Module webview 

Engine-agnostic embedded web view plumbing.

The crate::widget::WebView widget displays frames produced by a WebViewEngine backend and forwards input back into it. The engine runs on its own thread (or entirely synchronously, for tests): commands flow in through WebViewEngine::send, rendered pixels come out through a shared FrameSlot, and navigation/UI state changes come out as WebViewEvents drained by the host app during sync.

Backends:

• test_engine::TestEngine — deterministic, dependency-free engine used by unit tests and --shots headless renders.
• chromium::ChromiumEngine — the Tilo system engine: a Chromium (CEF) host process rendering real pages offscreen, delivered as its own signed runtime (see chromium::runtime).

Coordinates in commands are physical pixels relative to the web view’s top-left corner — the widget does the logical→physical translation so engines never see toolkit layout space.

Modules

chromium

Chromium helper transport, independent of native CEF build dependencies.

key_code

A key’s place on the keyboard, named as the DOM names it (KeyboardEvent.code), for the keys whose meaning a layout changes: the letters, digits and punctuation. Named keys (Enter, the arrows) mean the same on every layout and travel by name alone.

page

Typed requests against a live page’s content.

paint

The paint stream: a page as a display list instead of pixels.

profile

Lightweight instrumentation for the WebView pipeline. Off by default; enabled by setting TILO_WEBVIEW_PROFILE in the environment.

test_engine

Deterministic in-process engine used by unit tests and --shots headless renders. It loads no network content: every “page” is a flat colour derived from a stable hash of the URL, with a darker header band, so different URLs render visibly different frames and pixel assertions stay byte-stable across runs.

text_input

Private, acknowledged edits. Neither replies nor transcripts are app events.

Structs

AddressFields

CredentialAccount

CredentialForm

CredentialReply

CredentialRequest

ExtensionActionChange

What an extension changed of its toolbar button (chrome.action). Each field is None when it did not change; Some(None) takes back what it set for one tab, so that tab shows what every tab shows.

ExtensionNotice

What an extension’s notification (chrome.notifications) shows.

ExtensionPermissionSet

API permissions and site patterns, as chrome.permissions names a set of them.

ExtensionShortcut

A key one of extensions’ commands holds (commands in a manifest), as Chrome names it (“Y”, “9”, “Comma”, “Up”), with its modifiers: meta is Command on macOS.

Frame

One rendered frame from the engine: tightly-packed RGBA8 at physical pixel resolution. The buffer is shared, never copied per draw — the widget detects staleness via the allocation pointer.

FrameDamage

Where a frame differs from the ones its engine made before it: a view that drew one of those repaints, and uploads, only there.

FrameId

A frame’s place in the page: the id its parent’s outline printed, a dot between the numbers of nested frames (2, then 2.1), at most eight deep.

KeyModifiers

Forwarded into the page so editing shortcuts (Ctrl+Backspace, Shift+Arrow, …) reach the web content.

MediaElementInfo

A visible media element expressed relative to the web viewport. Keeping this normalised makes it independent of physical display scale and lets browser chrome map it onto the current app surface after a resize.

NavigationEntry

An actual session entry; ids are engine-owned and valid for its snapshot.

OmniboxSuggestion

One suggestion an extension made for what follows its keyword: what choosing it enters, and what it says, in Chrome’s markup (<match>, <dim>, <url>).

PageDialog

A question the page waits on until it is answered with WebViewCommand::AnswerPageDialog, or the engine says it no longer waits (WebViewEvent::PageDialogClosed). Everything but id and kind is the page’s own text.

PageFailure

Why a page request did nothing. code is stable, such as stale_element, obscured or unavailable.

PageKey

One key plus modifiers, written as a chord such as Enter, Shift+Tab or Control+a.

PageReply

What a completed page request observed.

PixelRect

A rect of a frame, in its pixels.

PointerStep

One step of a PageRequest::Pointer gesture.

Popup

A popup window a page opened, with the size it asked for (0 when it named none), in CSS pixels.

ServiceSessionReply

Import completion proves storage writes, never provider authentication.

ServiceSessionRequest

SiteStatus

Bounded snapshot for one committed top-level origin and document generation.

TextField

The page’s focused editable field, as an engine reports it for the platform input method: what it takes, and where on the page it and the text being composed in it are, so the input method’s candidates appear where the person types.

Enums

ContextMenuItem

A row of a page’s context menu, as the engine offers it.

CredentialAction

ExtensionActionIcon

An icon an extension gave its toolbar button.

ExtensionMenuItem

A row of an extension’s toolbar button menu (chrome.contextMenus items made for its button), chosen by key (WebViewCommand::ExtensionMenuChoice).

ExtensionSidePanelChange

What an extension asks of its side panel beside a tab’s page; each address is among the extension’s own pages.

KeyInput

Winit-independent so engines don’t take a winit dependency.

MouseButton

NamedKey

NavigationCommand

An owned main-frame navigation. Its final URL may differ after redirects.

NavigationDirection

OmniboxInput

What the person did in the Browser’s address after an extension’s keyword (the manifest’s omnibox), which the extension hears of as in Chrome (chrome.omnibox).

PageDialogKind

What a page asks with a dialog of its own.

PageNavigation

Whether a page request led the page to another document, as far as the engine can tell when it answers.

PageRequest

PointerButton

PointerPoint

Where a step happens: inside an element’s box or at a viewport point.

PointerStepKind

ScrollTarget

Where a PageRequest::Scroll goes instead of a distance.

WebViewCommand

WebViewEvent

Navigation / UI state changes from the engine to the host app, folded into its own state (address bar text, title, progress) during sync.

Constants

BROWSER_APP_ID

The Browser’s app id: the app the desktop opens a web address in when nothing else is chosen for it.

MAX_PAGE_DIALOG_ANSWER

The longest answer to a page’s prompt an engine takes, in bytes.

MAX_POINTER_STEPS

Upper bound on the steps of one pointer gesture.

VISITOR_WINDOW_FLAG

The switch a Browser window is launched with when it is opened for an agent ([runtime_portal::windows::VISITOR_WINDOW_FLAG]). Reading such a page takes no authority beyond a visitor’s. A launch switch is part of the local window door, so the portable toolkit, which no launcher starts, has none.

Traits

WebViewEngine

A running web engine instance. Implementations are Send + Sync so the widget, the host app, and the engine’s own thread can share one handle.

Type Aliases

FrameSlot

Latest-frame mailbox between an engine and the widget. Engines overwrite the slot on every paint; the widget reads it on every draw.

SharedEngine

Shared engine handle, as stored by the widget and the host app.