Class: QgsHistogramWidget¶

Graphical histogram for displaying distributions of field values.

Class Hierarchy¶

Base classes¶

QWidget
QObject
QPaintDevice

Subclasses¶

QgsGraduatedHistogramWidget

Graphical histogram for displaying distribution of field values and editing range breaks for a QgsGraduatedSymbolRenderer renderer.

Methods

`brush`	Returns the brush used when drawing histogram bars.
`graduatedRanges`	Returns the graduated ranges associated with the histogram.
`layer`	Returns the layer currently associated with the widget.
`pen`	Returns the pen used when drawing histogram bars.
`refresh`	Redraws the histogram.
`refreshValues`	Refreshes the values for the histogram by fetching them from the layer.
`setBrush`	Sets the brush used for drawing histogram bars.
`setGraduatedRanges`	Sets the graduated ranges associated with the histogram.
`setLayer`	Sets the vector layer associated with the histogram.
`setPen`	Sets the pen to use when drawing histogram bars.
`setSourceFieldExp`	Sets the source field or expression to use for values in the histogram.
`setXAxisTitle`	Sets the title for the histogram's x-axis.
`setYAxisTitle`	Sets the title for the histogram's y-axis.
`sourceFieldExp`	Returns the source field name or expression used to calculate values displayed in the histogram.
`xAxisTitle`	Returns the title for the histogram's x-axis.
`yAxisTitle`	Returns the title for the histogram's y-axis.

Virtual Methods

In PyQGIS, only methods marked as virtual can be safely overridden in a Python subclass of QgsHistogramWidget. See the FAQ for more details.

drawHistogram

Updates and redraws the histogram.

class qgis.gui.QgsHistogramWidget[source]¶

Bases: QWidget

__init__(parent: QWidget | None = None, layer: QgsVectorLayer | None = None, fieldOrExp: str | None = '')

QgsHistogramWidget constructor. If layer and fieldOrExp are specified then the histogram will be initially populated with the corresponding values.

Parameters:

parent (Optional[QWidget] = None) – parent widget
layer (Optional[QgsVectorLayer] = None) – source vector layer
fieldOrExp (Optional[str] = '') – field name or expression string

brush(self) → QBrush[source]¶

Returns the brush used when drawing histogram bars.

See also

setBrush()

See also

pen()

Return type:: QBrush

virtual drawHistogram(self)[source]¶: Updates and redraws the histogram.

graduatedRanges(self) → List[QgsRendererRange][source]¶

Returns the graduated ranges associated with the histogram. If set, the ranges will be used to color the histogram bars and for showing vertical dividers at the histogram breaks.

Return type:: List[QgsRendererRange]
Returns:: graduated range list

See also

setGraduatedRanges()

layer(self) → QgsVectorLayer | None[source]¶

Returns the layer currently associated with the widget.

See also

setLayer()

See also

sourceFieldExp()

Return type:: Optional[QgsVectorLayer]

pen(self) → QPen[source]¶

Returns the pen used when drawing histogram bars.

See also

setPen()

See also

brush()

Return type:: QPen

refresh(self)[source]¶: Redraws the histogram. Calling this slot does not update the values for the histogram, use refreshValues() to do this.

refreshValues(self)[source]¶: Refreshes the values for the histogram by fetching them from the layer.

setBrush(self, brush: QBrush | QColor | Qt.GlobalColor | QGradient)[source]¶

Sets the brush used for drawing histogram bars. If ranges have been set using setGraduatedRanges() then the pen and brush will have no effect.

Parameters:: brush (Union[QBrush, Union[QColor, Qt.GlobalColor], QGradient]) – histogram brush

See also

brush()

See also

setPen()

setGraduatedRanges(self, ranges: Iterable[QgsRendererRange])[source]¶

Sets the graduated ranges associated with the histogram. If set, the ranges will be used to color the histogram bars and for showing vertical dividers at the histogram breaks.

Parameters:: ranges (Iterable[QgsRendererRange]) – graduated range list

See also

graduatedRanges()

setLayer(self, layer: QgsVectorLayer | None)[source]¶

Sets the vector layer associated with the histogram.

Parameters:: layer (Optional[QgsVectorLayer]) – source vector layer

See also

setSourceFieldExp()

setPen(self, pen: QPen | QColor | Qt.GlobalColor)[source]¶

Sets the pen to use when drawing histogram bars. If set to Qt.NoPen then the pen will be automatically calculated. If ranges have been set using setGraduatedRanges() then the pen and brush will have no effect.