
| 137 | } |