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# Source code for pyqtgraph.graphicsItems.LinearRegionItem

    from .. import debug
    from .. import functions as fn
    from ..Qt import QtCore, QtGui
    from .GraphicsObject import GraphicsObject
    from .InfiniteLine import InfiniteLine

    __all__ = ['LinearRegionItem']

    class LinearRegionItem(GraphicsObject):
        """
        **Bases:** :class:`GraphicsObject <pyqtgraph.GraphicsObject>`

        Used for marking a horizontal or vertical region in plots.
        The region can be dragged and is bounded by lines which can be dragged individually.

        ===============================  =============================================================================
        **Signals:**
        sigRegionChangeFinished(self)    Emitted when the user has finished dragging the region (or one of its lines)
                                         and when the region is changed programatically.
        sigRegionChanged(self)           Emitted while the user is dragging the region (or one of its lines)
                                         and when the region is changed programatically.
        ===============================  =============================================================================
        """

        sigRegionChangeFinished = QtCore.Signal(object)
        sigRegionChanged = QtCore.Signal(object)
        Vertical = 0
        Horizontal = 1
        _orientation_axis = {
            Vertical: 0,
            Horizontal: 1,
            'vertical': 0,
            'horizontal': 1,
            }

        def __init__(self, values=(0, 1), orientation='vertical', brush=None, pen=None,
                     hoverBrush=None, hoverPen=None, movable=True, bounds=None,
                     span=(0, 1), swapMode='sort', clipItem=None):
            """Create a new LinearRegionItem.

            ==============  =====================================================================
            **Arguments:**
            values          A list of the positions of the lines in the region. These are not
                            limits; limits can be set by specifying bounds.
            orientation     Options are 'vertical' or 'horizontal'
                            The default is 'vertical', indicating that the region is bounded
                            by vertical lines.
            brush           Defines the brush that fills the region. Can be any arguments that
                            are valid for :func:`mkBrush <pyqtgraph.mkBrush>`. Default is
                            transparent blue.
            pen             The pen to use when drawing the lines that bound the region.
            hoverBrush      The brush to use when the mouse is hovering over the region.
            hoverPen        The pen to use when the mouse is hovering over the region.
            movable         If True, the region and individual lines are movable by the user; if
                            False, they are static.
            bounds          Optional [min, max] bounding values for the region
            span            Optional [min, max] giving the range over the view to draw
                            the region. For example, with a vertical line, use
                            ``span=(0.5, 1)`` to draw only on the top half of the
                            view.
            swapMode        Sets the behavior of the region when the lines are moved such that
                            their order reverses:

                              * "block" means the user cannot drag one line past the other
                              * "push" causes both lines to be moved if one would cross the other
                              * "sort" means that lines may trade places, but the output of
                                getRegion always gives the line positions in ascending order.
                              * None means that no attempt is made to handle swapped line
                                positions.

                            The default is "sort".
            clipItem        An item whose bounds will be used to limit the region bounds.
                            This is useful when a LinearRegionItem is added on top of an
                            :class:`~pyqtgraph.ImageItem` or
                            :class:`~pyqtgraph.PlotDataItem` and the visual region should
                            not extend beyond its range. This overrides ``bounds``.
            ==============  =====================================================================
            """

            GraphicsObject.__init__(self)
            self.orientation = orientation
            self.blockLineSignal = False
            self.moving = False
            self.mouseHovering = False
            self.span = span
            self.swapMode = swapMode
            self.clipItem = clipItem

            self._boundingRectCache = None
            self._clipItemBoundsCache = None

            # note LinearRegionItem.Horizontal and LinearRegionItem.Vertical
            # are kept for backward compatibility.
            lineKwds = dict(
                movable=movable,
                bounds=bounds,
                span=span,
                pen=pen,
                hoverPen=hoverPen,
            )

