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Diffstat (limited to 'src/gui/text/qstatictext.cpp')
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1 files changed, 616 insertions, 0 deletions
diff --git a/src/gui/text/qstatictext.cpp b/src/gui/text/qstatictext.cpp new file mode 100644 index 0000000..a7138b9 --- /dev/null +++ b/src/gui/text/qstatictext.cpp @@ -0,0 +1,616 @@ +/**************************************************************************** +** +** Copyright (C) 2010 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 <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 maximum + size. The text will then occupy a single line. + + If you set a maximum size on the QStaticText object, this will bound the text. The text will + be formatted so that no line exceeds the given width. When the object is painted, it will + be clipped at the given size. 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. + + QStaticText will attempt to guess the format of the input text using Qt::mightBeRichText(). + 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. + + \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 and bounded by the given \a size. + + If an invalid size is passed for \a size the text will be unbounded. +*/ +QStaticText::QStaticText(const QString &text, const QSizeF &size) + : data(new QStaticTextPrivate) +{ + data->text = text; + data->maximumSize = size; + data->init(); +} + +/*! + 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 the + painter's font or matrix is different from the one used for the currently cached layout. By + default, QStaticText will use a default constructed QFont and an identity matrix to create + its layout. + + To avoid the overhead of creating the layout the first time you draw the QStaticText with + a painter whose matrix or font are different from the defaults, you can use the prepare() + function and pass in the matrix and 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 maximum sizes + are equal. +*/ +bool QStaticText::operator==(const QStaticText &other) const +{ + return (data == other.data + || (data->text == other.data->text + && data->font == other.data->font + && data->maximumSize == other.data->maximumSize)); +} + +/*! + 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 be recalculated. + + \sa text() +*/ +void QStaticText::setText(const QString &text) +{ + detach(); + data->text = text; + data->init(); +} + +/*! + 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 be recalculated. + + \sa textFormat(), setText(), text() +*/ +void QStaticText::setTextFormat(Qt::TextFormat textFormat) +{ + detach(); + data->textFormat = textFormat; + data->init(); +} + +/*! + 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. This hint can be 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 be recalculated. + + \sa performanceHint() +*/ +void QStaticText::setPerformanceHint(PerformanceHint performanceHint) +{ + if ((performanceHint == ModerateCaching && !data->useBackendOptimizations) + || (performanceHint == AggressiveCaching && data->useBackendOptimizations)) { + return; + } + detach(); + data->useBackendOptimizations = (performanceHint == AggressiveCaching); + data->init(); +} + +/*! + Returns which performance hint is set for the QStaticText. + + \sa setPerformanceHint() +*/ +QStaticText::PerformanceHint QStaticText::performanceHint() const +{ + return data->useBackendOptimizations ? AggressiveCaching : ModerateCaching; +} + +/*! + Sets the maximum size of the QStaticText to \a size. + + \note This function will cause the layout of the text to be recalculated. + + \sa maximumSize(), size() +*/ +void QStaticText::setMaximumSize(const QSizeF &size) +{ + detach(); + data->maximumSize = size; + data->init(); +} + +/*! + Returns the maximum size of the QStaticText. + + \sa setMaximumSize() +*/ +QSizeF QStaticText::maximumSize() const +{ + return data->maximumSize; +} + +/*! + Returns the size of the bounding rect for this QStaticText. + + \sa maximumSize() +*/ +QSizeF QStaticText::size() const +{ + return data->actualSize; +} + +QStaticTextPrivate::QStaticTextPrivate() + : items(0), itemCount(0), glyphPool(0), positionPool(0), needsClipRect(false), + useBackendOptimizations(false), textFormat(Qt::AutoText) +{ + ref = 1; +} + +QStaticTextPrivate::QStaticTextPrivate(const QStaticTextPrivate &other) + : text(other.text), font(other.font), maximumSize(other.maximumSize), matrix(other.matrix), + items(0), itemCount(0), glyphPool(0), positionPool(0), needsClipRect(false), + useBackendOptimizations(false), textFormat(other.textFormat) +{ + ref = 1; +} + +QStaticTextPrivate::~QStaticTextPrivate() +{ + delete[] items; + delete[] glyphPool; + delete[] positionPool; +} + +QStaticTextPrivate *QStaticTextPrivate::get(const QStaticText *q) +{ + return q->data.data(); +} + +extern int qt_defaultDpiX(); +extern int qt_defaultDpiY(); + +namespace { + + class