blob: ea46fd5647e9c5aef4067e6277aadf228070d421 [file] [log] [blame]
// Copyright 2014 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.
#ifndef UI_CHROMEOS_TOUCH_EXPLORATION_CONTROLLER_H_
#define UI_CHROMEOS_TOUCH_EXPLORATION_CONTROLLER_H_
#include "base/time/tick_clock.h"
#include "base/timer/timer.h"
#include "base/values.h"
#include "ui/chromeos/ui_chromeos_export.h"
#include "ui/events/event.h"
#include "ui/events/event_rewriter.h"
#include "ui/events/gesture_detection/gesture_detector.h"
#include "ui/events/gestures/gesture_provider_aura.h"
#include "ui/gfx/geometry/point.h"
namespace aura {
class Window;
}
namespace ui {
class Event;
class EventHandler;
class GestureEvent;
class GestureProviderAura;
class TouchEvent;
// A delegate to handle commands in response to detected accessibility gesture
// events.
class TouchExplorationControllerDelegate {
public:
virtual ~TouchExplorationControllerDelegate() {}
// Takes an int from 0.0 to 100.0 that indicates the percent the volume
// should be set to.
virtual void SetOutputLevel(int volume) = 0;
// Silences spoken feedback.
virtual void SilenceSpokenFeedback() = 0;
// This function should be called when the volume adjust earcon should be
// played
virtual void PlayVolumeAdjustEarcon() = 0;
// This function should be called when the passthrough earcon should be
// played.
virtual void PlayPassthroughEarcon() = 0;
// This function should be called when the exit screen earcon should be
// played.
virtual void PlayExitScreenEarcon() = 0;
// This function should be called when the enter screen earcon should be
// played.
virtual void PlayEnterScreenEarcon() = 0;
};
// TouchExplorationController is used in tandem with "Spoken Feedback" to
// make the touch UI accessible. Gestures performed in the middle of the screen
// are mapped to accessibility key shortcuts while gestures performed on the
// edge of the screen can change settings.
//
// ** Short version **
//
// At a high-level, single-finger events are used for accessibility -
// exploring the screen gets turned into mouse moves (which can then be
// spoken by an accessibility service running), a single tap while the user
// is in touch exploration or a double-tap simulates a click, and gestures
// can be used to send high-level accessibility commands. For example, a swipe
// right would correspond to the keyboard short cut shift+search+right.
// Swipes with up to four fingers are also mapped to commands. Slide
// gestures performed on the edge of the screen can change settings
// continuously. For example, sliding a finger along the right side of the
// screen will change the volume. When a user double taps and holds with one
// finger, the finger is passed through as if accessibility was turned off. If
// the user taps the screen with two fingers, the user can silence spoken
// feedback if it is playing.
//
// ** Long version **
//
// Here are the details of the implementation:
//
// When the first touch is pressed, a 300 ms grace period timer starts.
//
// If the user keeps their finger down for more than 300 ms and doesn't
// perform a supported accessibility gesture in that time (e.g. swipe right),
// they enter touch exploration mode, and all movements are translated into
// synthesized mouse move events.
//
// Also, if the user moves their single finger outside a certain slop region
// (without performing a gesture), they enter touch exploration mode earlier
// than 300 ms.
//
// If the user taps and releases their finger, after 300 ms from the initial
// touch, a single mouse move is fired.
//
// While in touch exploration mode, the user can perform a single tap
// if the user releases their finger and taps before 300 ms passes.
// This will result in a click on the last successful touch exploration
// location. This allows the user to perform a single tap
// anywhere to activate it.
//
// The user can perform swipe gestures in one of the four cardinal directions
// which will be interpreted and used to control the UI. All gestures will only
// be registered if the fingers move outside the slop, and all fingers will only
// be registered if they are completed within the grace period. If a single
// finger gesture fails to be completed within the grace period, the state
// changes to touch exploration mode. If a multi finger gesture fails to be
// completed within the grace period, the user must lift all fingers before
// completing any more actions.
//
// If the user double-taps, the second tap is passed through, allowing the
// user to click - however, the double-tap location is changed to the location
// of the last successful touch exploration - that allows the user to explore
// anywhere on the screen, hear its description, then double-tap anywhere
// to activate it.
//
// If the user double taps and holds, any event from that finger is passed
// through. These events are passed through with an offset such that the first
// touch is offset to be at the location of the last touch exploration
// location, and every following event is offset by the same amount.
