KisLevelsSlider Class Reference

A base class for levels slider like widgets: a slider with a gradient and multiple handles. More...

#include <KisLevelsSlider.h>

Inheritance diagram for KisLevelsSlider:

Classes
struct	Handle

Public Slots
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	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
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
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	paintGradient (QPainter &painter, const QRect &rect)=0
	Derived classes must override this function to draw the gradient inside the given rect. A border is automatically drawn after.
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.

Protected Attributes
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
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

A base class for levels slider like widgets: a slider with a gradient and multiple handles.

Definition at line 21 of file KisLevelsSlider.h.

Constructor & Destructor Documentation

KisLevelsSlider()

KisLevelsSlider::KisLevelsSlider

(

QWidget *

parent

)

Definition at line 19 of file KisLevelsSlider.cpp.

    : QWidget(parent)
    , m_constrainPositions(true)
    , m_selectedHandle(-1)
    , m_hoveredHandle(-1)
{
    setFocusPolicy(Qt::WheelFocus);
    setMouseTracking(true);
}

~KisLevelsSlider()

KisLevelsSlider::~KisLevelsSlider

(

)

Definition at line 29 of file KisLevelsSlider.cpp.

{}

Member Function Documentation

closestHandleToPosition()

int KisLevelsSlider::closestHandleToPosition ( qreal position ) const

protected

Given a normalized position, this function returns the closest handle to that position.

Definition at line 113 of file KisLevelsSlider.cpp.

{
    const QVector<Handle> sortedHandles_ = sortedHandles();
    int handleIndex = -1;
 
    if (position <= sortedHandles_.first().position) {
        handleIndex = sortedHandles_.first().index;
    } else if (position >= sortedHandles_.last().position) {
        handleIndex = sortedHandles_.last().index;
    } else {
        for (int i = 0; i < sortedHandles_.size() - 1; ++i) {
            if (position >= sortedHandles_[i + 1].position) {
                continue;
            }
            const qreal middlePoint = (sortedHandles_[i].position + sortedHandles_[i + 1].position) / 2.0;
            handleIndex = position <= middlePoint ? sortedHandles_[i].index : sortedHandles_[i + 1].index;
            break;
        }
    }
 
    return handleIndex;
}

References sortedHandles().

closestHandleToX()

int KisLevelsSlider::closestHandleToX ( int x ) const

protected

Given a widget-relative x position, this function returns the closest handle to that position.

Definition at line 142 of file KisLevelsSlider.cpp.

{
    return closestHandleToPosition(positionFromX(x));
}

References closestHandleToPosition(), and positionFromX().

gradientRect()

QRect KisLevelsSlider::gradientRect ( ) const

virtual

Gets the rect where the gradient will be painted.

Definition at line 95 of file KisLevelsSlider.cpp.

{
    const int margin = handleWidth / 2;
    return rect().adjusted(margin, 0, -margin, -handleHeight);
}

References handleHeight, and handleWidth.

handleColor()

QColor KisLevelsSlider::handleColor

(

int

handleIndex

)

const

Gets the color associated with a given handle.

Definition at line 39 of file KisLevelsSlider.cpp.

{
    Q_ASSERT(handleIndex >= 0 && handleIndex < m_handles.size());
 
    return m_handles[handleIndex].color;
}

References m_handles.

handleColorChanged

void KisLevelsSlider::handleColorChanged ( int handleIndex, const QColor & color )

signal

Signal emitted when the color associated with a handle changes.

handleIncrementInput()

void KisLevelsSlider::handleIncrementInput ( int direction, Qt::KeyboardModifiers modifiers )

protected

Definition at line 153 of file KisLevelsSlider.cpp.