DrawTextItemRecorder: public QPaintEngine + { + public: + DrawTextItemRecorder(int expectedItemCount, QStaticTextItem *items, + int expectedGlyphCount, QFixedPoint *positionPool, glyph_t *glyphPool) + : m_items(items), + m_itemCount(0), m_glyphCount(0), + m_expectedItemCount(expectedItemCount), + m_expectedGlyphCount(expectedGlyphCount), + m_glyphPool(glyphPool), + m_positionPool(positionPool) + { + } + + virtual void drawTextItem(const QPointF &position, const QTextItem &textItem) + { + const QTextItemInt &ti = static_cast<const QTextItemInt &>(textItem); + + m_itemCount++; + m_glyphCount += ti.glyphs.numGlyphs; + if (m_items == 0) + return; + + Q_ASSERT(m_itemCount <= m_expectedItemCount); + Q_ASSERT(m_glyphCount <= m_expectedGlyphCount); + + QStaticTextItem *currentItem = (m_items + (m_itemCount - 1)); + currentItem->fontEngine = ti.fontEngine; + currentItem->font = ti.font(); + currentItem->chars = ti.chars; + currentItem->numChars = ti.num_chars; + currentItem->numGlyphs = ti.glyphs.numGlyphs; + currentItem->glyphs = m_glyphPool; + currentItem->glyphPositions = m_positionPool; + currentItem->color = state->pen().color(); + + QTransform matrix = 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 == ti.glyphs.numGlyphs); + Q_ASSERT(size == positions.size()); + + memmove(currentItem->glyphs, glyphs.constData(), sizeof(glyph_t) * size); + memmove(currentItem->glyphPositions, positions.constData(), sizeof(QFixedPoint) * size); + + m_glyphPool += size; + m_positionPool += size; + } + + + virtual bool begin(QPaintDevice *) { return true; } + virtual bool end() { return true; } + virtual void updateState(const QPaintEngineState &) {} + virtual void drawPixmap(const QRectF &, const QPixmap &, const QRectF &) {} + virtual Type type() const + { + return User; + } + + int itemCount() const + { + return m_itemCount; + } + + int glyphCount() const + { + return m_glyphCount; + } + + private: + QStaticTextItem *m_items; + int m_itemCount; + int m_glyphCount; + int m_expectedItemCount; + int m_expectedGlyphCount; + + glyph_t *m_glyphPool; + QFixedPoint *m_positionPool; + }; + + class DrawTextItemDevice: public QPaintDevice + { + public: + DrawTextItemDevice(int expectedItemCount = -1, QStaticTextItem *items = 0, + int expectedGlyphCount = -1, QFixedPoint *positionPool = 0, + glyph_t *glyphPool = 0) + { + m_paintEngine = new DrawTextItemRecorder(expectedItemCount, items, + expectedGlyphCount, positionPool, glyphPool); + } + + ~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; + } + + int itemCount() const + { + return m_paintEngine->itemCount(); + } + + int glyphCount() const + { + return m_paintEngine->glyphCount(); + } + + private: + DrawTextItemRecorder *m_paintEngine; + }; +} + +void QStaticTextPrivate::paintText(const QPointF &pos, QPainter *p) +{ + bool preferRichText = textFormat == Qt::RichText + || (textFormat == Qt::AutoText && Qt::mightBeRichText(text)); + + if (!preferRichText) { + if (maximumSize.isValid()) { + QRectF boundingRect; + p->drawText(QRectF(pos, maximumSize), Qt::TextWordWrap, text, &boundingRect); + + actualSize = boundingRect.size(); + needsClipRect = boundingRect.width() > maximumSize.width() + || boundingRect.height() > maximumSize.height(); + } else { + p->drawText(pos, text); + needsClipRect = false; + + QFontMetrics fm(font); + actualSize = fm.boundingRect(text).size(); + } + } else { + QTextDocument document; + document.setDefaultFont(font); + document.setHtml(text); + + QRectF rect = maximumSize.isValid() ? QRectF(pos, maximumSize) : QRectF(); + document.adjustSize(); + p->save(); + p->translate(pos); + document.drawContents(p, rect); + p->restore(); + actualSize = document.size(); + needsClipRect = maximumSize.isValid() + && (actualSize.width() > maximumSize.width() + || actualSize.height() > maximumSize.height()); + } +} + +void QStaticTextPrivate::init() +{ + delete[] items; + delete[] glyphPool; + delete[] positionPool; + + position = QPointF(0, 0); + + // Draw once to count number of items and glyphs, so that we can use as little memory + // as possible to store the data + DrawTextItemDevice counterDevice; + { + QPainter painter(&counterDevice); + painter.setFont(font); + painter.setTransform(matrix); + + paintText(QPointF(0, 0), &painter); + + } + + itemCount = counterDevice.itemCount(); + items = new QStaticTextItem[itemCount]; + + if (useBackendOptimizations) { + for (int i=0; i<itemCount; ++i) + items[i].useBackendOptimizations = true; + } + + + int glyphCount = counterDevice.glyphCount(); + glyphPool = new glyph_t[glyphCount]; + positionPool = new QFixedPoint[glyphCount]; + + // Draw again to actually record the items and glyphs + DrawTextItemDevice recorderDevice(itemCount, items, glyphCount, positionPool, glyphPool); + { + QPainter painter(&recorderDevice); + painter.setFont(font); + painter.setTransform(matrix); + + paintText(QPointF(0, 0), &painter); + } + +} + +QT_END_NAMESPACE |