rendertextcontrol.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) 2006, 2007 Apple Inc. All rights reserved.
 *           (C) 2008 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)  
 *
 * 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 "RenderTextControl.h"

#include "CharacterNames.h"
#include "Editor.h"
#include "Event.h"
#include "EventNames.h"
#include "Frame.h"
#include "HTMLBRElement.h"
#include "HTMLFormControlElement.h"
#include "HTMLNames.h"
#include "HitTestResult.h"
#include "RenderLayer.h"
#include "RenderText.h"
#include "ScrollbarTheme.h"
#include "SelectionController.h"
#include "Text.h"
#include "TextControlInnerElements.h"
#include "TextIterator.h"

using namespace std;

namespace WebCore {

using namespace HTMLNames;

// Value chosen by observation.  This can be tweaked.
static const int minColorContrastValue = 1300;

static Color disabledTextColor(const Color& textColor, const Color& backgroundColor)
{
    // The explicit check for black is an optimization for the 99% case (black on white).
    // This also means that black on black will turn into grey on black when disabled.
    Color disabledColor;
    if (textColor.rgb() == Color::black || differenceSquared(textColor, Color::white) > differenceSquared(backgroundColor, Color::white))
        disabledColor = textColor.light();
    else
        disabledColor = textColor.dark();
    
    // If there's not very much contrast between the disabled color and the background color,
    // just leave the text color alone.  We don't want to change a good contrast color scheme so that it has really bad contrast.
    // If the the contrast was already poor, then it doesn't do any good to change it to a different poor contrast color scheme.
    if (differenceSquared(disabledColor, backgroundColor) < minColorContrastValue)
        return textColor;
    
    return disabledColor;
}

RenderTextControl::RenderTextControl(Node* node)
    : RenderBlock(node)
    , m_edited(false)
    , m_userEdited(false)
{
}

RenderTextControl::~RenderTextControl()
{
    // The children renderers have already been destroyed by destroyLeftoverChildren
    if (m_innerText)
        m_innerText->detach();
}

void RenderTextControl::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
    RenderBlock::styleDidChange(diff, oldStyle);

    if (m_innerText) {
        RenderBlock* textBlockRenderer = toRenderBlock(m_innerText->renderer());
        RefPtr<RenderStyle> textBlockStyle = createInnerTextStyle(style());
        // We may have set the width and the height in the old style in layout().
        // Reset them now to avoid getting a spurious layout hint.
        textBlockRenderer->style()->setHeight(Length());
        textBlockRenderer->style()->setWidth(Length());
        textBlockRenderer->setStyle(textBlockStyle);
        for (Node* n = m_innerText->firstChild(); n; n = n->traverseNextNode(m_innerText.get())) {
            if (n->renderer())
                n->renderer()->setStyle(textBlockStyle);
        }
    }

    setHasOverflowClip(false);
    setReplaced(isInline());
}

static inline bool updateUserModifyProperty(Node* node, RenderStyle* style)
{
    bool isEnabled = true;
    bool isReadOnlyControl = false;

    if (node->isElementNode()) {
        FormControlElement* formControlElement = toFormControlElement(static_cast<Element*>(node));
        ASSERT(formControlElement);

        isEnabled = formControlElement->isEnabled();
        isReadOnlyControl = formControlElement->isReadOnlyControl();
    }

    style->setUserModify((isReadOnlyControl || !isEnabled) ? READ_ONLY : READ_WRITE_PLAINTEXT_ONLY);
    return !isEnabled;
}

void RenderTextControl::adjustInnerTextStyle(const RenderStyle* startStyle, RenderStyle* textBlockStyle) const
{
    // The inner block, if present, always has its direction set to LTR,
    // so we need to inherit the direction from the element.
    textBlockStyle->setDirection(style()->direction());

    bool disabled = updateUserModifyProperty(node(), textBlockStyle);
    if (disabled)
        textBlockStyle->setColor(disabledTextColor(textBlockStyle->color(), startStyle->backgroundColor()));
}

void RenderTextControl::createSubtreeIfNeeded(TextControlInnerElement* innerBlock)
{
    if (!m_innerText) {
        // Create the text block element
        // For non-search fields, there is no intermediate innerBlock as the shadow node.
        // m_innerText will be the shadow node in that case.        
        RenderStyle* parentStyle = innerBlock ? innerBlock->renderer()->style() : style();
        m_innerText = new TextControlInnerTextElement(document(), innerBlock ? 0 : node());
        m_innerText->attachInnerElement(innerBlock ? innerBlock : node(), createInnerTextStyle(parentStyle), renderArena());
    }
}

int RenderTextControl::textBlockHeight() const
{
    return height() - paddingTop() - paddingBottom() - borderTop() - borderBottom();
}

