Merge "Visualize the pressure as the opacity of ovals" into main

    TouchpadHardwareState mLatestHardwareState = new TouchpadHardwareState(0, 0, 0, 0,

            new TouchpadFingerState[]{});

    private final Paint mOvalPaint;

    private final Paint mOvalStrokePaint;

    private final Paint mOvalFillPaint;

    private final RectF mTempOvalRect = new RectF();

    public TouchpadVisualizationView(Context context,

            TouchpadHardwareProperties touchpadHardwareProperties) {

        super(context);

        mTouchpadHardwareProperties = touchpadHardwareProperties;

        mScaleFactor = 1;

        mOvalPaint = new Paint();

        mOvalPaint.setAntiAlias(true);

        mOvalPaint.setARGB(255, 0, 0, 0);

        mOvalPaint.setStyle(Paint.Style.STROKE);

        mOvalStrokePaint = new Paint();

        mOvalStrokePaint.setAntiAlias(true);

        mOvalStrokePaint.setARGB(255, 0, 0, 0);

        mOvalStrokePaint.setStyle(Paint.Style.STROKE);

        mOvalFillPaint = new Paint();

        mOvalFillPaint.setAntiAlias(true);

        mOvalFillPaint.setARGB(255, 0, 0, 0);

    }

    private final RectF mOvalRect = new RectF();

    private void drawOval(Canvas canvas, float x, float y, float major, float minor, float angle,

            Paint paint) {

    private void drawOval(Canvas canvas, float x, float y, float major, float minor, float angle) {

        canvas.save(Canvas.MATRIX_SAVE_FLAG);

        canvas.rotate(angle, x, y);

        mOvalRect.left = x - minor / 2;

        mOvalRect.right = x + minor / 2;

        mOvalRect.top = y - major / 2;

        mOvalRect.bottom = y + major / 2;

        canvas.drawOval(mOvalRect, paint);

        mTempOvalRect.left = x - minor / 2;

        mTempOvalRect.right = x + minor / 2;

        mTempOvalRect.top = y - major / 2;

        mTempOvalRect.bottom = y + major / 2;

        canvas.drawOval(mTempOvalRect, mOvalStrokePaint);

        canvas.drawOval(mTempOvalRect, mOvalFillPaint);

        canvas.restore();

    }

    @Override

    protected void onDraw(Canvas canvas) {

        float maximumPressure = 0;

        for (TouchpadFingerState touchpadFingerState : mLatestHardwareState.getFingerStates()) {

            maximumPressure = Math.max(maximumPressure, touchpadFingerState.getPressure());

        }

        for (TouchpadFingerState touchpadFingerState : mLatestHardwareState.getFingerStates()) {

            float newX = translateRange(mTouchpadHardwareProperties.getLeft(),

                    mTouchpadHardwareProperties.getRight(), 0, getWidth(),

            float newTouchMajor = touchpadFingerState.getTouchMajor() * mScaleFactor / resY;

            float newTouchMinor = touchpadFingerState.getTouchMinor() * mScaleFactor / resX;

            drawOval(canvas, newX, newY, newTouchMajor, newTouchMinor, newAngle, mOvalPaint);

            float pressureToOpacity = translateRange(0, maximumPressure, 0, 255,

                    touchpadFingerState.getPressure());

            mOvalFillPaint.setAlpha((int) pressureToOpacity);

            drawOval(canvas, newX, newY, newTouchMajor, newTouchMinor, newAngle);

        }

    }