Moving GraphicsContext and dependencies from core to platform.

Source/core/platform/mac/ScrollElasticityController.mm

Index: Source/core/platform/mac/ScrollElasticityController.mm
diff --git a/Source/core/platform/mac/ScrollElasticityController.mm b/Source/core/platform/mac/ScrollElasticityController.mm
deleted file mode 100644
index f2693a78419fdfbef4c9fbb3469b542613db3360..0000000000000000000000000000000000000000
--- a/Source/core/platform/mac/ScrollElasticityController.mm
+++ /dev/null
@@ -1,428 +0,0 @@
-/*
- * Copyright (C) 2011 Apple Inc. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in the
- *    documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
- * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
- * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
- * THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include "config.h"
-#include "core/platform/mac/ScrollElasticityController.h"
-
-#include "platform/PlatformWheelEvent.h"
-#include <sys/sysctl.h>
-#include <sys/time.h>
-
-#if USE(RUBBER_BANDING)
-
-static NSTimeInterval systemUptime()
-{
-    if ([[NSProcessInfo processInfo] respondsToSelector:@selector(systemUptime)])
-        return [[NSProcessInfo processInfo] systemUptime];
-
-    // Get how long system has been up. Found by looking getting "boottime" from the kernel.
-    static struct timeval boottime = {0, 0};
-    if (!boottime.tv_sec) {
-        int mib[2] = {CTL_KERN, KERN_BOOTTIME};
-        size_t size = sizeof(boottime);
-        if (-1 == sysctl(mib, 2, &boottime, &size, 0, 0))
-            boottime.tv_sec = 0;
-    }
-    struct timeval now;
-    if (boottime.tv_sec && -1 != gettimeofday(&now, 0)) {
-        struct timeval uptime;
-        timersub(&now, &boottime, &uptime);
-        NSTimeInterval result = uptime.tv_sec + (uptime.tv_usec / 1E+6);
-        return result;
-    }
-    return 0;
-}
-
-namespace WebCore {
-
-static const float scrollVelocityZeroingTimeout = 0.10f;
-static const float rubberbandDirectionLockStretchRatio = 1;
-static const float rubberbandMinimumRequiredDeltaBeforeStretch = 10;
-
-static const float rubberbandStiffness = 20;
-static const float rubberbandAmplitude = 0.31f;
-static const float rubberbandPeriod = 1.6f;
-
-static float elasticDeltaForTimeDelta(float initialPosition, float initialVelocity, float elapsedTime)
-{
-    float amplitude = rubberbandAmplitude;
-    float period = rubberbandPeriod;
-    float criticalDampeningFactor = expf((-elapsedTime * rubberbandStiffness) / period);
-
-    return (initialPosition + (-initialVelocity * elapsedTime * amplitude)) * criticalDampeningFactor;
-}
-
-static float elasticDeltaForReboundDelta(float delta)
-{
-    float stiffness = std::max(rubberbandStiffness, 1.0f);
-    return delta / stiffness;
-}
-
-static float reboundDeltaForElasticDelta(float delta)
-{
-    return delta * rubberbandStiffness;
-}
-
-static float scrollWheelMultiplier()
-{
-    static float multiplier = -1;
-    if (multiplier < 0) {
-        multiplier = [[NSUserDefaults standardUserDefaults] floatForKey:@"NSScrollWheelMultiplier"];
-        if (multiplier <= 0)
-            multiplier = 1;
-    }
-    return multiplier;
-}
-
-ScrollElasticityController::ScrollElasticityController(ScrollElasticityControllerClient* client)
-    : m_client(client)
-    , m_inScrollGesture(false)
-    , m_momentumScrollInProgress(false)
-    , m_ignoreMomentumScrolls(false)
-    , m_lastMomentumScrollTimestamp(0)
-    , m_startTime(0)
-    , m_snapRubberbandTimerIsActive(false)
-{
-}
-
-bool ScrollElasticityController::handleWheelEvent(const PlatformWheelEvent& wheelEvent)
-{
-    if (wheelEvent.phase() == PlatformWheelEventPhaseBegan) {
-        // First, check if we should rubber-band at all.
