renderbox.cpp

linux下开源浏览器WebKit的源码,市面上的很多商用浏览器都是移植自WebKit

/*
 * Copyright (C) 1999 Lars Knoll ([e-mail])
 *           (C) 1999 Antti Koivisto ([e-mail])
 *           (C) 2005 Allan Sandfeld Jensen ([e-mail])
 *           (C) 2005, 2006 Samuel Weinig ([e-mail])
 * Copyright (C) 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 *
 */

#include "config.h"
#include "RenderBox.h"

#include "CachedImage.h"
#include "ChromeClient.h"
#include "Document.h"
#include "FrameView.h"
#include "GraphicsContext.h"
#include "htmlediting.h"
#include "HTMLElement.h"
#include "HTMLNames.h"
#include "ImageBuffer.h"
#include "FloatQuad.h"
#include "Frame.h"
#include "Page.h"
#include "RenderArena.h"
#include "RenderFlexibleBox.h"
#include "RenderInline.h"
#include "RenderLayer.h"
#include "RenderTableCell.h"
#include "RenderTheme.h"
#include "RenderView.h"
#include "TransformState.h"
#include <algorithm>
#include <math.h>

#if ENABLE(WML)
#include "WMLNames.h"
#endif

using namespace std;

namespace WebCore {

using namespace HTMLNames;

// Used by flexible boxes when flexing this element.
typedef WTF::HashMap<const RenderBox*, int> OverrideSizeMap;
static OverrideSizeMap* gOverrideSizeMap = 0;

bool RenderBox::s_hadOverflowClip = false;

RenderBox::RenderBox(Node* node)
    : RenderBoxModelObject(node)
    , m_marginLeft(0)
    , m_marginRight(0)
    , m_marginTop(0)
    , m_marginBottom(0)
    , m_minPrefWidth(-1)
    , m_maxPrefWidth(-1)
    , m_inlineBoxWrapper(0)
{
    setIsBox();
}

RenderBox::~RenderBox()
{
}

void RenderBox::destroy()
{
    // A lot of the code in this function is just pasted into
    // RenderWidget::destroy. If anything in this function changes,
    // be sure to fix RenderWidget::destroy() as well.
    if (hasOverrideSize())
        gOverrideSizeMap->remove(this);

    if (style() && (style()->height().isPercent() || style()->minHeight().isPercent() || style()->maxHeight().isPercent()))
        RenderBlock::removePercentHeightDescendant(this);

    RenderBoxModelObject::destroy();
}

void RenderBox::removeFloatingOrPositionedChildFromBlockLists()
{
    ASSERT(isFloatingOrPositioned());

    if (documentBeingDestroyed())
        return;

    if (isFloating()) {
        RenderBlock* outermostBlock = containingBlock();
        for (RenderBlock* p = outermostBlock; p && !p->isRenderView(); p = p->containingBlock()) {
            if (p->containsFloat(this))
                outermostBlock = p;
        }

        if (outermostBlock)
            outermostBlock->markAllDescendantsWithFloatsForLayout(this, false);
    }

    if (isPositioned()) {
        RenderObject* p;
        for (p = parent(); p; p = p->parent()) {
            if (p->isRenderBlock())
                toRenderBlock(p)->removePositionedObject(this);
        }
    }
}

void RenderBox::styleWillChange(StyleDifference diff, const RenderStyle* newStyle)
{
    s_hadOverflowClip = hasOverflowClip();

    if (style()) {
        // The background of the root element or the body element could propagate up to
        // the canvas.  Just dirty the entire canvas when our style changes substantially.
        if (diff >= StyleDifferenceRepaint && node() &&
                (node()->hasTagName(htmlTag) || node()->hasTagName(bodyTag)))
            view()->repaint();
        else if (parent() && !isText()) {
            // Do a repaint with the old style first, e.g., for example if we go from
            // having an outline to not having an outline.
            if (diff == StyleDifferenceRepaintLayer) {
                layer()->repaintIncludingDescendants();
                if (!(style()->clip() == newStyle->clip()))
                    layer()->clearClipRectsIncludingDescendants();
            } else if (diff == StyleDifferenceRepaint || newStyle->outlineSize() < style()->outlineSize())
                repaint();
        }

        if (diff == StyleDifferenceLayout) {
            // When a layout hint happens, we go ahead and do a repaint of the layer, since the layer could
            // end up being destroyed.
            if (hasLayer()) {
                if (style()->position() != newStyle->position() ||
                    style()->zIndex() != newStyle->zIndex() ||
                    style()->hasAutoZIndex() != newStyle->hasAutoZIndex() ||
                    !(style()->clip() == newStyle->clip()) ||
                    style()->hasClip() != newStyle->hasClip() ||
                    style()->opacity() != newStyle->opacity() ||
                    style()->transform() != newStyle->transform())
                layer()->repaintIncludingDescendants();
            } else if (newStyle->hasTransform() || newStyle->opacity() < 1) {
                // If we don't have a layer yet, but we are going to get one because of transform or opacity,
                //  then we need to repaint the old position of the object.
                repaint();
            }
        
            // When a layout hint happens and an object's position style changes, we have to do a layout
            // to dirty the render tree using the old position value now.
            if (parent() && style()->position() != newStyle->position()) {
                markContainingBlocksForLayout();
                if (style()->position() == StaticPosition)
                    repaint();
                if (isFloating() && !isPositioned() && (newStyle->position() == AbsolutePosition || newStyle->position() == FixedPosition))
                    removeFloatingOrPositionedChildFromBlockLists();
            }
        }
    }

