KisInputLevelsSliderWithGamma Class Reference

This is a input levels slider that has a gamma handle. The handles are constrained so that the black point handle can not pass the white point handle and vice-versa. More...

#include <KisLevelsSlider.h>

Inheritance diagram for KisInputLevelsSliderWithGamma:

Public Slots
void	reset (qreal newBlackPoint, qreal newWhitePoint) override
void	reset (qreal newBlackPoint, qreal newWhitePoint, qreal newGamma)
void	setGamma (qreal newGamma)
	Sets the gamma value.
void	setHandlePosition (int handleIndex, qreal newPosition) override
Public Slots inherited from KisInputLevelsSlider
virtual void	reset (qreal newBlackPoint, qreal newWhitePoint)
	Sometimes you want to set the range to a totally different place, but the new black point can be greater than the old white point so the new black point position will be constrained to the old white position. This function allows to set both values at once to prevent that undesirable effect. Use it when the widget has to show new values, for a different set of levels parameters for example.
virtual void	setBlackPoint (qreal newBlackPoint)
	Sets the black point.
virtual void	setWhitePoint (qreal newWhitePoint)
	Sets the white point.
Public Slots inherited from KisLevelsSlider
virtual void	setHandleColor (int handleIndex, const QColor &newColor)
	Sets the color associated with the given handle.
virtual void	setHandlePosition (int handleIndex, qreal newPosition)
	Sets the normalized position of the given handle.

Signals
void	gammaChanged (qreal newGamma)
	Signal emitted when the gamma value changes.
Signals inherited from KisInputLevelsSlider
void	blackPointChanged (qreal newBlackPoint)
	Signal emitted when the black point changes.
void	whitePointChanged (qreal newWhitePoint)
	Signal emitted when the white point changes.
Signals inherited from KisLevelsSlider
void	handleColorChanged (int handleIndex, const QColor &color)
	Signal emitted when the color associated with a handle changes.
void	handlePositionChanged (int handleIndex, qreal position)
	Signal emitted when the position of a handle changes.

Public Member Functions
qreal	gamma () const
	Get the gamma value.
	KisInputLevelsSliderWithGamma (QWidget *parent=nullptr)
	~KisInputLevelsSliderWithGamma ()
Public Member Functions inherited from KisInputLevelsSlider
qreal	blackPoint () const
	Get the normalized black point.
	KisInputLevelsSlider (QWidget *parent=nullptr)
qreal	whitePoint () const
	Get the normalized white point.
	~KisInputLevelsSlider ()
Public Member Functions inherited from KisLevelsSlider
virtual QRect	gradientRect () const
	Gets the rect where the gradient will be painted.
QColor	handleColor (int handleIndex) const
	Gets the color associated with a given handle.
qreal	handlePosition (int handleIndex) const
	Gets the normalized position of a given handle.
	KisLevelsSlider (QWidget *parent)
QSize	minimumSizeHint () const override
QSize	sizeHint () const override
	~KisLevelsSlider ()

Protected Member Functions
void	paintBottomGradientMiddleSection (QImage &gradientImage, const QVector< Handle > &sortedHandles_) override
	This is used to fill the space between the tho handles in the bottom bar of the "gradient". It just paints a linear gradient that goes from black (first handle's color) to white (last handle's color). Derived classes can override this function if they only want to change that area. "gradientImage" is a 256x1px image.
Protected Member Functions inherited from KisInputLevelsSlider
void	paintGradient (QPainter &painter, const QRect &rect) override
	Custom gradient painter. This paints two bars in the gradient rect, one on top of the other. The top one shows a simple black to white (more exactly, color of the first handle to color of the last handle) linear gradient. The bottom one shows black (first handle's color) from the right side of the rect to the black point, and white (last handle's color) from the white point to the left side of the rect. In the middle of the two handles, the "paintBottomGradientMiddleSection" is used to fill the bar.
Protected Member Functions inherited from KisLevelsSlider
int	closestHandleToPosition (qreal position) const
	Given a normalized position, this function returns the closest handle to that position.
int	closestHandleToX (int x) const
	Given a widget-relative x position, this function returns the closest handle to that position.
void	handleIncrementInput (int direction, Qt::KeyboardModifiers modifiers)
void	keyPressEvent (QKeyEvent *e) override
void	leaveEvent (QEvent *e) override
void	mouseMoveEvent (QMouseEvent *e) override
void	mousePressEvent (QMouseEvent *e) override
void	paintEvent (QPaintEvent *e) override
virtual void	paintHandle (QPainter &painter, const QRect &rect, const Handle &handle)
	Override this function to paint custom handles.
qreal	positionFromX (int x) const
	Given a widget-relative x position in pixels, this function returns the normalized position relative to the gradient rect.
QVector< Handle >	sortedHandles () const
	Regardless the index of a handle, they can be unordered in terms of the position. This returns a sorted vector with the handles that have a smaller position first. If two handles have the same position then the index is used for sorting.
void	wheelEvent (QWheelEvent *e) override
int	xFromPosition (qreal position) const
	Given a gradient rect relative position, this function returns the x position in pixels relative to the widget.

