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Diffstat (limited to 'src/gui/text/qstatictext.cpp')
| -rw-r--r-- | src/gui/text/qstatictext.cpp | 733 |
1 files changed, 733 insertions, 0 deletions
diff --git a/src/gui/text/qstatictext.cpp b/src/gui/text/qstatictext.cpp new file mode 100644 index 0000000000..1cfb4b61f9 --- /dev/null +++ b/src/gui/text/qstatictext.cpp @@ -0,0 +1,733 @@ +/**************************************************************************** +** +** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies). +** All rights reserved. +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the test suite of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the Technology Preview License Agreement accompanying +** this package. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain additional +** rights. These rights are described in the Nokia Qt LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** If you have questions regarding the use of this file, please contact +** Nokia at qt-info@nokia.com. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qstatictext.h" +#include "qstatictext_p.h" +#include <private/qtextengine_p.h> +#include <private/qfontengine_p.h> +#include <qabstracttextdocumentlayout.h> + +#include <QtGui/qapplication.h> + +QT_BEGIN_NAMESPACE + +/*! + \class QStaticText + \brief The QStaticText class enables optimized drawing of text when the text and its layout + is updated rarely. + \since 4.7 + + \ingroup multimedia + \ingroup text + \mainclass + + QStaticText provides a way to cache layout data for a block of text so that it can be drawn + more efficiently than by using QPainter::drawText() in which the layout information is + recalculated with every call. + + The class primarily provides an optimization for cases where the text, its font and the + transformations on the painter are static over several paint events. If the text or its layout + is changed for every iteration, QPainter::drawText() is the more efficient alternative, since + the static text's layout would have to be recalculated to take the new state into consideration. + + Translating the painter will not cause the layout of the text to be recalculated, but will cause + a very small performance impact on drawStaticText(). Altering any other parts of the painter's + transformation or the painter's font will cause the layout of the static text to be + recalculated. This should be avoided as often as possible to maximize the performance + benefit of using QStaticText. + + In addition, only affine transformations are supported by drawStaticText(). Calling + drawStaticText() on a projected painter will perform slightly worse than using the regular + drawText() call, so this should be avoided. + + \code + class MyWidget: public QWidget + { + public: + MyWidget(QWidget *parent = 0) : QWidget(parent), m_staticText("This is static text") + + protected: + void paintEvent(QPaintEvent *) + { + QPainter painter(this); + painter.drawStaticText(0, 0, m_staticText); + } + + private: + QStaticText m_staticText; + }; + \endcode + + The QStaticText class can be used to mimic the behavior of QPainter::drawText() to a specific + point with no boundaries, and also when QPainter::drawText() is called with a bounding + rectangle. + + If a bounding rectangle is not required, create a QStaticText object without setting a preferred + text width. The text will then occupy a single line. + + If you set a text width on the QStaticText object, this will bound the text. The text will + be formatted so that no line exceeds the given width. The text width set for QStaticText will + not automatically be used for clipping. To achieve clipping in addition to line breaks, use + QPainter::setClipRect(). The position of the text is decided by the argument passed to + QPainter::drawStaticText() and can change from call to call with a minimal impact on + performance. + + For extra convenience, it is possible to apply formatting to the text using the HTML subset + supported by QTextDocument. QStaticText will attempt to guess the format of the input text using + Qt::mightBeRichText(), and interpret it as rich text if this function returns true. To force + QStaticText to display