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QCanvasLinearGradient Class

QCanvasLinearGradient is a brush for linear gradient painting. More...

Header: #include <QCanvasLinearGradient>
CMake: find_package(Qt6 REQUIRED COMPONENTS CanvasPainter)
target_link_libraries(mytarget PRIVATE Qt6::CanvasPainter)
Since: Qt 6.11
Inherits: QCanvasGradient

Public Functions

QCanvasLinearGradient()
QCanvasLinearGradient(QPointF start, QPointF end)
QCanvasLinearGradient(qreal startX, qreal startY, qreal endX, qreal endY)
QCanvasLinearGradient(const QCanvasLinearGradient &)
QCanvasLinearGradient(QCanvasLinearGradient &&)
~QCanvasLinearGradient()
QPointF endPosition() const
void setEndPosition(qreal x, qreal y)
void setEndPosition(QPointF end)
void setStartPosition(qreal x, qreal y)
void setStartPosition(QPointF start)
QPointF startPosition() const
void swap(QCanvasLinearGradient &other)
QCanvasLinearGradient &operator=(QCanvasLinearGradient &&)
QCanvasLinearGradient &operator=(const QCanvasLinearGradient &)

Detailed Description

Liner gradient interpolate colors between start and end points along a linear pattern, so horizontally, vertically or diagonally. The gradient starts from startPosition() and ends to endPosition(). Outside this area, the colors are the starting and the ending color.

Four squares with linear gradients running vertically, horizontally, diagonally, and as horizontal color bands

Here is a simple example:

Square with a diagonal linear gradient from blue to red to yellow
QRectF rect1(0, 0, 200, 200);
QCanvasLinearGradient lg(rect1.topLeft(),
                    rect1.bottomRight());
lg.setColorAt(0.0, "#1a2a6c");
lg.setColorAt(0.5, "#b21f1f");
lg.setColorAt(1.0, "#fdbb2d");
p->setFillStyle(lg);
p->fillRect(rect1);

Member Function Documentation

QCanvasLinearGradient::QCanvasLinearGradient()

Constructs a default linear gradient. Gradient start color position is (0, 0) and end color position (0, 100).

QCanvasLinearGradient::QCanvasLinearGradient(QPointF start, QPointF end)

Constructs a linear gradient. Gradient start color position is start and end color position end.

QCanvasLinearGradient::QCanvasLinearGradient(qreal startX, qreal startY, qreal endX, qreal endY)

Constructs a linear gradient. Gradient start color position is (startX, startY) and end color position (endX, endY).

[constexpr noexcept default] QCanvasLinearGradient::QCanvasLinearGradient(const QCanvasLinearGradient &)

Copy-constructs an instance of QCanvasLinearGradient.

[constexpr noexcept default] QCanvasLinearGradient::QCanvasLinearGradient(QCanvasLinearGradient &&)

Move-constructs an instance of QCanvasLinearGradient.

[constexpr noexcept default] QCanvasLinearGradient::~QCanvasLinearGradient()

Destroys the instance of QCanvasLinearGradient.

QPointF QCanvasLinearGradient::endPosition() const

Returns the end point of linear gradient.

See also setEndPosition().

void QCanvasLinearGradient::setEndPosition(qreal x, qreal y)

Sets the end point of linear gradient to ( x, y).

See also endPosition().

void QCanvasLinearGradient::setEndPosition(QPointF end)

Sets the end point of linear gradient to end.

This is an overloaded function.

void QCanvasLinearGradient::setStartPosition(qreal x, qreal y)

Sets the start point of linear gradient to ( x, y).

See also startPosition().

void QCanvasLinearGradient::setStartPosition(QPointF start)

Sets the start point of linear gradient to start.

This is an overloaded function.

QPointF QCanvasLinearGradient::startPosition() const

Returns the start point of linear gradient.

See also setStartPosition().

[noexcept] void QCanvasLinearGradient::swap(QCanvasLinearGradient &other)

Swaps this gradient with other. This operation is very fast and never fails.

[noexcept default] QCanvasLinearGradient &QCanvasLinearGradient::operator=(QCanvasLinearGradient &&)

Move-assigns other to this QCanvasLinearGradient instance.

[noexcept default] QCanvasLinearGradient &QCanvasLinearGradient::operator=(const QCanvasLinearGradient &)

Copy-assigns other to this QCanvasLinearGradient instance.

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