//
// If any other fingers are added or removed, they are ignored. Once the
// passthrough finger is released, passthrough stops and the user is reset
// to no fingers down state.
//
// If the user enters touch exploration mode, they can click without lifting
// their touch exploration finger by tapping anywhere else on the screen with
// a second finger, while the touch exploration finger is still pressed.
//
// Once touch exploration mode has been activated, it remains in that mode until
// all fingers have been released.
//
// If the user places a finger on the edge of the screen and moves their finger
// past slop, a slide gesture is performed. The user can then slide one finger
// along an edge of the screen and continuously control a setting. Once the user
// enters this state, the boundaries that define an edge expand so that the user
// can now adjust the setting within a slightly bigger width along the screen.
// If the user exits this area without lifting their finger, they will not be
// able to perform any actions, however if they keep their finger down and
// return to the "hot edge," then they can still adjust the setting. In order to
// perform other touch accessibility movements, the user must lift their finger.
// If additional fingers are added while in this state, the user will transition
// to passthrough.
//
// Currently, only the right edge is mapped to control the volume. Volume
// control along the edge of the screen is directly proportional to where the
// user's finger is located on the screen. The top right corner of the screen
// automatically sets the volume to 100% and the bottome right corner of the
// screen automatically sets the volume to 0% once the user has moved past slop.
//
// If the user taps the screen with two fingers and lifts both fingers before
// the grace period has passed, spoken feedback is silenced.
//
// The user can also enter passthrough by placing a finger on one of the bottom
// corners of the screen until an earcon sounds. After the earcon sounds, the
// user is in passthrough so all subsequent fingers placed on the screen will be
// passed through. Once the finger in the corner has been released, the state
// will switch to wait for no fingers.
//
// The caller is expected to retain ownership of instances of this class and
// destroy them before |root_window| is destroyed.
class UI_CHROMEOS_EXPORT TouchExplorationController
: public ui::EventRewriter,
public ui::GestureProviderAuraClient {
public:
explicit TouchExplorationController(
aura::Window* root_window,
ui::TouchExplorationControllerDelegate* delegate);
~TouchExplorationController() override;
private:
friend class TouchExplorationControllerTestApi;
// Overridden from ui::EventRewriter
ui::EventRewriteStatus RewriteEvent(
const ui::Event& event,
scoped_ptr<ui::Event>* rewritten_event) override;
ui::EventRewriteStatus NextDispatchEvent(
const ui::Event& last_event,
scoped_ptr<ui::Event>* new_event) override;
// Event handlers based on the current state - see State, below.
ui::EventRewriteStatus InNoFingersDown(
const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
ui::EventRewriteStatus InSingleTapPressed(
const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
ui::EventRewriteStatus InSingleTapOrTouchExploreReleased(
const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
ui::EventRewriteStatus InDoubleTapPending(
const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
ui::EventRewriteStatus InTouchReleasePending(
const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
ui::EventRewriteStatus InTouchExploration(
const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
ui::EventRewriteStatus InCornerPassthrough(
const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
ui::EventRewriteStatus InOneFingerPassthrough(
const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
ui::EventRewriteStatus InGestureInProgress(
const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
ui::EventRewriteStatus InTouchExploreSecondPress(
const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
ui::EventRewriteStatus InWaitForNoFingers(
const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
ui::EventRewriteStatus InSlideGesture(
const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
ui::EventRewriteStatus InTwoFingerTap(
const ui::TouchEvent& event, scoped_ptr<ui::Event>* rewritten_event);
// Returns the current time of the tick clock.
base::TimeDelta Now();
// This timer is started every time we get the first press event, and
// it fires after the double-click timeout elapses (300 ms by default).
// If the user taps and releases within 300 ms and doesn't press again,
// we treat that as a single mouse move (touch exploration) event.
void StartTapTimer();
void OnTapTimerFired();
// This timer is started every timer we get the first press event and the
// finger is in the corner of the screen.
// It fires after the corner passthrough delay elapses. If the
// user is still in the corner by the time this timer fires, all subsequent
// fingers added on the screen will be passed through.
void OnPassthroughTimerFired();
// Dispatch a new event outside of the event rewriting flow.
void DispatchEvent(ui::Event* event);
// Overridden from GestureProviderAuraClient.
