KisHistogramPainter Class Reference

A class that can render different KisHistograms. It renders a somewhat smooth shape (with different colors for rgb, cmyk and xyz channels). It can also render the different channels of a colorspace overlapped. More...

#include <KisHistogramPainter.h>

Classes
class	Private

Public Member Functions
QList< int >	availableChannels () const
	Get a list containing all the indices of the channels that were setup using the "setup" function.
const QVector< int > &	channels () const
	Get the list of channels that are currently activated (the only ones that will be painted)
QColor	defaultColor () const
	Returns the color that is being used to paint a generic histogram. All the histogram channels will use this color with the exception of the red, green and blue channels in a rgba histogram; the cyan, magenta, yellow and black channels in a cmyka histogram; and the x, y, and z channels in a xyz histogram.
bool	isLogarithmic () const
	Returns true if the histogram shape being painted is formed by the logarithmic mapping of the original histogram values instead of the values themselves.
	KisHistogramPainter ()
QImage	paint (const QSize &imageSize)
	Returns a RGBA image of size "imageSize" with the result of rendering the selected histogram channels on it.
QImage	paint (int w, int h)
	Returns a RGBA image of size "w"x"h" with the result of rendering the selected histogram channels on it.
void	paint (QPainter &painter, const QRect &rect)
	Paints the selected histogram channels in the given rect using the given painter.
qreal	scale () const
	Return the vertical scale that is used to paint the histogram shape. A scale of 1 will paint all the histogram in the given rect. Scales less that 1 are not allowed.
void	setChannel (int channel)
	Set currently active channel (the one that will be painted)
void	setChannels (const QVector< int > &channels)
	Set currently active channels (the ones that will be painted)
void	setDefaultColor (const QColor &newDefaultColor)
	Set the default color used when there is no preference to color the selected histogram channel.
void	setLogarithmic (bool logarithmic)
	Set if the histogram shape being shown is formed by the logarithmic mapping of the original histogram values instead of the values themselves.
void	setScale (qreal newScale)
	Set the scale used to paint the histograms.
void	setScaleToCutLongPeaks ()
	Sometimes there can be some outliers in the histogram that show in the painted shape as long vertical peaks. Since a scale of 1 will show all the histogram, this can make its interesting parts too small to take any valuable information from them. This function will try to come up with a scale value that favors those interesting parts over the long peaks, which will be pushed and will look cut.
void	setScaleToFit ()
	Set the scale used to paint the histograms to 1.
void	setup (KisHistogram *histogram, const KoColorSpace *colorSpace, QVector< int > channels={})
	Sets up the painter by passing a KisHistogram, the color space for the histogram and the channels that must be set up for it.
int	totalNumberOfAvailableChannels () const
	Get the number of channels that are being used. It can be less than the total number of channels in the KisHistogram. This can be set by using the setup function.
	~KisHistogramPainter ()

Private Attributes
QScopedPointer< Private >	m_d

Detailed Description

A class that can render different KisHistograms. It renders a somewhat smooth shape (with different colors for rgb, cmyk and xyz channels). It can also render the different channels of a colorspace overlapped.

Definition at line 27 of file KisHistogramPainter.h.

Constructor & Destructor Documentation

KisHistogramPainter()

KisHistogramPainter::KisHistogramPainter

(

)

Definition at line 289 of file KisHistogramPainter.cpp.

    : m_d(new Private)
{
    m_d->defaultColor = Qt::gray;
}

References m_d.

~KisHistogramPainter()

KisHistogramPainter::~KisHistogramPainter

(

)

Definition at line 295 of file KisHistogramPainter.cpp.

{}

Member Function Documentation

availableChannels()

QList< int > KisHistogramPainter::availableChannels

(

)

const

Get a list containing all the indices of the channels that were setup using the "setup" function.

See also

setup

Definition at line 366 of file KisHistogramPainter.cpp.

{
    return m_d->histogramChannelShapeInfo.keys();
}

References m_d.

channels()

const QVector< int > & KisHistogramPainter::channels

(

)

const

Get the list of channels that are currently activated (the only ones that will be painted)

See also

setChannel

setChannels

Definition at line 371 of file KisHistogramPainter.cpp.

{
    return m_d->channelsToPaint;
}

References m_d.

defaultColor()

QColor KisHistogramPainter::defaultColor

(

)

const

Returns the color that is being used to paint a generic histogram. All the histogram channels will use this color with the exception of the red, green and blue channels in a rgba histogram; the cyan, magenta, yellow and black channels in a cmyka histogram; and the x, y, and z channels in a xyz histogram.

See also

setDefaultColor

Definition at line 386 of file KisHistogramPainter.cpp.