{
    if (direction == 0) {
        return;
    }
    if (modifiers & Qt::ControlModifier) {
        m_selectedHandle += direction < 0 ? -1 : 1;
        m_selectedHandle = qBound(0, m_selectedHandle, m_handles.size() - 1);
        update();
    } else if (m_selectedHandle >= 0 && m_selectedHandle < m_handles.size()) {
        const qreal increment = modifiers & Qt::ShiftModifier ? slowPositionIncrement : normalPositionIncrement;
        const qreal position = m_handles[m_selectedHandle].position + (direction < 0 ? -increment : increment);
        setHandlePosition(m_selectedHandle, position);
    }
}

References m_handles, m_selectedHandle, normalPositionIncrement, setHandlePosition(), and slowPositionIncrement.

handlePosition()

qreal KisLevelsSlider::handlePosition

(

int

handleIndex

)

const

Gets the normalized position of a given handle.

Definition at line 32 of file KisLevelsSlider.cpp.

{
    Q_ASSERT(handleIndex >= 0 && handleIndex < m_handles.size());
 
    return m_handles[handleIndex].position;
}

References m_handles.

handlePositionChanged

void KisLevelsSlider::handlePositionChanged ( int handleIndex, qreal position )

signal

Signal emitted when the position of a handle changes.

keyPressEvent()

void KisLevelsSlider::keyPressEvent ( QKeyEvent * e )

overrideprotected

Definition at line 287 of file KisLevelsSlider.cpp.

{
    if (m_handles.size() == 0) {
        return;
    }
    if (m_selectedHandle == -1) {
        return;
    }
 
    switch (e->key()) {
    case Qt::Key_Left:
        handleIncrementInput(-1, e->modifiers());
        return;
    case Qt::Key_Right:
        handleIncrementInput(1, e->modifiers());
        return;
    default:
        QWidget::keyPressEvent(e);
    }
}

References handleIncrementInput(), m_handles, and m_selectedHandle.

leaveEvent()

void KisLevelsSlider::leaveEvent ( QEvent * e )

overrideprotected

Definition at line 280 of file KisLevelsSlider.cpp.

{
    m_hoveredHandle = -1;
    update();
    QWidget::leaveEvent(e);
}

References m_hoveredHandle.

minimumSizeHint()

QSize KisLevelsSlider::minimumSizeHint ( ) const

override

Definition at line 90 of file KisLevelsSlider.cpp.

{
    return QSize(128, 20) + QSize(handleWidth, handleHeight);
}

References handleHeight, and handleWidth.

mouseMoveEvent()

void KisLevelsSlider::mouseMoveEvent ( QMouseEvent * e )

overrideprotected

Definition at line 262 of file KisLevelsSlider.cpp.

{
    if (m_handles.size() == 0) {
        return;
    }
 
    if (e->buttons() & Qt::LeftButton && m_selectedHandle != -1) {
        setHandlePosition(m_selectedHandle, positionFromX(e->x()));
    } else {
        int handleIndex = closestHandleToX(e->x());
        if (handleIndex != -1) {
            m_hoveredHandle = handleIndex;
            update();
        }
    }
 
}

References closestHandleToX(), m_handles, m_hoveredHandle, m_selectedHandle, positionFromX(), and setHandlePosition().

mousePressEvent()

void KisLevelsSlider::mousePressEvent ( QMouseEvent * e )

overrideprotected

Definition at line 239 of file KisLevelsSlider.cpp.

{
    if (m_handles.size() == 0) {
        return;
    }
    if (e->button() != Qt::LeftButton) {
        return;
    }
 
    qreal mousePosition = positionFromX(e->x());
    int handleIndex = closestHandleToPosition(mousePosition);
 
    if (handleIndex != -1) {
        m_selectedHandle = handleIndex;
        const int handleX = xFromPosition(m_handles[handleIndex].position);
        if (qAbs(handleX - e->x()) > handleWidth) {
            setHandlePosition(handleIndex, mousePosition);
        } else {
            update();
        }
    }
}

References closestHandleToPosition(), handleWidth, m_handles, m_selectedHandle, positionFromX(), setHandlePosition(), and xFromPosition().

paintEvent()

void KisLevelsSlider::paintEvent ( QPaintEvent * e )

overrideprotected

Definition at line 212 of file KisLevelsSlider.cpp.