-        if (m_client->pinnedInDirection(FloatSize(-wheelEvent.deltaX(), 0)) &&
-            !shouldRubberBandInHorizontalDirection(wheelEvent))
-            return false;
-
-        m_inScrollGesture = true;
-        m_momentumScrollInProgress = false;
-        m_ignoreMomentumScrolls = false;
-        m_lastMomentumScrollTimestamp = 0;
-        m_momentumVelocity = FloatSize();
-
-        IntSize stretchAmount = m_client->stretchAmount();
-        m_stretchScrollForce.setWidth(reboundDeltaForElasticDelta(stretchAmount.width()));
-        m_stretchScrollForce.setHeight(reboundDeltaForElasticDelta(stretchAmount.height()));
-        m_overflowScrollDelta = FloatSize();
-
-        stopSnapRubberbandTimer();
-
-        return true;
-    }
-
-    if (wheelEvent.phase() == PlatformWheelEventPhaseEnded) {
-        bool wasRubberBandInProgress = isRubberBandInProgress();
-        // Call snapRubberBand() even if isRubberBandInProgress() is false. For example,
-        // m_inScrollGesture may be true (and needs to be reset on a phase end) even if
-        // isRubberBandInProgress() is not (e.g. the overhang area is empty).
-        snapRubberBand();
-        return wasRubberBandInProgress;
-    }
-
-    bool isMomentumScrollEvent = (wheelEvent.momentumPhase() != PlatformWheelEventPhaseNone);
-    if (m_ignoreMomentumScrolls && (isMomentumScrollEvent || m_snapRubberbandTimerIsActive)) {
-        if (wheelEvent.momentumPhase() == PlatformWheelEventPhaseEnded) {
-            m_ignoreMomentumScrolls = false;
-            return true;
-        }
-        return false;
-    }
-
-    float deltaX = m_overflowScrollDelta.width();
-    float deltaY = m_overflowScrollDelta.height();
-
-    // Reset overflow values because we may decide to remove delta at various points and put it into overflow.
-    m_overflowScrollDelta = FloatSize();
-
-    IntSize stretchAmount = m_client->stretchAmount();
-    bool isVerticallyStretched = stretchAmount.height();
-    bool isHorizontallyStretched = stretchAmount.width();
-
-    float eventCoalescedDeltaX;
-    float eventCoalescedDeltaY;
-
-    if (isVerticallyStretched || isHorizontallyStretched) {
-        eventCoalescedDeltaX = -wheelEvent.unacceleratedScrollingDeltaX();
-        eventCoalescedDeltaY = -wheelEvent.unacceleratedScrollingDeltaY();
-    } else {
-        eventCoalescedDeltaX = -wheelEvent.deltaX();
-        eventCoalescedDeltaY = -wheelEvent.deltaY();
-    }
-
-    deltaX += eventCoalescedDeltaX;
-    deltaY += eventCoalescedDeltaY;
-
-    // Slightly prefer scrolling vertically by applying the = case to deltaY
-    if (fabsf(deltaY) >= fabsf(deltaX))
-        deltaX = 0;
-    else
-        deltaY = 0;
-
-    bool shouldStretch = false;
-
-    PlatformWheelEventPhase momentumPhase = wheelEvent.momentumPhase();
-
-    // If we are starting momentum scrolling then do some setup.
-    if (!m_momentumScrollInProgress && (momentumPhase == PlatformWheelEventPhaseBegan || momentumPhase == PlatformWheelEventPhaseChanged)) {
-        m_momentumScrollInProgress = true;
-        // Start the snap rubber band timer if it's not running. This is needed to
-        // snap back from the over scroll caused by momentum events.
-        if (!m_snapRubberbandTimerIsActive && m_startTime == 0)
-            snapRubberBand();
-    }
-
-    CFTimeInterval timeDelta = wheelEvent.timestamp() - m_lastMomentumScrollTimestamp;
-    if (m_inScrollGesture || m_momentumScrollInProgress) {
-        if (m_lastMomentumScrollTimestamp && timeDelta > 0 && timeDelta < scrollVelocityZeroingTimeout) {
-            m_momentumVelocity.setWidth(eventCoalescedDeltaX / (float)timeDelta);
-            m_momentumVelocity.setHeight(eventCoalescedDeltaY / (float)timeDelta);
-            m_lastMomentumScrollTimestamp = wheelEvent.timestamp();
-        } else {
-            m_lastMomentumScrollTimestamp = wheelEvent.timestamp();
-            m_momentumVelocity = FloatSize();
-        }
-
-        if (isVerticallyStretched) {
-            if (!isHorizontallyStretched && m_client->pinnedInDirection(FloatSize(deltaX, 0))) {
-                // Stretching only in the vertical.
-                if (deltaY != 0 && (fabsf(deltaX / deltaY) < rubberbandDirectionLockStretchRatio))
-                    deltaX = 0;
-                else if (fabsf(deltaX) < rubberbandMinimumRequiredDeltaBeforeStretch) {
-                    m_overflowScrollDelta.setWidth(m_overflowScrollDelta.width() + deltaX);
-                    deltaX = 0;
-                } else
-                    m_overflowScrollDelta.setWidth(m_overflowScrollDelta.width() + deltaX);
-            }
-        } else if (isHorizontallyStretched) {
-            // Stretching only in the horizontal.
