SliderThumbElement.cpp   [plain text]

/*
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 * Copyright (C) 2010 Google Inc. All rights reserved.
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 * contributors may be used to endorse or promote products derived from
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 *
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#include "config.h"
#include "SliderThumbElement.h"

#include "CSSValueKeywords.h"
#include "ElementShadow.h"
#include "Event.h"
#include "EventHandler.h"
#include "Frame.h"
#include "HTMLInputElement.h"
#include "HTMLParserIdioms.h"
#include "MouseEvent.h"
#include "RenderFlexibleBox.h"
#include "RenderSlider.h"
#include "RenderTheme.h"
#include "ShadowRoot.h"
#include "StepRange.h"
#include <wtf/MathExtras.h>

#if PLATFORM(IOS)
#if ENABLE(TOUCH_EVENTS)
#include "Document.h"
#include "Page.h"
#include "TouchEvent.h"
#endif
#endif

using namespace std;

namespace WebCore {

using namespace HTMLNames;

inline static Decimal sliderPosition(HTMLInputElement* element)
{
    const StepRange stepRange(element->createStepRange(RejectAny));
    const Decimal oldValue = parseToDecimalForNumberType(element->value(), stepRange.defaultValue());
    return stepRange.proportionFromValue(stepRange.clampValue(oldValue));
}

inline static bool hasVerticalAppearance(HTMLInputElement* input)
{
    ASSERT(input->renderer());
    RenderStyle* sliderStyle = input->renderer()->style();

#if ENABLE(VIDEO)
    if (sliderStyle->appearance() == MediaVolumeSliderPart && input->renderer()->theme()->usesVerticalVolumeSlider())
        return true;
#endif

    return sliderStyle->appearance() == SliderVerticalPart;
}

SliderThumbElement* sliderThumbElementOf(Node* node)
{
    ASSERT(node);
    ShadowRoot* shadow = node->toInputElement()->userAgentShadowRoot();
    ASSERT(shadow);
    Node* thumb = shadow->firstChild()->firstChild()->firstChild();
    ASSERT(thumb);
    return toSliderThumbElement(thumb);
}

HTMLElement* sliderTrackElementOf(Node* node)
{
    ASSERT(node);
    ShadowRoot* shadow = node->toInputElement()->userAgentShadowRoot();
    ASSERT(shadow);
    Node* track = shadow->firstChild()->firstChild();
    ASSERT(track);
    return toHTMLElement(track);
}

// --------------------------------

RenderSliderThumb::RenderSliderThumb(SliderThumbElement* element)
    : RenderBlock(element)
{
}

void RenderSliderThumb::updateAppearance(RenderStyle* parentStyle)
{
    if (parentStyle->appearance() == SliderVerticalPart)
        style()->setAppearance(SliderThumbVerticalPart);
    else if (parentStyle->appearance() == SliderHorizontalPart)
        style()->setAppearance(SliderThumbHorizontalPart);
    else if (parentStyle->appearance() == MediaSliderPart)
        style()->setAppearance(MediaSliderThumbPart);
    else if (parentStyle->appearance() == MediaVolumeSliderPart)
        style()->setAppearance(MediaVolumeSliderThumbPart);
    else if (parentStyle->appearance() == MediaFullScreenVolumeSliderPart)
        style()->setAppearance(MediaFullScreenVolumeSliderThumbPart);
    if (style()->hasAppearance())
        theme()->adjustSliderThumbSize(style(), toElement(node()));
}

bool RenderSliderThumb::isSliderThumb() const
{
    return true;
}

// --------------------------------

// FIXME: Find a way to cascade appearance and adjust heights, and get rid of this class.
// http://webkit.org/b/62535
class RenderSliderContainer : public RenderFlexibleBox {
public:
    RenderSliderContainer(SliderContainerElement* element)
        : RenderFlexibleBox(element) { }
public:
    virtual void computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues&) const OVERRIDE;

private:
    virtual void layout() OVERRIDE;
};

void RenderSliderContainer::computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues& computedValues) const
{
    HTMLInputElement* input = node()->shadowHost()->toInputElement();
    bool isVertical = hasVerticalAppearance(input);

#if ENABLE(DATALIST_ELEMENT)
    if (input->renderer()->isSlider() && !isVertical && input->list()) {
        int offsetFromCenter = theme()->sliderTickOffsetFromTrackCenter();
        LayoutUnit trackHeight = 0;
        if (offsetFromCenter < 0)
            trackHeight = -2 * offsetFromCenter;
        else {
            int tickLength = theme()->sliderTickSize().height();
            trackHeight = 2 * (offsetFromCenter + tickLength);
        }
        float zoomFactor = style()->effectiveZoom();
        if (zoomFactor != 1.0)
            trackHeight *= zoomFactor;

