Source/platform/scroll/Scrollbar.cpp

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This source file includes following definitions.
create
m_isAlphaLocked
removeFromParent
parentScrollView
rootScrollView
scrollbarOverlayStyle
getTickmarks
isScrollableAreaActive
isScrollViewScrollbar
isLeftSideVerticalScrollbar
offsetDidChange
setProportion
updateThumb
updateThumbPosition
updateThumbProportion
paint
autoscrollTimerFired
thumbUnderMouse
autoscrollPressedPart
startTimerIfNeeded
stopTimerIfNeeded
pressedPartScrollDirection
pressedPartScrollGranularity
moveThumb
setHoveredPart
setPressedPart
gestureEvent
mouseMoved
mouseEntered
mouseExited
mouseUp
mouseDown
setFrameRect
setParent
setEnabled
isOverlayScrollbar
shouldParticipateInHitTesting
isWindowActive
invalidateRect
convertToContainingView
convertFromContainingView
convertToContainingView
convertFromContainingView
scrollableAreaCurrentPos
/*
 * Copyright (C) 2004, 2006, 2008 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 COMPUTER, INC. ``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 COMPUTER, INC. OR
 * 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 "platform/scroll/Scrollbar.h"

#include <algorithm>
#include "platform/graphics/GraphicsContext.h"
#include "platform/PlatformGestureEvent.h"
#include "platform/PlatformMouseEvent.h"
#include "platform/scroll/ScrollAnimator.h"
#include "platform/scroll/ScrollView.h"
#include "platform/scroll/ScrollableArea.h"
#include "platform/scroll/ScrollbarTheme.h"

using namespace std;

#if OS(POSIX) && !OS(MACOSX)
// The position of the scrollbar thumb affects the appearance of the steppers, so
// when the thumb moves, we have to invalidate them for painting.
#define THUMB_POSITION_AFFECTS_BUTTONS
#endif

namespace WebCore {

PassRefPtr<Scrollbar> Scrollbar::create(ScrollableArea* scrollableArea, ScrollbarOrientation orientation, ScrollbarControlSize size)
{
    return adoptRef(new Scrollbar(scrollableArea, orientation, size));
}

Scrollbar::Scrollbar(ScrollableArea* scrollableArea, ScrollbarOrientation orientation, ScrollbarControlSize controlSize, ScrollbarTheme* theme)
    : m_scrollableArea(scrollableArea)
    , m_orientation(orientation)
    , m_controlSize(controlSize)
    , m_theme(theme)
    , m_visibleSize(0)
    , m_totalSize(0)
    , m_currentPos(0)
    , m_dragOrigin(0)
    , m_hoveredPart(NoPart)
    , m_pressedPart(NoPart)
    , m_pressedPos(0)
    , m_scrollPos(0)
    , m_draggingDocument(false)
    , m_documentDragPos(0)
    , m_enabled(true)
    , m_scrollTimer(this, &Scrollbar::autoscrollTimerFired)
    , m_overlapsResizer(false)
    , m_suppressInvalidation(false)
    , m_isAlphaLocked(false)
{
    if (!m_theme)
        m_theme = ScrollbarTheme::theme();

    m_theme->registerScrollbar(this);

    // FIXME: This is ugly and would not be necessary if we fix cross-platform code to actually query for
    // scrollbar thickness and use it when sizing scrollbars (rather than leaving one dimension of the scrollbar
    // alone when sizing).
    int thickness = m_theme->scrollbarThickness(controlSize);
    Widget::setFrameRect(IntRect(0, 0, thickness, thickness));

    m_currentPos = scrollableAreaCurrentPos();
}

Scrollbar::~Scrollbar()
{
    stopTimerIfNeeded();

    m_theme->unregisterScrollbar(this);
}

void Scrollbar::removeFromParent()
{
    if (parent())
        toScrollView(parent())->removeChild(this);
}

ScrollView* Scrollbar::parentScrollView() const
{
    return toScrollView(parent());
}

ScrollView* Scrollbar::rootScrollView() const
{
    return toScrollView(root());
}

