# Source code for pyqtgraph.graphicsItems.LegendItem

    import math

    from .. import functions as fn
    from ..icons import invisibleEye
    from ..Point import Point
    from ..Qt import QtCore, QtGui, QtWidgets
    from .BarGraphItem import BarGraphItem
    from .GraphicsWidget import GraphicsWidget
    from .GraphicsWidgetAnchor import GraphicsWidgetAnchor
    from .LabelItem import LabelItem
    from .PlotDataItem import PlotDataItem
    from .ScatterPlotItem import ScatterPlotItem, drawSymbol

    __all__ = ['LegendItem', 'ItemSample']

    class LegendItem(GraphicsWidget, GraphicsWidgetAnchor):
        """
        Displays a legend used for describing the contents of a plot.

        LegendItems are most commonly created by calling :meth:`PlotItem.addLegend
        <pyqtgraph.PlotItem.addLegend>`.

        Note that this item should *not* be added directly to a PlotItem (via
        :meth:`PlotItem.addItem <pyqtgraph.PlotItem.addItem>`). Instead, make it a
        direct descendant of the PlotItem::

            legend.setParentItem(plotItem)

        """

        def __init__(self, size=None, offset=None, horSpacing=25, verSpacing=0,
                     pen=None, brush=None, labelTextColor=None, frame=True,
                     labelTextSize='9pt', colCount=1, sampleType=None, **kwargs):
            """
            ==============  ===============================================================
            **Arguments:**
            size            Specifies the fixed size (width, height) of the legend. If
                            this argument is omitted, the legend will automatically resize
                            to fit its contents.
            offset          Specifies the offset position relative to the legend's parent.
                            Positive values offset from the left or top; negative values
                            offset from the right or bottom. If offset is None, the
                            legend must be anchored manually by calling anchor() or
                            positioned by calling setPos().
            horSpacing      Specifies the spacing between the line symbol and the label.
            verSpacing      Specifies the spacing between individual entries of the legend
                            vertically. (Can also be negative to have them really close)
            pen             Pen to use when drawing legend border. Any single argument
                            accepted by :func:`mkPen <pyqtgraph.mkPen>` is allowed.
            brush           QBrush to use as legend background filling. Any single argument
                            accepted by :func:`mkBrush <pyqtgraph.mkBrush>` is allowed.
            labelTextColor  Pen to use when drawing legend text. Any single argument
                            accepted by :func:`mkPen <pyqtgraph.mkPen>` is allowed.
            labelTextSize   Size to use when drawing legend text. Accepts CSS style
                            string arguments, e.g. '9pt'.
            colCount        Specifies the integer number of columns that the legend should
                            be divided into. The number of rows will be calculated
                            based on this argument. This is useful for plots with many
                            curves displayed simultaneously. Default: 1 column.
            sampleType      Customizes the item sample class of the `LegendItem`.
            ==============  ===============================================================

            """
            GraphicsWidget.__init__(self)
            GraphicsWidgetAnchor.__init__(self)
            self.setFlag(self.GraphicsItemFlag.ItemIgnoresTransformations)
            self.layout = QtWidgets.QGraphicsGridLayout()
            self.layout.setVerticalSpacing(verSpacing)
            self.layout.setHorizontalSpacing(horSpacing)

            self.setLayout(self.layout)
            self.items = []
            self.size = size
            self.offset = offset
            self.frame = frame
            self.columnCount = colCount
            self.rowCount = 1
            if size is not None:
                self.setGeometry(QtCore.QRectF(0, 0, self.size[0], self.size[1]))

            if sampleType is not None:
                if not issubclass(sampleType, GraphicsWidget):
                    raise RuntimeError("Only classes of type `GraphicsWidgets` "
                                       "are allowed as `sampleType`")
                self.sampleType = sampleType
            else:
                self.sampleType = ItemSample

            self.opts = {
                'pen': fn.mkPen(pen),
                'brush': fn.mkBrush(brush),
                'labelTextColor': labelTextColor,
                'labelTextSize': labelTextSize,
                'offset': offset,
            }
            self.opts.update(kwargs)

        def setSampleType(self, sample):
            """Set the new sample item claspes"""
            if sample is self.sampleType:
                return

            # Clear the legend, but before create a list of items
            items = list(self.items)
            self.sampleType = sample
            self.clear()