//
// The gesture provider keeps track of all the touch events after
// the user moves fast enough to trigger a gesture. After the user
// completes their gesture, this method will decide what keyboard
// input their gesture corresponded to.
void OnGestureEvent(ui::GestureEvent* gesture) override;
// Process the gesture events that have been created.
void ProcessGestureEvents();
void OnSwipeEvent(ui::GestureEvent* swipe_gesture);
void SideSlideControl(ui::GestureEvent* gesture);
// Dispatches the keyboard short cut Shift+Search+<arrow key>
// outside the event rewritting flow.
void DispatchShiftSearchKeyEvent(const ui::KeyboardCode third_key);
// Binds DispatchShiftSearchKeyEvent to a specific third key.
base::Closure BindShiftSearchKeyEvent(const ui::KeyboardCode third_key);
// Dispatches a single key with the given flags.
void DispatchKeyWithFlags(const ui::KeyboardCode key, int flags);
// Binds DispatchKeyWithFlags to a specific key and flags.
base::Closure BindKeyEventWithFlags(const ui::KeyboardCode key, int flags);
scoped_ptr<ui::Event> CreateMouseMoveEvent(const gfx::PointF& location,
int flags);
void EnterTouchToMouseMode();
void PlaySoundForTimer();
// Some constants used in touch_exploration_controller:
// Within this many dips of the screen edge, the release event generated will
// reset the state to NoFingersDown.
const float kLeavingScreenEdge = 6;
// Swipe/scroll gestures within these bounds (in DIPs) will change preset
// settings.
const float kMaxDistanceFromEdge = 75;
// After a slide gesture has been triggered, if the finger is still within
// these bounds (in DIPs), the preset settings will still change.
const float kSlopDistanceFromEdge = kMaxDistanceFromEdge + 40;
// The split tap slop is a bit more generous since keeping two
// fingers in place is a bit harder.
float GetSplitTapTouchSlop();
enum State {
// No fingers are down and no events are pending.
NO_FINGERS_DOWN,
// A single finger is down, but we're not yet sure if this is going
// to be touch exploration or something else.
SINGLE_TAP_PRESSED,
// The user pressed and released a single finger - a tap - but we have
// to wait until the end of the grace period to allow the user to tap the
// second time. If the second tap doesn't occurs within the grace period,
// we dispatch a mouse move at the location of the first tap.
SINGLE_TAP_RELEASED,
// The user was in touch explore mode and released the finger.
// If another touch press occurs within the grace period, a single
// tap click occurs. This state differs from SINGLE_TAP_RELEASED
// in that if a second tap doesn't occur within the grace period,
// there is no mouse move dispatched.
TOUCH_EXPLORE_RELEASED,
// The user tapped once, and before the grace period expired, pressed
// one finger down to begin a double-tap, but has not released it yet.
// This could become passthrough, so no touch press is dispatched yet.
DOUBLE_TAP_PENDING,
// The user was doing touch exploration, started split tap, but lifted the
// touch exploration finger. Once they remove all fingers, a touch release
// will go through.
TOUCH_RELEASE_PENDING,
// We're in touch exploration mode. Anything other than the first finger
// is ignored, and movements of the first finger are rewritten as mouse
// move events. This mode is entered if a single finger is pressed and
// after the grace period the user hasn't added a second finger or
// moved the finger outside of the slop region. We'll stay in this
// mode until all fingers are lifted.
TOUCH_EXPLORATION,
// If the user moves their finger faster than the threshold velocity after a
// single tap, the touch events that follow will be translated into gesture
// events. If the user successfully completes a gesture within the grace
// period, the gesture will be interpreted and used to control the UI via
// discrete actions - currently by synthesizing key events corresponding to
// each gesture Otherwise, the collected gestures are discarded and the
// state changes to touch_exploration.
GESTURE_IN_PROGRESS,
// The user was in touch exploration, but has placed down another finger.
// If the user releases the second finger, a touch press and release
// will go through at the last touch explore location. If the user
// releases the touch explore finger, the touch press and release will
// still go through once the split tap finger is also lifted. If any
// fingers pressed past the first two, the touch press is cancelled and
// the user enters the wait state for the fingers to be removed.
TOUCH_EXPLORE_SECOND_PRESS,
// After the user double taps and holds with a single finger, all events
// for that finger are passed through, displaced by an offset. Adding
// extra fingers has no effect. This state is left when the user removes
// all fingers.
ONE_FINGER_PASSTHROUGH,
// If the user has pressed and held down the left corner past long press,
// then as long as they are holding the corner, all subsequent fingers
// registered will be in passthrough.
