rendertext.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

/*
 * (C) 1999 Lars Knoll ([e-mail])
 * (C) 2000 Dirk Mueller ([e-mail])
 * Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
 * Copyright (C) 2006 Andrew Wellington ([e-mail])
 * Copyright (C) 2006 Graham Dennis ([e-mail])
 *
 * 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 "RenderText.h"

#include "CharacterNames.h"
#include "FloatQuad.h"
#include "FrameView.h"
#include "InlineTextBox.h"
#include "Range.h"
#include "RenderArena.h"
#include "RenderBlock.h"
#include "RenderLayer.h"
#include "RenderView.h"
#include "Text.h"
#include "TextBreakIterator.h"
#include "VisiblePosition.h"
#include "break_lines.h"
#include <wtf/AlwaysInline.h>

using namespace std;
using namespace WTF;
using namespace Unicode;

namespace WebCore {

// FIXME: Move to StringImpl.h eventually.
static inline bool charactersAreAllASCII(StringImpl* text)
{
    return charactersAreAllASCII(text->characters(), text->length());
}

RenderText::RenderText(Node* node, PassRefPtr<StringImpl> str)
     : RenderObject(node)
     , m_text(str)
     , m_firstTextBox(0)
     , m_lastTextBox(0)
     , m_minWidth(-1)
     , m_maxWidth(-1)
     , m_beginMinWidth(0)
     , m_endMinWidth(0)
     , m_hasTab(false)
     , m_linesDirty(false)
     , m_containsReversedText(false)
     , m_isAllASCII(charactersAreAllASCII(m_text.get()))
{
    ASSERT(m_text);
    setIsText();
    m_text = document()->displayStringModifiedByEncoding(PassRefPtr<StringImpl>(m_text));

    view()->frameView()->setIsVisuallyNonEmpty();
}

#ifndef NDEBUG

RenderText::~RenderText()
{
    ASSERT(!m_firstTextBox);
    ASSERT(!m_lastTextBox);
}

#endif

const char* RenderText::renderName() const
{
    return "RenderText";
}

bool RenderText::isTextFragment() const
{
    return false;
}

bool RenderText::isWordBreak() const
{
    return false;
}

void RenderText::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle)
{
    // There is no need to ever schedule repaints from a style change of a text run, since
    // we already did this for the parent of the text run.
    // We do have to schedule layouts, though, since a style change can force us to
    // need to relayout.
    if (diff == StyleDifferenceLayout)
        setNeedsLayoutAndPrefWidthsRecalc();

    ETextTransform oldTransform = oldStyle ? oldStyle->textTransform() : TTNONE;
    ETextSecurity oldSecurity = oldStyle ? oldStyle->textSecurity() : TSNONE;

    if (oldTransform != style()->textTransform() || oldSecurity != style()->textSecurity()) {
        if (RefPtr<StringImpl> textToTransform = originalText())
            setText(textToTransform.release(), true);
    }
}

void RenderText::destroy()
{
    if (!documentBeingDestroyed()) {
        if (firstTextBox()) {
            if (isBR()) {
                RootInlineBox* next = firstTextBox()->root()->nextRootBox();
                if (next)
                    next->markDirty();
            }
            for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
                box->remove();
        } else if (parent())
            parent()->dirtyLinesFromChangedChild(this);
    }
    deleteTextBoxes();
    RenderObject::destroy();
}

void RenderText::extractTextBox(InlineTextBox* box)
{
    checkConsistency();

    m_lastTextBox = box->prevTextBox();
    if (box == m_firstTextBox)
        m_firstTextBox = 0;
    if (box->prevTextBox())
        box->prevTextBox()->setNextLineBox(0);
    box->setPreviousLineBox(0);
    for (InlineRunBox* curr = box; curr; curr = curr->nextLineBox())
        curr->setExtracted();

    checkConsistency();
}

void RenderText::attachTextBox(InlineTextBox* box)
{
    checkConsistency();

