Class: QgsMapHitTest

Runs a hit test with given map settings.

Based on the hit test it returns which symbols will be visible on the map - this is useful for content based legend.

List of all members, including inherited members

Methods

legendKeyVisible	Tests whether a given legend key is visible for a specified layer.
results	Returns the hit test results, which are a map of layer ID to visible symbol legend keys.
resultsRenderersUpdatedCanvas	Returns the hit test results, for layers with UpdatedCanvas renderers (raster/mesh layers).
run	Runs the map hit test
symbolVisible	Tests whether a symbol is visible for a specified layer.

class qgis.core.QgsMapHitTest

Bases: object

__init__(settings: QgsMapSettings, polygon: QgsGeometry = QgsGeometry(), layerFilterExpression: dict[str | None, str | None] = {})

Constructor for QgsMapHitTest.

Parameters:

• settings (QgsMapSettings) – Map settings used to evaluate symbols

• polygon (QgsGeometry = QgsGeometry()) – Polygon geometry to refine the hit test

• layerFilterExpression (dict[Optional[str], Optional[str]] = {}) – Expression string for each layer id to evaluate in order to refine the symbol selection

__init__(settings: QgsMapSettings, layerFilterExpression: dict[str | None, str | None])

Constructor version used with only expressions to filter symbols (no extent or polygon intersection)

Parameters:

• settings (QgsMapSettings)

• layerFilterExpression (dict[Optional[str], Optional[str]])

__init__(settings: QgsLayerTreeFilterSettings)

Constructor based off layer tree filter settings.

Added in version 3.32.

Parameters:

settings (QgsLayerTreeFilterSettings)

__init__(a0: QgsMapHitTest)

Parameters:

a0 (QgsMapHitTest)

legendKeyVisible(self, ruleKey: str | None, layer: QgsVectorLayer | None) → bool

Tests whether a given legend key is visible for a specified layer.

Parameters:

• ruleKey (Optional[str]) – legend rule key

• layer (Optional[QgsVectorLayer]) – vector layer

See also

symbolVisible()

Return type:

bool

results(self) → Any

Returns the hit test results, which are a map of layer ID to visible symbol legend keys.

Added in version 3.32.

Return type:

Any

resultsRenderersUpdatedCanvas(self) → dict[str, tuple[float, float]]

Returns the hit test results, for layers with UpdatedCanvas renderers (raster/mesh layers). Results are given as QMap of layer IDs to pairs of (min, max) values.

Added in version 4.0.

Return type:

dict[str, tuple[float, float]]

run(self)

Runs the map hit test

symbolVisible(self, symbol: QgsSymbol | None, layer: QgsVectorLayer | None) → bool

Tests whether a symbol is visible for a specified layer.

Parameters:

• symbol (Optional[QgsSymbol]) – symbol to find

• layer (Optional[QgsVectorLayer]) – vector layer

See also

legendKeyVisible()

Return type:

bool