        RenderBox::computeLogicalHeight(trackHeight, logicalTop, computedValues);
        return;
    }
#endif
    if (isVertical)
        logicalHeight = RenderSlider::defaultTrackLength;
    RenderBox::computeLogicalHeight(logicalHeight, logicalTop, computedValues);
}

void RenderSliderContainer::layout()
{
    HTMLInputElement* input = node()->shadowHost()->toInputElement();
    bool isVertical = hasVerticalAppearance(input);
    style()->setFlexDirection(isVertical ? FlowColumn : FlowRow);
    TextDirection oldTextDirection = style()->direction();
    if (isVertical) {
        // FIXME: Work around rounding issues in RTL vertical sliders. We want them to
        // render identically to LTR vertical sliders. We can remove this work around when
        // subpixel rendering is enabled on all ports.
        style()->setDirection(LTR);
    }

    RenderBox* thumb = input->sliderThumbElement() ? input->sliderThumbElement()->renderBox() : 0;
    RenderBox* track = input->sliderTrackElement() ? input->sliderTrackElement()->renderBox() : 0;
    // Force a layout to reset the position of the thumb so the code below doesn't move the thumb to the wrong place.
    // FIXME: Make a custom Render class for the track and move the thumb positioning code there.
    if (track)
        track->setChildNeedsLayout(true, MarkOnlyThis);

    RenderFlexibleBox::layout();

    style()->setDirection(oldTextDirection);
    // These should always exist, unless someone mutates the shadow DOM (e.g., in the inspector).
    if (!thumb || !track)
        return;

    double percentageOffset = sliderPosition(input).toDouble();
    LayoutUnit availableExtent = isVertical ? track->contentHeight() : track->contentWidth();
    availableExtent -= isVertical ? thumb->height() : thumb->width();
    LayoutUnit offset = percentageOffset * availableExtent;
    LayoutPoint thumbLocation = thumb->location();
    if (isVertical)
        thumbLocation.setY(thumbLocation.y() + track->contentHeight() - thumb->height() - offset);
    else if (style()->isLeftToRightDirection())
        thumbLocation.setX(thumbLocation.x() + offset);
    else
        thumbLocation.setX(thumbLocation.x() - offset);
    thumb->setLocation(thumbLocation);
}

// --------------------------------

void SliderThumbElement::setPositionFromValue()
{
    // Since the code to calculate position is in the RenderSliderThumb layout
    // path, we don't actually update the value here. Instead, we poke at the
    // renderer directly to trigger layout.
    if (renderer())
        renderer()->setNeedsLayout(true);
}

RenderObject* SliderThumbElement::createRenderer(RenderArena* arena, RenderStyle*)
{
    return new (arena) RenderSliderThumb(this);
}

bool SliderThumbElement::isDisabledFormControl() const
{
    HTMLInputElement* input = hostInput();
    return !input || input->isDisabledFormControl();
}

bool SliderThumbElement::matchesReadOnlyPseudoClass() const
{
    HTMLInputElement* input = hostInput();
    return input && input->matchesReadOnlyPseudoClass();
}

bool SliderThumbElement::matchesReadWritePseudoClass() const
{
    HTMLInputElement* input = hostInput();
    return input && input->matchesReadWritePseudoClass();
}

Element* SliderThumbElement::focusDelegate()
{
    return hostInput();
}

void SliderThumbElement::dragFrom(const LayoutPoint& point)
{
    RefPtr<SliderThumbElement> protect(this);
    setPositionFromPoint(point);
#if !PLATFORM(IOS)
    startDragging();
#endif
}

void SliderThumbElement::setPositionFromPoint(const LayoutPoint& point)
{
    RefPtr<HTMLInputElement> input(hostInput());
    HTMLElement* trackElement = sliderTrackElementOf(input.get());

    if (!input->renderer() || !renderBox() || !trackElement->renderBox())
        return;