{
    return m_d->defaultColor;
}

References m_d.

isLogarithmic()

bool KisHistogramPainter::isLogarithmic

(

)

const

Returns true if the histogram shape being painted is formed by the logarithmic mapping of the original histogram values instead of the values themselves.

See also

setLogarithmic

Definition at line 444 of file KisHistogramPainter.cpp.

{
    return m_d->isLogarithmic;
}

References m_d.

paint() [1/3]

QImage KisHistogramPainter::paint

(

const QSize &

imageSize

)

Returns a RGBA image of size "imageSize" with the result of rendering the selected histogram channels on it.

Definition at line 345 of file KisHistogramPainter.cpp.

{
    return m_d->paintChannels(imageSize, m_d->channelsToPaint, m_d->isLogarithmic);
}

References m_d.

paint() [2/3]

QImage KisHistogramPainter::paint	(	int	w,
		int	h )

Returns a RGBA image of size "w"x"h" with the result of rendering the selected histogram channels on it.

Definition at line 350 of file KisHistogramPainter.cpp.

{
    return paint(QSize(w, h));
}

References paint().

paint() [3/3]

void KisHistogramPainter::paint	(	QPainter &	painter,
		const QRect &	rect )

Paints the selected histogram channels in the given rect using the given painter.

Definition at line 355 of file KisHistogramPainter.cpp.

{
    const QImage image = m_d->paintChannels(rect.size(), m_d->channelsToPaint, m_d->isLogarithmic);
    painter.drawImage(rect.topLeft(), image);
}

References m_d.

scale()

qreal KisHistogramPainter::scale

(

)

const

Return the vertical scale that is used to paint the histogram shape. A scale of 1 will paint all the histogram in the given rect. Scales less that 1 are not allowed.

See also

setScale

setScaleToFit

setScaleToCutLongPeaks

Definition at line 396 of file KisHistogramPainter.cpp.

{
    return m_d->scale;
}

References m_d.

setChannel()

void KisHistogramPainter::setChannel

(

int

channel

)

Set currently active channel (the one that will be painted)

See also

channels

setChannels

Definition at line 376 of file KisHistogramPainter.cpp.

{
    setChannels({channel});
}

References setChannels().

setChannels()

void KisHistogramPainter::setChannels

(

const QVector< int > &

channels

)

Set currently active channels (the ones that will be painted)

See also

channels

setChannel

Definition at line 381 of file KisHistogramPainter.cpp.

{
    m_d->channelsToPaint = channels;
}

References channels(), and m_d.

setDefaultColor()

void KisHistogramPainter::setDefaultColor

(

const QColor &

newDefaultColor

)

Set the default color used when there is no preference to color the selected histogram channel.

See also

defaultColor

Definition at line 391 of file KisHistogramPainter.cpp.

{
    m_d->defaultColor = newDefaultColor;
}

References m_d.

setLogarithmic()

void KisHistogramPainter::setLogarithmic

(

bool

logarithmic

)

Set if the histogram shape being shown is formed by the logarithmic mapping of the original histogram values instead of the values themselves.

See also

isLogarithmic

Definition at line 449 of file KisHistogramPainter.cpp.

{
    m_d->isLogarithmic = logarithmic;
}

References m_d.

setScale()

void KisHistogramPainter::setScale

(

qreal

newScale

)

Set the scale used to paint the histograms.

See also

scale

setScaleToFit

setScaleToCutLongPeaks

Definition at line 401 of file KisHistogramPainter.cpp.

{
    m_d->scale = newScale;
}

References m_d.

setScaleToCutLongPeaks()

void KisHistogramPainter::setScaleToCutLongPeaks

(

)

Sometimes there can be some outliers in the histogram that show in the painted shape as long vertical peaks. Since a scale of 1 will show all the histogram, this can make its interesting parts too small to take any valuable information from them. This function will try to come up with a scale value that favors those interesting parts over the long peaks, which will be pushed and will look cut.

See also

scale

setScale

setScaleToFit

Definition at line 411 of file KisHistogramPainter.cpp.

