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Commit 25415e2b authored by Cary Clark's avatar Cary Clark
Browse files

draw filtered if dragging but not moving after a 100ms delay 

Some artifacts show up when dragging, but since the screen is in
motion, they're usually go unnoticed. If one quits moving, the
artifacts are more visible.

Some devices generate fractional movement data while the
screen is touched and held steady; others do not. Also, mouse-based
implementations will not generate random fractional movements. If
the device generates movements, invalidate the screen to transition
once from unfiltered to filtered drawing.

For the case that the device does not generate movements, fire a
timer when the screen is drawn and a drag is in progress to detect
that there is no drag motion.

The timer fires if the dragged screen is unmoved for 100 ms, then
invalidates so the next redraw uses filtering to remove the artifacts,
and starts a continuous timer to keep the scrollbar awake until
the drag ends or there is more drag motion.

When detecting that there is no effective movement on a noisy device,
use the original fractional deltas instead of the integer ones to
detect sub 1 pixel differences.

This was tested on the emulator (no noise) and a sapphire (noise)
to make sure that events load the queue only when required.

fixes http://b/issue?id=2092446
parent d4fa96ea

core/java/android/webkit/WebView.java

+78 −17
Original line number Diff line number Diff line
@@ -390,6 +390,8 @@ public class WebView extends AbsoluteLayout 
    private static final int LONG_PRESS_TIMEOUT = 1000;

    // needed to avoid flinging after a pause of no movement

    private static final int MIN_FLING_TIME = 250;

    // draw unfiltered after drag is held without movement

    private static final int MOTIONLESS_TIME = 100;

    // The time that the Zoom Controls are visible before fading away

    private static final long ZOOM_CONTROLS_TIMEOUT =

            ViewConfiguration.getZoomControlsTimeout();
@@ -427,6 +429,10 @@ public class WebView extends AbsoluteLayout 
    private Scroller mScroller;



    private boolean mWrapContent;

    private static final int MOTIONLESS_FALSE           = 0;

    private static final int MOTIONLESS_PENDING         = 1;

    private static final int MOTIONLESS_TRUE            = 2;

    private int mHeldMotionless;



    /**

     * Private message ids
@@ -438,6 +444,8 @@ public class WebView extends AbsoluteLayout 
    private static final int RELEASE_SINGLE_TAP         = 5;

    private static final int REQUEST_FORM_DATA          = 6;

    private static final int RESUME_WEBCORE_UPDATE      = 7;

    private static final int DRAG_HELD_MOTIONLESS       = 8;

    private static final int AWAKEN_SCROLL_BARS         = 9;



    //! arg1=x, arg2=y

    static final int SCROLL_TO_MSG_ID                   = 10;
@@ -468,9 +476,9 @@ public class WebView extends AbsoluteLayout 
        "SWITCH_TO_LONGPRESS", //            = 4;

        "RELEASE_SINGLE_TAP", //             = 5;

        "REQUEST_FORM_DATA", //              = 6;

        "SWITCH_TO_CLICK", //                = 7;

        "RESUME_WEBCORE_UPDATE", //          = 8;

        "9",

        "RESUME_WEBCORE_UPDATE", //          = 7;

        "DRAG_HELD_MOTIONLESS", //           = 8;

        "AWAKEN_SCROLL_BARS", //             = 9;

        "SCROLL_TO_MSG_ID", //               = 10;

        "SCROLL_BY_MSG_ID", //               = 11;

        "SPAWN_SCROLL_TO_MSG_ID", //         = 12;
@@ -2870,8 +2878,22 @@ public class WebView extends AbsoluteLayout 
        }



        boolean animateZoom = mZoomScale != 0;

        boolean animateScroll = !mScroller.isFinished()

                || mVelocityTracker != null;

        boolean animateScroll = (!mScroller.isFinished()

                || mVelocityTracker != null)

                && (mTouchMode != TOUCH_DRAG_MODE ||

                mHeldMotionless != MOTIONLESS_TRUE);

        if (mTouchMode == TOUCH_DRAG_MODE) {

            if (mHeldMotionless == MOTIONLESS_PENDING) {

                mPrivateHandler.removeMessages(DRAG_HELD_MOTIONLESS);

                mPrivateHandler.removeMessages(AWAKEN_SCROLL_BARS);

                mHeldMotionless = MOTIONLESS_FALSE;

            }

            if (mHeldMotionless == MOTIONLESS_FALSE) {

                mPrivateHandler.sendMessageDelayed(mPrivateHandler

                        .obtainMessage(DRAG_HELD_MOTIONLESS), MOTIONLESS_TIME);

                mHeldMotionless = MOTIONLESS_PENDING;

            }

        }

        if (animateZoom) {

            float zoomScale;

            int interval = (int) (SystemClock.uptimeMillis() - mZoomStart);
@@ -3726,8 +3748,10 @@ public class WebView extends AbsoluteLayout 
            mLastSentTouchTime = eventTime;

