qtextdocumentlayout.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

/****************************************************************************
**
** Copyright (C) 1992-2006 Trolltech ASA. All rights reserved.
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 as published by the Free Software Foundation
** and appearing in the file LICENSE.GPL included in the packaging of
** this file.  Please review the following information to ensure GNU
** General Public Licensing requirements will be met:
** http://www.trolltech.com/products/qt/opensource.html
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://www.trolltech.com/products/qt/licensing.html or contact the
** sales department at [e-mail].
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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#include "qtextdocumentlayout_p.h"
#include "qtextimagehandler_p.h"
#include "qtexttable.h"
#include "qtextlist.h"

#include "qabstracttextdocumentlayout_p.h"

#include <qpainter.h>
#include <qrect.h>
#include <qpalette.h>
#include <qdebug.h>
#include <qvarlengtharray.h>
#include <limits.h>
#include <qstyle.h>
#include <qbasictimer.h>

// #define LAYOUT_DEBUG

#ifdef LAYOUT_DEBUG
#define LDEBUG qDebug()
#define INC_INDENT debug_indent += "  "
#define DEC_INDENT debug_indent = debug_indent.left(debug_indent.length()-2)
#else
#define LDEBUG if(0) qDebug()
#define INC_INDENT do {} while(0)
#define DEC_INDENT do {} while(0)
#endif

// ################ should probably add frameFormatChange notification!

struct QLayoutStruct;

class QTextFrameData : public QTextFrameLayoutData
{
public:
    QTextFrameData()
        : minimumWidth(0), maximumWidth(INT_MAX), currentLayoutStruct(0),
          sizeDirty(true), layoutDirty(true)
        {}

    // relative to parent frame
    QPointF position;
    QSizeF size;

    // contents starts at (margin+border/margin+border)
    qreal margin;
    qreal border;
    qreal padding;
    // contents width includes padding (as we need to treat this on a per cell basis for tables)
    qreal contentsWidth;
    qreal contentsHeight;

    qreal minimumWidth;
    qreal maximumWidth;

    QTextFrameFormat::Position flow_position;

    QLayoutStruct *currentLayoutStruct;

    bool sizeDirty;
    bool layoutDirty;

    QList<QPointer<QTextFrame> > floats;
};

struct QLayoutStruct {
    QLayoutStruct() : contentsWidth(0), minimumWidth(0), maximumWidth(INT_MAX),
                      fullLayout(false), pageHeight(0.0),
                      pageBottom(0.0), pageMargin(0.0)
    {}
    QTextFrame *frame;
    qreal x_left;
    qreal x_right;
    qreal y;
    qreal contentsWidth;
    qreal minimumWidth;
    qreal maximumWidth;
    bool fullLayout;
    QList<QTextFrame *> pendingFloats;
    qreal pageHeight;
    qreal pageBottom;
    qreal pageMargin;
    QRectF updateRect;

    inline void newPage()
    { pageBottom += pageHeight; y = pageBottom - pageHeight + 2 * pageMargin; }
};

class QTextTableData : public QTextFrameData
{
public:
    inline QTextTableData() : cellSpacing(0), cellPadding(0) {}
    qreal cellSpacing, cellPadding;
    QVector<qreal> minWidths;
    QVector<qreal> maxWidths;
    QVector<qreal> widths;
    QVector<qreal> heights;
    QVector<qreal> columnPositions;
    QVector<qreal> rowPositions;
    // rows that appear at the top of a page after a page break
    QVector<int> rowPageBreaks;
    QVector<qreal> rowPositionsBeforePageBreak;

    inline qreal cellWidth(int column, int colspan) const
    { return columnPositions.at(column + colspan - 1) + widths.at(column + colspan - 1)
             - columnPositions.at(column) - 2 * cellPadding; }

    inline void calcRowPosition(int row)
    {
        if (row > 0)
            rowPositions[row] = rowPositions.at(row - 1) + heights.at(row - 1) + border + cellSpacing + border;
    }

    QRectF cellRect(const QTextTableCell &cell) const;

    inline QPointF cellPosition(int row, int col) const
    { return QPointF(columnPositions.at(col) + cellPadding, rowPositions.at(row) + cellPadding); }
    inline QPointF cellPosition(const QTextTableCell &cell) const
    { return cellPosition(cell.row(), cell.column()); }

    void updateSize();
};

static QTextFrameData *createData(QTextFrame *f)
{
    QTextFrameData *data;
    if (qobject_cast<QTextTable *>(f))
        data = new QTextTableData;
    else
        data = new QTextFrameData;
    f->setLayoutData(data);
    return data;
}

static inline QTextFrameData *data(QTextFrame *f)
{
    QTextFrameData *data = static_cast<QTextFrameData *>(f->layoutData());
    if (!data)
        data = createData(f);
    return data;
}

void QTextTableData::updateSize()
{
    const qreal effectiveMargin = this->margin + border + padding;
    qreal height = contentsHeight == -1
                   ? rowPositions.last() + heights.last() + padding + border + cellSpacing + effectiveMargin
                   : contentsHeight + 2*effectiveMargin;
    size = QSizeF(contentsWidth + 2*effectiveMargin, height);
}