-            if (m_client->pinnedInDirection(FloatSize(0, deltaY))) {
-                if (deltaX != 0 && (fabsf(deltaY / deltaX) < rubberbandDirectionLockStretchRatio))
-                    deltaY = 0;
-                else if (fabsf(deltaY) < rubberbandMinimumRequiredDeltaBeforeStretch) {
-                    m_overflowScrollDelta.setHeight(m_overflowScrollDelta.height() + deltaY);
-                    deltaY = 0;
-                } else
-                    m_overflowScrollDelta.setHeight(m_overflowScrollDelta.height() + deltaY);
-            }
-        } else {
-            // Not stretching at all yet.
-            if (m_client->pinnedInDirection(FloatSize(deltaX, deltaY))) {
-                if (fabsf(deltaY) >= fabsf(deltaX)) {
-                    if (fabsf(deltaX) < rubberbandMinimumRequiredDeltaBeforeStretch) {
-                        m_overflowScrollDelta.setWidth(m_overflowScrollDelta.width() + deltaX);
-                        deltaX = 0;
-                    } else
-                        m_overflowScrollDelta.setWidth(m_overflowScrollDelta.width() + deltaX);
-                }
-                shouldStretch = true;
-            }
-        }
-    }
-
-    if (deltaX != 0 || deltaY != 0) {
-        if (!(shouldStretch || isVerticallyStretched || isHorizontallyStretched)) {
-            if (deltaY != 0) {
-                deltaY *= scrollWheelMultiplier();
-                m_client->immediateScrollBy(FloatSize(0, deltaY));
-            }
-            if (deltaX != 0) {
-                deltaX *= scrollWheelMultiplier();
-                m_client->immediateScrollBy(FloatSize(deltaX, 0));
-            }
-        } else {
-            if (!m_client->allowsHorizontalStretching()) {
-                deltaX = 0;
-                eventCoalescedDeltaX = 0;
-            } else if ((deltaX != 0) && !isHorizontallyStretched && !m_client->pinnedInDirection(FloatSize(deltaX, 0))) {
-                deltaX *= scrollWheelMultiplier();
-
-                m_client->immediateScrollByWithoutContentEdgeConstraints(FloatSize(deltaX, 0));
-                deltaX = 0;
-            }
-
-            if (!m_client->allowsVerticalStretching()) {
-                deltaY = 0;
-                eventCoalescedDeltaY = 0;
-            } else if ((deltaY != 0) && !isVerticallyStretched && !m_client->pinnedInDirection(FloatSize(0, deltaY))) {
-                deltaY *= scrollWheelMultiplier();
-
-                m_client->immediateScrollByWithoutContentEdgeConstraints(FloatSize(0, deltaY));
-                deltaY = 0;
-            }
-
-            IntSize stretchAmount = m_client->stretchAmount();
-
-            if (m_momentumScrollInProgress) {
-                if ((m_client->pinnedInDirection(FloatSize(eventCoalescedDeltaX, eventCoalescedDeltaY)) || (fabsf(eventCoalescedDeltaX) + fabsf(eventCoalescedDeltaY) <= 0)) && m_lastMomentumScrollTimestamp) {
-                    m_ignoreMomentumScrolls = true;
-                    m_momentumScrollInProgress = false;
-                    snapRubberBand();
-                }
-            }
-
-            m_stretchScrollForce.setWidth(m_stretchScrollForce.width() + deltaX);
-            m_stretchScrollForce.setHeight(m_stretchScrollForce.height() + deltaY);
-
-            FloatSize dampedDelta(ceilf(elasticDeltaForReboundDelta(m_stretchScrollForce.width())), ceilf(elasticDeltaForReboundDelta(m_stretchScrollForce.height())));
-
-            m_client->immediateScrollByWithoutContentEdgeConstraints(dampedDelta - stretchAmount);
-        }
-    }
-
-    if (m_momentumScrollInProgress && momentumPhase == PlatformWheelEventPhaseEnded) {
-        m_momentumScrollInProgress = false;
-        m_ignoreMomentumScrolls = false;
-        m_lastMomentumScrollTimestamp = 0;
-    }
-
-    return true;
-}
-
-static inline float roundTowardZero(float num)
-{
-    return num > 0 ? ceilf(num - 0.5f) : floorf(num + 0.5f);
-}
-
-static inline float roundToDevicePixelTowardZero(float num)
-{
-    float roundedNum = roundf(num);
-    if (fabs(num - roundedNum) < 0.125)
-        num = roundedNum;
-
-    return roundTowardZero(num);
-}
-
-void ScrollElasticityController::snapRubberBandTimerFired()
-{
