QItemModelScatterDataProxy — PyQt Documentation v6.9.0 (original) (raw)

PyQt6.QtGraphs.QItemModelScatterDataProxy

Description¶

Proxy class for presenting data in item models with Q3DScatterWidgetItem.

QItemModelScatterDataProxy allows you to use QAbstractItemModel derived models as a data source for Q3DScatterWidgetItem. It maps roles of QAbstractItemModel to the XYZ-values of Q3DScatterWidgetItem points.

The data is resolved asynchronously whenever the mapping or the model changes. arrayReset is emitted when the data has been resolved. However, inserts, removes, and single data item changes after the model initialization are resolved synchronously, unless the same frame also contains a change that causes the whole model to be resolved.

Mapping ignores rows and columns of the QAbstractItemModel and treats all items equally. It requires the model to provide roles for the data items that can be mapped to X, Y, and Z-values for the scatter points.

For example, assume that you have a custom QAbstractItemModel for storing various measurements done on material samples, providing data for roles such as “density”, “hardness”, and “conductivity”. You could visualize these properties on a scatter graph using this proxy:

// Map "density" value to X-axis, "hardness" to Y-axis and "conductivity" to Z-axis.

QItemModelScatterDataProxy *proxy = new QItemModelScatterDataProxy(customModel,

QStringLiteral("density"),

QStringLiteral("hardness"),

QStringLiteral("conductivity"));

If the fields of the model do not contain the data in the exact format you need, you can specify a search pattern regular expression and a replace rule for each role to get the value in a format you need. For more information on how the replacement using regular expressions works, see the QString::replace(const QRegularExpression &rx, const QString &after) function documentation. Note that using regular expressions has an impact on performance, so it’s more efficient to utilize item models where doing search and replace is not necessary to get the desired values.

For example about using the search patterns in conjunction with the roles, see ItemModelBarDataProxy usage in Simple Bar Graph.

Methods¶

__init__(parent: QObject = None)

Constructs QItemModelScatterDataProxy with optional parent.

__init__(QAbstractItemModel, parent: QObject = None)

Constructs QItemModelScatterDataProxy with itemModel and an optional parent. Proxy doesn’t take ownership of the itemModel, as typically item models are owned by other controls.

__init__(QAbstractItemModel, Optional[str], Optional[str], Optional[str], parent: QObject = None)

Constructs QItemModelScatterDataProxy with itemModel and an optional parent. The proxy doesn’t take ownership of the itemModel, as item models are typically owned by other controls. The xPosRole() property is set to xPosRole, the yPosRole() property to yPosRole, and the zPosRole() property to zPosRole.

__init__(QAbstractItemModel, Optional[str], Optional[str], Optional[str], Optional[str], parent: QObject = None)