electron/docs/api/structures/web-preferences.md
michal-pichlinski-openfin 2190793fe6
fix: disable background throttling also in the viz::DisplayScheduler (#38924)
* fix: disable background throttling also in the `viz::DisplayScheduler`

`viz::DisplayScheduler` is responsible for drawing and swapping frames
in the `DisplayScheduler::DrawAndSwap` which is called from the
`DisplayScheduler::AttemptDrawAndSwap` if the `DisplayScheduler::ShouldDraw`
returns true. `ShouldDraw` depends on the `DisplayScheduler` visibility
and when it is not visible then it returns false.

In order to keep producing frames, disabling `backgroundThrottling`
should also prevent changing `DisplayScheduler` visibility to false.

`DisplayScheduler` lives in the `ui::Compositor` where every
`electron::NativewWindow` has its own `Compositor`. `electron::NativewWindow`
may be host of the multiple `electron::api::WebContents` instances which may
have different `WebPreferences` settings. Therefore if at least one
of the `WebContents` requires disabling throttling then all other `WebContents`
using the same window will have it disabled in the `ui::Compositor`.

BREAKING CHANGE:
`backgroundThrottling` set to false will disable frames throttling
in the `BrowserWindow` for all `WebContents` displayed by it.

Close: [#31016](https://github.com/electron/electron/issues/31016)

* fixup! fix: disable background throttling also in the `viz::DisplayScheduler`

* fixup! fix: disable background throttling also in the `viz::DisplayScheduler`

* fixup! fix: disable background throttling also in the `viz::DisplayScheduler`

---------

Co-authored-by: John Kleinschmidt <jkleinsc@electronjs.org>
2023-09-26 16:00:46 -04:00

