feat(screenshot): add webp output format

docs/src/api/params.md

@@ -1303,7 +1303,8 @@ Defaults to `false`.
 ## screenshot-option-quality
 - `quality` <[int]>
 
-The quality of the image, between 0-100. Not applicable to `png` images.
+The quality of the image, between 0-100. Not applicable to `png` images. For `jpeg` the default is `80`.
+For `webp`, a quality of `100` (the default) produces a lossless image, while lower values use lossy compression.
 
 ## screenshot-option-path
 - `path` <[path]>
@@ -1313,7 +1314,7 @@ relative path, then it is resolved relative to the current working directory. If
 saved to the disk.
 
 ## screenshot-option-type
-- `type` <[ScreenshotType]<"png"|"jpeg">>
+- `type` <[ScreenshotType]<"png"|"jpeg"|"webp">>
 
 Specify screenshot type, defaults to `png`.
 

eslint.config.mjs

@@ -48,6 +48,7 @@ const ignores = [
   "examples",
   "packages/*/lib/",
   "packages/playwright-core/bundles/utils/src/third_party/",
+  "packages/utils/webp/webp_codec.js",
   "packages/playwright-core/src/generated/*",
   "packages/playwright-core/src/third_party/",
   "packages/playwright-core/types/*",

packages/playwright-client/types/types.d.ts

@@ -13176,7 +13176,8 @@ export interface ElementHandle<T=Node> extends JSHandle<T> {
     path?: string;
 
     /**
-     * The quality of the image, between 0-100. Not applicable to `png` images.
+     * The quality of the image, between 0-100. Not applicable to `png` images. For `jpeg` the default is `80`. For
+     * `webp`, a quality of `100` (the default) produces a lossless image, while lower values use lossy compression.
      */
     quality?: number;
 
@@ -13218,7 +13219,7 @@ export interface ElementHandle<T=Node> extends JSHandle<T> {
     /**
      * Specify screenshot type, defaults to `png`.
      */
-    type?: "png"|"jpeg";
+    type?: "png"|"jpeg"|"webp";
   }): Promise<Buffer>;
 
   /**
@@ -25108,7 +25109,8 @@ export interface LocatorScreenshotOptions {
   path?: string;
 
   /**
-   * The quality of the image, between 0-100. Not applicable to `png` images.
+   * The quality of the image, between 0-100. Not applicable to `png` images. For `jpeg` the default is `80`. For
+   * `webp`, a quality of `100` (the default) produces a lossless image, while lower values use lossy compression.
    */
   quality?: number;
 
@@ -25150,7 +25152,7 @@ export interface LocatorScreenshotOptions {
   /**
    * Specify screenshot type, defaults to `png`.
    */
-  type?: "png"|"jpeg";
+  type?: "png"|"jpeg"|"webp";
 }
 
 interface ElementHandleWaitForSelectorOptions {
@@ -25825,7 +25827,8 @@ export interface PageScreenshotOptions {
   path?: string;
 
   /**
-   * The quality of the image, between 0-100. Not applicable to `png` images.
+   * The quality of the image, between 0-100. Not applicable to `png` images. For `jpeg` the default is `80`. For
+   * `webp`, a quality of `100` (the default) produces a lossless image, while lower values use lossy compression.
    */
   quality?: number;
 
@@ -25867,7 +25870,7 @@ export interface PageScreenshotOptions {
   /**
    * Specify screenshot type, defaults to `png`.
    */
-  type?: "png"|"jpeg";
+  type?: "png"|"jpeg"|"webp";
 }
 
 type Devices = {

packages/playwright-core/.npmignore

@@ -14,6 +14,8 @@
 !lib/**/*.ttf
 !lib/**/*.json
 !lib/**/*.md
+# Include the WebP codec WASM binary (see @utils/webp/webp).
+!lib/**/*.wasm
 !lib/xdg-open
 !lib/**/manifest.webmanifest
 # Exclude injected files. A preprocessed version of these is included via lib/generated.

