michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
michael@0: /* vim: set sw=2 ts=8 et tw=80 : */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "Axis.h"
michael@0: #include <math.h>                       // for fabsf, pow, powf
michael@0: #include <algorithm>                    // for max
michael@0: #include "AsyncPanZoomController.h"     // for AsyncPanZoomController
michael@0: #include "mozilla/layers/APZCTreeManager.h" // for APZCTreeManager
michael@0: #include "FrameMetrics.h"               // for FrameMetrics
michael@0: #include "mozilla/Attributes.h"         // for MOZ_FINAL
michael@0: #include "mozilla/Preferences.h"        // for Preferences
michael@0: #include "mozilla/gfx/Rect.h"           // for RoundedIn
michael@0: #include "mozilla/mozalloc.h"           // for operator new
michael@0: #include "nsMathUtils.h"                // for NS_lround
michael@0: #include "nsThreadUtils.h"              // for NS_DispatchToMainThread, etc
michael@0: #include "nscore.h"                     // for NS_IMETHOD
michael@0: #include "gfxPrefs.h"                   // for the preferences
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace layers {
michael@0: 
michael@0: Axis::Axis(AsyncPanZoomController* aAsyncPanZoomController)
michael@0:   : mPos(0),
michael@0:     mVelocity(0.0f),
michael@0:     mAxisLocked(false),
michael@0:     mAsyncPanZoomController(aAsyncPanZoomController)
michael@0: {
michael@0: }
michael@0: 
michael@0: void Axis::UpdateWithTouchAtDevicePoint(int32_t aPos, const TimeDuration& aTimeDelta) {
michael@0:   float newVelocity = mAxisLocked ? 0 : (mPos - aPos) / aTimeDelta.ToMilliseconds();
michael@0:   if (gfxPrefs::APZMaxVelocity() > 0.0f) {
michael@0:     newVelocity = std::min(newVelocity, gfxPrefs::APZMaxVelocity() * APZCTreeManager::GetDPI());
michael@0:   }
michael@0: 
michael@0:   mVelocity = newVelocity;
michael@0:   mPos = aPos;
michael@0: 
michael@0:   // Limit queue size pased on pref
michael@0:   mVelocityQueue.AppendElement(mVelocity);
michael@0:   if (mVelocityQueue.Length() > gfxPrefs::APZMaxVelocityQueueSize()) {
michael@0:     mVelocityQueue.RemoveElementAt(0);
michael@0:   }
michael@0: }
michael@0: 
michael@0: void Axis::StartTouch(int32_t aPos) {
michael@0:   mStartPos = aPos;
michael@0:   mPos = aPos;
michael@0:   mAxisLocked = false;
michael@0: }
michael@0: 
michael@0: float Axis::AdjustDisplacement(float aDisplacement, float& aOverscrollAmountOut) {
michael@0:   if (mAxisLocked) {
michael@0:     aOverscrollAmountOut = 0;
michael@0:     return 0;
michael@0:   }
michael@0: 
michael@0:   float displacement = aDisplacement;
michael@0: 
michael@0:   // If this displacement will cause an overscroll, throttle it. Can potentially
michael@0:   // bring it to 0 even if the velocity is high.
michael@0:   if (DisplacementWillOverscroll(displacement) != OVERSCROLL_NONE) {
michael@0:     // No need to have a velocity along this axis anymore; it won't take us
michael@0:     // anywhere, so we're just spinning needlessly.
michael@0:     mVelocity = 0.0f;
michael@0:     aOverscrollAmountOut = DisplacementWillOverscrollAmount(displacement);
michael@0:     displacement -= aOverscrollAmountOut;
michael@0:   }
michael@0:   return displacement;
michael@0: }
michael@0: 
michael@0: float Axis::PanDistance() {
michael@0:   return fabsf(mPos - mStartPos);
michael@0: }
michael@0: 
michael@0: float Axis::PanDistance(float aPos) {
michael@0:   return fabsf(aPos - mStartPos);
michael@0: }
michael@0: 
michael@0: void Axis::EndTouch() {
michael@0:   // Calculate the mean velocity and empty the queue.
