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Commit 3af0ee81 authored by Prabir Pradhan's avatar Prabir Pradhan Committed by Automerger Merge Worker
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MotionEvent: Simplify logic around transformations am: 6b38461a 

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/native/+/14556109

Change-Id: Ica0d6255b9460222122fd95ec4d8519646df9408
parents 6883fe67 6b38461a

libs/input/Input.cpp

+94 −96
Original line number Diff line number Diff line
@@ -39,6 +39,60 @@ using android::base::StringPrintf; 


namespace android {



namespace {



float transformAngle(const ui::Transform& transform, float angleRadians) {

    // Construct and transform a vector oriented at the specified clockwise angle from vertical.

    // Coordinate system: down is increasing Y, right is increasing X.

    float x = sinf(angleRadians);

    float y = -cosf(angleRadians);

    vec2 transformedPoint = transform.transform(x, y);



    // Determine how the origin is transformed by the matrix so that we

    // can transform orientation vectors.

    const vec2 origin = transform.transform(0, 0);



    transformedPoint.x -= origin.x;

    transformedPoint.y -= origin.y;



    // Derive the transformed vector's clockwise angle from vertical.

    float result = atan2f(transformedPoint.x, -transformedPoint.y);

    if (result < -M_PI_2) {

        result += M_PI;

    } else if (result > M_PI_2) {

        result -= M_PI;

    }

    return result;

}



// Rotates the given point to the transform's orientation. If the display width and height are

// provided, the point is rotated in the screen space. Otherwise, the point is rotated about the

// origin. This helper is used to avoid the extra overhead of creating new Transforms.

vec2 rotatePoint(const ui::Transform& transform, float x, float y, int32_t displayWidth = 0,

                 int32_t displayHeight = 0) {

    // 0x7 encapsulates all 3 rotations (see ui::Transform::RotationFlags)

    static const int ALL_ROTATIONS_MASK = 0x7;

    const uint32_t orientation = (transform.getOrientation() & ALL_ROTATIONS_MASK);

    if (orientation == ui::Transform::ROT_0) {

        return {x, y};

    }



    vec2 xy(x, y);

    if (orientation == ui::Transform::ROT_90) {

        xy.x = displayHeight - y;

        xy.y = x;

    } else if (orientation == ui::Transform::ROT_180) {

        xy.x = displayWidth - x;

        xy.y = displayHeight - y;

    } else if (orientation == ui::Transform::ROT_270) {

        xy.x = y;

        xy.y = displayWidth - x;

    }

    return xy;

}



} // namespace



const char* motionClassificationToString(MotionClassification classification) {

    switch (classification) {

        case MotionClassification::NONE:
@@ -315,9 +369,14 @@ void PointerCoords::copyFrom(const PointerCoords& other) { 
}



void PointerCoords::transform(const ui::Transform& transform) {

    vec2 newCoords = transform.transform(getX(), getY());

    setAxisValue(AMOTION_EVENT_AXIS_X, newCoords.x);

    setAxisValue(AMOTION_EVENT_AXIS_Y, newCoords.y);

    const vec2 xy = transform.transform(getXYValue());

    setAxisValue(AMOTION_EVENT_AXIS_X, xy.x);

    setAxisValue(AMOTION_EVENT_AXIS_Y, xy.y);



    if (BitSet64::hasBit(bits, AMOTION_EVENT_AXIS_ORIENTATION)) {

        const float val = getAxisValue(AMOTION_EVENT_AXIS_ORIENTATION);

        setAxisValue(AMOTION_EVENT_AXIS_ORIENTATION, transformAngle(transform, val));

    }

}



// --- PointerProperties ---
@@ -445,44 +504,31 @@ const PointerCoords* MotionEvent::getHistoricalRawPointerCoords( 


float MotionEvent::getHistoricalRawAxisValue(int32_t axis, size_t pointerIndex,

                                             size_t historicalIndex) const {

    if (axis != AMOTION_EVENT_AXIS_X && axis != AMOTION_EVENT_AXIS_Y) {

        return getHistoricalRawPointerCoords(pointerIndex, historicalIndex)->getAxisValue(axis);

    }

    // 0x7 encapsulates all 3 rotations (see ui::Transform::RotationFlags)

    static const int ALL_ROTATIONS_MASK = 0x7;

    uint32_t orientation = (mTransform.getOrientation() & ALL_ROTATIONS_MASK);

    if (orientation == ui::Transform::ROT_0) {

        return getHistoricalRawPointerCoords(pointerIndex, historicalIndex)->getAxisValue(axis);

    }

    const PointerCoords* coords = getHistoricalRawPointerCoords(pointerIndex, historicalIndex);



    // For compatibility, convert raw coordinates into "oriented screen space". Once app developers

    // are educated about getRaw, we can consider removing this.

    vec2 xy = getHistoricalRawPointerCoords(pointerIndex, historicalIndex)->getXYValue();

    const float unrotatedX = xy.x;

    if (orientation == ui::Transform::ROT_90) {

        xy.x = mDisplayHeight - xy.y;

        xy.y = unrotatedX;

    } else if (orientation == ui::Transform::ROT_180) {

        xy.x = mDisplayWidth - xy.x;

        xy.y = mDisplayHeight - xy.y;

    } else if (orientation == ui::Transform::ROT_270) {

        xy.x = xy.y;

        xy.y = mDisplayWidth - unrotatedX;

    }

    if (axis == AMOTION_EVENT_AXIS_X || axis == AMOTION_EVENT_AXIS_Y) {

        // For compatibility, convert raw coordinates into "oriented screen space". Once app

