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Commit c6df18f5 authored by Adam Powell's avatar Adam Powell
Browse files

Tweaks for ScaleGestureDetector 

Remove obsolete history and size tracking from ScaleGestureDetector.

Change-Id: I20c323a8a92e467b62eb412b718c2e9e906e7800
parent ebdb34d6

core/java/android/view/ScaleGestureDetector.java

+2 −86
Original line number Diff line number Diff line
@@ -145,13 +145,6 @@ public class ScaleGestureDetector { 
    private int mSpanSlop;

    private int mMinSpan;



    // Bounds for recently seen values

    private float mTouchUpper;

    private float mTouchLower;

    private float mTouchHistoryLastAccepted;

    private int mTouchHistoryDirection;

    private long mTouchHistoryLastAcceptedTime;

    private int mTouchMinMajor;

    private final Handler mHandler;



    private float mAnchoredScaleStartX;
@@ -207,8 +200,6 @@ public class ScaleGestureDetector { 
        mSpanSlop = ViewConfiguration.get(context).getScaledTouchSlop() * 2;



        final Resources res = context.getResources();

        mTouchMinMajor = res.getDimensionPixelSize(

                com.android.internal.R.dimen.config_minScalingTouchMajor);

        mMinSpan = res.getDimensionPixelSize(com.android.internal.R.dimen.config_minScalingSpan);

        mHandler = handler;

        // Quick scale is enabled by default after JB_MR2
@@ -222,77 +213,6 @@ public class ScaleGestureDetector { 
        }

    }



    /**

     * The touchMajor/touchMinor elements of a MotionEvent can flutter/jitter on

     * some hardware/driver combos. Smooth it out to get kinder, gentler behavior.

     * @param ev MotionEvent to add to the ongoing history

     */

    private void addTouchHistory(MotionEvent ev) {

        final long currentTime = SystemClock.uptimeMillis();

        final int count = ev.getPointerCount();

        boolean accept = currentTime - mTouchHistoryLastAcceptedTime >= TOUCH_STABILIZE_TIME;

        float total = 0;

        int sampleCount = 0;

        for (int i = 0; i < count; i++) {

            final boolean hasLastAccepted = !Float.isNaN(mTouchHistoryLastAccepted);

            final int historySize = ev.getHistorySize();

            final int pointerSampleCount = historySize + 1;

            for (int h = 0; h < pointerSampleCount; h++) {

                float major;

                if (h < historySize) {

                    major = ev.getHistoricalTouchMajor(i, h);

                } else {

                    major = ev.getTouchMajor(i);

                }

                if (major < mTouchMinMajor) major = mTouchMinMajor;

                total += major;



                if (Float.isNaN(mTouchUpper) || major > mTouchUpper) {

                    mTouchUpper = major;

                }

                if (Float.isNaN(mTouchLower) || major < mTouchLower) {

                    mTouchLower = major;

                }



                if (hasLastAccepted) {

                    final int directionSig = (int) Math.signum(major - mTouchHistoryLastAccepted);

                    if (directionSig != mTouchHistoryDirection ||

                            (directionSig == 0 && mTouchHistoryDirection == 0)) {

                        mTouchHistoryDirection = directionSig;

                        final long time = h < historySize ? ev.getHistoricalEventTime(h)

                                : ev.getEventTime();

                        mTouchHistoryLastAcceptedTime = time;

                        accept = false;

                    }

                }

            }

            sampleCount += pointerSampleCount;

        }



        final float avg = total / sampleCount;



        if (accept) {

            float newAccepted = (mTouchUpper + mTouchLower + avg) / 3;

            mTouchUpper = (mTouchUpper + newAccepted) / 2;

            mTouchLower = (mTouchLower + newAccepted) / 2;

            mTouchHistoryLastAccepted = newAccepted;

            mTouchHistoryDirection = 0;

            mTouchHistoryLastAcceptedTime = ev.getEventTime();

        }

    }



    /**

     * Clear all touch history tracking. Useful in ACTION_CANCEL or ACTION_UP.

     * @see #addTouchHistory(MotionEvent)

     */

    private void clearTouchHistory() {

        mTouchUpper = Float.NaN;

        mTouchLower = Float.NaN;

        mTouchHistoryLastAccepted = Float.NaN;

        mTouchHistoryDirection = 0;

        mTouchHistoryLastAcceptedTime = 0;

    }



    /**

     * Accepts MotionEvents and dispatches events to a {@link OnScaleGestureListener}

     * when appropriate.
@@ -344,7 +264,6 @@ public class ScaleGestureDetector { 
            }



            if (streamComplete) {

                clearTouchHistory();

                return true;

            }

        }
@@ -391,17 +310,14 @@ public class ScaleGestureDetector { 
            focusY = sumY / div;

        }



        addTouchHistory(event);



        // Determine average deviation from focal point

        float devSumX = 0, devSumY = 0;

        for (int i = 0; i < count; i++) {

            if (skipIndex == i) continue;



            // Convert the resulting diameter into a radius.

            final float touchSize = mTouchHistoryLastAccepted / 2;

            devSumX += Math.abs(event.getX(i) - focusX) + touchSize;

            devSumY += Math.abs(event.getY(i) - focusY) + touchSize;

            devSumX += Math.abs(event.getX(i) - focusX);

            devSumY += Math.abs(event.getY(i) - focusY);

        }

        final float devX = devSumX / div;

        final float devY = devSumY / div;