Capture a rendered element ONCE and return its full-frame RGBA bytes.
Use this when a spec needs whole-image analysis (histograms, per-region
statistics) rather than a handful of point samples — measuring several
regions of one identical frame is the point, and re-screenshotting per
region would let an unrelated frame difference masquerade as a defect.
The PNG is decoded in-page and handed back as base64 RGBA so the whole
frame crosses the CDP bridge exactly once. See
captureElementScreenshot for viewer-framebuffer versus embed/host
screenshot routing.
Capture a rendered element ONCE and return its full-frame RGBA bytes.
Use this when a spec needs whole-image analysis (histograms, per-region statistics) rather than a handful of point samples — measuring several regions of one identical frame is the point, and re-screenshotting per region would let an unrelated frame difference masquerade as a defect.
The PNG is decoded in-page and handed back as base64 RGBA so the whole frame crosses the CDP bridge exactly once. See
captureElementScreenshotfor viewer-framebuffer versus embed/host screenshot routing.