        // developers are educated about getRaw, we can consider removing this.

        const vec2 xy = rotatePoint(mTransform, coords->getX(), coords->getY(), mDisplayWidth,

                                    mDisplayHeight);

        static_assert(AMOTION_EVENT_AXIS_X == 0 && AMOTION_EVENT_AXIS_Y == 1);

        return xy[axis];

    }



    return coords->getAxisValue(axis);

}



float MotionEvent::getHistoricalAxisValue(int32_t axis, size_t pointerIndex,

        size_t historicalIndex) const {

    if (axis != AMOTION_EVENT_AXIS_X && axis != AMOTION_EVENT_AXIS_Y) {

        return getHistoricalRawPointerCoords(pointerIndex, historicalIndex)->getAxisValue(axis);

    }

    const PointerCoords* coords = getHistoricalRawPointerCoords(pointerIndex, historicalIndex);



    vec2 vals = mTransform.transform(

            getHistoricalRawPointerCoords(pointerIndex, historicalIndex)->getXYValue());

    if (axis == AMOTION_EVENT_AXIS_X || axis == AMOTION_EVENT_AXIS_Y) {

        const vec2 xy = mTransform.transform(coords->getXYValue());

        static_assert(AMOTION_EVENT_AXIS_X == 0 && AMOTION_EVENT_AXIS_Y == 1);

    return vals[axis];

        return xy[axis];

    }



    return coords->getAxisValue(axis);

}



ssize_t MotionEvent::findPointerIndex(int32_t pointerId) const {
@@ -513,78 +559,30 @@ void MotionEvent::scale(float globalScaleFactor) { 
    }

}



static vec2 transformPoint(const std::array<float, 9>& matrix, float x, float y) {

    // Apply perspective transform like Skia.

    float newX = matrix[0] * x + matrix[1] * y + matrix[2];

    float newY = matrix[3] * x + matrix[4] * y + matrix[5];

    float newZ = matrix[6] * x + matrix[7] * y + matrix[8];

    if (newZ) {

        newZ = 1.0f / newZ;

    }

    vec2 transformedPoint;

    transformedPoint.x = newX * newZ;

    transformedPoint.y = newY * newZ;

    return transformedPoint;

}



static float transformAngle(const std::array<float, 9>& matrix, float angleRadians, float originX,

                            float originY) {

    // Construct and transform a vector oriented at the specified clockwise angle from vertical.

    // Coordinate system: down is increasing Y, right is increasing X.

    float x = sinf(angleRadians);

    float y = -cosf(angleRadians);

    vec2 transformedPoint = transformPoint(matrix, x, y);



    transformedPoint.x -= originX;

    transformedPoint.y -= originY;



    // Derive the transformed vector's clockwise angle from vertical.

    float result = atan2f(transformedPoint.x, -transformedPoint.y);

    if (result < - M_PI_2) {

        result += M_PI;

    } else if (result > M_PI_2) {

        result -= M_PI;

    }

    return result;

}



void MotionEvent::transform(const std::array<float, 9>& matrix) {

    // We want to preserve the rawX and rawY so we just update the transform

    // using the values of the transform passed in

    // We want to preserve the raw axes values stored in the PointerCoords, so we just update the

    // transform using the values passed in.

    ui::Transform newTransform;

    newTransform.set(matrix);

    mTransform = newTransform * mTransform;



    // Determine how the origin is transformed by the matrix so that we

    // can transform orientation vectors.

    vec2 origin = transformPoint(matrix, 0, 0);



    // Apply the transformation to all samples.

    size_t numSamples = mSamplePointerCoords.size();

    for (size_t i = 0; i < numSamples; i++) {

        PointerCoords& c = mSamplePointerCoords.editItemAt(i);

    // We need to update the AXIS_ORIENTATION value here to maintain the old behavior where the

    // orientation angle is not affected by the initial transformation set in the MotionEvent.

    std::for_each(mSamplePointerCoords.begin(), mSamplePointerCoords.end(),

                  [&newTransform](PointerCoords& c) {

                      float orientation = c.getAxisValue(AMOTION_EVENT_AXIS_ORIENTATION);

                      c.setAxisValue(AMOTION_EVENT_AXIS_ORIENTATION,

                       transformAngle(matrix, orientation, origin.x, origin.y));

    }

                                     transformAngle(newTransform, orientation));

                  });

}



void MotionEvent::applyTransform(const std::array<float, 9>& matrix) {

    // Determine how the origin is transformed by the matrix so that we

    // can transform orientation vectors.

    vec2 origin = transformPoint(matrix, 0, 0);

    ui::Transform transform;

    transform.set(matrix);



    // Apply the transformation to all samples.

    size_t numSamples = mSamplePointerCoords.size();

    for (size_t i = 0; i < numSamples; i++) {

        PointerCoords& c = mSamplePointerCoords.editItemAt(i);

        float orientation = c.getAxisValue(AMOTION_EVENT_AXIS_ORIENTATION);

        c.setAxisValue(AMOTION_EVENT_AXIS_ORIENTATION,

                       transformAngle(matrix, orientation, origin.x, origin.y));

        vec2 xy = transformPoint(matrix, c.getX(), c.getY());

        c.setAxisValue(AMOTION_EVENT_AXIS_X, xy.x);

        c.setAxisValue(AMOTION_EVENT_AXIS_Y, xy.y);

    }

    std::for_each(mSamplePointerCoords.begin(), mSamplePointerCoords.end(),

                  [&transform](PointerCoords& c) { c.transform(transform); });

}



#ifdef __linux__