    if (m_lastTextBox) {
        m_lastTextBox->setNextLineBox(box);
        box->setPreviousLineBox(m_lastTextBox);
    } else
        m_firstTextBox = box;
    InlineTextBox* last = box;
    for (InlineTextBox* curr = box; curr; curr = curr->nextTextBox()) {
        curr->setExtracted(false);
        last = curr;
    }
    m_lastTextBox = last;

    checkConsistency();
}

void RenderText::removeTextBox(InlineTextBox* box)
{
    checkConsistency();

    if (box == m_firstTextBox)
        m_firstTextBox = box->nextTextBox();
    if (box == m_lastTextBox)
        m_lastTextBox = box->prevTextBox();
    if (box->nextTextBox())
        box->nextTextBox()->setPreviousLineBox(box->prevTextBox());
    if (box->prevTextBox())
        box->prevTextBox()->setNextLineBox(box->nextTextBox());

    checkConsistency();
}

void RenderText::deleteTextBoxes()
{
    if (firstTextBox()) {
        RenderArena* arena = renderArena();
        InlineTextBox* next;
        for (InlineTextBox* curr = firstTextBox(); curr; curr = next) {
            next = curr->nextTextBox();
            curr->destroy(arena);
        }
        m_firstTextBox = m_lastTextBox = 0;
    }
}

PassRefPtr<StringImpl> RenderText::originalText() const
{
    Node* e = node();
    return e ? static_cast<Text*>(e)->string() : 0;
}

void RenderText::absoluteRects(Vector<IntRect>& rects, int tx, int ty, bool)
{
    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
        rects.append(IntRect(tx + box->x(), ty + box->y(), box->width(), box->height()));
}

void RenderText::absoluteRectsForRange(Vector<IntRect>& rects, unsigned start, unsigned end, bool useSelectionHeight)
{
    // Work around signed/unsigned issues. This function takes unsigneds, and is often passed UINT_MAX
    // to mean "all the way to the end". InlineTextBox coordinates are unsigneds, so changing this 
    // function to take ints causes various internal mismatches. But selectionRect takes ints, and 
    // passing UINT_MAX to it causes trouble. Ideally we'd change selectionRect to take unsigneds, but 
    // that would cause many ripple effects, so for now we'll just clamp our unsigned parameters to INT_MAX.
    ASSERT(end == UINT_MAX || end <= INT_MAX);
    ASSERT(start <= INT_MAX);
    start = min(start, static_cast<unsigned>(INT_MAX));
    end = min(end, static_cast<unsigned>(INT_MAX));
    
    FloatPoint absPos = localToAbsolute(FloatPoint());

    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
        // Note: box->end() returns the index of the last character, not the index past it
        if (start <= box->start() && box->end() < end) {
            IntRect r = IntRect(absPos.x() + box->x(), absPos.y() + box->y(), box->width(), box->height());
            if (useSelectionHeight) {
                IntRect selectionRect = box->selectionRect(absPos.x(), absPos.y(), start, end);
                r.setHeight(selectionRect.height());
                r.setY(selectionRect.y());
            }
            rects.append(r);
        } else {
            unsigned realEnd = min(box->end() + 1, end);
            IntRect r = box->selectionRect(absPos.x(), absPos.y(), start, realEnd);
            if (!r.isEmpty()) {
                if (!useSelectionHeight) {
                    // change the height and y position because selectionRect uses selection-specific values
                    r.setHeight(box->height());
                    r.setY(absPos.y() + box->y());
                }
                rects.append(r);
            }
        }
    }
}

void RenderText::absoluteQuads(Vector<FloatQuad>& quads, bool)
{
    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox())
        quads.append(localToAbsoluteQuad(FloatRect(box->x(), box->y(), box->width(), box->height())));
}