Private Member Functions
qreal	gammaToPosition () const
qreal	positionToGamma () const

Private Attributes
qreal	m_gamma

Additional Inherited Members
Protected Attributes inherited from KisLevelsSlider
int	m_constrainPositions
	This variable indicates if the handles can have unordered positions. If it is set to true then the user won't be able to move a handle pass another one. If it is set to false then the ser will be able to move the handles freely.
QVector< Handle >	m_handles
	The collection of handles.
int	m_hoveredHandle
int	m_selectedHandle
Static Protected Attributes inherited from KisLevelsSlider
static constexpr int	handleHeight {11}
static constexpr int	handleWidth {11}
static constexpr qreal	minimumSpaceBetweenHandles {0.001}
static constexpr qreal	normalPositionIncrement {0.01}
static constexpr qreal	slowPositionIncrement {0.001}

Detailed Description

This is a input levels slider that has a gamma handle. The handles are constrained so that the black point handle can not pass the white point handle and vice-versa.

Definition at line 220 of file KisLevelsSlider.h.

Constructor & Destructor Documentation

KisInputLevelsSliderWithGamma()

KisInputLevelsSliderWithGamma::KisInputLevelsSliderWithGamma

(

QWidget *

parent = nullptr

)

Definition at line 454 of file KisLevelsSlider.cpp.

    : KisInputLevelsSlider(parent)
    , m_gamma(1.0)
{
    m_handles.last().index = 2;
    m_handles.insert(1, {1, 0.5, Qt::gray});
}

References KisLevelsSlider::m_handles.

~KisInputLevelsSliderWithGamma()

KisInputLevelsSliderWithGamma::~KisInputLevelsSliderWithGamma

(

)

Definition at line 462 of file KisLevelsSlider.cpp.

{}

Member Function Documentation

gamma()

qreal KisInputLevelsSliderWithGamma::gamma

(

)

const

Get the gamma value.

Definition at line 465 of file KisLevelsSlider.cpp.

{
    return m_gamma;
}

References m_gamma.

gammaChanged

void KisInputLevelsSliderWithGamma::gammaChanged ( qreal newGamma )

signal

Signal emitted when the gamma value changes.

gammaToPosition()

qreal KisInputLevelsSliderWithGamma::gammaToPosition ( ) const

private

Definition at line 550 of file KisLevelsSlider.cpp.

{
    qreal relativePosition;
    const qreal log1_2 = std::log(0.5);
    // the function would be "relativePosition = exp(gamma * ln(1/2)" but since
    // we want to limit the gamma from 0.1 to 10 we map the gamma
    // in a way such that "exp(max_gamma * ln(1/2)) = 1" and
    // "exp(min_gamma * ln(1/2)) = 0"
    if (m_gamma > 1.0) {
        const qreal mappedPosition = std::exp(10.0 * log1_2);
        relativePosition = (std::exp(m_gamma * log1_2) - mappedPosition) / (1.0 - mappedPosition * 2.0);
    } else {
        const qreal mappedPosition = std::exp(0.1 * log1_2);
        relativePosition = (std::exp(m_gamma * log1_2) + mappedPosition - 1.0) / (mappedPosition * 2.0 - 1.0);
    }
    return blackPoint() + relativePosition * (whitePoint() - blackPoint());
}

References KisInputLevelsSlider::blackPoint(), m_gamma, and KisInputLevelsSlider::whitePoint().

paintBottomGradientMiddleSection()

void KisInputLevelsSliderWithGamma::paintBottomGradientMiddleSection ( QImage & gradientImage, const QVector< Handle > & sortedHandles_ )

overrideprotectedvirtual

This is used to fill the space between the tho handles in the bottom bar of the "gradient". It just paints a linear gradient that goes from black (first handle's color) to white (last handle's color). Derived classes can override this function if they only want to change that area. "gradientImage" is a 256x1px image.

Reimplemented from KisInputLevelsSlider.

Definition at line 526 of file KisLevelsSlider.cpp.

{
    if (m_handles.size() < 2) {
        return;
    }
    if (m_handles.size() < 3) {
        KisInputLevelsSlider::paintBottomGradientMiddleSection(gradientImage, sortedHandles_);
        return;
    }
 
    const qreal inverseGamma = 1.0 / m_gamma;
    const int startPos = static_cast<int>(qRound(sortedHandles_.first().position * static_cast<qreal>(gradientImage.width() - 1)));
    const int endPos = static_cast<int>(qRound(sortedHandles_.last().position * static_cast<qreal>(gradientImage.width() - 1))) + 1;
    QRgb *pixel = reinterpret_cast<QRgb*>(gradientImage.bits()) + startPos;
    for (int x = startPos; x < endPos; ++x, ++pixel) {
        const qreal t = static_cast<qreal>(x - startPos) / static_cast<qreal>(endPos - startPos);
        *pixel =KisPaintingTweaks::blendColors(
                    sortedHandles_.last().color,
                    sortedHandles_.first().color,
                    std::pow(t, inverseGamma)
                ).rgba();
    }
}

References KisPaintingTweaks::blendColors(), m_gamma, KisLevelsSlider::m_handles, and KisInputLevelsSlider::paintBottomGradientMiddleSection().

positionToGamma()

qreal KisInputLevelsSliderWithGamma::positionToGamma ( ) const

private

Definition at line 568 of file KisLevelsSlider.cpp.