its contents as either plain text or rich text, use the function + QStaticText::setTextFormat() and pass in, respectively, Qt::PlainText and Qt::RichText. + + QStaticText can only represent text, so only HTML tags which alter the layout or appearance of + the text will be respected. Adding an image to the input HTML, for instance, will cause the + image to be included as part of the layout, affecting the positions of the text glyphs, but it + will not be displayed. The result will be an empty area the size of the image in the output. + Similarly, using tables will cause the text to be laid out in table format, but the borders + will not be drawn. + + If it's the first time the static text is drawn, or if the static text, or the painter's font + has been altered since the last time it was drawn, the text's layout has to be + recalculated. On some paint engines, changing the matrix of the painter will also cause the + layout to be recalculated. In particular, this will happen for any engine except for the + OpenGL2 paint engine. Recalculating the layout will impose an overhead on the + QPainter::drawStaticText() call where it occurs. To avoid this overhead in the paint event, you + can call prepare() ahead of time to ensure that the layout is calculated. + + \sa QPainter::drawText(), QPainter::drawStaticText(), QTextLayout, QTextDocument +*/ + +/*! + \enum QStaticText::PerformanceHint + + This enum the different performance hints that can be set on the QStaticText. These hints + can be used to indicate that the QStaticText should use additional caches, if possible, + to improve performance at the expense of memory. In particular, setting the performance hint + AggressiveCaching on the QStaticText will improve performance when using the OpenGL graphics + system or when drawing to a QGLWidget. + + \value ModerateCaching Do basic caching for high performance at a low memory cost. + \value AggressiveCaching Use additional caching when available. This may improve performance + at a higher memory cost. +*/ + +/*! + Constructs an empty QStaticText +*/ +QStaticText::QStaticText() + : data(new QStaticTextPrivate) +{ +} + +/*! + Constructs a QStaticText object with the given \a text. +*/ +QStaticText::QStaticText(const QString &text) + : data(new QStaticTextPrivate) +{ + data->text = text; + data->invalidate(); +} + +/*! + Constructs a QStaticText object which is a copy of \a other. +*/ +QStaticText::QStaticText(const QStaticText &other) +{ + data = other.data; +} + +/*! + Destroys the QStaticText. +*/ +QStaticText::~QStaticText() +{ + Q_ASSERT(!data || data->ref >= 1); +} + +/*! + \internal +*/ +void QStaticText::detach() +{ + if (data->ref != 1) + data.detach(); +} + +/*! + Prepares the QStaticText object for being painted with the given \a matrix and the given \a font + to avoid overhead when the actual drawStaticText() call is made. + + When drawStaticText() is called, the layout of the QStaticText will be recalculated if any part + of the QStaticText object has changed since the last time it was drawn. It will also be + recalculated if the painter's font is not the same as when the QStaticText was last drawn, or, + on any other paint engine than the OpenGL2 engine, if the painter's matrix has been altered + since the static text was last drawn. + + To avoid the overhead of creating the layout the first time you draw the QStaticText after + making changes, you can use the prepare() function and pass in the \a matrix and \a font you + expect to use when drawing the text. + + \sa QPainter::setFont(), QPainter::setMatrix() +*/ +void QStaticText::prepare(const QTransform &matrix, const QFont &font) +{ + data->matrix = matrix; + data->font = font; + data->init(); +} + + +/*! + Assigns \a other to this QStaticText. +*/ +QStaticText &QStaticText::operator=(const QStaticText &other) +{ + data = other.data; + return *this; +} + +/*! + Compares \a other to this QStaticText. Returns true if the texts, fonts and text widths + are equal. +*/ +bool QStaticText::operator==(const QStaticText &other) const +{ + return (data == other.data + || (data->text == other.data->text + && data->font == other.data->font + && data->textWidth == other.data->textWidth)); +} + +/*! + Compares \a other to this QStaticText. Returns true if the texts, fonts or maximum sizes + are different. +*/ +bool QStaticText::operator!