            if orientation in ('horizontal', LinearRegionItem.Horizontal):
                self.lines = [
                    # rotate lines to 180 to preserve expected line orientation
                    # with respect to region. This ensures that placing a '<|'
                    # marker on lines[0] causes it to point left in vertical mode
                    # and down in horizontal mode.
                    InfiniteLine(QtCore.QPointF(0, values[0]), angle=0, **lineKwds),
                    InfiniteLine(QtCore.QPointF(0, values[1]), angle=0, **lineKwds)]
                tr = QtGui.QTransform.fromScale(1, -1)
                self.lines[0].setTransform(tr, True)
                self.lines[1].setTransform(tr, True)
            elif orientation in ('vertical', LinearRegionItem.Vertical):
                self.lines = [
                    InfiniteLine(QtCore.QPointF(values[0], 0), angle=90, **lineKwds),
                    InfiniteLine(QtCore.QPointF(values[1], 0), angle=90, **lineKwds)]
            else:
                raise Exception("Orientation must be 'vertical' or 'horizontal'.")

            for l in self.lines:
                l.setParentItem(self)
                l.sigPositionChangeFinished.connect(self.lineMoveFinished)
            self.lines[0].sigPositionChanged.connect(self._line0Moved)
            self.lines[1].sigPositionChanged.connect(self._line1Moved)

            if brush is None:
                brush = QtGui.QBrush(QtGui.QColor(0, 0, 255, 50))
            self.setBrush(brush)

            if hoverBrush is None:
                c = self.brush.color()
                c.setAlpha(min(c.alpha() * 2, 255))
                hoverBrush = fn.mkBrush(c)
            self.setHoverBrush(hoverBrush)

            self.setMovable(movable)

        def getRegion(self):
            """Return the values at the edges of the region."""

            r = (self.lines[0].value(), self.lines[1].value())
            if self.swapMode == 'sort':
                return (min(r), max(r))
            else:
                return r

        def setRegion(self, rgn):
            """Set the values for the edges of the region.

            ==============   ==============================================
            **Arguments:**
            rgn              A list or tuple of the lower and upper values.
            ==============   ==============================================
            """
            if self.lines[0].value() == rgn[0] and self.lines[1].value() == rgn[1]:
                return
            self.blockLineSignal = True
            self.lines[0].setValue(rgn[0])
            self.blockLineSignal = False
            self.lines[1].setValue(rgn[1])
            #self.blockLineSignal = False
            self.lineMoved(0)
            self.lineMoved(1)
            self.lineMoveFinished()

        def setBrush(self, *br, **kargs):
            """Set the brush that fills the region. Can have any arguments that are valid
            for :func:`mkBrush <pyqtgraph.mkBrush>`.
            """
            self.brush = fn.mkBrush(*br, **kargs)
            self.currentBrush = self.brush

        def setHoverBrush(self, *br, **kargs):
            """Set the brush that fills the region when the mouse is hovering over.
            Can have any arguments that are valid
            for :func:`mkBrush <pyqtgraph.mkBrush>`.
            """
            self.hoverBrush = fn.mkBrush(*br, **kargs)

        def setBounds(self, bounds):
            """Set ``(min, max)`` bounding values for the region.

            The current position is only affected it is outside the new bounds. See
            :func:`~pyqtgraph.LinearRegionItem.setRegion` to set the position of the region.

            Use ``(None, None)`` to disable bounds.
            """
            if self.clipItem is not None:
                self.setClipItem(None)
            self._setBounds(bounds)

        def _setBounds(self, bounds):
            # internal impl so user-facing setBounds can clear clipItem and clipItem can
            # set bounds without clearing itself
            for line in self.lines:
                line.setBounds(bounds)

        def setMovable(self, m=True):
            """Set lines to be movable by the user, or not. If lines are movable, they will
            also accept HoverEvents."""
            for line in self.lines:
                line.setMovable(m)
            self.movable = m
            self.setAcceptHoverEvents(m)

        def setSpan(self, mn, mx):
            if self.span == (mn, mx):
                return
            self.span = (mn, mx)
            for line in self.lines:
                line.setSpan(mn, mx)
            self.update()

        def setClipItem(self, item=None):
            """Set an item to which the region is bounded.