packages/playwright-core/src/client/channels.d.ts

@@ -3334,7 +3334,7 @@ export type ElementHandleQuerySelectorAllResult = {
 };
 export type ElementHandleScreenshotParams = {
   timeout: number,
-  type?: 'png' | 'jpeg',
+  type?: 'png' | 'jpeg' | 'webp',
   quality?: number,
   omitBackground?: boolean,
   caret?: 'hide' | 'initial',
@@ -3348,7 +3348,7 @@ export type ElementHandleScreenshotParams = {
   style?: string,
 };
 export type ElementHandleScreenshotOptions = {
-  type?: 'png' | 'jpeg',
+  type?: 'png' | 'jpeg' | 'webp',
   quality?: number,
   omitBackground?: boolean,
   caret?: 'hide' | 'initial',
@@ -4194,6 +4194,7 @@ export type PageExpectScreenshotParams = {
   threshold?: number,
   fullPage?: boolean,
   clip?: Rect,
+  type?: 'png' | 'jpeg' | 'webp',
   omitBackground?: boolean,
   caret?: 'hide' | 'initial',
   animations?: 'disabled' | 'allow',
@@ -4217,6 +4218,7 @@ export type PageExpectScreenshotOptions = {
   threshold?: number,
   fullPage?: boolean,
   clip?: Rect,
+  type?: 'png' | 'jpeg' | 'webp',
   omitBackground?: boolean,
   caret?: 'hide' | 'initial',
   animations?: 'disabled' | 'allow',
@@ -4241,7 +4243,7 @@ export type PageExpectScreenshotErrorDetails = {
 };
 export type PageScreenshotParams = {
   timeout: number,
-  type?: 'png' | 'jpeg',
+  type?: 'png' | 'jpeg' | 'webp',
   quality?: number,
   fullPage?: boolean,
   clip?: Rect,
@@ -4257,7 +4259,7 @@ export type PageScreenshotParams = {
   style?: string,
 };
 export type PageScreenshotOptions = {
-  type?: 'png' | 'jpeg',
+  type?: 'png' | 'jpeg' | 'webp',
   quality?: number,
   fullPage?: boolean,
   clip?: Rect,

packages/playwright-core/src/client/elementHandle.ts

@@ -320,13 +320,15 @@ export async function convertInputFiles(files: string | FilePayload | string[] |
   return { payloads };
 }
 
-export function determineScreenshotType(options: { path?: string, type?: 'png' | 'jpeg' }): 'png' | 'jpeg' | undefined {
+export function determineScreenshotType(options: { path?: string, type?: 'png' | 'jpeg' | 'webp' }): 'png' | 'jpeg' | 'webp' | undefined {
   if (options.path) {
     const mimeType = getMimeTypeForPath(options.path);
     if (mimeType === 'image/png')
       return 'png';
     else if (mimeType === 'image/jpeg')
       return 'jpeg';
+    else if (mimeType === 'image/webp')
+      return 'webp';
     throw new Error(`path: unsupported mime type "${mimeType}"`);
   }
   return options.type;

packages/playwright-core/src/protocol/validator.ts

@@ -1898,7 +1898,7 @@ scheme.ElementHandleQuerySelectorAllResult = tObject({
 });
 scheme.ElementHandleScreenshotParams = tObject({
   timeout: tFloat,
-  type: tOptional(tEnum(['png', 'jpeg'])),
+  type: tOptional(tEnum(['png', 'jpeg', 'webp'])),
   quality: tOptional(tInt),
   omitBackground: tOptional(tBoolean),
   caret: tOptional(tEnum(['hide', 'initial'])),
@@ -2438,6 +2438,7 @@ scheme.PageExpectScreenshotParams = tObject({
   threshold: tOptional(tFloat),
   fullPage: tOptional(tBoolean),
   clip: tOptional(tType('Rect')),
+  type: tOptional(tEnum(['png', 'jpeg', 'webp'])),
   omitBackground: tOptional(tBoolean),
   caret: tOptional(tEnum(['hide', 'initial'])),
   animations: tOptional(tEnum(['disabled', 'allow'])),
@@ -2462,7 +2463,7 @@ scheme.PageExpectScreenshotErrorDetails = tObject({
 });
 scheme.PageScreenshotParams = tObject({
   timeout: tFloat,
-  type: tOptional(tEnum(['png', 'jpeg'])),
+  type: tOptional(tEnum(['png', 'jpeg', 'webp'])),
   quality: tOptional(tInt),
   fullPage: tOptional(tBoolean),
   clip: tOptional(tType('Rect')),

packages/playwright-core/src/server/bidi/bidiPage.ts

@@ -489,6 +489,8 @@ export class BidiPage implements PageDelegate {
   }
 
   async takeScreenshot(progress: Progress, format: string, documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, quality: number | undefined, fitsViewport: boolean, scale: 'css' | 'device'): Promise<Buffer> {
+    if (format === 'webp')
+      throw new Error('webp screenshots are not supported via WebDriver BiDi');
     const rect = (documentRect || viewportRect)!;
     const { data } = await progress.race(this._session.send('browsingContext.captureScreenshot', {
       context: this._session.sessionId,

