Source/core/rendering/RenderFrameBase.cpp

/*
 * Copyright (C) 2010 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 "core/rendering/RenderFrameBase.h"

#include "core/html/HTMLFrameElementBase.h"
#include "core/page/Frame.h"
#include "core/page/FrameView.h"
#include "core/rendering/RenderView.h"

namespace WebCore {
    
RenderFrameBase::RenderFrameBase(Element* element)
    : RenderPart(element)
{
}

inline bool shouldExpandFrame(LayoutUnit width, LayoutUnit height, bool hasFixedWidth, bool hasFixedHeight)
{
    // If the size computed to zero never expand.
    if (!width || !height)
        return false;
    // Really small fixed size frames can't be meant to be scrolled and are there probably by mistake. Avoid expanding.
    static unsigned smallestUsefullyScrollableDimension = 8;
    if (hasFixedWidth && width < LayoutUnit(smallestUsefullyScrollableDimension))
        return false;
    if (hasFixedHeight && height < LayoutUnit(smallestUsefullyScrollableDimension))
        return false;
    return true;
}

void RenderFrameBase::layoutWithFlattening(bool hasFixedWidth, bool hasFixedHeight)
{
    FrameView* childFrameView = toFrameView(widget());
    RenderView* childRoot = childFrameView ? childFrameView->frame()->contentRenderer() : 0;

    if (!childRoot || !shouldExpandFrame(width(), height(), hasFixedWidth, hasFixedHeight)) {
        updateWidgetPosition();
        if (childFrameView)
            childFrameView->layout();
        setNeedsLayout(false);
        return;
    }

    // need to update to calculate min/max correctly
    updateWidgetPosition();

    // if scrollbars are off, and the width or height are fixed
    // we obey them and do not expand. With frame flattening
    // no subframe much ever become scrollable.

    HTMLFrameElementBase* element = static_cast<HTMLFrameElementBase*>(node());
    bool isScrollable = element->scrollingMode() != ScrollbarAlwaysOff;

    // consider iframe inset border
    int hBorder = borderLeft() + borderRight();
    int vBorder = borderTop() + borderBottom();

    // make sure minimum preferred width is enforced
    if (isScrollable || !hasFixedWidth) {
        setWidth(max(width(), childRoot->minPreferredLogicalWidth() + hBorder));
        // update again to pass the new width to the child frame
        updateWidgetPosition();
        childFrameView->layout();
    }

    // expand the frame by setting frame height = content height
    if (isScrollable || !hasFixedHeight || childRoot->isFrameSet())
        setHeight(max<LayoutUnit>(height(), childFrameView->contentsHeight() + vBorder));
    if (isScrollable || !hasFixedWidth || childRoot->isFrameSet())
        setWidth(max<LayoutUnit>(width(), childFrameView->contentsWidth() + hBorder));

    updateWidgetPosition();

    ASSERT(!childFrameView->layoutPending());
    ASSERT(!childRoot->needsLayout());
    ASSERT(!childRoot->firstChild() || !childRoot->firstChild()->firstChild() || !childRoot->firstChild()->firstChild()->needsLayout());

    setNeedsLayout(false);
}

}