dvDeviceTypeFor function

String dvDeviceTypeFor({ required String platform, required String breakpoint, bool isTV = false, bool isWatch = false, bool isWeb = false, bool isFoldable = false, })

What kind of device this is.

Separated from DVPlatform so it can be asserted on directly, and because getting it wrong is invisible until an application takes a layout branch on the wrong platform.

It used to answer from breakpoint alone, which meant the same desktop application reported a different device depending on how wide its window was. Running the example on two platforms and comparing the screenshots showed it plainly: Linux at 1280px said desktop, Windows at 1024px said tablet. Same framework, same app, same class of machine — the only difference was the window, and anything branching on the result took the tablet path on Windows.

Width is the right input for layout, which is what breakpoint remains for and which is unchanged. It is the wrong input for what the device is.

Implementation

String dvDeviceTypeFor({
  required String platform,
  required String breakpoint,
  bool isTV = false,
  bool isWatch = false,
  bool isWeb = false,
  bool isFoldable = false,
}) {
  // The explicit kinds first: a television is a television at any width, and
  // calling it a desktop would send an application down the pointer-and-window
  // path on a device driven by a remote control.
  if (isTV || _dvTelevisionPlatforms.contains(platform)) return 'tv';
  if (isWatch) return 'watch';
  if (isWeb) return 'web';

  // The platform, before the window. A desktop OS is a desktop however narrow
  // the window has been dragged.
  if (_dvDesktopPlatforms.contains(platform)) return 'desktop';

  // On a mobile OS the screen genuinely is the signal, because the same system
  // runs on both phones and tablets.
  if (breakpoint == 'desktop' || breakpoint == 'tablet') return 'tablet';
  if (isFoldable) return 'foldable';
  return 'phone';
}