QRectF QTextTableData::cellRect(const QTextTableCell &cell) const
{
    const int row = cell.row();
    const int rowSpan = cell.rowSpan();
    const int column = cell.column();
    const int colSpan = cell.columnSpan();

    return QRectF(columnPositions.at(column),
                  rowPositions.at(row),
                  columnPositions.at(column + colSpan - 1) + widths.at(column + colSpan - 1) - columnPositions.at(column),
                  rowPositions.at(row + rowSpan - 1) + heights.at(row + rowSpan - 1) - rowPositions.at(row));
}

static inline bool isEmptyBlockBeforeTable(const QTextBlock &block, const QTextFrame::Iterator &nextIt)
{
    return !nextIt.atEnd()
           && qobject_cast<QTextTable *>(nextIt.currentFrame())
           && block.isValid()
           && block.length() == 1
           && !block.blockFormat().hasProperty(QTextFormat::BlockTrailingHorizontalRulerWidth)
           && nextIt.currentFrame()->firstPosition() == block.position() + 1
           ;
}

static inline bool isEmptyBlockBeforeTable(QTextFrame::Iterator it)
{
    QTextFrame::Iterator next = it; ++next;
    return it.currentFrame() == 0
           && isEmptyBlockBeforeTable(it.currentBlock(), next);
}

static inline bool isEmptyBlockAfterTable(const QTextBlock &block, const QTextFrame *lastFrame)
{
    return qobject_cast<const QTextTable *>(lastFrame)
           && block.isValid()
           && block.length() == 1
           && lastFrame->lastPosition() == block.position() - 1
           ;
}

/*

Optimisation strategies:

HTML layout:

* Distinguish between normal and special flow. For normal flow the condition:
  y1 > y2 holds for all blocks with b1.key() > b2.key().
* Special flow is: floats, table cells

* Normal flow within table cells. Tables (not cells) are part of the normal flow.


* If blocks grows/shrinks in height and extends over whole page width at the end, move following blocks.
* If height doesn't change, no need to do anything

Table cells:

* If minWidth of cell changes, recalculate table width, relayout if needed.
* What about maxWidth when doing auto layout?

Floats:
* need fixed or proportional width, otherwise don't float!
* On width/height change relayout surrounding paragraphs.

Document width change:
* full relayout needed


Float handling:

* Floats are specified by a special format object.
* currently only floating images are implemented.

*/

/*

   On the table layouting:

   +---[ table border ]-------------------------
   |      [ cell spacing ]
   |  +------[ cell border ]-----+  +--------
   |  |                          |  |
   |  |
   |  |
   |  |
   |

   rowPositions[i] and columnPositions[i] point at the cell content
   position. So for example the left border is drawn at
   x = columnPositions[i] - fd->border and similar for y.

*/

enum {
    TextIndentValue = 40
};

struct QCheckPoint
{
    qreal y;
    int positionInFrame;
    qreal minimumWidth;
    qreal maximumWidth;
    qreal contentsWidth;
};
Q_DECLARE_TYPEINFO(QCheckPoint, Q_PRIMITIVE_TYPE);

static bool operator<(const QCheckPoint &checkPoint, qreal y)
{
    return checkPoint.y < y;
}

static bool operator<(const QCheckPoint &checkPoint, int pos)
{
    return checkPoint.positionInFrame < pos;
}

class QTextDocumentLayoutPrivate : public QAbstractTextDocumentLayoutPrivate
{
    Q_DECLARE_PUBLIC(QTextDocumentLayout)
public:

#if 0
    struct Page {
        QTextBlock first;
        QTextBlock last;
    };
    QList<Page> pages;
#endif

    QTextDocumentLayoutPrivate()
        : blockTextFlags(0), wordWrapMode(QTextOption::WrapAtWordBoundaryOrAnywhere),
          fixedColumnWidth(-1),
          tabStopWidth(80), // same default as in qtextengine.cpp
          currentLazyLayoutPosition(-1),
          lazyLayoutStepSize(1000),
          showLayoutProgress(true)
    { }

    bool pagedLayout;

    int blockTextFlags;
    QTextOption::WrapMode wordWrapMode;
#ifdef LAYOUT_DEBUG
    mutable QString debug_indent;
#endif

    int fixedColumnWidth;
    qreal tabStopWidth;

    mutable int currentLazyLayoutPosition;
    mutable int lazyLayoutStepSize;
    QBasicTimer layoutTimer;
    mutable QBasicTimer sizeChangedTimer;
    bool showLayoutProgress;

    qreal indent(QTextBlock bl) const;

    void drawFrame(const QPointF &offset, QPainter *painter, const QAbstractTextDocumentLayout::PaintContext &context,
                   QTextFrame *f) const;
    void drawFlow(const QPointF &offset, QPainter *painter, const QAbstractTextDocumentLayout::PaintContext &context,
                  QTextFrame::Iterator it, QTextBlock *cursorBlockNeedingRepaint) const;
    void drawBlock(const QPointF &offset, QPainter *painter, const QAbstractTextDocumentLayout::PaintContext &context,
                   QTextBlock bl) const;
    void drawListItem(const QPointF &offset, QPainter *painter, const QAbstractTextDocumentLayout::PaintContext &context,
                      QTextBlock bl, const QTextCharFormat *selectionFormat) const;

    enum HitPoint {
        PointBefore,
        PointAfter,
        PointInside,
        PointExact
    };
    HitPoint hitTest(QTextFrame *frame, const QPointF &point, int *position, QTextLayout **l) const;
    HitPoint hitTest(QTextFrame::Iterator it, HitPoint hit, const QPointF &p, 
                     int *position, QTextLayout **l) const;
    HitPoint hitTest(QTextTable *table, const QPointF &point, int *position, QTextLayout **l) const;
    HitPoint hitTest(QTextBlock bl, const QPointF &point, int *position, QTextLayout **l) const;