            # Refill the legend with the item list and new sample item
            for sample, label in items:
                plot_item = sample.item
                plot_name = label.text
                self.addItem(plot_item, plot_name)

            self.updateSize()

        def offset(self):
            """Get the offset position relative to the parent."""
            return self.opts['offset']

        def setOffset(self, offset):
            """Set the offset position relative to the parent."""
            self.opts['offset'] = offset

            offset = Point(self.opts['offset'])
            anchorx = 1 if offset[0] <= 0 else 0
            anchory = 1 if offset[1] <= 0 else 0
            anchor = (anchorx, anchory)
            self.anchor(itemPos=anchor, parentPos=anchor, offset=offset)

        def pen(self):
            """Get the QPen used to draw the border around the legend."""
            return self.opts['pen']

        def setPen(self, *args, **kargs):
            """Set the pen used to draw a border around the legend.

            Accepts the same arguments as :func:`~pyqtgraph.mkPen`.
            """
            pen = fn.mkPen(*args, **kargs)
            self.opts['pen'] = pen

            self.update()

        def brush(self):
            """Get the QBrush used to draw the legend background."""
            return self.opts['brush']

        def setBrush(self, *args, **kargs):
            """Set the brush used to draw the legend background.

            Accepts the same arguments as :func:`~pyqtgraph.mkBrush`.
            """
            brush = fn.mkBrush(*args, **kargs)
            if self.opts['brush'] == brush:
                return
            self.opts['brush'] = brush

            self.update()

        def labelTextColor(self):
            """Get the QColor used for the item labels."""
            return self.opts['labelTextColor']

        def setLabelTextColor(self, *args, **kargs):
            """Set the color of the item labels.

            Accepts the same arguments as :func:`~pyqtgraph.mkColor`.
            """
            self.opts['labelTextColor'] = fn.mkColor(*args, **kargs)
            for sample, label in self.items:
                label.setAttr('color', self.opts['labelTextColor'])

            self.update()

        def labelTextSize(self):
            """Get the `labelTextSize` used for the item labels."""
            return self.opts['labelTextSize']

        def setLabelTextSize(self, size):
            """Set the `size` of the item labels.

            Accepts the CSS style string arguments, e.g. '8pt'.
            """
            self.opts['labelTextSize'] = size
            for _, label in self.items:
                label.setAttr('size', self.opts['labelTextSize'])

            self.update()

        def setParentItem(self, p):
            """Set the parent."""
            ret = GraphicsWidget.setParentItem(self, p)
            if self.opts['offset'] is not None:
                offset = Point(self.opts['offset'])
                anchorx = 1 if offset[0] <= 0 else 0
                anchory = 1 if offset[1] <= 0 else 0
                anchor = (anchorx, anchory)
                self.anchor(itemPos=anchor, parentPos=anchor, offset=offset)
            return ret

        def addItem(self, item, name):
            """
            Add a new entry to the legend.

            ==============  ========================================================
            **Arguments:**
            item            A :class:`~pyqtgraph.PlotDataItem` from which the line
                            and point style of the item will be determined or an
                            instance of ItemSample (or a subclass), allowing the
                            item display to be customized.
            title           The title to display for this item. Simple HTML allowed.
            ==============  ========================================================
            """
            label = LabelItem(name, color=self.opts['labelTextColor'],
                              justify='left', size=self.opts['labelTextSize'])
            if isinstance(item, self.sampleType):
                sample = item
            else:
                sample = self.sampleType(item)
            self.items.append((sample, label))
            self._addItemToLayout(sample, label)
            self.updateSize()

        def _addItemToLayout(self, sample, label):
            col = self.layout.columnCount()
            row = self.layout.rowCount()
            if row:
                row -= 1
            nCol = self.columnCount * 2
            # FIRST ROW FULL
            if col == nCol:
                for col in range(0, nCol, 2):
                    # FIND RIGHT COLUMN
                    if not self.layout.itemAt(row, col):
                        break
                else:
                    if col + 2 == nCol:
                        # MAKE NEW ROW
                        col = 0
                        row += 1
            self.layout.addItem(sample, row, col)
            self.layout.addItem(label, row, col + 1)
            # Keep rowCount in sync with the number of rows if items are added
            self.rowCount = max(self.rowCount, row + 1)

        def setColumnCount(self, columnCount):
            """change the orientation of all items of the legend
            """
            if columnCount != self.columnCount:
                self.columnCount = columnCount

                self.rowCount = math.ceil(len(self.items) / columnCount)
                for i in range(self.layout.count() - 1, -1, -1):
                    self.layout.removeAt(i)  # clear layout
                for sample, label in self.items:
                    self._addItemToLayout(sample, label)
                self.updateSize()

        def getLabel(self, plotItem):
            """Return the labelItem inside the legend for a given plotItem

            The label-text can be changed via labelItem.setText
            """
            out = [(it, lab) for it, lab in self.items if it.item == plotItem]
            try:
                return out[0][1]
            except IndexError:
                return None

        def removeItem(self, item):
            """Removes one item from the legend.

