Dashboard item module

This module defines the DashboardItem class, which serves as the abstract base class (template) for all dashboard widgets. Subclasses should extend DashboardItem and implement or override specific methods to define their behavior, parameters, and appearance.

Classes

DashboardItem

Abstract superclass for all dashboard items. Manages common UI behavior (resizing, parameter trees, mouse interactions) and defines the interface subclasses must implement.

class dashboard_item.DashboardItem(dashboard, params=None)

Parameters:

• dashboard – The parent Dashboard instance to which this item belongs.

• params – Optional JSON string of serialized parameters to restore state.

Methods

__init__(dashboard, params=None)

Initialize the widget: - Store the dashboard reference. - Enable mouse tracking for resize handles. - Initialize corner-grab state (size, index, flags). - Create a pyqtgraph.Parameter group with "width" and "height" children. - Call add_parameters() to insert widget-specific parameters. - Wrap parameters in a custom ParameterTree for display. - Restore state from params if provided and set up resize callbacks.

resizeEvent(event)

Called when the widget is resized. Updates the "width" and "height" parameters to match the new size and invokes the dashboard’s resize callback.

add_parameters() → list[Parameter]

Return a list of pyqtgraph.Parameter objects defining this widget’s custom properties (aside from size). Called once when the item is added.

get_name() → str

Abstract/static method. Return a human-friendly name for this item type. Must be overridden by subclasses (default raises NotImplementedError).

get_parameters() → Parameter

Return the root pyqtgraph.Parameter group containing all parameters (size + custom) for this widget. Used to build the property panel.

get_serialized_parameters() → str

Serialize the current parameter state to a JSON string suitable for saving to a dashboard configuration file.

on_delete()

Called when this widget is removed from the dashboard. Subclasses may override to clean up subscriptions or resources (default is a no-op).

dynamic_corner_size() → int | float

Compute and return the size of the corner “grabber” handle based on the widget’s dimensions and the dashboard’s mouse_resize setting (0 if resizing is disabled).

mousePressEvent(event)

If the click occurs within a corner “grabber” region (and resizing is enabled), begin resizing mode; otherwise, defer to the base QWidget handler.

mouseMoveEvent(event)

Change the mouse cursor to indicate resize readiness when hovering over a corner handle; reset the cursor otherwise.

mouseReleaseEvent(event)

End resizing mode on mouse release, reset grab state, and recompute corner handle size; otherwise, pass the event to the base handler.

corner_hit(pos) → bool

Check whether the given point (a QPoint in widget coordinates) lies within any of the four resize handles. If so, update corner_index and return True.

paintEvent(event)

Override the paint event to draw the corner grab handles when the mouse is hovering over them.

draw_corner(painter)

Draw the four invisible corner rectangles and, if active, fill the current corner grabber to indicate it can be dragged.