packages/flutter/lib/src/material/constants.dart

// Copyright 2014 The Flutter Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/painting.dart';

/// The minimum dimension of any interactive region according to Material
/// guidelines.
///
/// This is used to avoid small regions that are hard for the user to interact
/// with. It applies to both dimensions of a region, so a square of size
/// kMinInteractiveDimension x kMinInteractiveDimension is the smallest
/// acceptable region that should respond to gestures.
///
/// See also:
///
///  * [kMinInteractiveDimensionCupertino]
///  * The Material spec on touch targets at <https://material.io/design/usability/accessibility.html#layout-typography>.
const double kMinInteractiveDimension = 48.0;

/// The height of the toolbar component of the [AppBar].
const double kToolbarHeight = 56.0;

/// The height of the bottom navigation bar.
const double kBottomNavigationBarHeight = 56.0;

/// The height of a tab bar containing text.
const double kTextTabBarHeight = kMinInteractiveDimension;

/// The amount of time theme change animations should last.
const Duration kThemeChangeDuration = Duration(milliseconds: 200);

/// The radius of a circular material ink response in logical pixels.
const double kRadialReactionRadius = 20.0;

/// The amount of time a circular material ink response should take to expand to its full size.
const Duration kRadialReactionDuration = Duration(milliseconds: 100);

/// The value of the alpha channel to use when drawing a circular material ink response.
const int kRadialReactionAlpha = 0x1F;

/// The duration of the horizontal scroll animation that occurs when a tab is tapped.
const Duration kTabScrollDuration = Duration(milliseconds: 300);

/// The horizontal padding included by [Tab]s.
const EdgeInsets kTabLabelPadding = EdgeInsets.symmetric(horizontal: 16.0);

/// The padding added around material list items.
const EdgeInsets kMaterialListPadding = EdgeInsets.symmetric(vertical: 8.0);