CORNER_PASSTHROUGH,
// If the user added another finger in SINGLE_TAP_PRESSED, or if the user
// has multiple fingers fingers down in any other state between
// passthrough, touch exploration, and gestures, they must release
// all fingers before completing any more actions. This state is
// generally useful for developing new features, because it creates a
// simple way to handle a dead end in user flow.
WAIT_FOR_NO_FINGERS,
// If the user is within the given bounds from an edge of the screen, not
// including corners, then the resulting movements will be interpreted as
// slide gestures.
SLIDE_GESTURE,
// If the user taps the screen with two fingers and releases both fingers
// before the grace period has passed, spoken feedback will be silenced.
TWO_FINGER_TAP,
};
enum ScreenLocation {
// Hot "edges" of the screen are each represented by a respective bit.
NO_EDGE = 0,
RIGHT_EDGE = 1 << 0,
TOP_EDGE = 1 << 1,
LEFT_EDGE = 1 << 2,
BOTTOM_EDGE = 1 << 3,
BOTTOM_LEFT_CORNER = LEFT_EDGE | BOTTOM_EDGE,
BOTTOM_RIGHT_CORNER = RIGHT_EDGE | BOTTOM_EDGE,
};
// Given a point, if it is within the given bounds of an edge, returns the
// edge. If it is within the given bounds of two edges, returns an int with
// both bits that represent the respective edges turned on. Otherwise returns
// SCREEN_CENTER.
int FindEdgesWithinBounds(gfx::Point point, float bounds);
// Set the state and modifies any variables related to the state change.
// (e.g. resetting the gesture provider).
void SetState(State new_state, const char* function_name);
void VlogState(const char* function_name);
void VlogEvent(const ui::TouchEvent& event, const char* function_name);
// Gets enum name from integer value.
const char* EnumStateToString(State state);
// Maps each single/multi finger swipe to the function that dispatches
// the corresponding key events.
void InitializeSwipeGestureMaps();
aura::Window* root_window_;
// Handles volume control. Not owned.
ui::TouchExplorationControllerDelegate* delegate_;
// A set of touch ids for fingers currently touching the screen.
std::vector<int> current_touch_ids_;
// Map of touch ids to their last known location.
std::map<int, gfx::PointF> touch_locations_;
// The current state.
State state_;
// A copy of the event from the initial touch press.
scoped_ptr<ui::TouchEvent> initial_press_;
// Map of touch ids to where its initial press occurred relative to the
// screen.
std::map<int, gfx::Point> initial_presses_;
// In one finger passthrough, the touch is displaced relative to the
// last touch exploration location.
gfx::Vector2d passthrough_offset_;
// Stores the most recent event from a finger that is currently not
// sending events through, but might in the future (e.g. before a finger
// enters double-tap-hold passthrough, we need to update its location.)
scoped_ptr<ui::TouchEvent> last_unused_finger_event_;
// The last synthesized mouse move event. When the user double-taps,
// we send the passed-through tap to the location of this event.
scoped_ptr<ui::TouchEvent> last_touch_exploration_;
// A timer that fires after the double-tap delay.
base::OneShotTimer<TouchExplorationController> tap_timer_;
// A timer that fires to enter passthrough.
base::OneShotTimer<TouchExplorationController> passthrough_timer_;
// A timer to fire an indicating sound when sliding to change volume.
base::RepeatingTimer<TouchExplorationController> sound_timer_;
// A default gesture detector config, so we can share the same
// timeout and pixel slop constants.
ui::GestureDetector::Config gesture_detector_config_;
// Gesture Handler to interpret the touch events.
scoped_ptr<ui::GestureProviderAura> gesture_provider_;
// The previous state entered.
State prev_state_;
// A copy of the previous event passed.
scoped_ptr<ui::TouchEvent> prev_event_;
// This toggles whether VLOGS are turned on or not.
bool VLOG_on_;
// When touch_exploration_controller gets time relative to real time during
// testing, this clock is set to the simulated clock and used.
base::TickClock* tick_clock_;
// Maps the number of fingers in a swipe to the resulting functions that
// dispatch key events.
std::map<int, base::Closure> left_swipe_gestures_;
std::map<int, base::Closure> right_swipe_gestures_;
std::map<int, base::Closure> up_swipe_gestures_;
std::map<int, base::Closure> down_swipe_gestures_;
DISALLOW_COPY_AND_ASSIGN(TouchExplorationController);
};
} // namespace ui
#endif // UI_CHROMEOS_TOUCH_EXPLORATION_CONTROLLER_H_