docs(screenshot): note webp limitation on WebKit macOS

Author: yury-s

docs/src/api/params.md

@@ -1289,7 +1289,8 @@ saved to the disk.
 ## screenshot-option-type
 - `type` <[ScreenshotType]<"png"|"jpeg"|"webp">>
 
-Specify screenshot type, defaults to `png`.
+Specify screenshot type, defaults to `png`. The `webp` type is not supported in
+WebKit on macOS because macOS CoreGraphics does not provide a webp encoder.
 
 ## screenshot-option-mask
 - `mask` <[Array]<[Locator]>>

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

@@ -12311,7 +12311,8 @@ export interface ElementHandle<T=Node> extends JSHandle<T> {
     timeout?: number;
 
     /**
-     * Specify screenshot type, defaults to `png`.
+     * Specify screenshot type, defaults to `png`. The `webp` type is not supported in WebKit on macOS because macOS
+     * CoreGraphics does not provide a webp encoder.
      */
     type?: "png"|"jpeg"|"webp";
   }): Promise<Buffer>;
@@ -24122,7 +24123,8 @@ export interface LocatorScreenshotOptions {
   timeout?: number;
 
   /**
-   * Specify screenshot type, defaults to `png`.
+   * Specify screenshot type, defaults to `png`. The `webp` type is not supported in WebKit on macOS because macOS
+   * CoreGraphics does not provide a webp encoder.
    */
   type?: "png"|"jpeg"|"webp";
 }
@@ -24795,7 +24797,8 @@ export interface PageScreenshotOptions {
   timeout?: number;
 
   /**
-   * Specify screenshot type, defaults to `png`.
+   * Specify screenshot type, defaults to `png`. The `webp` type is not supported in WebKit on macOS because macOS
+   * CoreGraphics does not provide a webp encoder.
    */
   type?: "png"|"jpeg"|"webp";
 }

packages/playwright-core/src/tools/backend/screenshot.ts

@@ -30,7 +30,7 @@ import type * as playwright from '../../..';
 type ImageFormat = 'png' | 'jpeg' | 'webp';
 
 const screenshotSchema = optionalElementSchema.extend({
-  type: z.enum(['png', 'jpeg', 'webp']).optional().describe('Image format for the screenshot. If unset, inferred from the filename extension, otherwise png.'),
+  type: z.enum(['png', 'jpeg', 'webp']).optional().describe('Image format for the screenshot. If unset, inferred from the filename extension, otherwise png. Note: `webp` is not supported in WebKit on macOS.'),
   filename: z.string().optional().describe('File name to save the screenshot to. Defaults to `page-{timestamp}.{png|jpeg|webp}` if not specified. Prefer relative file names to stay within the output directory.'),
   fullPage: z.boolean().optional().describe('When true, takes a screenshot of the full scrollable page, instead of the currently visible viewport. Cannot be used with element screenshots.'),
 });

packages/playwright-core/src/tools/cli-daemon/commands.ts

@@ -790,7 +790,7 @@ const screenshot = declareCommand({
   }),
   options: z.object({
     filename: z.string().optional().describe('File name to save the screenshot to. Defaults to `page-{timestamp}.{png|jpeg|webp}` if not specified.'),
-    type: z.enum(['png', 'jpeg', 'webp']).optional().describe('Image format. If unset, inferred from the filename extension, otherwise png.'),
+    type: z.enum(['png', 'jpeg', 'webp']).optional().describe('Image format. If unset, inferred from the filename extension, otherwise png. webp is not supported in WebKit on macOS.'),
     ['full-page']: z.boolean().optional().describe('When true, takes a screenshot of the full scrollable page, instead of the currently visible viewport.'),
   }),
   toolName: 'browser_take_screenshot',

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

@@ -12311,7 +12311,8 @@ export interface ElementHandle<T=Node> extends JSHandle<T> {
     timeout?: number;
 
     /**
-     * Specify screenshot type, defaults to `png`.
+     * Specify screenshot type, defaults to `png`. The `webp` type is not supported in WebKit on macOS because macOS
+     * CoreGraphics does not provide a webp encoder.
      */
     type?: "png"|"jpeg"|"webp";
   }): Promise<Buffer>;
@@ -24122,7 +24123,8 @@ export interface LocatorScreenshotOptions {
   timeout?: number;
 
   /**
-   * Specify screenshot type, defaults to `png`.
+   * Specify screenshot type, defaults to `png`. The `webp` type is not supported in WebKit on macOS because macOS
+   * CoreGraphics does not provide a webp encoder.
    */
   type?: "png"|"jpeg"|"webp";
 }
@@ -24795,7 +24797,8 @@ export interface PageScreenshotOptions {
   timeout?: number;
 
   /**
-   * Specify screenshot type, defaults to `png`.
+   * Specify screenshot type, defaults to `png`. The `webp` type is not supported in WebKit on macOS because macOS
+   * CoreGraphics does not provide a webp encoder.
    */
   type?: "png"|"jpeg"|"webp";
 }