diff options
Diffstat (limited to 'android/experimental/LOAndroid2/app/src/main/java/org/mozilla/gecko/ui/Axis.java')
| -rw-r--r-- | android/experimental/LOAndroid2/app/src/main/java/org/mozilla/gecko/ui/Axis.java | 271 |
1 files changed, 0 insertions, 271 deletions
diff --git a/android/experimental/LOAndroid2/app/src/main/java/org/mozilla/gecko/ui/Axis.java b/android/experimental/LOAndroid2/app/src/main/java/org/mozilla/gecko/ui/Axis.java deleted file mode 100644 index 8c0fce4c73b3..000000000000 --- a/android/experimental/LOAndroid2/app/src/main/java/org/mozilla/gecko/ui/Axis.java +++ /dev/null @@ -1,271 +0,0 @@ -/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*- - * ***** BEGIN LICENSE BLOCK ***** - * Version: MPL 1.1/GPL 2.0/LGPL 2.1 - * - * The contents of this file are subject to the Mozilla Public License Version - * 1.1 (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.mozilla.org/MPL/ - * - * Software distributed under the License is distributed on an "AS IS" basis, - * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License - * for the specific language governing rights and limitations under the - * License. - * - * The Original Code is Mozilla Android code. - * - * The Initial Developer of the Original Code is Mozilla Foundation. - * Portions created by the Initial Developer are Copyright (C) 2012 - * the Initial Developer. All Rights Reserved. - * - * Contributor(s): - * Patrick Walton <pcwalton@mozilla.com> - * Kartikaya Gupta <kgupta@mozilla.com> - * - * Alternatively, the contents of this file may be used under the terms of - * either the GNU General Public License Version 2 or later (the "GPL"), or - * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), - * in which case the provisions of the GPL or the LGPL are applicable instead - * of those above. If you wish to allow use of your version of this file only - * under the terms of either the GPL or the LGPL, and not to allow others to - * use your version of this file under the terms of the MPL, indicate your - * decision by deleting the provisions above and replace them with the notice - * and other provisions required by the GPL or the LGPL. If you do not delete - * the provisions above, a recipient may use your version of this file under - * the terms of any one of the MPL, the GPL or the LGPL. - * - * ***** END LICENSE BLOCK ***** */ - -package org.mozilla.gecko.ui; - -import org.mozilla.gecko.util.FloatUtils; - -/** - * This class represents the physics for one axis of movement (i.e. either - * horizontal or vertical). It tracks the different properties of movement - * like displacement, velocity, viewport dimensions, etc. pertaining to - * a particular axis. - */ -abstract class Axis { - // This fraction of velocity remains after every animation frame when the velocity is low. - private static final float FRICTION_SLOW = 0.85f; - // This fraction of velocity remains after every animation frame when the velocity is high. - private static final float FRICTION_FAST = 0.97f; - // Below this velocity (in pixels per frame), the friction starts increasing from FRICTION_FAST - // to FRICTION_SLOW. - private static final float VELOCITY_THRESHOLD = 10.0f; - // The maximum velocity change factor between events, per ms, in %. - // Direction changes are excluded. - private static final float MAX_EVENT_ACCELERATION = 0.012f; - - // The rate of deceleration when the surface has overscrolled. - private static final float OVERSCROLL_DECEL_RATE = 0.04f; - // The percentage of the surface which can be overscrolled before it must snap back. - private static final float SNAP_LIMIT = 0.75f; - - // The minimum amount of space that must be present for an axis to be considered scrollable, - // in pixels. - private static final float MIN_SCROLLABLE_DISTANCE = 0.5f; - // The number of milliseconds per frame assuming 60 fps - private static final float MS_PER_FRAME = 1000.0f / 60.0f; - - private enum FlingStates { - STOPPED, - PANNING, - FLINGING, - } - - private enum Overscroll { - NONE, - MINUS, // Overscrolled in the negative direction - PLUS, // Overscrolled in the positive direction - BOTH, // Overscrolled in both directions (page is zoomed to smaller than screen) - } - - private final SubdocumentScrollHelper mSubscroller; - - private float mFirstTouchPos; /* Position of the first touch event on the current drag. */ - private float mTouchPos; /* Position of the most recent touch event on the current drag. */ - private float mLastTouchPos; /* Position of the touch event before touchPos. */ - private float mVelocity; /* Velocity in this direction; pixels per animation frame. */ - public boolean mScrollingDisabled; /* Whether movement on this axis is locked. */ - private boolean mDisableSnap; /* Whether overscroll snapping is disabled. */ - private float mDisplacement; - - private FlingStates mFlingState; /* The fling state we're in on this axis. */ - - protected abstract float getOrigin(); - protected abstract float getViewportLength(); - protected