1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/layers/apz/src/Axis.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,219 @@
1.4 +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
1.5 +/* vim: set sw=2 ts=8 et tw=80 : */
1.6 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +#ifndef mozilla_layers_Axis_h
1.11 +#define mozilla_layers_Axis_h
1.12 +
1.13 +#include <sys/types.h> // for int32_t
1.14 +#include "Units.h" // for CSSRect, CSSPoint
1.15 +#include "mozilla/TimeStamp.h" // for TimeDuration
1.16 +#include "nsTArray.h" // for nsTArray
1.17 +
1.18 +namespace mozilla {
1.19 +namespace layers {
1.20 +
1.21 +const float EPSILON = 0.0001f;
1.22 +
1.23 +class AsyncPanZoomController;
1.24 +
1.25 +/**
1.26 + * Helper class to maintain each axis of movement (X,Y) for panning and zooming.
1.27 + * Note that everything here is specific to one axis; that is, the X axis knows
1.28 + * nothing about the Y axis and vice versa.
1.29 + */
1.30 +class Axis {
1.31 +public:
1.32 + Axis(AsyncPanZoomController* aAsyncPanZoomController);
1.33 +
1.34 + enum Overscroll {
1.35 + // Overscroll is not happening at all.
1.36 + OVERSCROLL_NONE = 0,
1.37 + // Overscroll is happening in the negative direction. This means either to
1.38 + // the left or to the top depending on the axis.
1.39 + OVERSCROLL_MINUS,
1.40 + // Overscroll is happening in the positive direction. This means either to
1.41 + // the right or to the bottom depending on the axis.
1.42 + OVERSCROLL_PLUS,
1.43 + // Overscroll is happening both ways. This only means something when the
1.44 + // page is scaled out to a smaller size than the viewport.
1.45 + OVERSCROLL_BOTH
1.46 + };
1.47 +
1.48 + /**
1.49 + * Notify this Axis that a new touch has been received, including a time delta
1.50 + * indicating how long it has been since the previous one. This triggers a
1.51 + * recalculation of velocity.
1.52 + */
1.53 + void UpdateWithTouchAtDevicePoint(int32_t aPos, const TimeDuration& aTimeDelta);
1.54 +
1.55 + /**
1.56 + * Notify this Axis that a touch has begun, i.e. the user has put their finger
1.57 + * on the screen but has not yet tried to pan.
1.58 + */
1.59 + void StartTouch(int32_t aPos);
1.60 +
1.61 + /**
1.62 + * Notify this Axis that a touch has ended gracefully. This may perform
1.63 + * recalculations of the axis velocity.
1.64 + */
1.65 + void EndTouch();
1.66 +
1.67 + /**
1.68 + * Notify this Axis that a touch has ended forcefully. Useful for stopping
1.69 + * flings when a user puts their finger down in the middle of one (i.e. to
1.70 + * stop a previous touch including its fling so that a new one can take its
1.71 + * place).
1.72 + */
1.73 + void CancelTouch();
1.74 +
1.75 + /**
1.76 + * Takes a requested displacement to the position of this axis, and adjusts it
1.77 + * to account for overscroll (which might decrease the displacement; this is
1.78 + * to prevent the viewport from overscrolling the page rect), and axis locking
1.79 + * (which might prevent any displacement from happening). If overscroll
1.80 + * ocurred, its amount is written to |aOverscrollAmountOut|.
1.81 + * The adjusted displacement is returned.
1.82 + */
1.83 + float AdjustDisplacement(float aDisplacement, float& aOverscrollAmountOut);
1.84 +
1.85 + /**
1.86 + * Gets the distance between the starting position of the touch supplied in
1.87 + * startTouch() and the current touch from the last
1.88 + * updateWithTouchAtDevicePoint().
1.89 + */
1.90 + float PanDistance();
1.91 +
1.92 + /**
1.93 + * Gets the distance between the starting position of the touch supplied in
1.94 + * startTouch() and the supplied position.
1.95 + */
1.96 + float PanDistance(float aPos);
1.97 +
1.98 + /**
1.99 + * Applies friction during a fling, or cancels the fling if the velocity is
1.100 + * too low. Returns true if the fling should continue to another frame, or
1.101 + * false if it should end. |aDelta| is the amount of time that has passed
1.102 + * since the last time friction was applied.
1.103 + */
1.104 + bool FlingApplyFrictionOrCancel(const TimeDuration& aDelta);
1.105 +
1.106 + /*
1.107 + * Returns true if the page is zoomed in to some degree along this axis such that scrolling is
1.108 + * possible and this axis has not been scroll locked while panning. Otherwise, returns false.
1.109 + */
1.110 + bool Scrollable();
1.111 +
1.112 + void SetAxisLocked(bool aAxisLocked) { mAxisLocked = aAxisLocked; }
1.113 +
1.114 + /**
1.115 + * Gets the overscroll state of the axis in its current position.