9.7 KiB

WebPreferences Object

  • devTools boolean (optional) - Whether to enable DevTools. If it is set to false, can not use BrowserWindow.webContents.openDevTools() to open DevTools. Default is true.
  • nodeIntegration boolean (optional) - Whether node integration is enabled. Default is false.
  • nodeIntegrationInWorker boolean (optional) - Whether node integration is enabled in web workers. Default is false. More about this can be found in Multithreading.
  • nodeIntegrationInSubFrames boolean (optional) - Experimental option for enabling Node.js support in sub-frames such as iframes and child windows. All your preloads will load for every iframe, you can use process.isMainFrame to determine if you are in the main frame or not.
  • preload string (optional) - Specifies a script that will be loaded before other scripts run in the page. This script will always have access to node APIs no matter whether node integration is turned on or off. The value should be the absolute file path to the script. When node integration is turned off, the preload script can reintroduce Node global symbols back to the global scope. See example here.
  • sandbox boolean (optional) - If set, this will sandbox the renderer associated with the window, making it compatible with the Chromium OS-level sandbox and disabling the Node.js engine. This is not the same as the nodeIntegration option and the APIs available to the preload script are more limited. Read more about the option here.
  • session Session (optional) - Sets the session used by the page. Instead of passing the Session object directly, you can also choose to use the partition option instead, which accepts a partition string. When both session and partition are provided, session will be preferred. Default is the default session.
  • partition string (optional) - Sets the session used by the page according to the session's partition string. If partition starts with persist:, the page will use a persistent session available to all pages in the app with the same partition. If there is no persist: prefix, the page will use an in-memory session. By assigning the same partition, multiple pages can share the same session. Default is the default session.
  • zoomFactor number (optional) - The default zoom factor of the page, 3.0 represents 300%. Default is 1.0.
  • javascript boolean (optional) - Enables JavaScript support. Default is true.
  • webSecurity boolean (optional) - When false, it will disable the same-origin policy (usually using testing websites by people), and set allowRunningInsecureContent to true if this options has not been set by user. Default is true.
  • allowRunningInsecureContent boolean (optional) - Allow an https page to run JavaScript, CSS or plugins from http URLs. Default is false.
  • images boolean (optional) - Enables image support. Default is true.
  • imageAnimationPolicy string (optional) - Specifies how to run image animations (E.g. GIFs). Can be animate, animateOnce or noAnimation. Default is animate.
  • textAreasAreResizable boolean (optional) - Make TextArea elements resizable. Default is true.
  • webgl boolean (optional) - Enables WebGL support. Default is true.
  • plugins boolean (optional) - Whether plugins should be enabled. Default is false.
  • experimentalFeatures boolean (optional) - Enables Chromium's experimental features. Default is false.
  • scrollBounce boolean (optional) macOS - Enables scroll bounce (rubber banding) effect on macOS. Default is false.
  • enableBlinkFeatures string (optional) - A list of feature strings separated by ,, like CSSVariables,KeyboardEventKey to enable. The full list of supported feature strings can be found in the RuntimeEnabledFeatures.json5 file.
  • disableBlinkFeatures string (optional) - A list of feature strings separated by ,, like CSSVariables,KeyboardEventKey to disable. The full list of supported feature strings can be found in the RuntimeEnabledFeatures.json5 file.
  • defaultFontFamily Object (optional) - Sets the default font for the font-family.
    • standard string (optional) - Defaults to Times New Roman.
    • serif string (optional) - Defaults to Times New Roman.
    • sansSerif string (optional) - Defaults to Arial.
    • monospace string (optional) - Defaults to Courier New.
    • cursive string (optional) - Defaults to Script.
    • fantasy string (optional) - Defaults to Impact.
    • math string (optional) - Defaults to Latin Modern Math.
  • defaultFontSize Integer (optional) - Defaults to 16.
  • defaultMonospaceFontSize Integer (optional) - Defaults to 13.
  • minimumFontSize Integer (optional) - Defaults to 0.
  • defaultEncoding string (optional) - Defaults to ISO-8859-1.
  • backgroundThrottling boolean (optional) - Whether to throttle animations and timers when the page becomes background. This also affects the Page Visibility API. When at least one webContents displayed in a single browserWindow has disabled backgroundThrottling then frames will be drawn and swapped for the whole window and other webContents displayed by it. Defaults to true.
  • offscreen boolean (optional) - Whether to enable offscreen rendering for the browser window. Defaults to false. See the offscreen rendering tutorial for more details.
  • contextIsolation boolean (optional) - Whether to run Electron APIs and the specified preload script in a separate JavaScript context. Defaults to true. The context that the preload script runs in will only have access to its own dedicated document and window globals, as well as its own set of JavaScript builtins (Array, Object, JSON, etc.), which are all invisible to the loaded content. The Electron API will only be available in the preload script and not the loaded page. This option should be used when loading potentially untrusted remote content to ensure the loaded content cannot tamper with the preload script and any Electron APIs being used. This option uses the same technique used by Chrome Content Scripts. You can access this context in the dev tools by selecting the 'Electron Isolated Context' entry in the combo box at the top of the Console tab.
  • webviewTag boolean (optional) - Whether to enable the <webview> tag. Defaults to false. Note: The preload script configured for the <webview> will have node integration enabled when it is executed so you should ensure remote/untrusted content is not able to create a <webview> tag with a possibly malicious preload script. You can use the will-attach-webview event on webContents to strip away the preload script and to validate or alter the <webview>'s initial settings.
  • additionalArguments string[] (optional) - A list of strings that will be appended to process.argv in the renderer process of this app. Useful for passing small bits of data down to renderer process preload scripts.
  • safeDialogs boolean (optional) - Whether to enable browser style consecutive dialog protection. Default is false.
  • safeDialogsMessage string (optional) - The message to display when consecutive dialog protection is triggered. If not defined the default message would be used, note that currently the default message is in English and not localized.
  • disableDialogs boolean (optional) - Whether to disable dialogs completely. Overrides safeDialogs. Default is false.
  • navigateOnDragDrop boolean (optional) - Whether dragging and dropping a file or link onto the page causes a navigation. Default is false.
  • autoplayPolicy string (optional) - Autoplay policy to apply to content in the window, can be no-user-gesture-required, user-gesture-required, document-user-activation-required. Defaults to no-user-gesture-required.
  • disableHtmlFullscreenWindowResize boolean (optional) - Whether to prevent the window from resizing when entering HTML Fullscreen. Default is false.
  • accessibleTitle string (optional) - An alternative title string provided only to accessibility tools such as screen readers. This string is not directly visible to users.
  • spellcheck boolean (optional) - Whether to enable the builtin spellchecker. Default is true.
  • enableWebSQL boolean (optional) - Whether to enable the WebSQL api. Default is true.
  • v8CacheOptions string (optional) - Enforces the v8 code caching policy used by blink. Accepted values are
    • none - Disables code caching
    • code - Heuristic based code caching
    • bypassHeatCheck - Bypass code caching heuristics but with lazy compilation
    • bypassHeatCheckAndEagerCompile - Same as above except compilation is eager. Default policy is code.
  • enablePreferredSizeMode boolean (optional) - Whether to enable preferred size mode. The preferred size is the minimum size needed to contain the layout of the document—without requiring scrolling. Enabling this will cause the preferred-size-changed event to be emitted on the WebContents when the preferred size changes. Default is false.