pyqtgraph/graphicsItems/LegendItem.py

from .GraphicsWidget import GraphicsWidget
from .LabelItem import LabelItem
from ..Qt import QtGui, QtCore
from .. import functions as fn
from ..Point import Point
from .GraphicsWidgetAnchor import GraphicsWidgetAnchor
__all__ = ['LegendItem']

class LegendItem(GraphicsWidget, GraphicsWidgetAnchor):
    """
    Displays a legend used for describing the contents of a plot.
    LegendItems are most commonly created by calling PlotItem.addLegend().

    Note that this item should not be added directly to a PlotItem. Instead,
    Make it a direct descendant of the PlotItem::

        legend.setParentItem(plotItem)

    """
    def __init__(self, size=None, offset=None):
        """
        ==========  ===============================================================
        Arguments
        size        Specifies the fixed size (width, height) of the legend. If 
                    this argument is omitted, the legend will autimatically 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(). 
        ==========  ===============================================================
        
        """
        
        
        GraphicsWidget.__init__(self)
        GraphicsWidgetAnchor.__init__(self)
        self.setFlag(self.ItemIgnoresTransformations)
        self.layout = QtGui.QGraphicsGridLayout()
        self.setLayout(self.layout)
        self.items = []
        self.size = size
        self.offset = offset
        if size is not None:
            self.setGeometry(QtCore.QRectF(0, 0, self.size[0], self.size[1]))
        
    def setParentItem(self, p):
        ret = GraphicsWidget.setParentItem(self, p)
        if self.offset is not None:
            offset = Point(self.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 PlotDataItem from which the line and point style
                    of the item will be determined
        title       The title to display for this item. Simple HTML allowed.
        =========== ========================================================
        """
        label = LabelItem(name)
        sample = ItemSample(item)
        row = len(self.items)
        self.items.append((sample, label))
        self.layout.addItem(sample, row, 0)
        self.layout.addItem(label, row, 1)
        self.updateSize()
        
    def updateSize(self):
        if self.size is not None:
            return
            
        height = 0
        width = 0
        #print("-------")
        for sample, label in self.items:
            height += max(sample.height(), label.height()) + 3
            width = max(width, sample.width()+label.width())
            #print(width, height)
        #print width, height
        self.setGeometry(0, 0, width+25, height)
        
    def boundingRect(self):
        return QtCore.QRectF(0, 0, self.width(), self.height())
        
    def paint(self, p, *args):
        p.setPen(fn.mkPen(255,255,255,100))
        p.setBrush(fn.mkBrush(100,100,100,50))
        p.drawRect(self.boundingRect())
        
        
class ItemSample(GraphicsWidget):
    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('fillLevel',None) is not None and opts.get('fillBrush',None) is not None:
            p.setBrush(fn.mkBrush(opts['fillBrush']))
            p.setPen(fn.mkPen(None))
            p.drawPolygon(QtGui.QPolygonF([QtCore.QPointF(2,18), QtCore.QPointF(18,2), QtCore.QPointF(18,18)]))
        
        p.setPen(fn.mkPen(opts['pen']))
        p.drawLine(2, 18, 18, 2)