ScrollbarOverlayStyle Scrollbar::scrollbarOverlayStyle() const
{
    return m_scrollableArea ? m_scrollableArea->scrollbarOverlayStyle() : ScrollbarOverlayStyleDefault;
}

void Scrollbar::getTickmarks(Vector<IntRect>& tickmarks) const
{
    if (m_scrollableArea)
        m_scrollableArea->getTickmarks(tickmarks);
}

bool Scrollbar::isScrollableAreaActive() const
{
    return m_scrollableArea && m_scrollableArea->isActive();
}

bool Scrollbar::isScrollViewScrollbar() const
{
    return parent() && parent()->isFrameView() && toScrollView(parent())->isScrollViewScrollbar(this);
}

bool Scrollbar::isLeftSideVerticalScrollbar() const
{
    if (m_orientation == VerticalScrollbar && m_scrollableArea)
        return m_scrollableArea->shouldPlaceVerticalScrollbarOnLeft();
    return false;
}

void Scrollbar::offsetDidChange()
{
    ASSERT(m_scrollableArea);

    float position = scrollableAreaCurrentPos();
    if (position == m_currentPos)
        return;

    int oldThumbPosition = theme()->thumbPosition(this);
    m_currentPos = position;
    updateThumbPosition();
    if (m_pressedPart == ThumbPart)
        setPressedPos(m_pressedPos + theme()->thumbPosition(this) - oldThumbPosition);
}

void Scrollbar::setProportion(int visibleSize, int totalSize)
{
    if (visibleSize == m_visibleSize && totalSize == m_totalSize)
        return;

    m_visibleSize = visibleSize;
    m_totalSize = totalSize;

    updateThumbProportion();
}

void Scrollbar::updateThumb()
{
#ifdef THUMB_POSITION_AFFECTS_BUTTONS
    invalidate();
#else
    theme()->invalidateParts(this, ForwardTrackPart | BackTrackPart | ThumbPart);
#endif
}

void Scrollbar::updateThumbPosition()
{
    updateThumb();
}

void Scrollbar::updateThumbProportion()
{
    updateThumb();
}

void Scrollbar::paint(GraphicsContext* context, const IntRect& damageRect)
{
    if (context->updatingControlTints() && theme()->supportsControlTints()) {
        invalidate();
        return;
    }

    if (context->paintingDisabled() || !frameRect().intersects(damageRect))
        return;

    if (!theme()->paint(this, context, damageRect))
        Widget::paint(context, damageRect);
}

void Scrollbar::autoscrollTimerFired(Timer<Scrollbar>*)
{
    autoscrollPressedPart(theme()->autoscrollTimerDelay());
}

static bool thumbUnderMouse(Scrollbar* scrollbar)
{
    int thumbPos = scrollbar->theme()->trackPosition(scrollbar) + scrollbar->theme()->thumbPosition(scrollbar);
    int thumbLength = scrollbar->theme()->thumbLength(scrollbar);
    return scrollbar->pressedPos() >= thumbPos && scrollbar->pressedPos() < thumbPos + thumbLength;
}

void Scrollbar::autoscrollPressedPart(double delay)
{
    // Don't do anything for the thumb or if nothing was pressed.
    if (m_pressedPart == ThumbPart || m_pressedPart == NoPart)
        return;

    // Handle the track.
    if ((m_pressedPart == BackTrackPart || m_pressedPart == ForwardTrackPart) && thumbUnderMouse(this)) {
        theme()->invalidatePart(this, m_pressedPart);
        setHoveredPart(ThumbPart);
        return;
    }

    // Handle the arrows and track.
    if (m_scrollableArea && m_scrollableArea->scroll(pressedPartScrollDirection(), pressedPartScrollGranularity()))
        startTimerIfNeeded(delay);
}

void Scrollbar::startTimerIfNeeded(double delay)
{
    // Don't do anything for the thumb.
    if (m_pressedPart == ThumbPart)
        return;

    // Handle the track.  We halt track scrolling once the thumb is level
    // with us.
    if ((m_pressedPart == BackTrackPart || m_pressedPart == ForwardTrackPart) && thumbUnderMouse(this)) {
        theme()->invalidatePart(this, m_pressedPart);
        setHoveredPart(ThumbPart);
        return;
    }

    // We can't scroll if we've hit the beginning or end.
    ScrollDirection dir = pressedPartScrollDirection();
    if (dir == ScrollUp || dir == ScrollLeft) {
        if (m_currentPos == 0)
            return;
    } else {
        if (m_currentPos == maximum())
            return;
    }

    m_scrollTimer.startOneShot(delay, FROM_HERE);
}

void Scrollbar::stopTimerIfNeeded()
{
    if (m_scrollTimer.isActive())
        m_scrollTimer.stop();
}