    input->setTextAsOfLastFormControlChangeEvent(input->value());
    LayoutPoint offset = roundedLayoutPoint(input->renderer()->absoluteToLocal(point, UseTransforms));
    bool isVertical = hasVerticalAppearance(input.get());
    bool isLeftToRightDirection = renderBox()->style()->isLeftToRightDirection();
    LayoutUnit trackSize;
    LayoutUnit position;
    LayoutUnit currentPosition;
    // We need to calculate currentPosition from absolute points becaue the
    // renderer for this node is usually on a layer and renderBox()->x() and
    // y() are unusable.
    // FIXME: This should probably respect transforms.
    LayoutPoint absoluteThumbOrigin = renderBox()->absoluteBoundingBoxRectIgnoringTransforms().location();
    LayoutPoint absoluteSliderContentOrigin = roundedLayoutPoint(input->renderer()->localToAbsolute());
    IntRect trackBoundingBox = trackElement->renderer()->absoluteBoundingBoxRectIgnoringTransforms();
    IntRect inputBoundingBox = input->renderer()->absoluteBoundingBoxRectIgnoringTransforms();
    if (isVertical) {
        trackSize = trackElement->renderBox()->contentHeight() - renderBox()->height();
        position = offset.y() - renderBox()->height() / 2 - trackBoundingBox.y() + inputBoundingBox.y() - renderBox()->marginBottom();
        currentPosition = absoluteThumbOrigin.y() - absoluteSliderContentOrigin.y();
    } else {
        trackSize = trackElement->renderBox()->contentWidth() - renderBox()->width();
        position = offset.x() - renderBox()->width() / 2 - trackBoundingBox.x() + inputBoundingBox.x();
        position -= isLeftToRightDirection ? renderBox()->marginLeft() : renderBox()->marginRight();
        currentPosition = absoluteThumbOrigin.x() - absoluteSliderContentOrigin.x();
    }
    position = max<LayoutUnit>(0, min(position, trackSize));
    const Decimal ratio = Decimal::fromDouble(static_cast<double>(position) / trackSize);
    const Decimal fraction = isVertical || !isLeftToRightDirection ? Decimal(1) - ratio : ratio;
    StepRange stepRange(input->createStepRange(RejectAny));
    Decimal value = stepRange.clampValue(stepRange.valueFromProportion(fraction));

#if ENABLE(DATALIST_ELEMENT)
    const LayoutUnit snappingThreshold = renderer()->theme()->sliderTickSnappingThreshold();
    if (snappingThreshold > 0) {
        Decimal closest = input->findClosestTickMarkValue(value);
        if (closest.isFinite()) {
            double closestFraction = stepRange.proportionFromValue(closest).toDouble();
            double closestRatio = isVertical || !isLeftToRightDirection ? 1.0 - closestFraction : closestFraction;
            LayoutUnit closestPosition = trackSize * closestRatio;
            if ((closestPosition - position).abs() <= snappingThreshold)
                value = closest;
        }
    }
#endif

    String valueString = serializeForNumberType(value);
    if (valueString == input->value())
        return;

    // FIXME: This is no longer being set from renderer. Consider updating the method name.
    input->setValueFromRenderer(valueString);
    if (renderer())
        renderer()->setNeedsLayout(true);
    input->dispatchFormControlChangeEvent();
}

void SliderThumbElement::startDragging()
{
    if (Frame* frame = document()->frame()) {
        frame->eventHandler()->setCapturingMouseEventsNode(this);
        m_inDragMode = true;
    }
}

void SliderThumbElement::stopDragging()
{
    if (!m_inDragMode)
        return;

    if (Frame* frame = document()->frame())
        frame->eventHandler()->setCapturingMouseEventsNode(0);
    m_inDragMode = false;
    if (renderer())
        renderer()->setNeedsLayout(true);
}

#if !PLATFORM(IOS)
void SliderThumbElement::defaultEventHandler(Event* event)
{
    if (!event->isMouseEvent()) {
        HTMLDivElement::defaultEventHandler(event);
        return;
    }

    // FIXME: Should handle this readonly/disabled check in more general way.
    // Missing this kind of check is likely to occur elsewhere if adding it in each shadow element.
    HTMLInputElement* input = hostInput();
    if (!input || input->isDisabledOrReadOnly()) {
        stopDragging();
        HTMLDivElement::defaultEventHandler(event);
        return;
    }

    MouseEvent* mouseEvent = static_cast<MouseEvent*>(event);
    bool isLeftButton = mouseEvent->button() == LeftButton;
    const AtomicString& eventType = event->type();

