Add Page.captureScreenshot CDP support#56307
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Summary: Implement the `Page.captureScreenshot` CDP command in the inspector backend, allowing DevTools to capture an on-demand screenshot of the current app view. This is a minimal implementation supporting only the `format` (jpeg/png/webp) and `quality` (0-100, jpeg only) parameters, returning base64-encoded image data. The feature is gated behind a new `fuseboxCaptureScreenshotEnabled` React Native feature flag, wired through `InspectorFlags` following the same pattern as frame recording. **Motivation** Improve agent verification / user feedback during AI sessions. We've proven that screenshots (in performance traces) are useful for understanding how components render on screen, and exposing this as an on-demand CDP method is relatively cheap today vs the larger task of modelling the DOM (Elements panel). **Changes** - New `fuseboxCaptureScreenshotEnabled` feature flag + `InspectorFlags` wiring (C++, Android JNI, Kotlin) - `HostTargetDelegate::captureScreenshot()` virtual method with async callback - C++ CDP handler in `HostAgent` — parses `format`/`quality`, delegates to platform, sends async CDP response (gated by flag) - iOS (`RCTHost.mm`): Captures key window via `UIGraphicsImageRenderer` + `drawViewHierarchyInRect`, encodes to PNG/JPEG - Android (`ReactHostImpl.kt`): Captures decor view via `Bitmap` + `Canvas` + `View.draw()`, encodes to PNG/JPEG/WebP - 4 C++ tests: success, failure, param forwarding, flag-disabled rejection Changelog: [Internal] Differential Revision: D99099930
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Summary:
Implement the
Page.captureScreenshotCDP command in the inspector backend, allowing DevTools to capture an on-demand screenshot of the current app view. This is a minimal implementation supporting only theformat(jpeg/png/webp) andquality(0-100, jpeg only) parameters, returning base64-encoded image data.The feature is gated behind a new
fuseboxCaptureScreenshotEnabledReact Native feature flag, wired throughInspectorFlagsfollowing the same pattern as frame recording.Motivation
Improve agent verification / user feedback during AI sessions. We've proven that screenshots (in performance traces) are useful for understanding how components render on screen, and exposing this as an on-demand CDP method is relatively cheap today vs the larger task of modelling the DOM (Elements panel).
Changes
fuseboxCaptureScreenshotEnabledfeature flag +InspectorFlagswiring (C++, Android JNI, Kotlin)HostTargetDelegate::captureScreenshot()virtual method with async callbackHostAgent— parsesformat/quality, delegates to platform, sends async CDP response (gated by flag)RCTHost.mm): Captures key window viaUIGraphicsImageRenderer+drawViewHierarchyInRect, encodes to PNG/JPEGReactHostImpl.kt): Captures decor view viaBitmap+Canvas+View.draw(), encodes to PNG/JPEG/WebPChangelog: [Internal]
Differential Revision: D99099930