packages/playwright-core/src/server/channels.d.ts

@@ -3337,7 +3337,7 @@ export type ElementHandleQuerySelectorAllResult = {
 };
 export type ElementHandleScreenshotParams = {
   timeout: number,
-  type?: 'png' | 'jpeg',
+  type?: 'png' | 'jpeg' | 'webp',
   quality?: number,
   omitBackground?: boolean,
   caret?: 'hide' | 'initial',
@@ -3351,7 +3351,7 @@ export type ElementHandleScreenshotParams = {
   style?: string,
 };
 export type ElementHandleScreenshotOptions = {
-  type?: 'png' | 'jpeg',
+  type?: 'png' | 'jpeg' | 'webp',
   quality?: number,
   omitBackground?: boolean,
   caret?: 'hide' | 'initial',
@@ -4197,6 +4197,7 @@ export type PageExpectScreenshotParams = {
   threshold?: number,
   fullPage?: boolean,
   clip?: Rect,
+  type?: 'png' | 'jpeg' | 'webp',
   omitBackground?: boolean,
   caret?: 'hide' | 'initial',
   animations?: 'disabled' | 'allow',
@@ -4220,6 +4221,7 @@ export type PageExpectScreenshotOptions = {
   threshold?: number,
   fullPage?: boolean,
   clip?: Rect,
+  type?: 'png' | 'jpeg' | 'webp',
   omitBackground?: boolean,
   caret?: 'hide' | 'initial',
   animations?: 'disabled' | 'allow',
@@ -4244,7 +4246,7 @@ export type PageExpectScreenshotErrorDetails = {
 };
 export type PageScreenshotParams = {
   timeout: number,
-  type?: 'png' | 'jpeg',
+  type?: 'png' | 'jpeg' | 'webp',
   quality?: number,
   fullPage?: boolean,
   clip?: Rect,
@@ -4260,7 +4262,7 @@ export type PageScreenshotParams = {
   style?: string,
 };
 export type PageScreenshotOptions = {
-  type?: 'png' | 'jpeg',
+  type?: 'png' | 'jpeg' | 'webp',
   quality?: number,
   fullPage?: boolean,
   clip?: Rect,

packages/playwright-core/src/server/chromium/crPage.ts

@@ -247,7 +247,7 @@ export class CRPage implements PageDelegate {
     await this._mainFrameSession._client.send('Emulation.setDefaultBackgroundColorOverride', { color });
   }
 
-  async takeScreenshot(progress: Progress, format: 'png' | 'jpeg', documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, quality: number | undefined, fitsViewport: boolean, scale: 'css' | 'device'): Promise<Buffer> {
+  async takeScreenshot(progress: Progress, format: 'png' | 'jpeg' | 'webp', documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, quality: number | undefined, fitsViewport: boolean, scale: 'css' | 'device'): Promise<Buffer> {
     const { visualViewport, contentSize, cssContentSize } = await progress.race(this._mainFrameSession._client.send('Page.getLayoutMetrics'));
     if (!documentRect) {
       documentRect = {

packages/playwright-core/src/server/firefox/ffPage.ts

@@ -459,7 +459,7 @@ export class FFPage implements PageDelegate {
       throw new Error('Not implemented');
   }
 
-  async takeScreenshot(progress: Progress, format: 'png' | 'jpeg', documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, quality: number | undefined, fitsViewport: boolean, scale: 'css' | 'device'): Promise<Buffer> {
+  async takeScreenshot(progress: Progress, format: 'png' | 'jpeg' | 'webp', documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, quality: number | undefined, fitsViewport: boolean, scale: 'css' | 'device'): Promise<Buffer> {
     if (!documentRect) {
       const scrollOffset = await this._page.mainFrame().waitForFunctionValueInUtility(progress, () => ({ x: window.scrollX, y: window.scrollY }));
       documentRect = {
@@ -470,7 +470,7 @@ export class FFPage implements PageDelegate {
       };
     }
     const { data } = await progress.race(this._session.send('Page.screenshot', {
-      mimeType: ('image/' + format) as ('image/png' | 'image/jpeg'),
+      mimeType: ('image/' + format) as ('image/png' | 'image/jpeg' | 'image/webp'),
       clip: documentRect,
       quality,
       omitDeviceScaleFactor: scale === 'css',

packages/playwright-core/src/server/page.ts

@@ -719,7 +719,10 @@ export class Page extends SdkObject<PageEventMap> {
       return await this.screenshotter.screenshotPage(progress, options || {});
     };
 
-    const comparator = getComparator('image/png');
+    // Reset to the actual format once options are validated inside the try below;
+    // validation (clip, quality, ...) must stay inside the try so its errors are
+    // surfaced as a friendly diff rather than thrown.
+    let comparator = getComparator('image/png');
     let intermediateResult: {
       actual?: Buffer,
       previous?: Buffer,
@@ -739,8 +742,7 @@ export class Page extends SdkObject<PageEventMap> {
       if (!options.expected && options.isNot)
         throw new Error('"not" matcher requires expected result');
       const format = validateScreenshotOptions(options || {});
-      if (format !== 'png')
-        throw new Error('Only PNG screenshots are supported');
+      comparator = getComparator(`image/${format}`);
       let actual: Buffer | undefined;
       let previous: Buffer | undefined;
       const pollIntervals = [0, 100, 250, 500];

packages/playwright-core/src/server/screenshotter.ts

@@ -35,7 +35,7 @@ declare global {
 }
 
 export type ScreenshotOptions = {
-  type?: 'png' | 'jpeg';
+  type?: 'png' | 'jpeg' | 'webp';
   quality?: number;
   omitBackground?: boolean;
   animations?: 'disabled' | 'allow';
@@ -297,7 +297,7 @@ export class Screenshotter {
     }
   }
 