    // We intentionally do not call event->setDefaultHandled() here because
    // MediaControlTimelineElement::defaultEventHandler() wants to handle these
    // mouse events.
    if (eventType == eventNames().mousedownEvent && isLeftButton) {
        startDragging();
        return;
    } else if (eventType == eventNames().mouseupEvent && isLeftButton) {
        stopDragging();
        return;
    } else if (eventType == eventNames().mousemoveEvent) {
        if (m_inDragMode)
            setPositionFromPoint(mouseEvent->absoluteLocation());
        return;
    }

    HTMLDivElement::defaultEventHandler(event);
}
#endif

#if !PLATFORM(IOS)
bool SliderThumbElement::willRespondToMouseMoveEvents()
{
    const HTMLInputElement* input = hostInput();
    if (input && !input->isDisabledOrReadOnly() && m_inDragMode)
        return true;

    return HTMLDivElement::willRespondToMouseMoveEvents();
}

bool SliderThumbElement::willRespondToMouseClickEvents()
{
    const HTMLInputElement* input = hostInput();
    if (input && !input->isDisabledOrReadOnly())
        return true;

    return HTMLDivElement::willRespondToMouseClickEvents();
}
#endif // !PLATFORM(IOS)

void SliderThumbElement::detach(const AttachContext& context)
{
    if (m_inDragMode) {
        if (Frame* frame = document()->frame())
            frame->eventHandler()->setCapturingMouseEventsNode(0);
    }
#if PLATFORM(IOS)
#if ENABLE(TOUCH_EVENTS)
    unregisterForTouchEvents();
#endif
#endif
    HTMLDivElement::detach(context);
}

#if PLATFORM(IOS)
#if ENABLE(TOUCH_EVENTS)
unsigned SliderThumbElement::exclusiveTouchIdentifier() const
{
    return m_exclusiveTouchIdentifier;
}

void SliderThumbElement::setExclusiveTouchIdentifier(unsigned identifier)
{
    ASSERT(m_exclusiveTouchIdentifier == NoIdentifier);
    m_exclusiveTouchIdentifier = identifier;
}

void SliderThumbElement::clearExclusiveTouchIdentifier()
{
    m_exclusiveTouchIdentifier = NoIdentifier;
}

static Touch* findTouchWithIdentifier(TouchList* list, unsigned identifier)
{
    for (unsigned i = 0; i < list->length(); ++i) {
        Touch* touch = list->item(i);
        if (touch->identifier() == identifier)
            return touch;
    }

    return 0;
}

void SliderThumbElement::handleTouchStart(TouchEvent* touchEvent)
{
    TouchList* targetTouches = touchEvent->targetTouches();
    if (targetTouches->length() != 1)
        return;

    // Ignore the touch if it is not really inside the thumb.
    Touch* touch = targetTouches->item(0);
    IntRect boundingBox = renderer()->absoluteBoundingBoxRect();
    if (!boundingBox.contains(touch->pageX(), touch->pageY()))
        return;

    setExclusiveTouchIdentifier(touch->identifier());

    startDragging();
    touchEvent->setDefaultHandled();
}

void SliderThumbElement::handleTouchMove(TouchEvent* touchEvent)
{
    unsigned identifier = exclusiveTouchIdentifier();
    if (identifier == NoIdentifier)
        return;

    Touch* touch = findTouchWithIdentifier(touchEvent->targetTouches(), identifier);
    if (!touch)
        return;

    if (m_inDragMode)
        setPositionFromPoint(IntPoint(touch->pageX(), touch->pageY()));
    touchEvent->setDefaultHandled();
}

void SliderThumbElement::handleTouchEndAndCancel(TouchEvent* touchEvent)
{
    unsigned identifier = exclusiveTouchIdentifier();
    if (identifier == NoIdentifier)
        return;

    // If our exclusive touch still exists, it was not the touch
    // that ended, so we should not stop dragging.
    Touch* exclusiveTouch = findTouchWithIdentifier(touchEvent->targetTouches(), identifier);
    if (exclusiveTouch)
        return;

    clearExclusiveTouchIdentifier();

    stopDragging();
}

void SliderThumbElement::attach(const AttachContext& context)
{
    HTMLDivElement::attach(context);

    if (shouldAcceptTouchEvents())
        registerForTouchEvents();
}

void SliderThumbElement::handleTouchEvent(TouchEvent* touchEvent)
{
    HTMLInputElement* input = hostInput();
    if (input->isReadOnly() || input->isDisabledFormControl()) {
        clearExclusiveTouchIdentifier();
        stopDragging();
        touchEvent->setDefaultHandled();
        HTMLDivElement::defaultEventHandler(touchEvent);
        return;
    }

    const AtomicString& eventType = touchEvent->type();
    if (eventType == eventNames().touchstartEvent) {
        handleTouchStart(touchEvent);
        return;
    } else if (eventType == eventNames().touchendEvent || eventType == eventNames().touchcancelEvent) {
        handleTouchEndAndCancel(touchEvent);
        return;
    } else if (eventType == eventNames().touchmoveEvent) {
        handleTouchMove(touchEvent);
        return;
    }

