sources/android/ndk_helper/gestureDetector.h

/*
 * Copyright 2013 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#pragma once

#include <vector>

#include <android/sensor.h>
#include <android/log.h>
#include <android_native_app_glue.h>
#include <android/native_window_jni.h>
#include "JNIHelper.h"
#include "vecmath.h"

namespace ndk_helper
{
//--------------------------------------------------------------------------------
// Constants
//--------------------------------------------------------------------------------
const int32_t DOUBLE_TAP_TIMEOUT = 300 * 1000000;
const int32_t TAP_TIMEOUT = 180 * 1000000;
const int32_t DOUBLE_TAP_SLOP = 100;
const int32_t TOUCH_SLOP = 8;

enum
{
    GESTURE_STATE_NONE = 0,
    GESTURE_STATE_START = 1,
    GESTURE_STATE_MOVE = 2,
    GESTURE_STATE_END = 4,
    GESTURE_STATE_ACTION = (GESTURE_STATE_START | GESTURE_STATE_END),
};
typedef int32_t GESTURE_STATE;

/******************************************************************
 * Base class of Gesture Detectors
 * GestureDetectors handles input events and detect gestures
 * Note that different detectors may detect gestures with an event at
 * same time. The caller needs to manage gesture priority accordingly
 *
 */
class GestureDetector
{
protected:
    float dp_factor_;
public:
    GestureDetector();
    virtual ~GestureDetector()
    {
    }
    virtual void SetConfiguration( AConfiguration* config );

    virtual GESTURE_STATE Detect( const AInputEvent* motion_event ) = 0;
};

/******************************************************************
 * Tap gesture detector
 * Returns GESTURE_STATE_ACTION when a tap gesture is detected
 *
 */
class TapDetector: public GestureDetector
{
private:
    int32_t down_pointer_id_;
    float down_x_;
    float down_y_;
public:
    TapDetector()
    {
    }
    virtual ~TapDetector()
    {
    }
    virtual GESTURE_STATE Detect( const AInputEvent* motion_event );
};

/******************************************************************
 * Pinch gesture detector
 * Returns GESTURE_STATE_ACTION when a double-tap gesture is detected
 *
 */
class DoubletapDetector: public GestureDetector
{
private:
    TapDetector tap_detector_;
    int64_t last_tap_time_;
    float last_tap_x_;
    float last_tap_y_;

public:
    DoubletapDetector()
    {
    }
    virtual ~DoubletapDetector()
    {
    }
    virtual GESTURE_STATE Detect( const AInputEvent* motion_event );
    virtual void SetConfiguration( AConfiguration* config );
};

/******************************************************************
 * Double gesture detector
 * Returns pinch gesture state when a pinch gesture is detected
 * The class handles multiple touches more than 2
 * When the finger 1,2,3 are tapped and then finger 1 is released,
 * the detector start new pinch gesture with finger 2 & 3.
 */
class PinchDetector: public GestureDetector
{
private:
    int32_t FindIndex( const AInputEvent* event, int32_t id );
    const AInputEvent* event_;
    std::vector<int32_t> vec_pointers_;

public:
    PinchDetector()
    {
    }
    virtual ~PinchDetector()
    {
    }
    virtual GESTURE_STATE Detect( const AInputEvent* event );
    bool GetPointers( Vec2& v1, Vec2& v2 );
};

/******************************************************************
 * Drag gesture detector
 * Returns drag gesture state when a drag-tap gesture is detected
 *
 */
class DragDetector: public GestureDetector
{
private:
    int32_t FindIndex( const AInputEvent* event, int32_t id );
    const AInputEvent* event_;
    std::vector<int32_t> vec_pointers_;
public:
    DragDetector()
    {
    }
    virtual ~DragDetector()
    {
    }
    virtual GESTURE_STATE Detect( const AInputEvent* event );
    bool GetPointer( Vec2& v );
};

}   //namespace ndkHelper