    RenderBoxModelObject::styleWillChange(diff, newStyle);
}

void RenderBox::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
    RenderBoxModelObject::styleDidChange(diff, oldStyle);

    if (needsLayout() && oldStyle && (oldStyle->height().isPercent() || oldStyle->minHeight().isPercent() || oldStyle->maxHeight().isPercent()))
        RenderBlock::removePercentHeightDescendant(this);

    // If our zoom factor changes and we have a defined scrollLeft/Top, we need to adjust that value into the
    // new zoomed coordinate space.
    if (hasOverflowClip() && oldStyle && style() && oldStyle->effectiveZoom() != style()->effectiveZoom()) {
        int left = scrollLeft();
        if (left) {
            left = (left / oldStyle->effectiveZoom()) * style()->effectiveZoom();
            setScrollLeft(left);
        }
        int top = scrollTop();
        if (top) {
            top = (top / oldStyle->effectiveZoom()) * style()->effectiveZoom();
            setScrollTop(top);
        }
    }

    // Set the text color if we're the body.
    if (isBody())
        document()->setTextColor(style()->color());
}

void RenderBox::updateBoxModelInfoFromStyle()
{
    RenderBoxModelObject::updateBoxModelInfoFromStyle();

    bool isRootObject = isRoot();
    bool isViewObject = isRenderView();

    // The root and the RenderView always paint their backgrounds/borders.
    if (isRootObject || isViewObject)
        setHasBoxDecorations(true);

    setPositioned(style()->position() == AbsolutePosition || style()->position() == FixedPosition);
    setFloating(!isPositioned() && style()->isFloating());

    // We also handle <body> and <html>, whose overflow applies to the viewport.
    if (style()->overflowX() != OVISIBLE && !isRootObject && (isRenderBlock() || isTableRow() || isTableSection())) {
        bool boxHasOverflowClip = true;
        if (isBody()) {
            // Overflow on the body can propagate to the viewport under the following conditions.
            // (1) The root element is <html>.
            // (2) We are the primary <body> (can be checked by looking at document.body).
            // (3) The root element has visible overflow.
            if (document()->documentElement()->hasTagName(htmlTag) &&
                document()->body() == node() &&
                document()->documentElement()->renderer()->style()->overflowX() == OVISIBLE)
                boxHasOverflowClip = false;
        }
        
        // Check for overflow clip.
        // It's sufficient to just check one direction, since it's illegal to have visible on only one overflow value.
        if (boxHasOverflowClip) {
            if (!s_hadOverflowClip)
                // Erase the overflow
                repaint();
            setHasOverflowClip();
        }
    }

    setHasTransform(style()->hasTransformRelatedProperty());
    setHasReflection(style()->boxReflect());
}

void RenderBox::layout()
{
    ASSERT(needsLayout());

    RenderObject* child = firstChild();
    if (!child) {
        setNeedsLayout(false);
        return;
    }

    LayoutStateMaintainer statePusher(view(), this, IntSize(x(), y()));
    while (child) {
        child->layoutIfNeeded();
        ASSERT(!child->needsLayout());
        child = child->nextSibling();
    }
    statePusher.pop();
    setNeedsLayout(false);
}

// More IE extensions.  clientWidth and clientHeight represent the interior of an object
// excluding border and scrollbar.
int RenderBox::clientWidth() const
{
    return width() - borderLeft() - borderRight() - verticalScrollbarWidth();
}

int RenderBox::clientHeight() const
{
    return height() - borderTop() - borderBottom() - horizontalScrollbarHeight();
}

// scrollWidth/scrollHeight will be the same as overflowWidth/overflowHeight unless the
// object has overflow:hidden/scroll/auto specified and also has overflow.
// FIXME: It's not completely clear how scrollWidth/Height should behave for 
// objects with visible overflow.
int RenderBox::scrollWidth() const
{
    if (hasOverflowClip())
        return layer()->scrollWidth();
    return overflowWidth();
}

int RenderBox::scrollHeight() const
{
    if (hasOverflowClip())
        return layer()->scrollHeight();
    return overflowHeight();
}

int RenderBox::scrollLeft() const
{
    return hasOverflowClip() ? layer()->scrollXOffset() : 0;
}

int RenderBox::scrollTop() const
{
    return hasOverflowClip() ? layer()->scrollYOffset() : 0;
}

void RenderBox::setScrollLeft(int newLeft)
{
    if (hasOverflowClip())
        layer()->scrollToXOffset(newLeft);
}

void RenderBox::setScrollTop(int newTop)
{
    if (hasOverflowClip())
        layer()->scrollToYOffset(newTop);
}

void RenderBox::absoluteRects(Vector<IntRect>& rects, int tx, int ty, bool)
{
    rects.append(IntRect(tx, ty, width(), height()));
}

void RenderBox::absoluteQuads(Vector<FloatQuad>& quads, bool)
{
    quads.append(localToAbsoluteQuad(FloatRect(0, 0, width(), height())));
}

IntRect RenderBox::absoluteContentBox() const
{
    IntRect rect = contentBoxRect();
    FloatPoint absPos = localToAbsolute(FloatPoint());
    rect.move(absPos.x(), absPos.y());
    return rect;
}

FloatQuad RenderBox::absoluteContentQuad() const
{
    IntRect rect = contentBoxRect();
    return localToAbsoluteQuad(FloatRect(rect));
}


IntRect RenderBox::outlineBoundsForRepaint(RenderBoxModelObject* /*repaintContainer*/) const
{
    IntRect box = borderBoundingBox();
    adjustRectForOutlineAndShadow(box);