=(const QStaticText &other) const +{ + return !(*this == other); +} + +/*! + Sets the text of the QStaticText to \a text. + + \note This function will cause the layout of the text to require recalculation. + + \sa text() +*/ +void QStaticText::setText(const QString &text) +{ + detach(); + data->text = text; + data->invalidate(); +} + +/*! + Sets the text format of the QStaticText to \a textFormat. If \a textFormat is set to + Qt::AutoText (the default), the format of the text will try to be determined using the + function Qt::mightBeRichText(). If the text format is Qt::PlainText, then the text will be + displayed as is, whereas it will be interpreted as HTML if the format is Qt::RichText. HTML tags + that alter the font of the text, its color, or its layout are supported by QStaticText. + + \note This function will cause the layout of the text to require recalculation. + + \sa textFormat(), setText(), text() +*/ +void QStaticText::setTextFormat(Qt::TextFormat textFormat) +{ + detach(); + data->textFormat = textFormat; + data->invalidate(); +} + +/*! + Returns the text format of the QStaticText. + + \sa setTextFormat(), setText(), text() +*/ +Qt::TextFormat QStaticText::textFormat() const +{ + return Qt::TextFormat(data->textFormat); +} + +/*! + Returns the text of the QStaticText. + + \sa setText() +*/ +QString QStaticText::text() const +{ + return data->text; +} + +/*! + Sets the performance hint of the QStaticText according to the \a + performanceHint provided. The \a performanceHint is used to + customize how much caching is done internally to improve + performance. + + The default is QStaticText::ModerateCaching. + + \note This function will cause the layout of the text to require recalculation. + + \sa performanceHint() +*/ +void QStaticText::setPerformanceHint(PerformanceHint performanceHint) +{ + if ((performanceHint == ModerateCaching && !data->useBackendOptimizations) + || (performanceHint == AggressiveCaching && data->useBackendOptimizations)) { + return; + } + detach(); + data->useBackendOptimizations = (performanceHint == AggressiveCaching); + data->invalidate(); +} + +/*! + Returns which performance hint is set for the QStaticText. + + \sa setPerformanceHint() +*/ +QStaticText::PerformanceHint QStaticText::performanceHint() const +{ + return data->useBackendOptimizations ? AggressiveCaching : ModerateCaching; +} + +/*! + Sets the text option structure that controls the layout process to the given \a textOption. + + \sa textOption() +*/ +void QStaticText::setTextOption(const QTextOption &textOption) +{ + detach(); + data->textOption = textOption; + data->invalidate(); +} + +/*! + Returns the current text option used to control the layout process. +*/ +QTextOption QStaticText::textOption() const +{ + return data->textOption; +} + +/*! + Sets the preferred width for this QStaticText. If the text is wider than the specified width, + it will be broken into multiple lines and grow vertically. If the text cannot be split into + multiple lines, it will be larger than the specified \a textWidth. + + Setting the preferred text width to a negative number will cause the text to be unbounded. + + Use size() to get the actual size of the text. + + \note This function will cause the layout of the text to require recalculation. + + \sa textWidth(), size() +*/ +void QStaticText::setTextWidth(qreal textWidth) +{ + detach(); + data->textWidth = textWidth; + data->invalidate(); +} + +/*! + Returns the preferred width for this QStaticText. + + \sa setTextWidth() +*/ +qreal QStaticText::textWidth() const +{ + return data->textWidth; +} + +/*! + Returns the size of the bounding rect for this QStaticText. + + \sa textWidth() +*/ +QSizeF QStaticText::size() const +{ + if (data->needsRelayout) + data->init(); + return data->actualSize; +} + +QStaticTextPrivate::QStaticTextPrivate() + : textWidth(-1.0), items(0), itemCount(0), glyphPool(0), positionPool(0), charPool(0), + needsRelayout(true), useBackendOptimizations(false), textFormat(Qt::AutoText), + untransformedCoordinates(false) +{ +} + +QStaticTextPrivate::QStaticTextPrivate(const