void RenderText::absoluteQuadsForRange(Vector<FloatQuad>& quads, unsigned start, unsigned end, bool useSelectionHeight)
{
    // Work around signed/unsigned issues. This function takes unsigneds, and is often passed UINT_MAX
    // to mean "all the way to the end". InlineTextBox coordinates are unsigneds, so changing this 
    // function to take ints causes various internal mismatches. But selectionRect takes ints, and 
    // passing UINT_MAX to it causes trouble. Ideally we'd change selectionRect to take unsigneds, but 
    // that would cause many ripple effects, so for now we'll just clamp our unsigned parameters to INT_MAX.
    ASSERT(end == UINT_MAX || end <= INT_MAX);
    ASSERT(start <= INT_MAX);
    start = min(start, static_cast<unsigned>(INT_MAX));
    end = min(end, static_cast<unsigned>(INT_MAX));
    
    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
        // Note: box->end() returns the index of the last character, not the index past it
        if (start <= box->start() && box->end() < end) {
            IntRect r = IntRect(box->x(), box->y(), box->width(), box->height());
            if (useSelectionHeight) {
                IntRect selectionRect = box->selectionRect(0, 0, start, end);
                r.setHeight(selectionRect.height());
                r.setY(selectionRect.y());
            }
            quads.append(localToAbsoluteQuad(FloatRect(r)));
        } else {
            unsigned realEnd = min(box->end() + 1, end);
            IntRect r = box->selectionRect(0, 0, start, realEnd);
            if (!r.isEmpty()) {
                if (!useSelectionHeight) {
                    // change the height and y position because selectionRect uses selection-specific values
                    r.setHeight(box->height());
                    r.setY(box->y());
                }
                quads.append(localToAbsoluteQuad(FloatRect(r)));
            }
        }
    }
}

InlineTextBox* RenderText::findNextInlineTextBox(int offset, int& pos) const
{
    // The text runs point to parts of the RenderText's m_text
    // (they don't include '\n')
    // Find the text run that includes the character at offset
    // and return pos, which is the position of the char in the run.

    if (!m_firstTextBox)
        return 0;

    InlineTextBox* s = m_firstTextBox;
    int off = s->len();
    while (offset > off && s->nextTextBox()) {
        s = s->nextTextBox();
        off = s->start() + s->len();
    }
    // we are now in the correct text run
    pos = (offset > off ? s->len() : s->len() - (off - offset) );
    return s;
}

VisiblePosition RenderText::positionForPoint(const IntPoint& point)
{
    if (!firstTextBox() || textLength() == 0)
        return VisiblePosition(node(), 0, DOWNSTREAM);

    // Get the offset for the position, since this will take rtl text into account.
    int offset;

    // FIXME: We should be able to roll these special cases into the general cases in the loop below.
    if (firstTextBox() && point.y() <  firstTextBox()->root()->bottomOverflow() && point.x() < firstTextBox()->m_x) {
        // at the y coordinate of the first line or above
        // and the x coordinate is to the left of the first text box left edge
        offset = firstTextBox()->offsetForPosition(point.x());
        return VisiblePosition(node(), offset + firstTextBox()->start(), DOWNSTREAM);
    }
    if (lastTextBox() && point.y() >= lastTextBox()->root()->topOverflow() && point.x() >= lastTextBox()->m_x + lastTextBox()->m_width) {
        // at the y coordinate of the last line or below
        // and the x coordinate is to the right of the last text box right edge
        offset = lastTextBox()->offsetForPosition(point.x());
        return VisiblePosition(node(), offset + lastTextBox()->start(), DOWNSTREAM);
    }