ScrollDirection Scrollbar::pressedPartScrollDirection()
{
    if (m_orientation == HorizontalScrollbar) {
        if (m_pressedPart == BackButtonStartPart || m_pressedPart == BackButtonEndPart || m_pressedPart == BackTrackPart)
            return ScrollLeft;
        return ScrollRight;
    } else {
        if (m_pressedPart == BackButtonStartPart || m_pressedPart == BackButtonEndPart || m_pressedPart == BackTrackPart)
            return ScrollUp;
        return ScrollDown;
    }
}

ScrollGranularity Scrollbar::pressedPartScrollGranularity()
{
    if (m_pressedPart == BackButtonStartPart || m_pressedPart == BackButtonEndPart ||  m_pressedPart == ForwardButtonStartPart || m_pressedPart == ForwardButtonEndPart)
        return ScrollByLine;
    return ScrollByPage;
}

void Scrollbar::moveThumb(int pos, bool draggingDocument)
{
    if (!m_scrollableArea)
        return;

    int delta = pos - m_pressedPos;

    if (draggingDocument) {
        if (m_draggingDocument)
            delta = pos - m_documentDragPos;
        m_draggingDocument = true;
        FloatPoint currentPosition = m_scrollableArea->scrollAnimator()->currentPosition();
        float destinationPosition = (m_orientation == HorizontalScrollbar ? currentPosition.x() : currentPosition.y()) + delta;
        destinationPosition = m_scrollableArea->clampScrollPosition(m_orientation, destinationPosition);
        m_scrollableArea->scrollToOffsetWithoutAnimation(m_orientation, destinationPosition);
        m_documentDragPos = pos;
        return;
    }

    if (m_draggingDocument) {
        delta += m_pressedPos - m_documentDragPos;
        m_draggingDocument = false;
    }

    // Drag the thumb.
    int thumbPos = theme()->thumbPosition(this);
    int thumbLen = theme()->thumbLength(this);
    int trackLen = theme()->trackLength(this);
    if (delta > 0)
        delta = min(trackLen - thumbLen - thumbPos, delta);
    else if (delta < 0)
        delta = max(-thumbPos, delta);

    float minPos = m_scrollableArea->minimumScrollPosition(m_orientation);
    float maxPos = m_scrollableArea->maximumScrollPosition(m_orientation);
    if (delta) {
        float newPosition = static_cast<float>(thumbPos + delta) * (maxPos - minPos) / (trackLen - thumbLen) + minPos;
        m_scrollableArea->scrollToOffsetWithoutAnimation(m_orientation, newPosition);
    }
}

void Scrollbar::setHoveredPart(ScrollbarPart part)
{
    if (part == m_hoveredPart)
        return;

    if ((m_hoveredPart == NoPart || part == NoPart) && theme()->invalidateOnMouseEnterExit())
        invalidate();  // Just invalidate the whole scrollbar, since the buttons at either end change anyway.
    else if (m_pressedPart == NoPart) {  // When there's a pressed part, we don't draw a hovered state, so there's no reason to invalidate.
        theme()->invalidatePart(this, part);
        theme()->invalidatePart(this, m_hoveredPart);
    }
    m_hoveredPart = part;
}

void Scrollbar::setPressedPart(ScrollbarPart part)
{
    if (m_pressedPart != NoPart)
        theme()->invalidatePart(this, m_pressedPart);
    m_pressedPart = part;
    if (m_pressedPart != NoPart)
        theme()->invalidatePart(this, m_pressedPart);
    else if (m_hoveredPart != NoPart)  // When we no longer have a pressed part, we can start drawing a hovered state on the hovered part.
        theme()->invalidatePart(this, m_hoveredPart);
}