{
    Q_UNUSED(e);
 
    QPainter painter(this);
    const QRect gradientRect_ = gradientRect();
    // Gradient
    painter.save();
    paintGradient(painter, gradientRect_);
    painter.restore();
    // Border
    QColor borderColor = palette().text().color();
    borderColor.setAlpha(64);
    painter.setPen(borderColor);
    painter.drawRect(gradientRect_.adjusted(0, 0, -1, -1));
    // Handles
    const QVector<Handle> sortedHandles_ = sortedHandles();
    const int halfHandleWidth = handleWidth / 2;
    painter.save();
    for (const Handle &handle : sortedHandles_) {
        const int handleX = static_cast<int>(qRound(handle.position * static_cast<qreal>(gradientRect_.width() - 1))) + halfHandleWidth;
        const QRect handleRect(handleX - halfHandleWidth, gradientRect_.bottom() + 1, handleWidth, handleHeight);
        paintHandle(painter, handleRect, handle);
    }
    painter.restore();
}

References gradientRect(), handleHeight, handleWidth, paintGradient(), paintHandle(), palette, and sortedHandles().

paintGradient()

virtual void KisLevelsSlider::paintGradient ( QPainter & painter, const QRect & rect )

protectedpure virtual

Derived classes must override this function to draw the gradient inside the given rect. A border is automatically drawn after.

Implemented in KisInputLevelsSlider.

paintHandle()

void KisLevelsSlider::paintHandle ( QPainter & painter, const QRect & rect, const Handle & handle )

protectedvirtual

Override this function to paint custom handles.

Reimplemented in KisThresholdSlider.

Definition at line 169 of file KisLevelsSlider.cpp.

{
    painter.setRenderHint(QPainter::Antialiasing, false);
    const int halfHandleWidth = handleWidth / 2.0;
    {
        const QPolygon shape({
            {rect.left() + halfHandleWidth, rect.top()},
            {rect.right() + 1, rect.top() + halfHandleWidth},
            {rect.right() + 1, rect.bottom() + 1},
            {rect.left(), rect.bottom() + 1},
            {rect.left(), rect.top() + halfHandleWidth}
        });
        painter.setPen(Qt::NoPen);
        const bool isSelected = handle.index == m_selectedHandle;
        QColor brushColor =
            isSelected && hasFocus()
            ? KisPaintingTweaks::blendColors(handle.color, palette().highlight().color(), 0.25)
            : handle.color;
        if (!isEnabled()) {
            brushColor.setAlpha(64);
        }
        painter.setBrush(brushColor);
        painter.drawPolygon(shape);
    }
    {
        const QPolygon shape({
            {rect.left() + halfHandleWidth, rect.top()},
            {rect.right(), rect.top() + halfHandleWidth},
            {rect.right(), rect.bottom()},
            {rect.left(), rect.bottom()},
            {rect.left(), rect.top() + halfHandleWidth}
        });
        const bool isHovered = handle.index == m_hoveredHandle;
        QColor penColor = isHovered && isEnabled() ? palette().highlight().color() : palette().text().color();
        if (!isHovered) {
            penColor.setAlpha(64);
        }
        painter.setPen(penColor);
        painter.setBrush(Qt::NoBrush);
        painter.drawPolygon(shape);
    }
}

References KisPaintingTweaks::blendColors(), KisLevelsSlider::Handle::color, handleWidth, KisLevelsSlider::Handle::index, m_hoveredHandle, m_selectedHandle, and palette.

positionFromX()

qreal KisLevelsSlider::positionFromX ( int x ) const

protected

Given a widget-relative x position in pixels, this function returns the normalized position relative to the gradient rect.

Definition at line 136 of file KisLevelsSlider.cpp.

{
    const QRect gradientRect_ = gradientRect();
    return static_cast<qreal>(x - gradientRect_.left()) / static_cast<qreal>(gradientRect_.width());
}

References gradientRect().

setHandleColor

void KisLevelsSlider::setHandleColor ( int handleIndex, const QColor & newColor )

virtualslot

Sets the color associated with the given handle.

