Added a Parameter interpolate_pickpos

mpldatacursor/__init__.py

@@ -21,6 +21,6 @@
 """
 __version__ = '0.4-dev'
 
-from convenience import datacursor
-from datacursor import DataCursor, HighlightingDataCursor
+from .convenience import datacursor
+from .datacursor import DataCursor, HighlightingDataCursor
 __all__ = ['datacursor', 'DataCursor', 'HighlightingDataCursor']

mpldatacursor/convenience.py

@@ -22,7 +22,7 @@
 from matplotlib import _pylab_helpers as pylab_helpers
 from matplotlib import cbook
 
-from datacursor import DataCursor
+from .datacursor import DataCursor
 
 def datacursor(artists=None, axes=None, **kwargs):
     """

mpldatacursor/datacursor.py

@@ -29,7 +29,7 @@
 from matplotlib.collections import PatchCollection, PolyCollection, QuadMesh
 from matplotlib.lines import Line2D
 
-import pick_info
+from . import pick_info
 
 class DataCursor(object):
     """A simple data cursor widget that displays the x,y location of a
@@ -41,7 +41,7 @@ class DataCursor(object):
                 arrowprops=dict(arrowstyle='->', connectionstyle='arc3,rad=0'))
 
     def __init__(self, artists, tolerance=5, formatter=None, point_labels=None,
-                 display='one-per-axes', draggable=False, **kwargs):
+                 display='one-per-axes', draggable=False,interpolate_pickpos=False, **kwargs):
         """Create the data cursor and connect it to the relevant figure.
 
         Parameters
@@ -66,9 +66,20 @@ def __init__(self, artists, tolerance=5, formatter=None, point_labels=None,
         draggable : boolean, optional
             Controls whether or not the annotation box will be interactively
             draggable to a new location after being displayed. Default: False.
+        interpolate_pickpos: boolean defines what kind of line pick function to use.
+            If set to true the interpolated version will be used.
+            If false the nearest point to the left will be picked.            
         **kwargs : additional keyword arguments, optional
             Additional keyword arguments are passed on to annotate.
         """
+        #define which kind of line_props to use. 
+        #line_props <- easy version
+        #line_props_interpolated <- interpolated version
+        if (interpolate_pickpos):
+            self.line_props = pick_info.line_props_interpolated
+        else:
+            self.line_props = pick_info.line_props
+
         def filter_artists(artists):
             """Replace ContourSets with their constituent artists."""
             output = []
@@ -150,7 +161,7 @@ def default_func(event):
                 AxesImage : [pick_info.image_props],
                 PathCollection : [pick_info.scatter_props, self._contour_info, 
                                   pick_info.collection_props],
-                Line2D : [pick_info.line_props],
+                Line2D : [self.line_props],
                 LineCollection : [pick_info.collection_props, 
                                   self._contour_info],
                 PatchCollection : [pick_info.collection_props, 

mpldatacursor/pick_info.py

@@ -71,7 +71,7 @@ def image_props(event):
         z = ', '.join('{:0.3g}'.format(item) for item in z)
     return dict(z=z, i=i, j=j)
 
-def line_props(event):
+def line_props_interpolated(event):
     """
     Get information for a pick event on a Line2D artist (as created with
     ``plot``.)
@@ -110,6 +110,38 @@ def line_props(event):
     x, y = np.array([x0, y0]) + dist_along * vec1
 
     return dict(x=x, y=y)
+
+def line_props(event):
+    """
+    Get information for a pick event on a Line2D artist (as created with
+    ``plot``.)
+
+    This will yield x and y values on the nearest pick position of the mouse
+
+
+    Parameters
+    -----------
+    event : PickEvent
+        The pick event to process
+
+    Returns
+    --------
+    props : dict
+        A dict with keys: x & y
+    """
+    xclick, yclick = event.mouseevent.xdata, event.mouseevent.ydata
+    #i = event.ind[0]
+    #Search the nearest point
+    xorig, yorig = event.artist.get_xydata().T
+    d = ((xclick-xorig[0])**2 + (yclick-yorig[0])**2)**0.5
+    i=0
+
+    for itmp,(xo,yo) in enumerate(zip(xorig[1:],yorig[1:])):
+        dtmp = ((xclick-xo)**2 + (yclick-yo)**2)**0.5
+        if dtmp<d:
+            d = dtmp
+            i=itmp+1
+    return dict(x=xorig[i], y=yorig[i])
 
 def collection_props(event):
     """