// Copyright 2015 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. // Modeled after Android's ViewConfiguration: // https://github.com/android/platform_frameworks_base/blob/master/core/java/android/view/ViewConfiguration.java /// The time that must elapse before a tap gesture sends onTapDown, if there's /// any doubt that the gesture is a tap. const Duration kPressTimeout = const Duration(milliseconds: 100); /// Maximum length of time between a tap down and a tap up for the gesture to be /// considered a tap. (Currently not honored by the TapGestureRecognizer.) // TODO(ianh): Remove this, or implement a hover-tap gesture recognizer which // uses this. const Duration kHoverTapTimeout = const Duration(milliseconds: 150); /// Maximum distance between the down and up pointers for a tap. (Currently not /// honored by the [TapGestureRecognizer]; [PrimaryPointerGestureRecognizer], /// which TapGestureRecognizer inherits from, uses [kTouchSlop].) // TODO(ianh): Remove this or implement it correctly. const double kHoverTapSlop = 20.0; // Logical pixels /// The time before a long press gesture attempts to win. const Duration kLongPressTimeout = const Duration(milliseconds: 500); /// The maximum time from the start of the first tap to the start of the second /// tap in a double-tap gesture. // TODO(ianh): In Android, this is actually the time from the first's up event // to the second's down event, according to the ViewConfiguration docs. const Duration kDoubleTapTimeout = const Duration(milliseconds: 300); /// The minimum time from the end of the first tap to the start of the second /// tap in a double-tap gesture. (Currently not honored by the /// DoubleTapGestureRecognizer.) // TODO(ianh): Either implement this or remove the constant. const Duration kDoubleTapMinTime = const Duration(milliseconds: 40); /// The maximum distance that the first touch in a double-tap gesture can travel /// before deciding that it is not part of a double-tap gesture. /// DoubleTapGestureRecognizer also restricts the second touch to this distance. const double kDoubleTapTouchSlop = kTouchSlop; // Logical pixels /// Distance between the initial position of the first touch and the start /// position of a potential second touch for the second touch to be considered /// the second touch of a double-tap gesture. const double kDoubleTapSlop = 100.0; // Logical pixels /// The time for which zoom controls (e.g. in a map interface) are to be /// displayed on the screen, from the moment they were last requested. const Duration kZoomControlsTimeout = const Duration(milliseconds: 3000); /// The distance a touch has to travel for the framework to be confident that /// the gesture is a scroll gesture, or, inversely, the maximum distance that a /// touch can travel before the framework becomes confident that it is not a /// tap. // This value was empirically derived. We started at 8.0 and increased it to // 18.0 after getting complaints that it was too difficult to hit targets. const double kTouchSlop = 18.0; // Logical pixels /// The distance a touch has to travel for the framework to be confident that /// the gesture is a paging gesture. (Currently not used, because paging uses a /// regular drag gesture, which uses kTouchSlop.) // TODO(ianh): Create variants of HorizontalDragGestureRecognizer et al for // paging, which use this constant. const double kPagingTouchSlop = kTouchSlop * 2.0; // Logical pixels /// The distance a touch has to travel for the framework to be confident that /// the gesture is a panning gesture. const double kPanSlop = kTouchSlop * 2.0; // Logical pixels /// The distance a touch has to travel for the framework to be confident that /// the gesture is a scale gesture. const double kScaleSlop = kTouchSlop; // Logical pixels /// The margin around a dialog, popup menu, or other window-like widget inside /// which we do not consider a tap to dismiss the widget. (Not currently used.) // TODO(ianh): Make ModalBarrier support this. const double kWindowTouchSlop = 16.0; // Logical pixels /// The minimum velocity for a touch to consider that touch to trigger a fling /// gesture. // TODO(ianh): Make sure nobody has their own version of this. const double kMinFlingVelocity = 50.0; // Logical pixels / second // const Velocity kMinFlingVelocity = const Velocity(pixelsPerSecond: 50.0); /// Drag gesture fling velocities are clipped to this value. // TODO(ianh): Make sure nobody has their own version of this. const double kMaxFlingVelocity = 8000.0; // Logical pixels / second /// The maximum time from the start of the first tap to the start of the second /// tap in a jump-tap gesture. // TODO(ianh): Implement jump-tap gestures. const Duration kJumpTapTimeout = const Duration(milliseconds: 500);