Class: QgsEffectStack

class qgis.core.QgsEffectStack

Bases: qgis._core.QgsPaintEffect

Constructor for empty QgsEffectStack.

QgsEffectStack(other: QgsEffectStack)

QgsEffectStack(effect: QgsPaintEffect) Creates a new QgsEffectStack effect from a single initial effect.

Parameters:effect – initial effect to add to the stack. The effect will be cloned, so ownership is not transferred to the stack.
Returns:new QgsEffectStack containing initial effect

A paint effect which consists of a stack of other chained paint effects

Effect stacks can be used to apply multiple paint effects to a QPicture. For instance, an effect stack may blur then apply a drop shadow.

The way in which effects apply to a stack is controlled by the effect’s drawMode. Effects can either render their results onto the destination paint device, or just modify the source picture which is drawn by subsequent effects in the stack. For instance, a blur effect with a Modifier drawMode will blur the source picture for the following drop shadow effect without actually drawing the blurred picture to the paint device. If the blur effect had a Render drawMode then the blurred picture will be drawn on the paint device, but the following drop shadow effect will be drawn using the original picture, not the blurred version.

New in version 2.9: Enums

Methods

appendEffect Appends an effect to the end of the stack.
boundingRect
changeEffect Replaces the effect at a specified position within the stack.
clone
count Returns count of effects contained by the stack
create Creates a new QgsEffectStack effect.
draw
drawSource
effect Returns a pointer to the effect at a specified index within the stack
effectList Returns a pointer to the list of effects currently contained by the stack
fixQPictureDpi
imageOffset
insertEffect Inserts an effect at a specified index within the stack.
properties Unused for QgsEffectStack, will always return an empty string map
readProperties readProperties(self, props: Dict[str, str]) Unused for QgsEffectStack, props parameter will be ignored
saveProperties
source
sourceAsImage
takeEffect Removes an effect from the stack and returns a pointer to it.
type

Signals

Attributes

appendEffect(self, effect: QgsPaintEffect)

Appends an effect to the end of the stack.

Parameters:effect – QgsPaintEffect to append. Ownership of the effect will be transferred to the stack object.

See also

insertEffect()

boundingRect()
changeEffect(self, index: int, effect: QgsPaintEffect) → bool

Replaces the effect at a specified position within the stack.

Parameters:
  • index – position of effect to replace
  • effect – QgsPaintEffect to replace with. Ownership of the effect will be transferred to the stack object.
clone(self) → QgsEffectStack
count(self) → int

Returns count of effects contained by the stack

Returns:count of effects
create(map: Dict[str, str]) → QgsPaintEffect

Creates a new QgsEffectStack effect. This method ignores the map parameter, and always returns an empty effect stack.

Parameters:map – unused encoded properties string map
Returns:new QgsEffectStack
draw(self, context: QgsRenderContext)
drawSource()
effect(self, index: int) → QgsPaintEffect

Returns a pointer to the effect at a specified index within the stack

Parameters:index – position of effect to return
Returns:QgsPaintEffect at specified position
effectList(self) → object

Returns a pointer to the list of effects currently contained by the stack

Returns:list of QgsPaintEffects within the stack
fixQPictureDpi()
imageOffset()
insertEffect(self, index: int, effect: QgsPaintEffect) → bool

Inserts an effect at a specified index within the stack.

Parameters:
  • index – position to insert the effect
  • effect – QgsPaintEffect to insert. Ownership of the effect will be transferred to the stack object.

See also

appendEffect()

properties(self) → Dict[str, str]

Unused for QgsEffectStack, will always return an empty string map

readProperties(self, element: QDomElement) → bool

readProperties(self, props: Dict[str, str]) Unused for QgsEffectStack, props parameter will be ignored

saveProperties(self, doc: QDomDocument, element: QDomElement) → bool
source()
sourceAsImage()
takeEffect(self, index: int) → QgsPaintEffect

Removes an effect from the stack and returns a pointer to it.

Parameters:index – position of effect to take
type(self) → str