Class: QgsMapLayerStyleManager¶

Management of styles for use with one map layer.

Stored styles are identified by their names. The manager always keep track of which style of the stored ones is currently active. When the current style is changed, the new style is applied to the associated layer.

The class takes care of updating itself when the layer’s current style configuration changes. When some of layer style’s properties change (e.g. opacity / colors), the style manager will record them in the currently active style without any extra effort required.

When an instance is created, it creates “default” style (with empty name) recorded from the associated map layer and it is set as the current style. The instance must always contain at least one style (which is the current).

The style which is marked as current has no style data stored in its entry. This is to avoid duplication of data as all data is stored in map layer and can be retrieved easily. Also when saving, the entry for the current style will be saved with no data because everything is already saved by the map layer itself.

The class also features support for temporary change of the layer’s style, ideal for short-term use of a custom style followed by restoration of the original style (for example, when rendering a map with a different than current style).

Class Hierarchy¶

Base classes¶

QObject

Methods

`addStyle`	Add a style with given name and data
`addStyleFromLayer`	Add style by cloning the current one
`copyStylesFrom`	Copies all styles from other.
`currentStyle`	Returns name of the current style
`layer`	Gets pointer to the associated map layer
`mapLayerStyles`	Gets available styles for the associated map layer.
`readXml`	Read configuration (for project loading)
`removeStyle`	Remove a stored style
`renameStyle`	Rename a stored style to a different name
`reset`	Reset the style manager to a basic state - with one default style which is set as current
`restoreOverrideStyle`	Restore the original store after a call to `setOverrideStyle()`
`setCurrentStyle`	Set a different style as the current style - will apply it to the layer
`setOverrideStyle`	Temporarily apply a different style to the layer.
`style`	Returns data of a stored style - accessed by its unique name
`styles`	Returns list of all defined style names
`writeXml`	Write configuration (for project saving)

Static Methods

isDefault

Returns True if this is the default style

Signals

`currentStyleChanged`	Emitted when the current style has been changed
`styleAdded`	Emitted when a new style has been added
`styleRemoved`	Emitted when a style has been removed
`styleRenamed`	Emitted when a style has been renamed

class qgis.core.QgsMapLayerStyleManager[source]¶

Bases: QObject

__init__(layer: QgsMapLayer | None)

Construct a style manager associated with a map layer (must not be None). The style manager will be parented to layer.

Parameters:: layer (Optional[QgsMapLayer])

addStyle(self, name: str | None, style: QgsMapLayerStyle) → bool[source]¶

Add a style with given name and data

Return type:

bool

Returns:

True on success (name is unique and style is valid)

Parameters:

name (Optional[str])
style (QgsMapLayerStyle)

addStyleFromLayer(self, name: str | None) → bool[source]¶

Add style by cloning the current one

Return type:: bool
Returns:: True on success
Parameters:: name (Optional[str])

copyStylesFrom(self, other: QgsMapLayerStyleManager | None)[source]¶

Copies all styles from other. In case there is already a style with the same name it will be overwritten.

Added in version 3.14.

Parameters:: other (Optional[QgsMapLayerStyleManager])

currentStyle(self) → str[source]¶

Returns name of the current style

Return type:: str

signal currentStyleChanged(currentName: str)[source]¶

Emitted when the current style has been changed

Parameters:: currentName (str)

static isDefault(styleName: str | None) → bool[source]¶

Returns True if this is the default style

Parameters:: styleName (Optional[str])
Return type:: bool

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

Gets pointer to the associated map layer

Return type:: Optional[QgsMapLayer]

mapLayerStyles(self) → Dict[str, QgsMapLayerStyle]¶

Gets available styles for the associated map layer.

Return type:: Dict[str, QgsMapLayerStyle]
Returns:: A map of map layer style by style name

readXml(self, mgrElement: QDomElement)[source]¶

Read configuration (for project loading)

Parameters:: mgrElement (QDomElement)

removeStyle(self, name: str | None) → bool[source]¶

Remove a stored style

Return type:: bool
Returns:: True on success (style exists and it is not the last one)
Parameters:: name (Optional[str])

renameStyle(self, name: str | None, newName: str | None) → bool[source]¶

Rename a stored style to a different name

Return type:

bool

Returns:

True on success (style exists and new name is unique)

Parameters:

name (Optional[str])
newName (Optional[str])

reset(self)[source]¶: Reset the style manager to a basic state - with one default style which is set as current

restoreOverrideStyle(self) → bool[source]¶

Restore the original store after a call to setOverrideStyle()

Return type:: bool

setCurrentStyle(self, name: str | None) → bool[source]¶

Set a different style as the current style - will apply it to the layer

Return type:: bool
Returns:: True on success
Parameters:: name (Optional[str])

setOverrideStyle(self, styleDef: str | None) → bool[source]¶

Temporarily apply a different style to the layer. The argument can be either a style name or a full QML style definition. Each call must be paired with restoreOverrideStyle()

Parameters:: styleDef (Optional[str])
Return type:: bool

style(self, name: str | None) → QgsMapLayerStyle[source]¶

Returns data of a stored style - accessed by its unique name

Parameters:: name (Optional[str])
Return type:: QgsMapLayerStyle

signal styleAdded(name: str)[source]¶

Emitted when a new style has been added

Parameters:: name (str)

signal styleRemoved(name: str)[source]¶

Emitted when a style has been removed

Parameters:: name (str)

signal styleRenamed(oldName: str, newName: str)[source]¶

Emitted when a style has been renamed

Parameters:

oldName (str)
newName (str)

styles(self) → List[str][source]¶

Returns list of all defined style names

Return type:: List[str]

writeXml(self, mgrElement: QDomElement)[source]¶

Write configuration (for project saving)

Parameters:: mgrElement (QDomElement)