-  private async _screenshot(progress: Progress, format: 'png' | 'jpeg', documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, fitsViewport: boolean, options: ScreenshotOptions): Promise<Buffer> {
+  private async _screenshot(progress: Progress, format: 'png' | 'jpeg' | 'webp', documentRect: types.Rect | undefined, viewportRect: types.Rect | undefined, fitsViewport: boolean, options: ScreenshotOptions): Promise<Buffer> {
     if ((options as any).__testHookBeforeScreenshot)
       await progress.race((options as any).__testHookBeforeScreenshot());
 
@@ -307,7 +307,8 @@ export class Screenshotter {
     const cleanupHighlight = await this._maskElements(progress, options);
 
     try {
-      const quality = format === 'jpeg' ? options.quality ?? 80 : undefined;
+      // webp treats quality 100 (or omitted) as lossless, so default it to that.
+      const quality = format === 'jpeg' ? options.quality ?? 80 : format === 'webp' ? options.quality ?? 100 : undefined;
       const buffer = await this._page.delegate.takeScreenshot(progress, format, documentRect, viewportRect, quality, fitsViewport, options.scale || 'device');
       await progress.race(cleanupHighlight());
       if (shouldSetDefaultBackground)
@@ -353,20 +354,20 @@ function trimClipToSize(clip: types.Rect, size: types.Size): types.Rect {
   return result;
 }
 
-export function validateScreenshotOptions(options: ScreenshotOptions): 'png' | 'jpeg' {
-  let format: 'png' | 'jpeg' | null = null;
+export function validateScreenshotOptions(options: ScreenshotOptions): 'png' | 'jpeg' | 'webp' {
+  let format: 'png' | 'jpeg' | 'webp' | null = null;
   // options.type takes precedence over inferring the type from options.path
   // because it may be a 0-length file with no extension created beforehand (i.e. as a temp file).
   if (options.type) {
-    assert(options.type === 'png' || options.type === 'jpeg', 'Unknown options.type value: ' + options.type);
+    assert(options.type === 'png' || options.type === 'jpeg' || options.type === 'webp', 'Unknown options.type value: ' + options.type);
     format = options.type;
   }
 
   if (!format)
     format = 'png';
 
   if (options.quality !== undefined) {
-    assert(format === 'jpeg', 'options.quality is unsupported for the ' + format + ' screenshots');
+    assert(format !== 'png', 'options.quality is unsupported for the ' + format + ' screenshots');
     assert(typeof options.quality === 'number', 'Expected options.quality to be a number but found ' + (typeof options.quality));
     assert(Number.isInteger(options.quality), 'Expected options.quality to be an integer');
     assert(options.quality >= 0 && options.quality <= 100, 'Expected options.quality to be between 0 and 100 (inclusive), got ' + options.quality);

packages/playwright-core/src/server/webkit/webview/wvPage.ts

@@ -23,6 +23,7 @@ import { ManualPromise } from '@isomorphic/manualPromise';
 import { splitErrorMessage } from '@utils/stackTrace';
 import { debugLogger } from '@utils/debugLogger';
 import { eventsHelper } from '@utils/eventsHelper';
+import { encodeWebp } from '@utils/webp/webp';
 import * as dialog from '../../dialog';
 import * as dom from '../../dom';
 import { TargetClosedError } from '../../errors';
@@ -767,8 +768,13 @@ export class WVPage implements PageDelegate {
     const result = await progress.race(this._session.send('Page.snapshotRect', { ...rect, coordinateSystem: documentRect ? 'Page' : 'Viewport' }));
     const prefix = 'data:image/png;base64,';
     let buffer: Buffer = Buffer.from(result.dataURL.substr(prefix.length), 'base64');
-    if (format === 'jpeg')
+    if (format === 'jpeg') {
       buffer = jpegjs.encode(PNG.sync.read(buffer), quality).data;
+    } else if (format === 'webp') {
+      const png = PNG.sync.read(buffer);
+      // Match the native WebKit encoder: webp quality 100 (or omitted) is lossless.
+      buffer = (quality === undefined || quality >= 100) ? encodeWebp(png, { lossless: true }) : encodeWebp(png, { quality });
+    }
     return buffer;
   }