{
    qreal overallHighest = 0.0;
    qreal fittedChannelHighest = 0.0;
    qreal bestCutOffHeight = 0.0;
    for (int channel : m_d->channelsToPaint) {
        if (!m_d->histogramChannelShapeInfo.contains(channel)) {
            continue;
        }
 
        const qreal channelBestCutOffHeight =
            isLogarithmic()
            ? m_d->histogramChannelShapeInfo[channel].logarithmicBestCutOffHeight
            : m_d->histogramChannelShapeInfo[channel].linearBestCutOffHeight;
        const qreal channelHighest = static_cast<qreal>(m_d->histogramChannelShapeInfo[channel].highest);
 
        if (channelBestCutOffHeight * channelHighest > bestCutOffHeight * fittedChannelHighest) {
            bestCutOffHeight = channelBestCutOffHeight;
            fittedChannelHighest = channelHighest;
        }
 
        if (channelHighest > overallHighest) {
            overallHighest = channelHighest;
        }
    }
    const qreal overallBestCutOffHeight = bestCutOffHeight * fittedChannelHighest / overallHighest;
    if (overallBestCutOffHeight < 0.8) {
        setScale(1.0 / overallBestCutOffHeight);
    } else {
        setScale(1.0);
    }
}

References isLogarithmic(), m_d, and setScale().

setScaleToFit()

void KisHistogramPainter::setScaleToFit

(

)

Set the scale used to paint the histograms to 1.

See also

scale

setScale

setScaleToCutLongPeaks

Definition at line 406 of file KisHistogramPainter.cpp.

{
    setScale(1.0);
}

References setScale().

setup()

void KisHistogramPainter::setup	(	KisHistogram *	histogram,
		const KoColorSpace *	colorSpace,
		QVector< int >	channels = {} )

Sets up the painter by passing a KisHistogram, the color space for the histogram and the channels that must be set up for it.

Parameters

histogram	A KisHistogram pointer to take the info from. The histogram pointer is not stored or owned internally, so you can safely delete it if you don't need it
colorSpaces	The color space associated with the histogram. It is used to color different channels. For example, the histogram for the red channel of a rgb histogram will be painted as a red shape
channels	A collection that contains the channel indices for the channels that must be used to compute the histogram. For example, if the histogram is a Lab histogram, and you are interested only in the lightness channel, the vector should have only one element, the number 0 (index of the lightness channel). If the collection is empty, then all the channels will be used

Definition at line 298 of file KisHistogramPainter.cpp.

{
    Q_ASSERT(histogram);
    Q_ASSERT(colorSpace);
 
    const int nChannels = static_cast<int>(colorSpace->channelCount());
    
    if (channels.size() == 0) {
        for (int i = 0; i < nChannels; ++i) {
            channels.append(i);
        }
    }
 
    m_d->histogramChannelShapeInfo.clear();
 
    for (int channel : channels) {
        if (channel < 0 || channel >= nChannels || m_d->histogramChannelShapeInfo.contains(channel)) {
            continue;
        }
        histogram->setChannel(channel);
        const quint32 highest = histogram->calculations().getHighest();
        QPair<QPolygonF, QPolygonF> shapes = Private::computeHistogramShape(histogram, channel, highest);
        const QPair<QColor, QPainter::CompositionMode> channelPaintingInfo =
            Private::computeChannelPaintingInfo(colorSpace, channel);
        const qreal linearBestCutOffHeight = Private::bestCutOffHeight(shapes.first);
        const qreal logarithmicBestCutOffHeight = Private::bestCutOffHeight(shapes.second);
 
        Private::smoothHistogramShape(shapes.first);
        Private::smoothHistogramShape(shapes.second);
        Private::simplifyHistogramShape(shapes.first);
        Private::simplifyHistogramShape(shapes.second);
 
        m_d->histogramChannelShapeInfo.insert(
            channel,
            {
                shapes.first,
                shapes.second,
                highest,
                linearBestCutOffHeight,
                logarithmicBestCutOffHeight,
                channelPaintingInfo.first,
                channelPaintingInfo.second
            }
        );
    }
}

References KisHistogramPainter::Private::bestCutOffHeight(), KisHistogram::calculations(), KoColorSpace::channelCount(), channels(), KisHistogramPainter::Private::computeChannelPaintingInfo(), KisHistogramPainter::Private::computeHistogramShape(), KisHistogram::Calculations::getHighest(), m_d, KisHistogram::setChannel(), KisHistogramPainter::Private::simplifyHistogramShape(), and KisHistogramPainter::Private::smoothHistogramShape().

totalNumberOfAvailableChannels()

int KisHistogramPainter::totalNumberOfAvailableChannels

(

)

const

Get the number of channels that are being used. It can be less than the total number of channels in the KisHistogram. This can be set by using the setup function.

See also

setup

Definition at line 361 of file KisHistogramPainter.cpp.

{
    return m_d->histogramChannelShapeInfo.size();
}

References m_d.

Member Data Documentation

m_d

QScopedPointer<Private> KisHistogramPainter::m_d

private

Definition at line 165 of file KisHistogramPainter.h.

---

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

• libs/ui/widgets/KisHistogramPainter.h
• libs/ui/widgets/KisHistogramPainter.cpp