QDeclarativeTextLayout Class Reference

The QDeclarativeTextLayout class is a version of QStaticText that works with QTextLayouts. More...

#include <qdeclarativetextlayout_p.h>

Inheritance diagram for QDeclarativeTextLayout:

Public Functions
void	beginLayout ()
void	clearLayout ()
void	draw (QPainter *, const QPointF &=QPointF())
void	prepare ()
	QDeclarativeTextLayout ()
	QDeclarativeTextLayout (const QString &)
	~QDeclarativeTextLayout ()
Public Functions inherited from QTextLayout
QList< FormatRange >	additionalFormats () const
	Returns the list of additional formats supported by the text layout. More...
void	beginLayout ()
	Begins the layout process. More...
QRectF	boundingRect () const
	The smallest rectangle that contains all the lines in the layout. More...
bool	cacheEnabled () const
	Returns true if the complete layout information is cached; otherwise returns false. More...
void	clearAdditionalFormats ()
	Clears the list of additional formats supported by the text layout. More...
void	clearLayout ()
	Clears the line information in the layout. More...
QTextLine	createLine ()
	Returns a new text line to be laid out if there is text to be inserted into the layout; otherwise returns an invalid text line. More...
Qt::CursorMoveStyle	cursorMoveStyle () const
	The cursor movement style of this QTextLayout. More...
void	draw (QPainter *p, const QPointF &pos, const QVector< FormatRange > &selections=QVector< FormatRange >(), const QRectF &clip=QRectF()) const
	Draws the whole layout on the painter p at the position specified by pos. More...
void	drawCursor (QPainter *p, const QPointF &pos, int cursorPosition) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Draws a text cursor with the current pen at the given position using the painter specified. More...
void	drawCursor (QPainter *p, const QPointF &pos, int cursorPosition, int width) const
	Draws a text cursor with the current pen and the specified width at the given position using the painter specified. More...
void	endLayout ()
	Ends the layout process. More...
QTextEngine *	engine () const
QFont	font () const
	Returns the current font that is used for the layout, or a default font if none is set. More...
QList< QGlyphRun >	glyphRuns () const
	Returns the glyph indexes and positions for all glyphs in this QTextLayout. More...
bool	isValidCursorPosition (int pos) const
	/ Returns true if position pos is a valid cursor position. More...
int	leftCursorPosition (int oldPos) const
	Returns the cursor position to the left of oldPos, next to it. More...
QTextLine	lineAt (int i) const
	Returns the {i}-th line of text in this text layout. More...
int	lineCount () const
	Returns the number of lines in this text layout. More...
QTextLine	lineForTextPosition (int pos) const
	Returns the line that contains the cursor position specified by pos. More...
qreal	maximumWidth () const
	The maximum width the layout could expand to; this is essentially the width of the entire text. More...
qreal	minimumWidth () const
	The minimum width the layout needs. More...
int	nextCursorPosition (int oldPos, CursorMode mode=SkipCharacters) const
	Returns the next valid cursor position after oldPos that respects the given cursor mode. More...
QPointF	position () const
	The global position of the layout. More...
int	preeditAreaPosition () const
	Returns the position of the area in the text layout that will be processed before editing occurs. More...
QString	preeditAreaText () const
	Returns the text that is inserted in the layout before editing occurs. More...
int	previousCursorPosition (int oldPos, CursorMode mode=SkipCharacters) const
	Returns the first valid cursor position before oldPos that respects the given cursor mode. More...
	QTextLayout ()
	Constructs an empty text layout. More...
	QTextLayout (const QString &text)
	Constructs a text layout to lay out the given text. More...
	QTextLayout (const QString &text, const QFont &font, QPaintDevice *paintdevice=0)
	Constructs a text layout to lay out the given text with the specified font. More...
	QTextLayout (const QTextBlock &b)
	Constructs a text layout to lay out the given block. More...
int	rightCursorPosition (int oldPos) const
	Returns the cursor position to the right of oldPos, next to it. More...
void	setAdditionalFormats (const QList< FormatRange > &overrides)
	Sets the additional formats supported by the text layout to formatList. More...
void	setCacheEnabled (bool enable)
	Enables caching of the complete layout information if enable is true; otherwise disables layout caching. More...
void	setCursorMoveStyle (Qt::CursorMoveStyle style)
	Set the cursor movement style. More...
void	setFlags (int flags)
void	setFont (const QFont &f)
	Sets the layout's font to the given font. More...
void	setPosition (const QPointF &p)
	Moves the text layout to point p. More...
void	setPreeditArea (int position, const QString &text)
	Sets the position and text of the area in the layout that is processed before editing occurs. More...
void	setText (const QString &string)
	Sets the layout's text to the given string. More...
void	setTextOption (const QTextOption &option)
	Sets the text option structure that controls the layout process to the given option. More...
QString	text () const
	Returns the layout's text. More...
QTextOption	textOption () const
	Returns the current text option used to control the layout process. More...
	~QTextLayout ()
	Destructs the layout. More...

Properties
QDeclarativeTextLayoutPrivate *	d

Additional Inherited Members
Public Types inherited from QTextLayout
enum	CursorMode { SkipCharacters, SkipWords }

Detailed Description

The QDeclarativeTextLayout class is a version of QStaticText that works with QTextLayouts.

Warning

This function is not part of the public interface.

This class is basically a copy of the QStaticText code, but it is adapted to source its text from QTextLayout.

It is also considerably faster to create a QDeclarativeTextLayout than a QStaticText because it uses a single, shared QPainter instance. QStaticText by comparison creates a new QPainter per instance. As a consequence this means that QDeclarativeTextLayout is not re-enterant. Adding a lock around the shared painter solves this, and only introduces a minor performance penalty, but is unnecessary for QDeclarativeTextLayout's current use (QDeclarativeText is already tied to the GUI thread).