            ==============  ========================================================
            **Arguments:**
            item            The item to remove or its name.
            ==============  ========================================================
            """
            for sample, label in self.items:
                if sample.item is item or label.text == item:
                    self.items.remove((sample, label))  # remove from itemlist
                    self.layout.removeItem(sample)  # remove from layout
                    sample.close()  # remove from drawing
                    self.layout.removeItem(label)
                    label.close()
                    self.updateSize()  # redraq box
                    return  # return after first match

        def clear(self):
            """Remove all items from the legend."""
            for sample, label in self.items:
                self.layout.removeItem(sample)
                sample.close()
                self.layout.removeItem(label)
                label.close()

            self.items = []
            self.updateSize()

        def updateSize(self):
            if self.size is not None:
                return
            height = 0
            width = 0
            for row in range(self.layout.rowCount()):
                row_height = 0
                col_width = 0
                for col in range(self.layout.columnCount()):
                    item = self.layout.itemAt(row, col)
                    if item:
                        col_width += item.width() + 3
                        row_height = max(row_height, item.height())
                width = max(width, col_width)
                height += row_height
            self.setGeometry(0, 0, width, height)
            return

        def boundingRect(self):
            return QtCore.QRectF(0, 0, self.width(), self.height())

        def paint(self, p, *args):
            if self.frame:
                p.setPen(self.opts['pen'])
                p.setBrush(self.opts['brush'])
                p.drawRect(self.boundingRect())

        def hoverEvent(self, ev):
            ev.acceptDrags(QtCore.Qt.MouseButton.LeftButton)

        def mouseDragEvent(self, ev):
            if ev.button() == QtCore.Qt.MouseButton.LeftButton:
                ev.accept()
                dpos = ev.pos() - ev.lastPos()
                self.autoAnchor(self.pos() + dpos)

    class ItemSample(GraphicsWidget):
        """Class responsible for drawing a single item in a LegendItem (sans label)
        """

        def __init__(self, item):
            GraphicsWidget.__init__(self)
            self.item = item

        def boundingRect(self):
            return QtCore.QRectF(0, 0, 20, 20)

        def paint(self, p, *args):
            opts = self.item.opts
            if opts.get('antialias'):
                p.setRenderHint(p.RenderHint.Antialiasing)

            visible = self.item.isVisible()
            if not visible:
                icon = invisibleEye.qicon
                p.drawPixmap(QtCore.QPoint(1, 1), icon.pixmap(18, 18))
                return

            if not isinstance(self.item, ScatterPlotItem):
                p.setPen(fn.mkPen(opts['pen']))
                p.drawLine(0, 11, 20, 11)

                if (opts.get('fillLevel', None) is not None and
                        opts.get('fillBrush', None) is not None):
                    p.setBrush(fn.mkBrush(opts['fillBrush']))
                    p.setPen(fn.mkPen(opts['pen']))
                    p.drawPolygon(QtGui.QPolygonF(
                        [QtCore.QPointF(2, 18), QtCore.QPointF(18, 2),
                         QtCore.QPointF(18, 18)]))

            symbol = opts.get('symbol', None)
            if symbol is not None:
                if isinstance(self.item, PlotDataItem):
                    opts = self.item.scatter.opts
                p.translate(10, 10)
                drawSymbol(p, symbol, opts['size'], fn.mkPen(opts['pen']),
                           fn.mkBrush(opts['brush']))

            if isinstance(self.item, BarGraphItem):
                p.setBrush(fn.mkBrush(opts['brush']))
                p.drawRect(QtCore.QRectF(2, 2, 18, 18))

        def mouseClickEvent(self, event):
            """Use the mouseClick event to toggle the visibility of the plotItem
            """
            if event.button() == QtCore.Qt.MouseButton.LeftButton:
                visible = self.item.isVisible()
                self.item.setVisible(not visible)

            event.accept()
            self.update()