renderlistbox.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

/*
 * This file is part of the select element renderer in WebCore.
 *
 * Copyright (C) 2006, 2007, 2008 Apple Inc. All rights reserved.
 *               2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
 *
 * 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. 
 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
 *     its contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE 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 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 "RenderListBox.h"

#include "AXObjectCache.h"
#include "CSSStyleSelector.h"
#include "Document.h"
#include "EventHandler.h"
#include "EventNames.h"
#include "FocusController.h"
#include "Frame.h"
#include "FrameView.h"
#include "GraphicsContext.h"
#include "HTMLNames.h"
#include "HTMLSelectElement.h"
#include "HitTestResult.h"
#include "OptionGroupElement.h"
#include "OptionElement.h"
#include "Page.h"
#include "RenderScrollbar.h"
#include "RenderTheme.h"
#include "RenderView.h"
#include "Scrollbar.h"
#include "SelectionController.h"
#include "NodeRenderStyle.h"
#include <math.h>

using namespace std;

namespace WebCore {

using namespace HTMLNames;
 
const int rowSpacing = 1;

const int optionsSpacingHorizontal = 2;

const int minSize = 4;
const int maxDefaultSize = 10;

// FIXME: This hardcoded baselineAdjustment is what we used to do for the old
// widget, but I'm not sure this is right for the new control.
const int baselineAdjustment = 7;

RenderListBox::RenderListBox(HTMLSelectElement* element)
    : RenderBlock(element)
    , m_optionsChanged(true)
    , m_scrollToRevealSelectionAfterLayout(false)
    , m_inAutoscroll(false)
    , m_optionsWidth(0)
    , m_indexOffset(0)
{
}

RenderListBox::~RenderListBox()
{
    setHasVerticalScrollbar(false);
}

void RenderListBox::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
    RenderBlock::styleDidChange(diff, oldStyle);
    setReplaced(isInline());
}

void RenderListBox::updateFromElement()
{
    if (m_optionsChanged) {
        const Vector<HTMLElement*>& listItems = static_cast<HTMLSelectElement*>(node())->listItems();
        int size = numItems();
        
        float width = 0;
        for (int i = 0; i < size; ++i) {
            HTMLElement* element = listItems[i];
            String text;
            Font itemFont = style()->font();
            if (OptionElement* optionElement = toOptionElement(element))
                text = optionElement->textIndentedToRespectGroupLabel();
            else if (OptionGroupElement* optionGroupElement = toOptionGroupElement(element)) {
                text = optionGroupElement->groupLabelText();
                FontDescription d = itemFont.fontDescription();
                d.setWeight(d.bolderWeight());
                itemFont = Font(d, itemFont.letterSpacing(), itemFont.wordSpacing());
                itemFont.update(document()->styleSelector()->fontSelector());
            }
                
            if (!text.isEmpty()) {
                float textWidth = itemFont.floatWidth(TextRun(text.impl(), 0, 0, 0, false, false, false, false));
                width = max(width, textWidth);
            }
        }
        m_optionsWidth = static_cast<int>(ceilf(width));
        m_optionsChanged = false;
        
        setHasVerticalScrollbar(true);

        setNeedsLayoutAndPrefWidthsRecalc();
    }
}

void RenderListBox::selectionChanged()
{
    repaint();
    if (!m_inAutoscroll) {
        if (m_optionsChanged || needsLayout())
            m_scrollToRevealSelectionAfterLayout = true;
        else
            scrollToRevealSelection();
    }
    
    if (AXObjectCache::accessibilityEnabled())
        document()->axObjectCache()->selectedChildrenChanged(this);
}

void RenderListBox::layout()
{
    RenderBlock::layout();
    if (m_scrollToRevealSelectionAfterLayout)
        scrollToRevealSelection();
}

void RenderListBox::scrollToRevealSelection()
{    
    HTMLSelectElement* select = static_cast<HTMLSelectElement*>(node());

    m_scrollToRevealSelectionAfterLayout = false;

    int firstIndex = select->activeSelectionStartListIndex();
    if (firstIndex >= 0 && !listIndexIsVisible(select->activeSelectionEndListIndex()))
        scrollToRevealElementAtListIndex(firstIndex);
}

void RenderListBox::calcPrefWidths()
{
    ASSERT(!m_optionsChanged);

    m_minPrefWidth = 0;
    m_maxPrefWidth = 0;

    if (style()->width().isFixed() && style()->width().value() > 0)
        m_minPrefWidth = m_maxPrefWidth = calcContentBoxWidth(style()->width().value());
    else {
        m_maxPrefWidth = m_optionsWidth + 2 * optionsSpacingHorizontal;
        if (m_vBar)
            m_maxPrefWidth += m_vBar->width();
    }

    if (style()->minWidth().isFixed() && style()->minWidth().value() > 0) {
        m_maxPrefWidth = max(m_maxPrefWidth, calcContentBoxWidth(style()->minWidth().value()));
        m_minPrefWidth = max(m_minPrefWidth, calcContentBoxWidth(style()->minWidth().value()));
    } else if (style()->width().isPercent() || (style()->width().isAuto() && style()->height().isPercent()))
        m_minPrefWidth = 0;
    else
        m_minPrefWidth = m_maxPrefWidth;

    if (style()->maxWidth().isFixed() && style()->maxWidth().value() != undefinedLength) {
        m_maxPrefWidth = min(m_maxPrefWidth, calcContentBoxWidth(style()->maxWidth().value()));
        m_minPrefWidth = min(m_minPrefWidth, calcContentBoxWidth(style()->maxWidth().value()));
    }