michael@0:   int count = mVelocityQueue.Length();
michael@0:   if (count) {
michael@0:     mVelocity = 0;
michael@0:     while (!mVelocityQueue.IsEmpty()) {
michael@0:       mVelocity += mVelocityQueue[0];
michael@0:       mVelocityQueue.RemoveElementAt(0);
michael@0:     }
michael@0:     mVelocity /= count;
michael@0:   }
michael@0: }
michael@0: 
michael@0: void Axis::CancelTouch() {
michael@0:   mVelocity = 0.0f;
michael@0:   while (!mVelocityQueue.IsEmpty()) {
michael@0:     mVelocityQueue.RemoveElementAt(0);
michael@0:   }
michael@0: }
michael@0: 
michael@0: bool Axis::Scrollable() {
michael@0:     if (mAxisLocked) {
michael@0:         return false;
michael@0:     }
michael@0:     return GetCompositionLength() < GetPageLength();
michael@0: }
michael@0: 
michael@0: bool Axis::FlingApplyFrictionOrCancel(const TimeDuration& aDelta) {
michael@0:   if (fabsf(mVelocity) <= gfxPrefs::APZFlingStoppedThreshold()) {
michael@0:     // If the velocity is very low, just set it to 0 and stop the fling,
michael@0:     // otherwise we'll just asymptotically approach 0 and the user won't
michael@0:     // actually see any changes.
michael@0:     mVelocity = 0.0f;
michael@0:     return false;
michael@0:   } else {
michael@0:     mVelocity *= pow(1.0f - gfxPrefs::APZFlingFriction(), float(aDelta.ToMilliseconds()));
michael@0:   }
michael@0:   return true;
michael@0: }
michael@0: 
michael@0: Axis::Overscroll Axis::GetOverscroll() {
michael@0:   // If the current pan takes the window to the left of or above the current
michael@0:   // page rect.
michael@0:   bool minus = GetOrigin() < GetPageStart();
michael@0:   // If the current pan takes the window to the right of or below the current
michael@0:   // page rect.
michael@0:   bool plus = GetCompositionEnd() > GetPageEnd();
michael@0:   if (minus && plus) {
michael@0:     return OVERSCROLL_BOTH;
michael@0:   }
michael@0:   if (minus) {
michael@0:     return OVERSCROLL_MINUS;
michael@0:   }
michael@0:   if (plus) {
michael@0:     return OVERSCROLL_PLUS;
michael@0:   }
michael@0:   return OVERSCROLL_NONE;
michael@0: }
michael@0: 
michael@0: float Axis::GetExcess() {
michael@0:   switch (GetOverscroll()) {
michael@0:   case OVERSCROLL_MINUS: return GetOrigin() - GetPageStart();
michael@0:   case OVERSCROLL_PLUS: return GetCompositionEnd() - GetPageEnd();
michael@0:   case OVERSCROLL_BOTH: return (GetCompositionEnd() - GetPageEnd()) +
michael@0:                                (GetPageStart() - GetOrigin());
michael@0:   default: return 0;
michael@0:   }
michael@0: }
michael@0: 
michael@0: Axis::Overscroll Axis::DisplacementWillOverscroll(float aDisplacement) {
michael@0:   // If the current pan plus a displacement takes the window to the left of or
michael@0:   // above the current page rect.
michael@0:   bool minus = GetOrigin() + aDisplacement < GetPageStart();
michael@0:   // If the current pan plus a displacement takes the window to the right of or
michael@0:   // below the current page rect.
michael@0:   bool plus = GetCompositionEnd() + aDisplacement > GetPageEnd();
michael@0:   if (minus && plus) {
michael@0:     return OVERSCROLL_BOTH;
michael@0:   }
michael@0:   if (minus) {
michael@0:     return OVERSCROLL_MINUS;
michael@0:   }
michael@0:   if (plus) {
michael@0:     return OVERSCROLL_PLUS;
michael@0:   }
michael@0:   return OVERSCROLL_NONE;
michael@0: }
michael@0: 
michael@0: float Axis::DisplacementWillOverscrollAmount(float aDisplacement) {
michael@0:   switch (DisplacementWillOverscroll(aDisplacement)) {
michael@0:   case OVERSCROLL_MINUS: return (GetOrigin() + aDisplacement) - GetPageStart();
michael@0:   case OVERSCROLL_PLUS: return (GetCompositionEnd() + aDisplacement) - GetPageEnd();
michael@0:   // Don't handle overscrolled in both directions; a displacement can't cause
michael@0:   // this, it must have already been zoomed out too far.
michael@0:   default: return 0;
michael@0:   }
michael@0: }
michael@0: 
michael@0: float Axis::ScaleWillOverscrollAmount(float aScale, float aFocus) {
michael@0:   float originAfterScale = (GetOrigin() + aFocus) - (aFocus / aScale);
michael@0: 
michael@0:   bool both = ScaleWillOverscrollBothSides(aScale);
michael@0:   bool minus = originAfterScale < GetPageStart();
michael@0:   bool plus = (originAfterScale + (GetCompositionLength() / aScale)) > GetPageEnd();
michael@0: 
michael@0:   if ((minus && plus) || both) {
michael@0:     // If we ever reach here it's a bug in the client code.
