New features for LegendItem:

  - Can be anchored to parent item at any location
  - Support for filled plot styles
  - Automatically resizes to fit contents
  - PlotItem can auto-generate legend

examples/Legend.py

@@ -6,13 +6,14 @@ from pyqtgraph.Qt import QtCore, QtGui
 
 plt = pg.plot()
 
-l = pg.LegendItem((100,60), (60,10))  # args are (size, position)
-l.setParentItem(plt.graphicsItem())   # Note we do NOT call plt.addItem in this case
+plt.addLegend()
+#l = pg.LegendItem((100,60), offset=(70,30))  # args are (size, offset)
+#l.setParentItem(plt.graphicsItem())   # Note we do NOT call plt.addItem in this case
 
-c1 = plt.plot([1,3,2,4], pen='r')
-c2 = plt.plot([2,1,4,3], pen='g')
-l.addItem(c1, 'red plot')
-l.addItem(c2, 'green plot')
+c1 = plt.plot([1,3,2,4], pen='r', name='red plot')
+c2 = plt.plot([2,1,4,3], pen='g', fillLevel=0, fillBrush=(255,255,255,30), name='green plot')
+#l.addItem(c1, 'red plot')
+#l.addItem(c2, 'green plot')
 
 
 ## Start Qt event loop unless running in interactive mode or using pyside.

graphicsItems/GraphicsWidgetAnchor.py

+from ..Qt import QtGui, QtCore
+from ..Point import Point
+
+
+class GraphicsWidgetAnchor:
+    """
+    Class used to allow GraphicsWidgets to anchor to a specific position on their
+    parent. 
+
+    """
+
+    def __init__(self):
+        self.__parent = None
+        self.__parentAnchor = None
+        self.__itemAnchor = None
+        self.__offset = (0,0)
+        if hasattr(self, 'geometryChanged'):
+            self.geometryChanged.connect(self.__geometryChanged)
+
+    def anchor(self, itemPos, parentPos, offset=(0,0)):
+        """
+        Anchors the item at its local itemPos to the item's parent at parentPos.
+        Both positions are expressed in values relative to the size of the item or parent;
+        a value of 0 indicates left or top edge, while 1 indicates right or bottom edge.
+        
+        Optionally, offset may be specified to introduce an absolute offset. 
+        
+        Example: anchor a box such that its upper-right corner is fixed 10px left
+        and 10px down from its parent's upper-right corner::
+        
+            box.anchor(itemPos=(1,0), parentPos=(1,0), offset=(-10,10))
+        """
+        parent = self.parentItem()
+        if parent is None:
+            raise Exception("Cannot anchor; parent is not set.")
+        
+        if self.__parent is not parent:
+            if self.__parent is not None:
+                self.__parent.geometryChanged.disconnect(self.__geometryChanged)
+                
+            self.__parent = parent
+            parent.geometryChanged.connect(self.__geometryChanged)
+        
+        self.__itemAnchor = itemPos
+        self.__parentAnchor = parentPos
+        self.__offset = offset
+        self.__geometryChanged()
+        
+    def __geometryChanged(self):
+        if self.__parent is None:
+            return
+        if self.__itemAnchor is None:
+            return
+            
+        o = self.mapToParent(Point(0,0))
+        a = self.boundingRect().bottomRight() * Point(self.__itemAnchor)
+        a = self.mapToParent(a)
+        p = self.__parent.boundingRect().bottomRight() * Point(self.__parentAnchor)
+        off = Point(self.__offset)
+        pos = p + (o-a) + off
+        self.setPos(pos)
+        
+        
\ No newline at end of file

graphicsItems/LegendItem.py

@@ -2,12 +2,14 @@ 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):
+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::
@@ -15,17 +17,45 @@ class LegendItem(GraphicsWidget):
         legend.setParentItem(plotItem)
 
     """
-    def __init__(self, size, offset):
+    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
-        self.setGeometry(QtCore.QRectF(self.offset[0], self.offset[1], self.size[0], self.size[1]))
+        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, title):
+    def addItem(self, item, name):
         """
         Add a new entry to the legend. 
 
@@ -36,15 +66,30 @@ class LegendItem(GraphicsWidget):
         title       The title to display for this item. Simple HTML allowed.
         =========== ========================================================
         """
-        label = LabelItem(title)
+        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.size[0], self.size[1])
+        return QtCore.QRectF(0, 0, self.width(), self.height())
         
     def paint(self, p, *args):
         p.setPen(fn.mkPen(255,255,255,100))
@@ -61,8 +106,16 @@ class ItemSample(GraphicsWidget):
         return QtCore.QRectF(0, 0, 20, 20)
         
     def paint(self, p, *args):
-        p.setPen(fn.mkPen(self.item.opts['pen']))
+        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)
         
         
         
+        

graphicsItems/PlotCurveItem.py

@@ -65,6 +65,7 @@ class PlotCurveItem(GraphicsObject):
             'fillLevel': None,
             'brush': None,
             'stepMode': False,
+            'name': None
         }
         self.setClickable(kargs.get('clickable', False))
         self.setData(*args, **kargs)
@@ -238,6 +239,9 @@ class PlotCurveItem(GraphicsObject):
         self.fillPath = None
         #self.xDisp = self.yDisp = None
         
+        if 'name' in kargs:
+            self.opts['name'] = kargs['name']
+        
         if 'pen' in kargs:
             self.setPen(kargs['pen'])
         if 'shadowPen' in kargs:

graphicsItems/PlotDataItem.py

@@ -317,6 +317,8 @@ class PlotDataItem(GraphicsObject):
         ## pull in all style arguments. 
         ## Use self.opts to fill in anything not present in kargs.
         
+        if 'name' in kargs:
+            self.opts['name'] = kargs['name']
 
         ## if symbol pen/brush are given with no symbol, then assume symbol is 'o'
         

graphicsItems/PlotItem/PlotItem.py

@@ -33,6 +33,7 @@ from .. PlotDataItem import PlotDataItem
 from .. ViewBox import ViewBox
 from .. AxisItem import AxisItem
 from .. LabelItem import LabelItem
+from .. LegendItem import LegendItem
 from .. GraphicsWidget import GraphicsWidget
 from .. ButtonItem import ButtonItem
 from pyqtgraph.WidgetGroup import WidgetGroup
@@ -528,6 +529,9 @@ class PlotItem(GraphicsWidget):
             #c.connect(c, QtCore.SIGNAL('plotChanged'), self.plotChanged)
             #item.sigPlotChanged.connect(self.plotChanged)
             #self.plotChanged()
+        name = kargs.get('name', getattr(item, 'opts', {}).get('name', None))
+        if name is not None and self.legend is not None:
+            self.legend.addItem(item, name=name)
             
 
     def addDataItem(self, item, *args):
@@ -596,6 +600,16 @@ class PlotItem(GraphicsWidget):
         
         return item
 
+    def addLegend(self, size=None, offset=(30, 30)):
+        """
+        Create a new LegendItem and anchor it over the internal ViewBox.
+        Plots will be automatically displayed in the legend if they
+        are created with the 'name' argument.
+        """
+        self.legend = LegendItem(size, offset)
+        self.legend.setParentItem(self.vb)
+        return self.legend
+        
     def scatterPlot(self, *args, **kargs):
         if 'pen' in kargs:
             kargs['symbolPen'] = kargs['pen']