Definition at line 71 of file KisLevelsSlider.cpp.

{
    Q_ASSERT(handleIndex >= 0 && handleIndex < m_handles.size());
 
    if (newColor == m_handles[handleIndex].color) {
        return;
    }
 
    m_handles[handleIndex].color = newColor;
    
    update();
    Q_EMIT handleColorChanged(handleIndex, newColor);
}

References handleColorChanged(), and m_handles.

setHandlePosition

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

virtualslot

Sets the normalized position of the given handle.

Definition at line 46 of file KisLevelsSlider.cpp.

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

References handlePositionChanged(), m_constrainPositions, m_handles, and minimumSpaceBetweenHandles.

sizeHint()

QSize KisLevelsSlider::sizeHint ( ) const

override

Definition at line 85 of file KisLevelsSlider.cpp.

{
    return QSize(256, 20) + QSize(handleWidth, handleHeight);
}

References handleHeight, and handleWidth.

sortedHandles()

QVector< KisLevelsSlider::Handle > KisLevelsSlider::sortedHandles ( ) const

protected

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.

Definition at line 101 of file KisLevelsSlider.cpp.

{
    QVector<Handle> sortedHandles_ = m_handles;
    std::sort(sortedHandles_.begin(), sortedHandles_.end(),
        [](const Handle &lhs, const Handle &rhs)
        {
            return qFuzzyCompare(lhs.position, rhs.position) ? lhs.index < rhs.index : lhs.position < rhs.position;
        }
    );
    return sortedHandles_;
}

References m_handles.

wheelEvent()

void KisLevelsSlider::wheelEvent ( QWheelEvent * e )

overrideprotected

Definition at line 308 of file KisLevelsSlider.cpp.

{
    if (e->angleDelta().y() != 0) {
        handleIncrementInput(e->angleDelta().y(), e->modifiers());
        e->accept();
    } else {
        QWidget::wheelEvent(e);
    }
}

References handleIncrementInput().

xFromPosition()

int KisLevelsSlider::xFromPosition ( qreal position ) const

protected

Given a gradient rect relative position, this function returns the x position in pixels relative to the widget.

Definition at line 147 of file KisLevelsSlider.cpp.

{
    const QRect gradientRect_ = gradientRect();
    return static_cast<int>(position * static_cast<qreal>(gradientRect_.width())) + gradientRect_.left();
}

References gradientRect().

Member Data Documentation

handleHeight

constexpr int KisLevelsSlider::handleHeight {11}

staticconstexprprotected

Definition at line 74 of file KisLevelsSlider.h.

{11};

handleWidth

constexpr int KisLevelsSlider::handleWidth {11}

staticconstexprprotected

Definition at line 73 of file KisLevelsSlider.h.

{11};

m_constrainPositions

int KisLevelsSlider::m_constrainPositions

protected

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.

Definition at line 89 of file KisLevelsSlider.h.

m_handles

QVector<Handle> KisLevelsSlider::m_handles

protected

The collection of handles.

Definition at line 82 of file KisLevelsSlider.h.

m_hoveredHandle

int KisLevelsSlider::m_hoveredHandle

protected

Definition at line 92 of file KisLevelsSlider.h.

m_selectedHandle

int KisLevelsSlider::m_selectedHandle

protected

Definition at line 91 of file KisLevelsSlider.h.

minimumSpaceBetweenHandles

constexpr qreal KisLevelsSlider::minimumSpaceBetweenHandles {0.001}

staticconstexprprotected

Definition at line 75 of file KisLevelsSlider.h.

{0.001};

normalPositionIncrement

constexpr qreal KisLevelsSlider::normalPositionIncrement {0.01}

staticconstexprprotected

Definition at line 76 of file KisLevelsSlider.h.

{0.01};

slowPositionIncrement

constexpr qreal KisLevelsSlider::slowPositionIncrement {0.001}

staticconstexprprotected

Definition at line 77 of file KisLevelsSlider.h.

{0.001};

---

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

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