code: func (c *Page) CaptureScreenshot(format string, quality int, clip *PageViewport, fromSurface bool) (string, error) {
  	var v PageCaptureScreenshotParams
  	v.Format = format
  	v.Quality = quality
  	v.Clip = clip
  	v.FromSurface = fromSurface
  	return c.CaptureScreenshotWithParams(&v)
  }
docs: // CaptureScreenshot - Capture page screenshot.
  // format - Image compression format (defaults to png).
  // quality - Compression quality from range [0..100] (jpeg only).
  // clip - Capture the screenshot of a given region only.
  // fromSurface - Capture the screenshot from the surface, rather than the view. Defaults to true.
  // Returns -  data - Base64-encoded image data.