QgsSimpleMarkerSymbolLayerBase class

Abstract base class for simple marker symbol layers.

Reference

Handles creation of the symbol shapes but leaves the actual drawing of the symbols to subclasses.

Base classes

class QgsMarkerSymbolLayer: Abstract base class for marker symbol layers.

Derived classes

class QgsFilledMarkerSymbolLayer: Filled marker symbol layer, consisting of a shape which is rendered using a QgsFillSymbol.
class QgsSimpleMarkerSymbolLayer: Simple marker symbol layer, consisting of a rendered shape with solid fill color and an stroke.

Public types

enum Shape { Square, Diamond, Pentagon, Hexagon, Triangle, EquilateralTriangle, Star, Arrow, Circle, Cross, CrossFill, Cross2, Line, ArrowHead, ArrowHeadFilled, SemiCircle, ThirdCircle, QuarterCircle, QuarterSquare, HalfSquare, DiagonalHalfSquare, RightHalfTriangle, LeftHalfTriangle }: Marker symbol shapes.

Public static functions

static auto availableShapes() -> QList<QgsSimpleMarkerSymbolLayerBase::Shape>: Returns a list of all available shape types.
static auto decodeShape(const QString& name, bool* ok = nullptr) -> QgsSimpleMarkerSymbolLayerBase::Shape: Attempts to decode a string representation of a shape name to the corresponding shape.
static auto encodeShape(QgsSimpleMarkerSymbolLayerBase::Shape shape) -> QString: Encodes a shape to its string representation.
static auto shapeIsFilled(QgsSimpleMarkerSymbolLayerBase::Shape shape) -> bool: Returns true if a symbol shape has a fill.

Constructors, destructors, conversion operators

QgsSimpleMarkerSymbolLayerBase(QgsSimpleMarkerSymbolLayerBase::Shape shape = Circle, double size = DEFAULT_SIMPLEMARKER_SIZE, double angle = DEFAULT_SIMPLEMARKER_ANGLE, QgsSymbol::ScaleMethod scaleMethod = DEFAULT_SCALE_METHOD): Constructor for QgsSimpleMarkerSymbolLayerBase.

Public functions

auto bounds(QPointF point, QgsSymbolRenderContext& context) -> QRectF override: Returns the approximate bounding box of the marker symbol layer, taking into account any data defined overrides and offsets which are set for the marker layer.
void renderPoint(QPointF point, QgsSymbolRenderContext& context) override: Renders a marker at the specified point.
void setShape(QgsSimpleMarkerSymbolLayerBase::Shape shape): Sets the rendered marker shape.
auto shape() const -> QgsSimpleMarkerSymbolLayerBase::Shape: Returns the shape for the rendered marker symbol.

Protected functions

void calculateOffsetAndRotation(QgsSymbolRenderContext& context, double scaledSize, bool& hasDataDefinedRotation, QPointF& offset, double& angle) const: Calculates the marker offset and rotation.
auto calculateSize(QgsSymbolRenderContext& context, bool& hasDataDefinedSize) const -> double: Calculates the desired size of the marker, considering data defined size overrides.
auto prepareMarkerPath(Shape symbol) -> bool: Prepares the layer for drawing the specified shape (QPainterPath version)
auto prepareMarkerShape(Shape shape) -> bool: Prepares the layer for drawing the specified shape (QPolygonF version)
auto shapeToPolygon(Shape shape, QPolygonF& polygon) const -> bool: Creates a polygon representing the specified shape.

Protected variables

QPainterPath mPath: Painter path representing shape. If mPolygon is empty then the shape is stored in mPath.
QPolygonF mPolygon: Polygon of points in shape. If polygon is empty then shape is using mPath.
Shape mShape: Symbol shape.

Private functions

void draw(QgsSymbolRenderContext& context, QgsSimpleMarkerSymbolLayerBase::Shape shape, const QPolygonF& polygon, const QPainterPath& path) =0SIP_FORCE virtual: Derived classes must implement draw() to handle drawing the generated shape onto the painter surface.

Enum documentation

enum QgsSimpleMarkerSymbolLayerBase::Shape

Marker symbol shapes.

Enumerators
Square	Square.
Diamond	Diamond.
Pentagon	Pentagon.
Hexagon	Hexagon.
Triangle	Triangle.
EquilateralTriangle	Equilateral triangle.
Star	Star.
Arrow	Arrow.
Circle	Circle.
Cross	Cross (lines only)
CrossFill	Solid filled cross.
Cross2	Rotated cross (lines only), "x" shape.
Line	Vertical line.
ArrowHead	Right facing arrow head (unfilled, lines only)
ArrowHeadFilled	Right facing filled arrow head.
SemiCircle	Semi circle (top half)
ThirdCircle	One third circle (top left third)
QuarterCircle	Quarter circle (top left quarter)
QuarterSquare	Quarter square (top left quarter)
HalfSquare	Half square (left half)
DiagonalHalfSquare	Diagonal half square (bottom left half)
RightHalfTriangle	Right half of triangle.
LeftHalfTriangle	Left half of triangle.

