QGraphicsItemGroup¶
The
QGraphicsItemGroup
class provides a container that treats a group of items as a single item. More…
Synopsis¶
Functions¶
def
addToGroup
(item)def
removeFromGroup
(item)
Detailed Description¶
A
QGraphicsItemGroup
is a special type of compound item that treats itself and all its children as one item (i.e., all events and geometries for all children are merged together). It’s common to use item groups in presentation tools, when the user wants to group several smaller items into one big item in order to simplify moving and copying of items.If all you want is to store items inside other items, you can use any
QGraphicsItem
directly by passing a suitable parent tosetParentItem()
.The
boundingRect()
function ofQGraphicsItemGroup
returns the bounding rectangle of all items in the item group.QGraphicsItemGroup
ignores theItemIgnoresTransformations
flag on its children (i.e., with respect to the geometry of the group item, the children are treated as if they were transformable).There are two ways to construct an item group. The easiest and most common approach is to pass a list of items (e.g., all selected items) to
createItemGroup()
, which returns a newQGraphicsItemGroup
item. The other approach is to manually construct aQGraphicsItemGroup
item, add it to the scene callingaddItem()
, and then add items to the group manually, one at a time by callingaddToGroup()
. To dismantle (“ungroup”) an item group, you can either calldestroyItemGroup()
, or you can manually remove all items from the group by callingremoveFromGroup()
.# Group all selected items together group = scene.createItemGroup(scene.selecteditems()) # Destroy the group, and delete the group item scene.destroyItemGroup(group)The operation of adding and removing items preserves the items’ scene-relative position and transformation, as opposed to calling
setParentItem()
, where only the child item’s parent-relative position and transformation are kept.The addtoGroup() function reparents the target item to this item group, keeping the item’s position and transformation intact relative to the scene. Visually, this means that items added via
addToGroup()
will remain completely unchanged as a result of this operation, regardless of the item or the group’s current position or transformation; although the item’s position and matrix are likely to change.The
removeFromGroup()
function has similar semantics tosetParentItem()
; it reparents the item to the parent item of the item group. As withaddToGroup()
, the item’s scene-relative position and transformation remain intact.See also
- class PySide2.QtWidgets.QGraphicsItemGroup([parent=None])¶
- param parent:
Constructs a
QGraphicsItemGroup
.parent
is passed toQGraphicsItem
‘s constructor.See also
- PySide2.QtWidgets.QGraphicsItemGroup.addToGroup(item)¶
- Parameters:
Adds the given
item
and item’s child items to this item group. The item and child items will be reparented to this group, but its position and transformation relative to the scene will stay intact.See also
- PySide2.QtWidgets.QGraphicsItemGroup.removeFromGroup(item)¶
- Parameters:
Removes the specified
item
from this group. The item will be reparented to this group’s parent item, or to 0 if this group has no parent. Its position and transformation relative to the scene will stay intact.See also
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