        }



        int deltaX = (int) (mLastTouchX - x);

        int deltaY = (int) (mLastTouchY - y);

        float fDeltaX = mLastTouchX - x;

        float fDeltaY = mLastTouchY - y;

        int deltaX = (int) fDeltaX;

        int deltaY = (int) fDeltaY;



        switch (action) {

            case MotionEvent.ACTION_DOWN: {
@@ -3853,13 +3877,27 @@ public class WebView extends AbsoluteLayout 


                // do pan

                int newScrollX = pinLocX(mScrollX + deltaX);

                deltaX = newScrollX - mScrollX;

                int newDeltaX = newScrollX - mScrollX;

                if (deltaX != newDeltaX) {

                    deltaX = newDeltaX;

                    fDeltaX = (float) newDeltaX;

                }

                int newScrollY = pinLocY(mScrollY + deltaY);

                deltaY = newScrollY - mScrollY;

                int newDeltaY = newScrollY - mScrollY;

                if (deltaY != newDeltaY) {

                    deltaY = newDeltaY;

                    fDeltaY = (float) newDeltaY;

                }

                boolean done = false;

                if (deltaX == 0 && deltaY == 0) {

                    done = true;

                boolean keepScrollBarsVisible = false;

                if (Math.abs(fDeltaX) < 1.0f && Math.abs(fDeltaY) < 1.0f) {

                    keepScrollBarsVisible = done = true;

                } else {

                    if (mHeldMotionless != MOTIONLESS_FALSE) {

                        mPrivateHandler.removeMessages(DRAG_HELD_MOTIONLESS);

                        mPrivateHandler.removeMessages(AWAKEN_SCROLL_BARS);

                        mHeldMotionless = MOTIONLESS_FALSE;

                    }

                    if (mSnapScrollMode == SNAP_X || mSnapScrollMode == SNAP_Y) {

                        int ax = Math.abs(deltaX);

                        int ay = Math.abs(deltaY);
@@ -3899,8 +3937,7 @@ public class WebView extends AbsoluteLayout 
                        if (deltaX == 0) {

                            // keep the scrollbar on the screen even there is no

                            // scroll

                            awakenScrollBars(ViewConfiguration

                                    .getScrollDefaultDelay(), false);

                            keepScrollBarsVisible = true;

                        } else {

                            scrollBy(deltaX, 0);

                        }
@@ -3910,8 +3947,7 @@ public class WebView extends AbsoluteLayout 
                        if (deltaY == 0) {

                            // keep the scrollbar on the screen even there is no

                            // scroll

                            awakenScrollBars(ViewConfiguration

                                    .getScrollDefaultDelay(), false);

                            keepScrollBarsVisible = true;

                        } else {

                            scrollBy(0, deltaY);

                        }
@@ -3938,13 +3974,17 @@ public class WebView extends AbsoluteLayout 
                    }

                }



                if (done) {

                if (keepScrollBarsVisible) {

                    if (mHeldMotionless != MOTIONLESS_TRUE) {

                        mHeldMotionless = MOTIONLESS_TRUE;

                        invalidate();

                    }

                    // keep the scrollbar on the screen even there is no scroll

                    awakenScrollBars(ViewConfiguration.getScrollDefaultDelay(),

                            false);

                    // return false to indicate that we can't pan out of the

                    // view space

                    return false;

                    return !done;

                }

                break;

            }
@@ -3997,6 +4037,9 @@ public class WebView extends AbsoluteLayout 
                            break;

                        }

                    case TOUCH_DRAG_MODE:

                        mPrivateHandler.removeMessages(DRAG_HELD_MOTIONLESS);

                        mPrivateHandler.removeMessages(AWAKEN_SCROLL_BARS);

                        mHeldMotionless = MOTIONLESS_TRUE;

                        // redraw in high-quality, as we're done dragging

                        invalidate();

                        // if the user waits a while w/o moving before the
@@ -4036,6 +4079,9 @@ public class WebView extends AbsoluteLayout 
                }

                mPrivateHandler.removeMessages(SWITCH_TO_SHORTPRESS);

                mPrivateHandler.removeMessages(SWITCH_TO_LONGPRESS);

                mPrivateHandler.removeMessages(DRAG_HELD_MOTIONLESS);

                mPrivateHandler.removeMessages(AWAKEN_SCROLL_BARS);

                mHeldMotionless = MOTIONLESS_TRUE;

                mTouchMode = TOUCH_DONE_MODE;

                nativeHideCursor();

                break;
@@ -5203,6 +5249,21 @@ public class WebView extends AbsoluteLayout 
                    }

                    break;



                case DRAG_HELD_MOTIONLESS:

                    mHeldMotionless = MOTIONLESS_TRUE;

                    invalidate();

                    // fall through to keep scrollbars awake



                case AWAKEN_SCROLL_BARS:

                    if (mTouchMode == TOUCH_DRAG_MODE

                            && mHeldMotionless == MOTIONLESS_TRUE) {

                        awakenScrollBars(ViewConfiguration

                                .getScrollDefaultDelay(), false);

                        mPrivateHandler.sendMessageDelayed(mPrivateHandler

                                .obtainMessage(AWAKEN_SCROLL_BARS),

                                ViewConfiguration.getScrollDefaultDelay());

                    }

                    break;

                default:

                    super.handleMessage(msg);

                    break;