Function documentation

static QgsSimpleMarkerSymbolLayerBase::Shape QgsSimpleMarkerSymbolLayerBase::decodeShape(const QString& name, bool* ok = nullptr)

Attempts to decode a string representation of a shape name to the corresponding shape.

Parameters
name	encoded shape name
ok	if specified, will be set to true if shape was successfully decoded
Returns	decoded name

static QString QgsSimpleMarkerSymbolLayerBase::encodeShape(QgsSimpleMarkerSymbolLayerBase::Shape shape)

Encodes a shape to its string representation.

Parameters
shape	shape to encode
Returns	encoded string

static bool QgsSimpleMarkerSymbolLayerBase::shapeIsFilled(QgsSimpleMarkerSymbolLayerBase::Shape shape)

Returns true if a symbol shape has a fill.

Parameters
shape	shape to test
Returns	true if shape uses a fill, or false if shape uses lines only

QgsSimpleMarkerSymbolLayerBase::QgsSimpleMarkerSymbolLayerBase(QgsSimpleMarkerSymbolLayerBase::Shape shape = Circle, double size = DEFAULT_SIMPLEMARKER_SIZE, double angle = DEFAULT_SIMPLEMARKER_ANGLE, QgsSymbol::ScaleMethod scaleMethod = DEFAULT_SCALE_METHOD)

Constructor for QgsSimpleMarkerSymbolLayerBase.

Parameters
shape	symbol shape for markers
size	symbol size (in mm)
angle	symbol rotation angle
scaleMethod	scaling method for data defined scaling

QRectF QgsSimpleMarkerSymbolLayerBase::bounds(QPointF point, QgsSymbolRenderContext& context) override

Returns the approximate bounding box of the marker symbol layer, taking into account any data defined overrides and offsets which are set for the marker layer.

Returns	approximate symbol bounds, in painter units

void QgsSimpleMarkerSymbolLayerBase::renderPoint(QPointF point, QgsSymbolRenderContext& context) override

Renders a marker at the specified point.

Parameters
point	position at which to render point, in painter units
context	symbol render context

Derived classes must implement this to handle drawing the point.

void QgsSimpleMarkerSymbolLayerBase::setShape(QgsSimpleMarkerSymbolLayerBase::Shape shape)

Sets the rendered marker shape.

Parameters
shape	new marker shape

QgsSimpleMarkerSymbolLayerBase::Shape QgsSimpleMarkerSymbolLayerBase::shape() const

Returns the shape for the rendered marker symbol.

void QgsSimpleMarkerSymbolLayerBase::calculateOffsetAndRotation(QgsSymbolRenderContext& context, double scaledSize, bool& hasDataDefinedRotation, QPointF& offset, double& angle) const protected

Calculates the marker offset and rotation.

Parameters
context	symbol render context
scaledSize	size of symbol to render
hasDataDefinedRotation	will be set to true if marker has data defined rotation
offset	will be set to calculated marker offset (in painter units)
angle	will be set to calculated marker angle

double QgsSimpleMarkerSymbolLayerBase::calculateSize(QgsSymbolRenderContext& context, bool& hasDataDefinedSize) const protected

Calculates the desired size of the marker, considering data defined size overrides.

Parameters
context	symbol render context
hasDataDefinedSize	will be set to true if marker uses data defined sizes
Returns	marker size, in original size units

bool QgsSimpleMarkerSymbolLayerBase::shapeToPolygon(Shape shape, QPolygonF& polygon) const protected

Creates a polygon representing the specified shape.

Parameters
shape	shape to create
polygon	destination polygon for shape
Returns	true if shape was successfully stored in polygon

void QgsSimpleMarkerSymbolLayerBase::draw(QgsSymbolRenderContext& context, QgsSimpleMarkerSymbolLayerBase::Shape shape, const QPolygonF& polygon, const QPainterPath& path) =0SIP_FORCE virtual private

Derived classes must implement draw() to handle drawing the generated shape onto the painter surface.

Parameters
context	symbol render context
shape	shape to draw
polygon	polygon representing transformed marker shape. May be empty, in which case the shape will be specified in the path argument.
path	transformed painter path representing shape to draw