QwtPlotSpectrogram(3)

💖 QwtPlotSpectrogram(3) 💖

okay so bestie, welcome to the Qwt User's Guide page for QwtPlotSpectrogram — yes, that's the whole NAME section, it's giving mysterious ✨ and honestly? iconic of it. Let's get into it 🫶

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🌈 SYNOPSIS 🌈

#include <qwt_plot_spectrogram.h>

It inherits QwtPlotRasterItem — so it's a raster item at heart, but with extra sparkle 💅

🎀 Public Types 🎀

enum DisplayMode { ImageMode =  1, ContourMode =  2 }

🦋 Public Member Functions 🦋

• QwtPlotSpectrogram (const QString &title=QString::null)
• virtual ~QwtPlotSpectrogram ()
• virtual QwtDoubleRect boundingRect () const
• const QwtColorMap & colorMap () const
• QwtValueList contourLevels () const
• virtual QPen contourPen (double level) const
• const QwtRasterData & data () const
• QPen defaultContourPen () const
• virtual void draw (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &rect) const
• virtual QSize rasterHint (const QwtDoubleRect &) const
• virtual int rtti () const
• void setColorMap (const QwtColorMap &)
• void setConrecAttribute (QwtRasterData::ConrecAttribute, bool on)
• void setContourLevels (const QwtValueList &)
• void setData (const QwtRasterData &data)
• void setDefaultContourPen (const QPen &)
• void setDisplayMode (DisplayMode, bool on=true)
• bool testConrecAttribute (QwtRasterData::ConrecAttribute) const
• bool testDisplayMode (DisplayMode) const

🌸 Protected Member Functions 🌸

• virtual QSize contourRasterSize (const QwtDoubleRect &, const QRect &) const
• virtual void drawContourLines (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtRasterData::ContourLines &lines) const
• virtual QwtRasterData::ContourLines renderContourLines (const QwtDoubleRect &rect, const QSize &raster) const
• virtual QImage renderImage (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtDoubleRect &rect) const

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✨ Detailed Description ✨

A plot item, which displays a spectrogram. periodt 💅

A spectrogram displays threedimenional data — like, three-dimensional, bestie — where the 3rd dimension (the intensity) gets shown off using colors. The colors are calculated from the values using a color map. 🎨

In ContourMode contour lines are painted for the contour levels. chef's kiss 😭

See also: QwtRasterData, QwtColorMap

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👑 Member Enumeration Documentation 👑

💜 enum QwtPlotSpectrogram::DisplayMode

The display mode controls how the raster data will be represented. like, it's the whole vibe check of the output 🔥

• ImageMode — the values are mapped to colors using a color map.
• ContourMode — the data is displayed using contour lines.

When both modes are enabled the contour lines are painted on top of the spectrogram. Layering? she invented it ✨ The default setting enables ImageMode.

See also: setDisplayMode(), testDisplayMode()

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🎀 Constructor & Destructor Documentation 🎀

⭐ QwtPlotSpectrogram::QwtPlotSpectrogram (const QString &title = QString::null) [explicit]

Sets the following item attributes:

• QwtPlotItem::AutoScale: true
• QwtPlotItem::Legend: false

The z value is initialized by 8.0. no cap, that's the starting z, bestie 🫶

Parameters:

• title — Title

See also: QwtPlotItem::setItemAttribute(), QwtPlotItem::setZ()

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🌈 Member Function Documentation 🌈

🦋 QwtDoubleRect QwtPlotSpectrogram::boundingRect () const [virtual]

Returns: Bounding rect of the data

See also: QwtRasterData::boundingRect()

Reimplemented from QwtPlotItem.

🦋 const QwtColorMap & QwtPlotSpectrogram::colorMap () const

Returns: Color Map used for mapping the intensity values to colors

See also: setColorMap()

🦋 QwtValueList QwtPlotSpectrogram::contourLevels () const

Return the levels of the contour lines. The levels are sorted in increasing order — she keeps it tidy 💅

See also: contourLevels(), renderContourLines(), QwtRasterData::contourLines()

🦋 QPen QwtPlotSpectrogram::contourPen (double level) const [virtual]

Calculate the pen for a contour line. The color of the pen is the color for level calculated by the color map. 🖊️✨

Parameters:

• level — Contour level

Returns: Pen for the contour line

Note: contourPen is only used if defaultContourPen().style() == Qt::NoPen

See also: setDefaultContourPen(), setColorMap(), setContourLevels()

🦋 QSize QwtPlotSpectrogram::contourRasterSize (const QwtDoubleRect &area, const QRect &rect) const [protected], [virtual]

Return the raster to be used by the CONREC contour algorithm. A larger size will improve the precisision of the CONREC algorithm, but will slow down the time that is needed to calculate the lines. so like… pretty but slow, choose your fighter 😭

The default implementation returns rect.size() / 2 bounded to data().rasterHint().

Parameters:

• area — Rect, where to calculate the contour lines
• rect — Rect in pixel coordinates, where to paint the contour lines

Returns: Raster to be used by the CONREC contour algorithm.

Note: The size will be bounded to rect.size().