michael@0:     MOZ_ASSERT(false, "In an OVERSCROLL_BOTH condition in ScaleWillOverscrollAmount");
michael@0:     return 0;
michael@0:   }
michael@0:   if (minus) {
michael@0:     return originAfterScale - GetPageStart();
michael@0:   }
michael@0:   if (plus) {
michael@0:     return originAfterScale + (GetCompositionLength() / aScale) - GetPageEnd();
michael@0:   }
michael@0:   return 0;
michael@0: }
michael@0: 
michael@0: float Axis::GetVelocity() {
michael@0:   return mAxisLocked ? 0 : mVelocity;
michael@0: }
michael@0: 
michael@0: void Axis::SetVelocity(float aVelocity) {
michael@0:   mVelocity = aVelocity;
michael@0: }
michael@0: 
michael@0: float Axis::GetCompositionEnd() const {
michael@0:   return GetOrigin() + GetCompositionLength();
michael@0: }
michael@0: 
michael@0: float Axis::GetPageEnd() const {
michael@0:   return GetPageStart() + GetPageLength();
michael@0: }
michael@0: 
michael@0: float Axis::GetOrigin() const {
michael@0:   CSSPoint origin = mAsyncPanZoomController->GetFrameMetrics().GetScrollOffset();
michael@0:   return GetPointOffset(origin);
michael@0: }
michael@0: 
michael@0: float Axis::GetCompositionLength() const {
michael@0:   const FrameMetrics& metrics = mAsyncPanZoomController->GetFrameMetrics();
michael@0:   return GetRectLength(metrics.CalculateCompositedRectInCssPixels());
michael@0: }
michael@0: 
michael@0: float Axis::GetPageStart() const {
michael@0:   CSSRect pageRect = mAsyncPanZoomController->GetFrameMetrics().mScrollableRect;
michael@0:   return GetRectOffset(pageRect);
michael@0: }
michael@0: 
michael@0: float Axis::GetPageLength() const {
michael@0:   CSSRect pageRect = mAsyncPanZoomController->GetFrameMetrics().mScrollableRect;
michael@0:   return GetRectLength(pageRect);
michael@0: }
michael@0: 
michael@0: bool Axis::ScaleWillOverscrollBothSides(float aScale) {
michael@0:   const FrameMetrics& metrics = mAsyncPanZoomController->GetFrameMetrics();
michael@0: 
michael@0:   CSSToParentLayerScale scale(metrics.GetZoomToParent().scale * aScale);
michael@0:   CSSRect cssCompositionBounds = metrics.mCompositionBounds / scale;
michael@0: 
michael@0:   return GetRectLength(metrics.mScrollableRect) < GetRectLength(cssCompositionBounds);
michael@0: }
michael@0: 
michael@0: bool Axis::HasRoomToPan() const {
michael@0:   return GetOrigin() > GetPageStart()
michael@0:       || GetCompositionEnd() < GetPageEnd();
michael@0: }
michael@0: 
michael@0: 
michael@0: AxisX::AxisX(AsyncPanZoomController* aAsyncPanZoomController)
michael@0:   : Axis(aAsyncPanZoomController)
michael@0: {
michael@0: 
michael@0: }
michael@0: 
michael@0: float AxisX::GetPointOffset(const CSSPoint& aPoint) const
michael@0: {
michael@0:   return aPoint.x;
michael@0: }
michael@0: 
michael@0: float AxisX::GetRectLength(const CSSRect& aRect) const
michael@0: {
michael@0:   return aRect.width;
michael@0: }
michael@0: 
michael@0: float AxisX::GetRectOffset(const CSSRect& aRect) const
michael@0: {
michael@0:   return aRect.x;
michael@0: }
michael@0: 
michael@0: AxisY::AxisY(AsyncPanZoomController* aAsyncPanZoomController)
michael@0:   : Axis(aAsyncPanZoomController)
michael@0: {
michael@0: 
michael@0: }
michael@0: 
michael@0: float AxisY::GetPointOffset(const CSSPoint& aPoint) const
michael@0: {
michael@0:   return aPoint.y;
michael@0: }
michael@0: 
michael@0: float AxisY::GetRectLength(const CSSRect& aRect) const
michael@0: {
michael@0:   return aRect.height;
michael@0: }
michael@0: 
michael@0: float AxisY::GetRectOffset(const CSSRect& aRect) const
michael@0: {
michael@0:   return aRect.y;
michael@0: }
michael@0: 
michael@0: }
michael@0: }