bool Scrollbar::gestureEvent(const PlatformGestureEvent& evt)
{
    switch (evt.type()) {
    case PlatformEvent::GestureTapDown:
        setPressedPart(theme()->hitTest(this, evt.position()));
        m_pressedPos = orientation() == HorizontalScrollbar ? convertFromContainingWindow(evt.position()).x() : convertFromContainingWindow(evt.position()).y();
        return true;
    case PlatformEvent::GestureTapDownCancel:
    case PlatformEvent::GestureScrollBegin:
        if (m_pressedPart != ThumbPart)
            return false;
        m_scrollPos = m_pressedPos;
        return true;
    case PlatformEvent::GestureScrollUpdate:
    case PlatformEvent::GestureScrollUpdateWithoutPropagation:
        if (m_pressedPart != ThumbPart)
            return false;
        m_scrollPos += orientation() == HorizontalScrollbar ? evt.deltaX() : evt.deltaY();
        moveThumb(m_scrollPos, false);
        return true;
    case PlatformEvent::GestureScrollEnd:
    case PlatformEvent::GestureLongPress:
    case PlatformEvent::GestureFlingStart:
        m_scrollPos = 0;
        m_pressedPos = 0;
        setPressedPart(NoPart);
        return false;
    case PlatformEvent::GestureTap: {
        if (m_pressedPart != ThumbPart && m_pressedPart != NoPart && m_scrollableArea
            && m_scrollableArea->scroll(pressedPartScrollDirection(), pressedPartScrollGranularity())) {
            return true;
        }
        m_scrollPos = 0;
        m_pressedPos = 0;
        setPressedPart(NoPart);
        return false;
    }
    default:
        // By default, we assume that gestures don't deselect the scrollbar.
        return true;
    }
}

void Scrollbar::mouseMoved(const PlatformMouseEvent& evt)
{
    if (m_pressedPart == ThumbPart) {
        if (theme()->shouldSnapBackToDragOrigin(this, evt)) {
            if (m_scrollableArea)
                m_scrollableArea->scrollToOffsetWithoutAnimation(m_orientation, m_dragOrigin);
        } else {
            moveThumb(m_orientation == HorizontalScrollbar ?
                      convertFromContainingWindow(evt.position()).x() :
                      convertFromContainingWindow(evt.position()).y(), theme()->shouldDragDocumentInsteadOfThumb(this, evt));
        }
        return;
    }

    if (m_pressedPart != NoPart)
        m_pressedPos = orientation() == HorizontalScrollbar ? convertFromContainingWindow(evt.position()).x() : convertFromContainingWindow(evt.position()).y();

    ScrollbarPart part = theme()->hitTest(this, evt.position());
    if (part != m_hoveredPart) {
        if (m_pressedPart != NoPart) {
            if (part == m_pressedPart) {
                // The mouse is moving back over the pressed part.  We
                // need to start up the timer action again.
                startTimerIfNeeded(theme()->autoscrollTimerDelay());
                theme()->invalidatePart(this, m_pressedPart);
            } else if (m_hoveredPart == m_pressedPart) {
                // The mouse is leaving the pressed part.  Kill our timer
                // if needed.
                stopTimerIfNeeded();
                theme()->invalidatePart(this, m_pressedPart);
            }
        }

        setHoveredPart(part);
    }

    return;
}

void Scrollbar::mouseEntered()
{
    if (m_scrollableArea)
        m_scrollableArea->mouseEnteredScrollbar(this);
}

void Scrollbar::mouseExited()
{
    if (m_scrollableArea)
        m_scrollableArea->mouseExitedScrollbar(this);
    setHoveredPart(NoPart);
}

void Scrollbar::mouseUp(const PlatformMouseEvent& mouseEvent)
{
    setPressedPart(NoPart);
    m_pressedPos = 0;
    m_draggingDocument = false;
    stopTimerIfNeeded();

    if (m_scrollableArea) {
        // m_hoveredPart won't be updated until the next mouseMoved or mouseDown, so we have to hit test
        // to really know if the mouse has exited the scrollbar on a mouseUp.
        ScrollbarPart part = theme()->hitTest(this, mouseEvent.position());
        if (part == NoPart)
            m_scrollableArea->mouseExitedScrollbar(this);
    }
}

void Scrollbar::mouseDown(const PlatformMouseEvent& evt)
{
    // Early exit for right click
    if (evt.button() == RightButton)
        return;

    setPressedPart(theme()->hitTest(this, evt.position()));
    int pressedPos = orientation() == HorizontalScrollbar ? convertFromContainingWindow(evt.position()).x() : convertFromContainingWindow(evt.position()).y();

    if ((m_pressedPart == BackTrackPart || m_pressedPart == ForwardTrackPart) && theme()->shouldCenterOnThumb(this, evt)) {
        setHoveredPart(ThumbPart);
        setPressedPart(ThumbPart);
        m_dragOrigin = m_currentPos;
        int thumbLen = theme()->thumbLength(this);
        int desiredPos = pressedPos;
        // Set the pressed position to the middle of the thumb so that when we do the move, the delta
        // will be from the current pixel position of the thumb to the new desired position for the thumb.
        m_pressedPos = theme()->trackPosition(this) + theme()->thumbPosition(this) + thumbLen / 2;
        moveThumb(desiredPos);
        return;
    } else if (m_pressedPart == ThumbPart)
        m_dragOrigin = m_currentPos;