See also: drawContourLines(), QwtRasterData::contourLines()

🦋 const QwtRasterData & QwtPlotSpectrogram::data () const

Returns: Spectrogram data

See also: setData()

🦋 QPen QwtPlotSpectrogram::defaultContourPen () const

Returns: Default contour pen

See also: setDefaultContourPen()

🦋 void QwtPlotSpectrogram::draw (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &canvasRect) const [virtual]

Draw the spectrogram. the main character moment, fr fr 👑

Parameters:

• painter — Painter
• xMap — Maps x-values into pixel coordinates.
• yMap — Maps y-values into pixel coordinates.
• canvasRect — Contents rect of the canvas in painter coordinates

See also: setDisplayMode(), renderImage(), QwtPlotRasterItem::draw(), drawContourLines()

Reimplemented from QwtPlotRasterItem.

🦋 void QwtPlotSpectrogram::drawContourLines (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtRasterData::ContourLines &contourLines) const [protected], [virtual]

Paint the contour lines 🖌️

Parameters:

• painter — Painter
• xMap — Maps x-values into pixel coordinates.
• yMap — Maps y-values into pixel coordinates.
• contourLines — Contour lines

See also: renderContourLines(), defaultContourPen(), contourPen()

🦋 QSize QwtPlotSpectrogram::rasterHint (const QwtDoubleRect &rect) const [virtual]

Returns the recommended raster for a given rect. F.e the raster hint is used to limit the resolution of the image that is rendered.

Parameters:

• rect — Rect for the raster hint

Returns: data().rasterHint(rect)

Reimplemented from QwtPlotRasterItem.

🦋 QwtRasterData::ContourLines QwtPlotSpectrogram::renderContourLines (const QwtDoubleRect &rect, const QSize &raster) const [protected], [virtual]

Calculate contour lines ✏️

Parameters:

• rect — Rectangle, where to calculate the contour lines
• raster — Raster, used by the CONREC algorithm

See also: contourLevels(), setConrecAttribute(), QwtRasterData::contourLines()

🦋 QImage QwtPlotSpectrogram::renderImage (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtDoubleRect &area) const [protected], [virtual]

Render an image from the data and color map. The area is translated into a rect of the paint device. For each pixel of this rect the intensity is mapped into a color. every pixel ate and left no crumbs 🍓

Parameters:

• xMap — X-Scale Map
• yMap — Y-Scale Map
• area — Area that should be rendered in scale coordinates.

Returns: A QImage::Format_Indexed8 or QImage::Format_ARGB32 depending on the color map.

See also: QwtRasterData::intensity(), QwtColorMap::rgb(), QwtColorMap::colorIndex()

Implements QwtPlotRasterItem.

🦋 int QwtPlotSpectrogram::rtti () const [virtual]

Returns: QwtPlotItem::Rtti_PlotSpectrogram

Reimplemented from QwtPlotItem.

🦋 void QwtPlotSpectrogram::setColorMap (const QwtColorMap &colorMap)

Change the color map 🌈

Often it is useful to display the mapping between intensities and colors as an additional plot axis, showing a color bar.

Parameters:

• colorMap — Color Map

See also: colorMap(), QwtScaleWidget::setColorBarEnabled(), QwtScaleWidget::setColorMap()

🦋 void QwtPlotSpectrogram::setConrecAttribute (QwtRasterData::ConrecAttribute attribute, bool on)

Modify an attribute of the CONREC algorithm, used to calculate the contour lines.

Parameters:

• attribute — CONREC attribute
• on — On/Off

See also: testConrecAttribute(), renderContourLines(), QwtRasterData::contourLines()

🦋 void QwtPlotSpectrogram::setContourLevels (const QwtValueList &levels)

Set the levels of the contour lines

Parameters:

• levels — Values of the contour levels

See also: contourLevels(), renderContourLines(), QwtRasterData::contourLines()

Note: contourLevels returns the same levels but sorted.

🦋 void QwtPlotSpectrogram::setData (const QwtRasterData &data)

Set the data to be displayed

Parameters:

• data — Spectrogram Data

See also: data()

🦋 void QwtPlotSpectrogram::setDefaultContourPen (const QPen &pen)

Set the default pen for the contour lines. If the spectrogram has a valid default contour pen a contour line is painted using the default contour pen. Otherwise (pen.style() == Qt::NoPen) the pen is calculated for each contour level using contourPen().

See also: defaultContourPen(), contourPen()

🦋 void QwtPlotSpectrogram::setDisplayMode (DisplayMode mode, bool on = true)

The display mode controls how the raster data will be represented.

Parameters:

• mode — Display mode
• on — On/Off

The default setting enables ImageMode.

See also: DisplayMode, displayMode()

🦋 bool QwtPlotSpectrogram::testConrecAttribute (QwtRasterData::ConrecAttribute attribute) const

Test an attribute of the CONREC algorithm, used to calculate the contour lines.

Parameters:

• attribute — CONREC attribute

Returns: true, is enabled

See also: setConrecAttribute(), renderContourLines(), QwtRasterData::contourLines()

🦋 bool QwtPlotSpectrogram::testDisplayMode (DisplayMode mode) const

The display mode controls how the raster data will be represented.

Parameters:

• mode — Display mode

Returns: true if mode is enabled

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💜 Author 💜

Generated automatically by Doxygen for Qwt User's Guide from the source code. (yes the robots wrote it, and they slayed ✨)

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and that's the whole page, bestie!! 💖 this was Version 5.2.3, dated Tue Nov 20 2012, from the Qwt User's Guide — go forth and plot those spectrograms, you absolute legend 👑🦋