abstract float getPageLength(); - - Axis(SubdocumentScrollHelper subscroller) { - mSubscroller = subscroller; - } - - private float getViewportEnd() { - return getOrigin() + getViewportLength(); - } - - void startTouch(float pos) { - mVelocity = 0.0f; - mScrollingDisabled = false; - mFirstTouchPos = mTouchPos = mLastTouchPos = pos; - } - - float panDistance(float currentPos) { - return currentPos - mFirstTouchPos; - } - - void setScrollingDisabled(boolean disabled) { - mScrollingDisabled = disabled; - } - - void saveTouchPos() { - mLastTouchPos = mTouchPos; - } - - void updateWithTouchAt(float pos, float timeDelta) { - float newVelocity = (mTouchPos - pos) / timeDelta * MS_PER_FRAME; - - // If there's a direction change, or current velocity is very low, - // allow setting of the velocity outright. Otherwise, use the current - // velocity and a maximum change factor to set the new velocity. - boolean curVelocityIsLow = Math.abs(mVelocity) < 1.0f; - boolean directionChange = (mVelocity > 0) != (newVelocity > 0); - if (curVelocityIsLow || (directionChange && !FloatUtils.fuzzyEquals(newVelocity, 0.0f))) { - mVelocity = newVelocity; - } else { - float maxChange = Math.abs(mVelocity * timeDelta * MAX_EVENT_ACCELERATION); - mVelocity = Math.min(mVelocity + maxChange, Math.max(mVelocity - maxChange, newVelocity)); - } - - mTouchPos = pos; - } - - boolean overscrolled() { - return getOverscroll() != Overscroll.NONE; - } - - private Overscroll getOverscroll() { - boolean minus = (getOrigin() < 0.0f); - boolean plus = (getViewportEnd() > getPageLength()); - if (minus && plus) { - return Overscroll.BOTH; - } else if (minus) { - return Overscroll.MINUS; - } else if (plus) { - return Overscroll.PLUS; - } else { - return Overscroll.NONE; - } - } - - // Returns the amount that the page has been overscrolled. If the page hasn't been - // overscrolled on this axis, returns 0. - private float getExcess() { - switch (getOverscroll()) { - case MINUS: return -getOrigin(); - case PLUS: return getViewportEnd() - getPageLength(); - case BOTH: return getViewportEnd() - getPageLength() - getOrigin(); - default: return 0.0f; - } - } - - /* - * Returns true if the page is zoomed in to some degree along this axis such that scrolling is - * possible and this axis has not been scroll locked while panning. Otherwise, returns false. - */ - private boolean scrollable() { - return getViewportLength() <= getPageLength() - MIN_SCROLLABLE_DISTANCE && - !mScrollingDisabled; - } - - /* - * Returns the resistance, as a multiplier, that should be taken into account when - * tracking or pinching. - */ - float getEdgeResistance() { - float excess = getExcess(); - if (excess > 0.0f) { - // excess can be greater than viewport length, but the resistance - // must never drop below 0.0 - return Math.max(0.0f, SNAP_LIMIT - excess / getViewportLength()); - } - return 1.0f; - } - - /* Returns the velocity. If the axis is locked, returns 0. */ - float getRealVelocity() { - return scrollable() ? mVelocity : 0f; - } - - void startPan() { - mFlingState = FlingStates.PANNING; - } - - void startFling(boolean stopped) { - mDisableSnap = mSubscroller.scrolling(); - - if (stopped) { - mFlingState = FlingStates.STOPPED; - } else { - mFlingState = FlingStates.FLINGING; - } - } - - /* Advances a fling animation by one step. */ - boolean advanceFling() { - if (mFlingState != FlingStates.FLINGING) { - return false; - } - if (mSubscroller.scrolling() && !mSubscroller.lastScrollSucceeded()) { - // if the subdocument stopped scrolling, it's because it reached the end - // of the subdocument. we don't do overscroll on subdocuments, so there's - // no point in continuing this fling. - return false; - } - - float excess = getExcess(); - if (mDisableSnap || FloatUtils.fuzzyEquals(excess, 0.0f)) { - // If we aren't overscrolled, just apply friction. - if (Math.abs(mVelocity) >= VELOCITY_THRESHOLD) { - mVelocity *= FRICTION_FAST; - } else { - float t = mVelocity / VELOCITY_THRESHOLD; - mVelocity *= FloatUtils.interpolate(FRICTION_SLOW, FRICTION_FAST, t); - } - } else { - // Otherwise, decrease the velocity linearly. - float elasticity = 1.0f - excess / (getViewportLength() * SNAP_LIMIT); - if (getOverscroll() == Overscroll.MINUS) { - mVelocity = Math.min((mVelocity + OVERSCROLL_DECEL_RATE) * elasticity, 0.0f); - } else { // must be Overscroll.PLUS - mVelocity = Math.max((mVelocity - OVERSCROLL_DECEL_RATE) * elasticity, 0.0f); - } - } - - return true; - } - - void stopFling() { - mVelocity = 0.0f; - mFlingState = FlingStates.STOPPED; - } - - // Performs displacement of the viewport position according to the current velocity. - void displace() { - if (!mSubscroller.scrolling() && !scrollable()) - return; - - if (mFlingState == FlingStates.PANNING) - mDisplacement += (mLastTouchPos - mTouchPos) * getEdgeResistance(); - else - mDisplacement += mVelocity; - } - - float resetDisplacement() { - float d = mDisplacement; - mDisplacement = 0.0f; - return d; - } -} |