Source code for silx.gui.plot.items.marker

# coding: utf-8
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"""This module provides markers item of the :class:`Plot`.
"""

__authors__ = ["T. Vincent"]
__license__ = "MIT"
__date__ = "06/03/2017"


import logging

from .core import (Item, DraggableMixIn, ColorMixIn, SymbolMixIn,
                   ItemChangedType)


_logger = logging.getLogger(__name__)


class _BaseMarker(Item, DraggableMixIn, ColorMixIn):
    """Base class for markers"""

    _DEFAULT_COLOR = (0., 0., 0., 1.)
    """Default color of the markers"""

    def __init__(self):
        Item.__init__(self)
        DraggableMixIn.__init__(self)
        ColorMixIn.__init__(self)

        self._text = ''
        self._x = None
        self._y = None
        self._constraint = self._defaultConstraint

    def _addBackendRenderer(self, backend):
        """Update backend renderer"""
        # TODO not very nice way to do it, but simple
        symbol = self.getSymbol() if isinstance(self, Marker) else None

        return backend.addMarker(
            x=self.getXPosition(),
            y=self.getYPosition(),
            legend=self.getLegend(),
            text=self.getText(),
            color=self.getColor(),
            selectable=self.isSelectable(),
            draggable=self.isDraggable(),
            symbol=symbol,
            constraint=self.getConstraint(),
            overlay=self.isOverlay())

    def isOverlay(self):
        """Return true if marker is drawn as an overlay.

        A marker is an overlay if it is draggable.

        :rtype: bool
        """
        return self.isDraggable()

    def getText(self):
        """Returns marker text.

        :rtype: str
        """
        return self._text

    def setText(self, text):
        """Set the text of the marker.

        :param str text: The text to use
        """
        text = str(text)
        if text != self._text:
            self._text = text
            self._updated(ItemChangedType.TEXT)

    def getXPosition(self):
        """Returns the X position of the marker line in data coordinates

        :rtype: float or None
        """
        return self._x

    def getYPosition(self):
        """Returns the Y position of the marker line in data coordinates

        :rtype: float or None
        """
        return self._y

    def getPosition(self):
        """Returns the (x, y) position of the marker in data coordinates

        :rtype: 2-tuple of float or None
        """
        return self._x, self._y

    def setPosition(self, x, y):
        """Set marker position in data coordinates

        Constraint are applied if any.

        :param float x: X coordinates in data frame
        :param float y: Y coordinates in data frame
        """
        x, y = self.getConstraint()(x, y)
        x, y = float(x), float(y)
        if x != self._x or y != self._y:
            self._x, self._y = x, y
            self._updated(ItemChangedType.POSITION)

    def getConstraint(self):
        """Returns the dragging constraint of this item"""
        return self._constraint

    def _setConstraint(self, constraint):  # TODO support update
        """Set the constraint.

        This is private for now as update is not handled.

        :param callable constraint:
        :param constraint: A function filtering item displacement by
                           dragging operations or None for no filter.
                           This function is called each time the item is
                           moved.
                           This is only used if isDraggable returns True.
        :type constraint: None or a callable that takes the coordinates of
                          the current cursor position in the plot as input
                          and that returns the filtered coordinates.
        """
        if constraint is None:
            constraint = self._defaultConstraint
        assert callable(constraint)
        self._constraint = constraint

    @staticmethod
    def _defaultConstraint(*args):
        """Default constraint not doing anything"""
        return args


[docs]class Marker(_BaseMarker, SymbolMixIn): """Description of a marker""" _DEFAULT_SYMBOL = '+' """Default symbol of the marker""" def __init__(self): _BaseMarker.__init__(self) SymbolMixIn.__init__(self) self._x = 0. self._y = 0. def _setConstraint(self, constraint): """Set the constraint function of the marker drag. It also supports 'horizontal' and 'vertical' str as constraint. :param constraint: The constraint of the dragging of this marker :type: constraint: callable or str """ if constraint == 'horizontal': constraint = self._horizontalConstraint elif constraint == 'vertical': constraint = self._verticalConstraint super(Marker, self)._setConstraint(constraint) def _horizontalConstraint(self, _, y): return self.getXPosition(), y def _verticalConstraint(self, x, _): return x, self.getYPosition()
[docs]class XMarker(_BaseMarker): """Description of a marker""" def __init__(self): _BaseMarker.__init__(self) self._x = 0.
[docs] def setPosition(self, x, y): """Set marker line position in data coordinates Constraint are applied if any. :param float x: X coordinates in data frame :param float y: Y coordinates in data frame """ x, _ = self.getConstraint()(x, y) x = float(x) if x != self._x: self._x = x self._updated(ItemChangedType.POSITION)
[docs]class YMarker(_BaseMarker): """Description of a marker""" def __init__(self): _BaseMarker.__init__(self) self._y = 0.
[docs] def setPosition(self, x, y): """Set marker line position in data coordinates Constraint are applied if any. :param float x: X coordinates in data frame :param float y: Y coordinates in data frame """ _, y = self.getConstraint()(x, y) y = float(y) if y != self._y: self._y = y self._updated(ItemChangedType.POSITION)