1.116 + */
1.117 + Overscroll GetOverscroll();
1.118 +
1.119 + /**
1.120 + * If there is overscroll, returns the amount. Sign depends on in what
1.121 + * direction it is overscrolling. Positive excess means that it is
1.122 + * overscrolling in the positive direction, whereas negative excess means
1.123 + * that it is overscrolling in the negative direction. If there is overscroll
1.124 + * in both directions, this returns 0; it assumes that you check
1.125 + * GetOverscroll() first.
1.126 + */
1.127 + float GetExcess();
1.128 +
1.129 + /**
1.130 + * Gets the raw velocity of this axis at this moment.
1.131 + */
1.132 + float GetVelocity();
1.133 +
1.134 + /**
1.135 + * Sets the raw velocity of this axis at this moment.
1.136 + * Intended to be called only when the axis "takes over" a velocity from
1.137 + * another APZC, in which case there are no touch points available to call
1.138 + * UpdateWithTouchAtDevicePoint. In other circumstances,
1.139 + * UpdateWithTouchAtDevicePoint should be used and the velocity calculated
1.140 + * there.
1.141 + */
1.142 + void SetVelocity(float aVelocity);
1.143 +
1.144 + /**
1.145 + * Gets the overscroll state of the axis given an additional displacement.
1.146 + * That is to say, if the given displacement is applied, this will tell you
1.147 + * whether or not it will overscroll, and in what direction.
1.148 + */
1.149 + Overscroll DisplacementWillOverscroll(float aDisplacement);
1.150 +
1.151 + /**
1.152 + * If a displacement will overscroll the axis, this returns the amount and in
1.153 + * what direction. Similar to GetExcess() but takes a displacement to apply.
1.154 + */
1.155 + float DisplacementWillOverscrollAmount(float aDisplacement);
1.156 +
1.157 + /**
1.158 + * If a scale will overscroll the axis, this returns the amount and in what
1.159 + * direction. Similar to GetExcess() but takes a displacement to apply.
1.160 + *
1.161 + * |aFocus| is the point at which the scale is focused at. We will offset the
1.162 + * scroll offset in such a way that it remains in the same place on the page
1.163 + * relative.
1.164 + */
1.165 + float ScaleWillOverscrollAmount(float aScale, float aFocus);
1.166 +
1.167 + /**
1.168 + * Checks if an axis will overscroll in both directions by computing the
1.169 + * content rect and checking that its height/width (depending on the axis)
1.170 + * does not overextend past the viewport.
1.171 + *
1.172 + * This gets called by ScaleWillOverscroll().
1.173 + */
1.174 + bool ScaleWillOverscrollBothSides(float aScale);
1.175 +
1.176 + /**
1.177 + * Returns whether there is room to pan on this axis in either direction.
1.178 + */
1.179 + bool HasRoomToPan() const;
1.180 +
1.181 + float GetOrigin() const;
1.182 + float GetCompositionLength() const;
1.183 + float GetPageStart() const;
1.184 + float GetPageLength() const;
1.185 + float GetCompositionEnd() const;
1.186 + float GetPageEnd() const;
1.187 +
1.188 + int32_t GetPos() const { return mPos; }
1.189 +
1.190 + virtual float GetPointOffset(const CSSPoint& aPoint) const = 0;
1.191 + virtual float GetRectLength(const CSSRect& aRect) const = 0;
1.192 + virtual float GetRectOffset(const CSSRect& aRect) const = 0;
1.193 +
1.194 +protected:
1.195 + int32_t mPos;
1.196 + int32_t mStartPos;
1.197 + float mVelocity;
1.198 + bool mAxisLocked; // Whether movement on this axis is locked.
1.199 + AsyncPanZoomController* mAsyncPanZoomController;
1.200 + nsTArray<float> mVelocityQueue;
1.201 +};
1.202 +
1.203 +class AxisX : public Axis {
1.204 +public:
1.205 + AxisX(AsyncPanZoomController* mAsyncPanZoomController);
1.206 + virtual float GetPointOffset(const CSSPoint& aPoint) const;
1.207 + virtual float GetRectLength(const CSSRect& aRect) const;
1.208 + virtual float GetRectOffset(const CSSRect& aRect) const;
1.209 +};
1.210 +
1.211 +class AxisY : public Axis {
1.212 +public:
1.213 + AxisY(AsyncPanZoomController* mAsyncPanZoomController);
1.214 + virtual float GetPointOffset(const CSSPoint& aPoint) const;
1.215 + virtual float GetRectLength(const CSSRect& aRect) const;
1.216 + virtual float GetRectOffset(const CSSRect& aRect) const;
1.217 +};
1.218 +
1.219 +}
1.220 +}
1.221 +
1.222 +#endif