{
    const qreal relativePosition = (handlePosition(1) - blackPoint()) / (whitePoint() - blackPoint());
    const qreal log1_2 = std::log(0.5);
    // the function would be "gamma = ln(relativePosition) / ln(1/2)" but since
    // we want to limit the gamma from 0.1 to 10 we map the relative position
    // in a way such that "ln(min_relativePosition) / ln(1/2) = 10" and
    // "ln(max_relativePosition) / ln(1/2) = 0.1"
    if (relativePosition < 0.5) {
        const qreal mappedPosition = std::exp(10.0 * log1_2);
        return std::log(mappedPosition + relativePosition - relativePosition * mappedPosition * 2.0) / log1_2;
    } else {
        const qreal mappedPosition = std::exp(0.1 * log1_2);
        return std::log(1 - (mappedPosition + relativePosition) + relativePosition * mappedPosition * 2.0) / log1_2;
    }
}

References KisInputLevelsSlider::blackPoint(), KisLevelsSlider::handlePosition(), and KisInputLevelsSlider::whitePoint().

reset [1/2]

void KisInputLevelsSliderWithGamma::reset ( qreal newBlackPoint, qreal newWhitePoint )

overrideslot

See also

KisInputLevelsSlider::reset

Definition at line 515 of file KisLevelsSlider.cpp.

{
    KisInputLevelsSlider::reset(newBlackPoint, newWhitePoint);
}

References KisInputLevelsSlider::reset().

reset [2/2]

void KisInputLevelsSliderWithGamma::reset ( qreal newBlackPoint, qreal newWhitePoint, qreal newGamma )

slot

See also

KisInputLevelsSlider::reset

Definition at line 520 of file KisLevelsSlider.cpp.

{
    reset(newBlackPoint, newWhitePoint);
    setGamma(newGamma);
}

References reset(), and setGamma().

setGamma

void KisInputLevelsSliderWithGamma::setGamma ( qreal newGamma )

slot

Sets the gamma value.

Definition at line 502 of file KisLevelsSlider.cpp.

{
    newGamma = qBound(0.1, newGamma, 10.0);
    if (newGamma == m_gamma) {
        return;
    }
    m_gamma = newGamma;
    m_handles[1].position = gammaToPosition();
    update();
    Q_EMIT gammaChanged(m_gamma);
    Q_EMIT handlePositionChanged(1, m_handles[1].position);
}

References gammaChanged(), gammaToPosition(), KisLevelsSlider::handlePositionChanged(), m_gamma, and KisLevelsSlider::m_handles.

setHandlePosition

void KisInputLevelsSliderWithGamma::setHandlePosition ( int handleIndex, qreal newPosition )

overrideslot

Definition at line 470 of file KisLevelsSlider.cpp.

{
    Q_ASSERT(handleIndex >= 0 && handleIndex < m_handles.size());
 
    if (handleIndex == 1) {
        newPosition = qBound(m_handles.first().position, newPosition, m_handles.last().position);
        if (newPosition == m_handles[1].position) {
            return;
        }
        m_handles[1].position = newPosition;
        m_gamma = positionToGamma();
        update();
        Q_EMIT handlePositionChanged(1, newPosition);
        Q_EMIT gammaChanged(m_gamma);
    } else {
        if (handleIndex == m_handles.first().index) {
            newPosition = qBound(0.0, newPosition, m_handles.last().position - minimumSpaceBetweenHandles);
        } else if (handleIndex == m_handles.last().index) {
            newPosition = qBound(m_handles.first().position + minimumSpaceBetweenHandles, newPosition, 1.0);
        }
        if (newPosition == m_handles[handleIndex].position) {
            return;
        }
        m_handles[handleIndex].position = newPosition;
        m_handles[1].position = gammaToPosition();
        update();
        Q_EMIT handlePositionChanged(handleIndex, newPosition);
        Q_EMIT handlePositionChanged(1, newPosition);
    }
 
}

References gammaChanged(), gammaToPosition(), KisLevelsSlider::handlePositionChanged(), m_gamma, KisLevelsSlider::m_handles, KisLevelsSlider::minimumSpaceBetweenHandles, and positionToGamma().

Member Data Documentation

m_gamma

qreal KisInputLevelsSliderWithGamma::m_gamma

private

Definition at line 258 of file KisLevelsSlider.h.

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

• libs/widgets/KisLevelsSlider.h
• libs/widgets/KisLevelsSlider.cpp