QStaticTextPrivate &other) + : text(other.text), font(other.font), textWidth(other.textWidth), matrix(other.matrix), + items(0), itemCount(0), glyphPool(0), positionPool(0), charPool(0), textOption(other.textOption), + needsRelayout(true), useBackendOptimizations(other.useBackendOptimizations), + textFormat(other.textFormat), untransformedCoordinates(other.untransformedCoordinates) +{ +} + +QStaticTextPrivate::~QStaticTextPrivate() +{ + delete[] items; + delete[] glyphPool; + delete[] positionPool; + delete[] charPool; +} + +QStaticTextPrivate *QStaticTextPrivate::get(const QStaticText *q) +{ + return q->data.data(); +} + +namespace { + + class DrawTextItemRecorder: public QPaintEngine + { + public: + DrawTextItemRecorder(bool untransformedCoordinates, bool useBackendOptimizations) + : m_dirtyPen(false), m_useBackendOptimizations(useBackendOptimizations), + m_untransformedCoordinates(untransformedCoordinates) + { + } + + virtual void updateState(const QPaintEngineState &newState) + { + if (newState.state() & QPaintEngine::DirtyPen) + m_dirtyPen = true; + } + + virtual void drawTextItem(const QPointF &position, const QTextItem &textItem) + { + const QTextItemInt &ti = static_cast<const QTextItemInt &>(textItem); + + QStaticTextItem currentItem; + currentItem.setFontEngine(ti.fontEngine); + currentItem.font = ti.font(); + currentItem.charOffset = m_chars.size(); + currentItem.numChars = ti.num_chars; + currentItem.glyphOffset = m_glyphs.size(); // Store offset into glyph pool + currentItem.positionOffset = m_glyphs.size(); // Offset into position pool + currentItem.useBackendOptimizations = m_useBackendOptimizations; + if (m_dirtyPen) + currentItem.color = state->pen().color(); + + QTransform matrix = m_untransformedCoordinates ? QTransform() : state->transform(); + matrix.translate(position.x(), position.y()); + + QVarLengthArray<glyph_t> glyphs; + QVarLengthArray<QFixedPoint> positions; + ti.fontEngine->getGlyphPositions(ti.glyphs, matrix, ti.flags, glyphs, positions); + + int size = glyphs.size(); + Q_ASSERT(size == positions.size()); + currentItem.numGlyphs = size; + + m_glyphs.resize(m_glyphs.size() + size); + m_positions.resize(m_glyphs.size()); + m_chars.resize(m_chars.size() + ti.num_chars); + + glyph_t *glyphsDestination = m_glyphs.data() + currentItem.glyphOffset; + memcpy(glyphsDestination, glyphs.constData(), sizeof(glyph_t) * currentItem.numGlyphs); + + QFixedPoint *positionsDestination = m_positions.data() + currentItem.positionOffset; + memcpy(positionsDestination, positions.constData(), sizeof(QFixedPoint) * currentItem.numGlyphs); + + QChar *charsDestination = m_chars.data() + currentItem.charOffset; + memcpy(charsDestination, ti.chars, sizeof(QChar) * currentItem.numChars); + + m_items.append(currentItem); + } + + virtual void drawPolygon(const QPointF *, int , PolygonDrawMode ) + { + /* intentionally empty */ + } + + virtual bool begin(QPaintDevice *) { return true; } + virtual bool end() { return true; } + virtual void drawPixmap(const QRectF &, const QPixmap &, const QRectF &) {} + virtual Type type() const + { + return User; + } + + QVector<QStaticTextItem> items() const + { + return m_items; + } + + QVector<QFixedPoint> positions() const + { + return m_positions; + } + + QVector<glyph_t> glyphs() const + { + return m_glyphs; + } + + QVector<QChar> chars() const + { + return m_chars; + } + + private: + QVector<QStaticTextItem> m_items; + QVector<QFixedPoint> m_positions; + QVector<glyph_t> m_glyphs; + QVector<QChar> m_chars; + + bool m_dirtyPen; + bool m_useBackendOptimizations; + bool m_untransformedCoordinates; + }; + + class DrawTextItemDevice: public QPaintDevice + { + public: + DrawTextItemDevice(bool untransformedCoordinates, bool useBackendOptimizations) + { + m_paintEngine = new DrawTextItemRecorder(untransformedCoordinates, + useBackendOptimizations); + } + + ~DrawTextItemDevice() + { + delete m_paintEngine; + } + + int metric(PaintDeviceMetric m) const + { + int val; + switch (m) { + case PdmWidth: + case PdmHeight: + case PdmWidthMM: + case PdmHeightMM: + val = 0; + break; + case PdmDpiX: + case PdmPhysicalDpiX: + val = qt_defaultDpiX(); + break; + case PdmDpiY: + case PdmPhysicalDpiY: + val = qt_defaultDpiY(); + break; + case PdmNumColors: + val = 16777216; + break; + case PdmDepth: + val = 24; + break; + default: + val = 0; + qWarning("DrawTextItemDevice::metric: Invalid metric command"); + } + return val; + } + + virtual QPaintEngine *paintEngine() const + { + return m_paintEngine; + } + + QVector<glyph_t> glyphs() const + { + return m_paintEngine->glyphs(); + } + + QVector<QFixedPoint> positions() const + { + return m_paintEngine->positions(); + } + + QVector<QStaticTextItem> items() const + { + return m_paintEngine->items(); + } + + QVector<QChar> chars() const + { + return m_paintEngine->chars(); + } + + private: + DrawTextItemRecorder *m_paintEngine; + }; +} + +void QStaticTextPrivate::paintText(const QPointF &topLeftPosition, QPainter *p) +{ + bool preferRichText = textFormat == Qt::RichText + || (textFormat == Qt::AutoText && Qt::mightBeRichText(text)); + + if (!preferRichText) { + QTextLayout textLayout; + textLayout.setText(text); + textLayout.setFont(font); + textLayout.setTextOption(textOption); + + qreal leading = QFontMetricsF(font).leading(); + qreal height = -leading; + + textLayout.beginLayout(); + while (1) { + QTextLine line = textLayout.createLine(); + if (!line.isValid()) + break; + + if (textWidth >= 0.0) + line.setLineWidth(textWidth); + height += leading; + line.setPosition(QPointF(0.0, height)); + height += line.height(); + } + textLayout.endLayout(); + + actualSize = textLayout.boundingRect().size(); + textLayout.draw(p, topLeftPosition); + } else { + QTextDocument document; +#ifndef QT_NO_CSSPARSER + QColor color = p->pen().color(); + document.setDefaultStyleSheet(QString::fromLatin1("body { color: #%1%2%3 }") + .arg(QString::number(color.red(), 16), 2, QLatin1Char('0')) + .arg(QString::number(color.green(), 16), 2, QLatin1Char('0')) + .arg(QString::number(color.blue(), 16), 2, QLatin1Char('0'))); +#endif + document.setDefaultFont(font); + document.setDocumentMargin(0.0); +#ifndef QT_NO_TEXTHTMLPARSER + document.setHtml(text); +#else + document.setPlainText(text); +#endif + if (textWidth >= 0.0) + document.setTextWidth(textWidth); + else + document.adjustSize(); + document.setDefaultTextOption(textOption); + + p->save(); + p->translate(topLeftPosition); + QAbstractTextDocumentLayout::PaintContext ctx; + ctx.palette.setColor(QPalette::Text, p->pen().color()); + document.documentLayout()->draw(p, ctx); + p->restore(); + + if (textWidth >= 0.0) + document.adjustSize(); // Find optimal size + + actualSize = document.size(); + } +} + +void QStaticTextPrivate::init() +{ + delete[] items; + delete[] glyphPool; + delete[] positionPool; + delete[] charPool; + + position = QPointF(0, 0); + + DrawTextItemDevice device(untransformedCoordinates, useBackendOptimizations); + { + QPainter painter(&device); + painter.setFont(font); + painter.setTransform(matrix); + + paintText(QPointF(0, 0), &painter); + } + + QVector<QStaticTextItem> deviceItems = device.items(); + QVector<QFixedPoint> positions = device.positions(); + QVector<glyph_t> glyphs = device.glyphs(); + QVector<QChar> chars = device.chars(); + + itemCount = deviceItems.size(); + items = new QStaticTextItem[itemCount]; + + glyphPool = new glyph_t[glyphs.size()]; + memcpy(glyphPool, glyphs.constData(), glyphs.size() * sizeof(glyph_t)); + + positionPool = new QFixedPoint[positions.size()]; + memcpy(positionPool, positions.constData(), positions.size() * sizeof(QFixedPoint)); + + charPool = new QChar[chars.size()]; + memcpy(charPool, chars.constData(), chars.size() * sizeof(QChar)); + + for (int i=0; i<itemCount; ++i) { + items[i] = deviceItems.at(i); + + items[i].glyphs = glyphPool + items[i].glyphOffset; + items[i].glyphPositions = positionPool + items[i].positionOffset; + items[i].chars = charPool + items[i].charOffset; + } + + needsRelayout = false; +} + +QStaticTextItem::~QStaticTextItem() +{ + if (m_userData != 0 && !m_userData->ref.deref()) + delete m_userData; + if (!m_fontEngine->ref.deref()) + delete m_fontEngine; +} + +void QStaticTextItem::setFontEngine(QFontEngine *fe) +{ + if (m_fontEngine != 0) { + if (!m_fontEngine->ref.deref()) + delete m_fontEngine; + } + + m_fontEngine = fe; + if (m_fontEngine != 0) + m_fontEngine->ref.ref(); +} + +QT_END_NAMESPACE |