Base class for graphics items with boundaries relative to a GraphicsView or ViewBox. The purpose of this class is to allow the creation of GraphicsItems which live inside a scalable view, but whose boundaries will always stay fixed relative to the view’s boundaries. For example: GridItem, InfiniteLine
The view can be specified on initialization or it can be automatically detected when the item is painted.
NOTE: Only the item’s boundingRect is affected; the item is not transformed in any way. Use viewRangeChanged to respond to changes in the view.
#view: The view box whose bounds will be used as a reference vor this item’s bounds bounds: QRectF with coordinates relative to view box. The default is QRectF(0,0,1,1),
which means the item will have the same bounds as the view.
Return the shape of this item after expanding by 2 pixels
Called by ViewBox for determining the auto-range bounds. If the height or with of the rect is 0, that dimension will be ignored. By default, UIGraphicsItems are excluded from autoRange by returning a zero-size rect.
Update the item’s bounding rect to match the viewport
Called whenever the view coordinates have changed. This is a good method to override if you want to respond to change of coordinates.
Called when the view widget/viewbox is resized/rescaled