    m_pressedPos = pressedPos;

    autoscrollPressedPart(theme()->initialAutoscrollTimerDelay());
}

void Scrollbar::setFrameRect(const IntRect& rect)
{
    // Get our window resizer rect and see if we overlap. Adjust to avoid the overlap
    // if necessary.
    IntRect adjustedRect(rect);
    bool overlapsResizer = false;
    ScrollView* view = parentScrollView();
    if (view && !rect.isEmpty() && !view->windowResizerRect().isEmpty()) {
        IntRect resizerRect = view->convertFromContainingWindow(view->windowResizerRect());
        if (rect.intersects(resizerRect)) {
            if (orientation() == HorizontalScrollbar) {
                int overlap = rect.maxX() - resizerRect.x();
                if (overlap > 0 && resizerRect.maxX() >= rect.maxX()) {
                    adjustedRect.setWidth(rect.width() - overlap);
                    overlapsResizer = true;
                }
            } else {
                int overlap = rect.maxY() - resizerRect.y();
                if (overlap > 0 && resizerRect.maxY() >= rect.maxY()) {
                    adjustedRect.setHeight(rect.height() - overlap);
                    overlapsResizer = true;
                }
            }
        }
    }
    if (overlapsResizer != m_overlapsResizer) {
        m_overlapsResizer = overlapsResizer;
        if (view)
            view->adjustScrollbarsAvoidingResizerCount(m_overlapsResizer ? 1 : -1);
    }

    Widget::setFrameRect(adjustedRect);
}

void Scrollbar::setParent(Widget* parentView)
{
    if (!parentView && m_overlapsResizer && parentScrollView())
        parentScrollView()->adjustScrollbarsAvoidingResizerCount(-1);
    Widget::setParent(parentView);
}

void Scrollbar::setEnabled(bool e)
{
    if (m_enabled == e)
        return;
    m_enabled = e;
    theme()->updateEnabledState(this);
    invalidate();
}

bool Scrollbar::isOverlayScrollbar() const
{
    return m_theme->usesOverlayScrollbars();
}

bool Scrollbar::shouldParticipateInHitTesting()
{
    // Non-overlay scrollbars should always participate in hit testing.
    if (!isOverlayScrollbar())
        return true;
    return m_scrollableArea->scrollAnimator()->shouldScrollbarParticipateInHitTesting(this);
}

bool Scrollbar::isWindowActive() const
{
    return m_scrollableArea && m_scrollableArea->isActive();
}

void Scrollbar::invalidateRect(const IntRect& rect)
{
    if (suppressInvalidation())
        return;

    if (m_scrollableArea)
        m_scrollableArea->invalidateScrollbar(this, rect);
}

IntRect Scrollbar::convertToContainingView(const IntRect& localRect) const
{
    if (m_scrollableArea)
        return m_scrollableArea->convertFromScrollbarToContainingView(this, localRect);

    return Widget::convertToContainingView(localRect);
}

IntRect Scrollbar::convertFromContainingView(const IntRect& parentRect) const
{
    if (m_scrollableArea)
        return m_scrollableArea->convertFromContainingViewToScrollbar(this, parentRect);

    return Widget::convertFromContainingView(parentRect);
}

IntPoint Scrollbar::convertToContainingView(const IntPoint& localPoint) const
{
    if (m_scrollableArea)
        return m_scrollableArea->convertFromScrollbarToContainingView(this, localPoint);

    return Widget::convertToContainingView(localPoint);
}

IntPoint Scrollbar::convertFromContainingView(const IntPoint& parentPoint) const
{
    if (m_scrollableArea)
        return m_scrollableArea->convertFromContainingViewToScrollbar(this, parentPoint);

    return Widget::convertFromContainingView(parentPoint);
}

float Scrollbar::scrollableAreaCurrentPos() const
{
    if (!m_scrollableArea)
        return 0;

    if (m_orientation == HorizontalScrollbar)
        return m_scrollableArea->scrollPosition().x() - m_scrollableArea->minimumScrollPosition().x();

    return m_scrollableArea->scrollPosition().y() - m_scrollableArea->minimumScrollPosition().y();
}

} // namespace WebCore
/* [<][>][^][v][top][bottom][index][help] */
root/Source/platform/scroll/Scrollbar.cpp

DEFINITIONS
