QItemModelScatterDataProxy Class

Proxy class for presenting data in item models with Q3DScatter. More...

This class was introduced in QtDataVisualization 1.0.

• List of all members, including inherited members

Properties

Public Functions

Signals

Detailed Description

QItemModelScatterDataProxy allows you to use QAbstractItemModel derived models as a data source for Q3DScatter. It maps roles of QAbstractItemModel to the XYZ-values of Q3DScatter points.

The data is resolved asynchronously whenever the mapping or the model changes. QScatterDataProxy::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 how the replace using regular expressions works, see QString::replace(const QRegExp &rx, const QString &after) function documentation. Note that using regular expressions has an impact on the 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 Qt Quick 2 Bars Example.

See also Qt Data Visualization Data Handling.

Member Function Documentation

QItemModelScatterDataProxy::QItemModelScatterDataProxy(QAbstractItemModel *itemModel, const QString &xPosRole, const QString &yPosRole, const QString &zPosRole, const QString &rotationRole, QObject *parent = nullptr)

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

QItemModelScatterDataProxy::QItemModelScatterDataProxy(QAbstractItemModel *itemModel, const QString &xPosRole, const QString &yPosRole, const QString &zPosRole, QObject *parent = nullptr)

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

QItemModelScatterDataProxy::QItemModelScatterDataProxy(QAbstractItemModel *itemModel, QObject *parent = nullptr)

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

QItemModelScatterDataProxy::QItemModelScatterDataProxy(QObject *parent = nullptr)

Constructs QItemModelScatterDataProxy with optional parent.

[virtual] QItemModelScatterDataProxy::~QItemModelScatterDataProxy()

Destroys QItemModelScatterDataProxy.

void QItemModelScatterDataProxy::remap(const QString &xPosRole, const QString &yPosRole, const QString &zPosRole, const QString &rotationRole)

Changes xPosRole, yPosRole, zPosRole, and rotationRole mapping.

void QItemModelScatterDataProxy::setItemModel(QAbstractItemModel *itemModel)

Sets itemModel as the item model for Q3DScatter. Does not take ownership of the model, but does connect to it to listen for changes.

Note: Setter function for property itemModel.

See also itemModel().