    HTMLDivElement::defaultEventHandler(touchEvent);
}

bool SliderThumbElement::shouldAcceptTouchEvents()
{
    if (!attached())
        return false;

    if (isDisabledFormControl())
        return false;

    return true;
}

void SliderThumbElement::registerForTouchEvents()
{
    if (m_isRegisteredAsTouchEventListener)
        return;

    ASSERT(shouldAcceptTouchEvents());

    document()->addTouchEventListener(this);
    m_isRegisteredAsTouchEventListener = true;
}

void SliderThumbElement::unregisterForTouchEvents()
{
    if (!m_isRegisteredAsTouchEventListener)
        return;

    clearExclusiveTouchIdentifier();
    stopDragging();

    document()->removeTouchEventListener(this);
    m_isRegisteredAsTouchEventListener = false;
}

void SliderThumbElement::disabledAttributeChanged()
{
    if (shouldAcceptTouchEvents())
        registerForTouchEvents();
    else
        unregisterForTouchEvents();
}
#endif
#endif

HTMLInputElement* SliderThumbElement::hostInput() const
{
    // Only HTMLInputElement creates SliderThumbElement instances as its shadow nodes.
    // So, shadowHost() must be an HTMLInputElement.
    Element* host = shadowHost();
    return host ? host->toInputElement() : 0;
}

static const AtomicString& sliderThumbShadowPseudoId()
{
    DEFINE_STATIC_LOCAL(const AtomicString, sliderThumb, ("-webkit-slider-thumb", AtomicString::ConstructFromLiteral));
    return sliderThumb;
}

static const AtomicString& mediaSliderThumbShadowPseudoId()
{
    DEFINE_STATIC_LOCAL(const AtomicString, mediaSliderThumb, ("-webkit-media-slider-thumb", AtomicString::ConstructFromLiteral));
    return mediaSliderThumb;
}

const AtomicString& SliderThumbElement::shadowPseudoId() const
{
    HTMLInputElement* input = hostInput();
    if (!input)
        return sliderThumbShadowPseudoId();

    RenderStyle* sliderStyle = input->renderer()->style();
    switch (sliderStyle->appearance()) {
    case MediaSliderPart:
    case MediaSliderThumbPart:
    case MediaVolumeSliderPart:
    case MediaVolumeSliderThumbPart:
    case MediaFullScreenVolumeSliderPart:
    case MediaFullScreenVolumeSliderThumbPart:
        return mediaSliderThumbShadowPseudoId();
    default:
        return sliderThumbShadowPseudoId();
    }
}

// --------------------------------

inline SliderContainerElement::SliderContainerElement(Document* document)
    : HTMLDivElement(HTMLNames::divTag, document)
{
}

PassRefPtr<SliderContainerElement> SliderContainerElement::create(Document* document)
{
    return adoptRef(new SliderContainerElement(document));
}

RenderObject* SliderContainerElement::createRenderer(RenderArena* arena, RenderStyle*)
{
    return new (arena) RenderSliderContainer(this);
}

const AtomicString& SliderContainerElement::shadowPseudoId() const
{
    DEFINE_STATIC_LOCAL(const AtomicString, mediaSliderContainer, ("-webkit-media-slider-container", AtomicString::ConstructFromLiteral));
    DEFINE_STATIC_LOCAL(const AtomicString, sliderContainer, ("-webkit-slider-container", AtomicString::ConstructFromLiteral));

    HTMLInputElement* input = shadowHost()->toInputElement();
    if (!input)
        return sliderContainer;

    RenderStyle* sliderStyle = input->renderer()->style();
    switch (sliderStyle->appearance()) {
    case MediaSliderPart:
    case MediaSliderThumbPart:
    case MediaVolumeSliderPart:
    case MediaVolumeSliderThumbPart:
    case MediaFullScreenVolumeSliderPart:
    case MediaFullScreenVolumeSliderThumbPart:
        return mediaSliderContainer;
    default:
        return sliderContainer;
    }
}

}