    InlineTextBox* lastBoxAbove = 0;
    for (InlineTextBox* box = firstTextBox(); box; box = box->nextTextBox()) {
        if (point.y() >= box->root()->topOverflow()) {
            int bottom = box->root()->nextRootBox() ? box->root()->nextRootBox()->topOverflow() : box->root()->bottomOverflow();
            if (point.y() < bottom) {
                offset = box->offsetForPosition(point.x());

                if (point.x() == box->m_x)
                    // the x coordinate is equal to the left edge of this box
                    // the affinity must be downstream so the position doesn't jump back to the previous line
                    return VisiblePosition(node(), offset + box->start(), DOWNSTREAM);

                if (point.x() < box->m_x + box->m_width)
                    // and the x coordinate is to the left of the right edge of this box
                    // check to see if position goes in this box
                    return VisiblePosition(node(), offset + box->start(), offset > 0 ? VP_UPSTREAM_IF_POSSIBLE : DOWNSTREAM);

                if (!box->prevOnLine() && point.x() < box->m_x)
                    // box is first on line
                    // and the x coordinate is to the left of the first text box left edge
                    return VisiblePosition(node(), offset + box->start(), DOWNSTREAM);

                if (!box->nextOnLine())
                    // box is last on line
                    // and the x coordinate is to the right of the last text box right edge
                    // generate VisiblePosition, use UPSTREAM affinity if possible
                    return VisiblePosition(node(), offset + box->start(), offset > 0 ? VP_UPSTREAM_IF_POSSIBLE : DOWNSTREAM);
            }
            lastBoxAbove = box;
        }
    }

    return VisiblePosition(node(), lastBoxAbove ? lastBoxAbove->start() + lastBoxAbove->len() : 0, DOWNSTREAM);
}

IntRect RenderText::localCaretRect(InlineBox* inlineBox, int caretOffset, int* extraWidthToEndOfLine)
{
    if (!inlineBox)
        return IntRect();

    ASSERT(inlineBox->isInlineTextBox());
    if (!inlineBox->isInlineTextBox())
        return IntRect();

    InlineTextBox* box = static_cast<InlineTextBox*>(inlineBox);

    int height = box->root()->bottomOverflow() - box->root()->topOverflow();
    int top = box->root()->topOverflow();

    int left = box->positionForOffset(caretOffset);

    int rootLeft = box->root()->x();
    // FIXME: should we use the width of the root inline box or the
    // width of the containing block for this?
    if (extraWidthToEndOfLine)
        *extraWidthToEndOfLine = (box->root()->width() + rootLeft) - (left + 1);

    RenderBlock* cb = containingBlock();
    if (style()->autoWrap()) {
        int availableWidth = cb->lineWidth(top, false);
        if (box->direction() == LTR)
            left = min(left, rootLeft + availableWidth - 1);
        else
            left = max(left, rootLeft);
    }

    return IntRect(left, top, caretWidth, height);
}

ALWAYS_INLINE int RenderText::widthFromCache(const Font& f, int start, int len, int xPos) const
{
    if (f.isFixedPitch() && !f.isSmallCaps() && m_isAllASCII) {
        int monospaceCharacterWidth = f.spaceWidth();
        int tabWidth = allowTabs() ? monospaceCharacterWidth * 8 : 0;
        int w = 0;
        bool isSpace;
        bool previousCharWasSpace = true; // FIXME: Preserves historical behavior, but seems wrong for start > 0.
        for (int i = start; i < start + len; i++) {
            char c = (*m_text)[i];
            if (c <= ' ') {
                if (c == ' ' || c == '\n') {
                    w += monospaceCharacterWidth;
                    isSpace = true;
                } else if (c == '\t') {
                    w += tabWidth ? tabWidth - ((xPos + w) % tabWidth) : monospaceCharacterWidth;
                    isSpace = true;
                } else
                    isSpace = false;
            } else {
                w += monospaceCharacterWidth;
                isSpace = false;
            }
            if (isSpace && !previousCharWasSpace)
                w += f.wordSpacing();
            previousCharWasSpace = isSpace;
        }
        return w;
    }

    return f.width(TextRun(text()->characters() + start, len, allowTabs(), xPos));
}