    int toAdd = paddingLeft() + paddingRight() + borderLeft() + borderRight();
    m_minPrefWidth += toAdd;
    m_maxPrefWidth += toAdd;
                                
    setPrefWidthsDirty(false);
}

int RenderListBox::size() const
{
    int specifiedSize = static_cast<HTMLSelectElement*>(node())->size();
    if (specifiedSize > 1)
        return max(minSize, specifiedSize);
    return min(max(minSize, numItems()), maxDefaultSize);
}

int RenderListBox::numVisibleItems() const
{
    // Only count fully visible rows. But don't return 0 even if only part of a row shows.
    return max(1, (contentHeight() + rowSpacing) / itemHeight());
}

int RenderListBox::numItems() const
{
    return static_cast<HTMLSelectElement*>(node())->listItems().size();
}

int RenderListBox::listHeight() const
{
    return itemHeight() * numItems() - rowSpacing;
}

void RenderListBox::calcHeight()
{
    int toAdd = paddingTop() + paddingBottom() + borderTop() + borderBottom();
 
    int itemHeight = RenderListBox::itemHeight();
    setHeight(itemHeight * size() - rowSpacing + toAdd);
    
    RenderBlock::calcHeight();
    
    if (m_vBar) {
        bool enabled = numVisibleItems() < numItems();
        m_vBar->setEnabled(enabled);
        m_vBar->setSteps(1, min(1, numVisibleItems() - 1), itemHeight);
        m_vBar->setProportion(numVisibleItems(), numItems());
        if (!enabled)
            m_indexOffset = 0;
    }
}

int RenderListBox::baselinePosition(bool, bool) const
{
    return height() + marginTop() + marginBottom() - baselineAdjustment;
}

IntRect RenderListBox::itemBoundingBoxRect(int tx, int ty, int index)
{
    return IntRect(tx + borderLeft() + paddingLeft(),
                   ty + borderTop() + paddingTop() + itemHeight() * (index - m_indexOffset),
                   contentWidth(), itemHeight());
}
    
void RenderListBox::paintObject(PaintInfo& paintInfo, int tx, int ty)
{
    if (style()->visibility() != VISIBLE)
        return;
    
    int listItemsSize = numItems();

    if (paintInfo.phase == PaintPhaseForeground) {
        int index = m_indexOffset;
        while (index < listItemsSize && index <= m_indexOffset + numVisibleItems()) {
            paintItemForeground(paintInfo, tx, ty, index);
            index++;
        }
    }

    // Paint the children.
    RenderBlock::paintObject(paintInfo, tx, ty);

    if (paintInfo.phase == PaintPhaseBlockBackground)
        paintScrollbar(paintInfo, tx, ty);
    else if (paintInfo.phase == PaintPhaseChildBlockBackground || paintInfo.phase == PaintPhaseChildBlockBackgrounds) {
        int index = m_indexOffset;
        while (index < listItemsSize && index <= m_indexOffset + numVisibleItems()) {
            paintItemBackground(paintInfo, tx, ty, index);
            index++;
        }
    }
}

void RenderListBox::paintScrollbar(PaintInfo& paintInfo, int tx, int ty)
{
    if (m_vBar) {
        IntRect scrollRect(tx + width() - borderRight() - m_vBar->width(),
                           ty + borderTop(),
                           m_vBar->width(),
                           height() - (borderTop() + borderBottom()));
        m_vBar->setFrameRect(scrollRect);
        m_vBar->paint(paintInfo.context, paintInfo.rect);
    }
}

void RenderListBox::paintItemForeground(PaintInfo& paintInfo, int tx, int ty, int listIndex)
{
    HTMLSelectElement* select = static_cast<HTMLSelectElement*>(node());
    const Vector<HTMLElement*>& listItems = select->listItems();
    HTMLElement* element = listItems[listIndex];
    OptionElement* optionElement = toOptionElement(element);

    String itemText;
    if (optionElement)
        itemText = optionElement->textIndentedToRespectGroupLabel();
    else if (OptionGroupElement* optionGroupElement = toOptionGroupElement(element))
        itemText = optionGroupElement->groupLabelText();      

    // Determine where the item text should be placed
    IntRect r = itemBoundingBoxRect(tx, ty, listIndex);
    r.move(optionsSpacingHorizontal, style()->font().ascent());

    RenderStyle* itemStyle = element->renderStyle();
    if (!itemStyle)
        itemStyle = style();
    
    Color textColor = element->renderStyle() ? element->renderStyle()->color() : style()->color();
    if (optionElement && optionElement->selected()) {
        if (document()->frame()->selection()->isFocusedAndActive() && document()->focusedNode() == node())
            textColor = theme()->activeListBoxSelectionForegroundColor();
        // Honor the foreground color for disabled items
        else if (!element->disabled())
            textColor = theme()->inactiveListBoxSelectionForegroundColor();
    }

    paintInfo.context->setFillColor(textColor);

    Font itemFont = style()->font();
    if (element->hasTagName(optgroupTag)) {
        FontDescription d = itemFont.fontDescription();
        d.setWeight(d.bolderWeight());
        itemFont = Font(d, itemFont.letterSpacing(), itemFont.wordSpacing());
        itemFont.update(document()->styleSelector()->fontSelector());
    }

    unsigned length = itemText.length();