Definition at line 54 of file qdeclarativetextlayout_p.h.

Constructors and Destructors

QDeclarativeTextLayout() [1/2]

QDeclarativeTextLayout::QDeclarativeTextLayout

(

)

Definition at line 268 of file qdeclarativetextlayout.cpp.

: d(0)
{
}

QDeclarativeTextLayout() [2/2]

QDeclarativeTextLayout::QDeclarativeTextLayout

(

const QString &

text

)

Definition at line 273 of file qdeclarativetextlayout.cpp.

: QTextLayout(text), d(0)
{
}

~QDeclarativeTextLayout()

QDeclarativeTextLayout::~QDeclarativeTextLayout

(

)

Definition at line 278 of file qdeclarativetextlayout.cpp.

{
    if (d) delete d;
}

Functions

beginLayout()

void QDeclarativeTextLayout::beginLayout

(

)

Definition at line 283 of file qdeclarativetextlayout.cpp.

{
    if (d && d->cached) {
        d->cached = false;
        d->items.clear();
        d->positions.clear();
        d->glyphs.clear();
        d->chars.clear();
        d->position = QPointF();
    }
    QTextLayout::beginLayout();
}

clearLayout()

void QDeclarativeTextLayout::clearLayout

(

)

Definition at line 296 of file qdeclarativetextlayout.cpp.

{
    if (d && d->cached) {
        d->cached = false;
        d->items.clear();
        d->positions.clear();
        d->glyphs.clear();
        d->chars.clear();
        d->position = QPointF();
    }
    QTextLayout::clearLayout();
}

draw()

void QDeclarativeTextLayout::draw	(	QPainter *	painter,
		const QPointF &	p = QPointF()
	)

Definition at line 342 of file qdeclarativetextlayout.cpp.

{
    QPainterPrivate *priv = QPainterPrivate::get(painter);

    bool paintEngineSupportsTransformations = priv->extended &&
                                              (priv->extended->type() == QPaintEngine::OpenGL2 ||
                                               priv->extended->type() == QPaintEngine::OpenVG ||
                                               priv->extended->type() == QPaintEngine::OpenGL);

    if (!paintEngineSupportsTransformations || !priv->state->matrix.isAffine()) {
        QTextLayout::draw(painter, p);
        return;
    }

    prepare();

    int itemCount = d->items.count();

    if (p != d->position) {
        QFixed fx = QFixed::fromReal(p.x());
        QFixed fy = QFixed::fromReal(p.y());
        QFixed oldX = QFixed::fromReal(d->position.x());
        QFixed oldY = QFixed::fromReal(d->position.y());
        for (int item = 0; item < itemCount; ++item) {
            QStaticTextItem &textItem = d->items[item];

            for (int ii = 0; ii < textItem.numGlyphs; ++ii) {
                textItem.glyphPositions[ii].x += fx - oldX;
                textItem.glyphPositions[ii].y += fy - oldY;
            }
            textItem.userDataNeedsUpdate = true;
        }

        d->position = p;
    }

    QPen oldPen = priv->state->pen;
    QColor currentColor = oldPen.color();
    QColor defaultColor = currentColor;
    for (int ii = 0; ii < itemCount; ++ii) {
        QStaticTextItem &item = d->items[ii];
        if (item.color.isValid() && currentColor != item.color) {
            // up-edge of a <font color="">text</font> tag
            // we set the painter pen to the text item's specified color.
            painter->setPen(item.color);
            currentColor = item.color;
        } else if (!item.color.isValid() && currentColor != defaultColor) {
            // down-edge of a <font color="">text</font> tag
            // we reset the painter pen back to the default color.
            currentColor = defaultColor;
            painter->setPen(currentColor);
        }
        priv->extended->drawStaticTextItem(&item);

        qt_draw_decoration_for_glyphs(painter, item.glyphs, item.glyphPositions,
                                      item.numGlyphs, item.fontEngine(), painter->font(),
                                      QTextCharFormat());
    }
    if (currentColor != oldPen.color())
        painter->setPen(oldPen);
}

prepare()

void QDeclarativeTextLayout::prepare

(

)

Definition at line 309 of file qdeclarativetextlayout.cpp.

Referenced by draw().

{
    if (!d || !d->cached) {

        if (!d)  
            d = new QDeclarativeTextLayoutPrivate;

        InertTextPainter *itp = inertTextPainter();
        itp->device.begin(d);
        QTextLayout::draw(&itp->painter, QPointF(0, 0));

        glyph_t *glyphPool = d->glyphs.data();
        QFixedPoint *positionPool = d->positions.data();
        QChar *charPool = d->chars.data();

        int itemCount = d->items.count();
        for (int ii = 0; ii < itemCount; ++ii) {
            QStaticTextItem &item = d->items[ii];
            item.glyphs = glyphPool + item.glyphOffset;
            item.glyphPositions = positionPool + item.positionOffset;
            item.chars = charPool + item.charOffset;
        }

        d->cached = true;
    }
}

Properties

d

QDeclarativeTextLayoutPrivate* QDeclarativeTextLayout::d

private

Definition at line 68 of file qdeclarativetextlayout_p.h.

Referenced by beginLayout(), clearLayout(), draw(), prepare(), and ~QDeclarativeTextLayout().

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The documentation for this class was generated from the following files:

• /src/declarative/graphicsitems/qdeclarativetextlayout_p.h
• /src/declarative/graphicsitems/qdeclarativetextlayout.cpp