-    if (!m_momentumScrollInProgress || m_ignoreMomentumScrolls) {
-        CFTimeInterval timeDelta = [NSDate timeIntervalSinceReferenceDate] - m_startTime;
-
-        if (m_startStretch == FloatSize()) {
-            m_startStretch = m_client->stretchAmount();
-            if (m_startStretch == FloatSize()) {
-                stopSnapRubberbandTimer();
-
-                m_stretchScrollForce = FloatSize();
-                m_startTime = 0;
-                m_origOrigin = FloatPoint();
-                m_origVelocity = FloatSize();
-                return;
-            }
-
-            m_origOrigin = m_client->absoluteScrollPosition() - m_startStretch;
-            m_origVelocity = m_momentumVelocity;
-
-            // Just like normal scrolling, prefer vertical rubberbanding
-            if (fabsf(m_origVelocity.height()) >= fabsf(m_origVelocity.width()))
-                m_origVelocity.setWidth(0);
-
-            // Don't rubber-band horizontally if it's not possible to scroll horizontally
-            if (!m_client->canScrollHorizontally())
-                m_origVelocity.setWidth(0);
-
-            // Don't rubber-band vertically if it's not possible to scroll vertically
-            if (!m_client->canScrollVertically())
-                m_origVelocity.setHeight(0);
-        }
-
-        FloatPoint delta(roundToDevicePixelTowardZero(elasticDeltaForTimeDelta(m_startStretch.width(), -m_origVelocity.width(), (float)timeDelta)),
-                         roundToDevicePixelTowardZero(elasticDeltaForTimeDelta(m_startStretch.height(), -m_origVelocity.height(), (float)timeDelta)));
-
-        if (fabs(delta.x()) >= 1 || fabs(delta.y()) >= 1) {
-            m_client->immediateScrollByWithoutContentEdgeConstraints(FloatSize(delta.x(), delta.y()) - m_client->stretchAmount());
-
-            FloatSize newStretch = m_client->stretchAmount();
-
-            m_stretchScrollForce.setWidth(reboundDeltaForElasticDelta(newStretch.width()));
-            m_stretchScrollForce.setHeight(reboundDeltaForElasticDelta(newStretch.height()));
-        } else {
-            m_client->immediateScrollBy(m_origOrigin - m_client->absoluteScrollPosition());
-
-            stopSnapRubberbandTimer();
-            m_stretchScrollForce = FloatSize();
-            m_startTime = 0;
-            m_startStretch = FloatSize();
-            m_origOrigin = FloatPoint();
-            m_origVelocity = FloatSize();
-        }
-    } else {
-        m_startTime = [NSDate timeIntervalSinceReferenceDate];
-        m_startStretch = FloatSize();
-    }
-}
-
-bool ScrollElasticityController::isRubberBandInProgress() const
-{
-    if (!m_inScrollGesture && !m_momentumScrollInProgress && !m_snapRubberbandTimerIsActive)
-        return false;
-
-    return !m_client->stretchAmount().isZero();
-}
-
-void ScrollElasticityController::stopSnapRubberbandTimer()
-{
-    m_client->stopSnapRubberbandTimer();
-    m_snapRubberbandTimerIsActive = false;
-}
-
-void ScrollElasticityController::snapRubberBand()
-{
-    CFTimeInterval timeDelta = systemUptime() - m_lastMomentumScrollTimestamp;
-    if (m_lastMomentumScrollTimestamp && timeDelta >= scrollVelocityZeroingTimeout)
-        m_momentumVelocity = FloatSize();
-
-    m_inScrollGesture = false;
-
-    if (m_snapRubberbandTimerIsActive)
-        return;
-
-    m_startStretch = FloatSize();
-    m_origOrigin = FloatPoint();
-    m_origVelocity = FloatSize();
-
-    // If there's no momentum scroll or stretch amount, no need to start the timer.
-    if (!m_momentumScrollInProgress && m_client->stretchAmount() == FloatSize()) {
-        m_startTime = 0;
-        m_stretchScrollForce = FloatSize();
-        return;
-    }
-
-    m_startTime = [NSDate timeIntervalSinceReferenceDate];
-    m_client->startSnapRubberbandTimer();
-    m_snapRubberbandTimerIsActive = true;
-}
-
-bool ScrollElasticityController::shouldRubberBandInHorizontalDirection(const PlatformWheelEvent& wheelEvent)
-{
-    if (wheelEvent.deltaX() > 0)
-        return m_client->shouldRubberBandInDirection(ScrollLeft);
-    if (wheelEvent.deltaX() < 0)
-        return m_client->shouldRubberBandInDirection(ScrollRight);
-
-    return true;
-}
-
-} // namespace WebCore
-
-#endif // USE(RUBBER_BANDING)