            If ``None``, bounds are disabled.
            """
            self.clipItem = item
            self._clipItemBoundsCache = None
            if item is None:
                self._setBounds((None, None))
            if item is not None:
                self._updateClipItemBounds()

        def _updateClipItemBounds(self):
            # set region bounds corresponding to clipItem
            item_vb = self.clipItem.getViewBox()
            if item_vb is None:
                return

            item_bounds = item_vb.childrenBounds(items=(self.clipItem,))
            if item_bounds == self._clipItemBoundsCache or None in item_bounds:
                return

            self._clipItemBoundsCache = item_bounds

            if self.orientation in ('horizontal', LinearRegionItem.Horizontal):
                self._setBounds(item_bounds[1])
            else:
                self._setBounds(item_bounds[0])

        def boundingRect(self):
            br = QtCore.QRectF(self.viewRect())  # bounds of containing ViewBox mapped to local coords.

            if self.clipItem is not None:
                self._updateClipItemBounds()

            rng = self.getRegion()
            if self.orientation in ('vertical', LinearRegionItem.Vertical):
                br.setLeft(rng[0])
                br.setRight(rng[1])
                length = br.height()
                br.setBottom(br.top() + length * self.span[1])
                br.setTop(br.top() + length * self.span[0])
            else:
                br.setTop(rng[0])
                br.setBottom(rng[1])
                length = br.width()
                br.setRight(br.left() + length * self.span[1])
                br.setLeft(br.left() + length * self.span[0])

            br = br.normalized()

            if self._boundingRectCache != br:
                self._boundingRectCache = br
                self.prepareGeometryChange()

            return br

        def paint(self, p, *args):
            profiler = debug.Profiler()  # noqa: profiler does prints on GC
            p.setBrush(self.currentBrush)
            p.setPen(fn.mkPen(None))
            p.drawRect(self.boundingRect())

        def dataBounds(self, axis, frac=1.0, orthoRange=None):
            if axis == self._orientation_axis[self.orientation]:
                return self.getRegion()
            else:
                return None

        def lineMoved(self, i):
            if self.blockLineSignal:
                return

            # lines swapped
            if self.lines[0].value() > self.lines[1].value():
                if self.swapMode == 'block':
                    self.lines[i].setValue(self.lines[1-i].value())
                elif self.swapMode == 'push':
                    self.lines[1-i].setValue(self.lines[i].value())

            self.prepareGeometryChange()
            self.sigRegionChanged.emit(self)

        def _line0Moved(self):
            self.lineMoved(0)

        def _line1Moved(self):
            self.lineMoved(1)

        def lineMoveFinished(self):
            self.sigRegionChangeFinished.emit(self)

        def mouseDragEvent(self, ev):
            if not self.movable or ev.button() != QtCore.Qt.MouseButton.LeftButton:
                return
            ev.accept()

            if ev.isStart():
                bdp = ev.buttonDownPos()
                self.cursorOffsets = [l.pos() - bdp for l in self.lines]
                self.startPositions = [l.pos() for l in self.lines]
                self.moving = True

            if not self.moving:
                return

            self.lines[0].blockSignals(True)  # only want to update once
            for i, l in enumerate(self.lines):
                l.setPos(self.cursorOffsets[i] + ev.pos())
            self.lines[0].blockSignals(False)
            self.prepareGeometryChange()

            if ev.isFinish():
                self.moving = False
                self.sigRegionChangeFinished.emit(self)
            else:
                self.sigRegionChanged.emit(self)

        def mouseClickEvent(self, ev):
            if self.moving and ev.button() == QtCore.Qt.MouseButton.RightButton:
                ev.accept()
                for i, l in enumerate(self.lines):
                    l.setPos(self.startPositions[i])
                self.moving = False
                self.sigRegionChanged.emit(self)
                self.sigRegionChangeFinished.emit(self)

        def hoverEvent(self, ev):
            if self.movable and (not ev.isExit()) and ev.acceptDrags(QtCore.Qt.MouseButton.LeftButton):
                self.setMouseHover(True)
            else:
                self.setMouseHover(False)

        def setMouseHover(self, hover):
            ## Inform the item that the mouse is(not) hovering over it
            if self.mouseHovering == hover:
                return
            self.mouseHovering = hover
            if hover:
                self.currentBrush = self.hoverBrush
            else:
                self.currentBrush = self.brush
            self.update()