int RenderTextControl::textBlockWidth() const
{
    return width() - paddingLeft() - paddingRight() - borderLeft() - borderRight()
           - m_innerText->renderBox()->paddingLeft() - m_innerText->renderBox()->paddingRight();
}

void RenderTextControl::updateFromElement()
{
    updateUserModifyProperty(node(), m_innerText->renderer()->style());
}

void RenderTextControl::setInnerTextValue(const String& innerTextValue)
{
    String value;

    if (innerTextValue.isNull())
        value = "";
    else {
        value = innerTextValue; 
        value = document()->displayStringModifiedByEncoding(value);
    }

    if (value != text() || !m_innerText->hasChildNodes()) {
        if (value != text()) {
            if (Frame* frame = document()->frame())
                frame->editor()->clearUndoRedoOperations();
        }

        ExceptionCode ec = 0;
        m_innerText->setInnerText(value, ec);
        ASSERT(!ec);

        if (value.endsWith("\n") || value.endsWith("\r")) {
            m_innerText->appendChild(new HTMLBRElement(brTag, document()), ec);
            ASSERT(!ec);
        }

        m_edited = false;
        m_userEdited = false;
    }

    formControlElement()->setValueMatchesRenderer();
}

void RenderTextControl::setUserEdited(bool isUserEdited)
{
    m_userEdited = isUserEdited;
    document()->setIgnoreAutofocus(isUserEdited);
}

int RenderTextControl::selectionStart()
{
    Frame* frame = document()->frame();
    if (!frame)
        return 0;
    return indexForVisiblePosition(frame->selection()->start());
}

int RenderTextControl::selectionEnd()
{
    Frame* frame = document()->frame();
    if (!frame)
        return 0;
    return indexForVisiblePosition(frame->selection()->end());
}

void RenderTextControl::setSelectionStart(int start)
{
    setSelectionRange(start, max(start, selectionEnd()));
}

void RenderTextControl::setSelectionEnd(int end)
{
    setSelectionRange(min(end, selectionStart()), end);
}

void RenderTextControl::select()
{
    setSelectionRange(0, text().length());
}

void RenderTextControl::setSelectionRange(int start, int end)
{
    end = max(end, 0);
    start = min(max(start, 0), end);

    document()->updateLayout();

    if (style()->visibility() == HIDDEN || !m_innerText || !m_innerText->renderer() || !m_innerText->renderBox()->height()) {
        cacheSelection(start, end);
        return;
    }
    VisiblePosition startPosition = visiblePositionForIndex(start);
    VisiblePosition endPosition;
    if (start == end)
        endPosition = startPosition;
    else
        endPosition = visiblePositionForIndex(end);

    ASSERT(startPosition.isNotNull() && endPosition.isNotNull());
    ASSERT(startPosition.deepEquivalent().node()->shadowAncestorNode() == node() && endPosition.deepEquivalent().node()->shadowAncestorNode() == node());

    VisibleSelection newSelection = VisibleSelection(startPosition, endPosition);

    if (Frame* frame = document()->frame())
        frame->selection()->setSelection(newSelection);

    // FIXME: Granularity is stored separately on the frame, but also in the selection controller.
    // The granularity in the selection controller should be used, and then this line of code would not be needed.
    if (Frame* frame = document()->frame())
        frame->setSelectionGranularity(CharacterGranularity);
}

VisibleSelection RenderTextControl::selection(int start, int end) const
{
    return VisibleSelection(VisiblePosition(m_innerText.get(), start, VP_DEFAULT_AFFINITY),
                     VisiblePosition(m_innerText.get(), end, VP_DEFAULT_AFFINITY));
}

VisiblePosition RenderTextControl::visiblePositionForIndex(int index)
{
    if (index <= 0)
        return VisiblePosition(m_innerText.get(), 0, DOWNSTREAM);
    ExceptionCode ec = 0;
    RefPtr<Range> range = Range::create(document());
    range->selectNodeContents(m_innerText.get(), ec);
    ASSERT(!ec);
    CharacterIterator it(range.get());
    it.advance(index - 1);
    Node* endContainer = it.range()->endContainer(ec);
    ASSERT(!ec);
    int endOffset = it.range()->endOffset(ec);
    ASSERT(!ec);
    return VisiblePosition(endContainer, endOffset, UPSTREAM);
}

int RenderTextControl::indexForVisiblePosition(const VisiblePosition& pos)
{
    Position indexPosition = pos.deepEquivalent();
    if (!indexPosition.node() || indexPosition.node()->rootEditableElement() != m_innerText)
        return 0;
    ExceptionCode ec = 0;
    RefPtr<Range> range = Range::create(document());
    range->setStart(m_innerText.get(), 0, ec);
    ASSERT(!ec);
    range->setEnd(indexPosition.node(), indexPosition.offset(), ec);
    ASSERT(!ec);