Hi,
I created a menu for selecting colormaps from a context menu on the
graph. The attached code cmapmenu.py contains a runnable example.
I've only implemented support for wx.
In general, I would like to be able to add context menu operations
to individual artists on the plot, and will be doing so for my
own applications. Is this something that could live in the
matplotlib backends? Are there users of Qt, Gtk, Tk, ... who
are willing to add support for them?
- Paul
# This program is public domain
"""
Defines CMapMenu, a wx submenu containing colormaps.
=== Example ===
The following defines a context menu with mapper::
import wx
import cmapmenu
...
def onContextMenu(self,event):
popup = wx.Menu()
item = popup.Append(wx.ID_ANY,'&Save image', 'Save image as PNG')
wx.EVT_MENU(self, item.GetId(), self.onSaveImage)
item = popup.Append(wx.ID_ANY,'&Grid on/off', 'Toggle grid lines')
wx.EVT_MENU(self, item.GetId(), self.onGridToggle)
item = popup.AppendMenu(wx.ID_ANY, "Colourmaps",
CMapMenu(self, self.mapper, self.canvas))
The assumption is that mapper and canvas are attributes of the panel for
which the context menu is defined. When the new colour map is selected,
the mapper will be reset and the figure redrawn.
Sometimes you will want to do more than just update the mapper for the
current canvas. You may for example want to record the new colormap name
in the application settings file so that it will be there when the
application is reloaded. To do this, call CMapMenu(callback=self.OnColormap).
This will call the method OnColormap with the parameter name giving the
name of the colormap.
"""
__all__ = ['CMapMenu']
import sys
import wx
import numpy
from matplotlib import cm
def colorbar_bitmap(colormap,length,thickness=10,orientation='horizontal'):
"""
Convert a colormap to a bitmap showing a colorbar for the colormap.
Orientation can be vertical or horizontal (only looks at the first letter).
"""
# Make an RGBA array from the colormap, either horizontally or vertically.
V = colormap(numpy.linspace(0,1,length),bytes=True)
if orientation[0].lower() == 'h':
V = numpy.tile(V,(thickness,1))
bitmap = wx.BitmapFromBufferRGBA(length,thickness,V)
elif orientation[0].lower() == 'v':
V = numpy.tile(V,(1,thickness))
bitmap = wx.BitmapFromBufferRGBA(thickness,length,V)
else:
raise ValueError,"expected orientation [V]ertical or [H]orizontal"
return bitmap
def all_colormaps():
"""
Iterate over the available colormaps
"""
maps = [name
for name in cm.datad.keys()
if not name.endswith("_r")]
maps.sort()
return maps
def grouped_colormaps():
"""
Colormaps grouped by source.
"""
mlab = ['autumn','winter','spring','summer',
'gray','bone','copper','pink',
'cool','hot',
'hsv','jet','spectral',
#'binary', # Seems to be a reverse of gray
'prism','flag']
mlab_r = [m+'_r' for m in mlab]
brewer = ['Accent','Dark2',
'Spectral',
'Paired',
'Blues','Greens','Greys','Oranges','Purples','Reds',
'Pastel1','Pastel2',
'Set1','Set2','Set3',
'BrBG','BuGn','BuPu','GnBu',
'OrRd',
'PiYG','PRGn','PuBu','PuBuGn',
'PuOr','PuRd',
'RdBu','RdGy','RdPu',
'RdYlBu','RdYlGn',
'YlGn','YlGnBu','YlOrBr','YlOrRd',
]
brewer_r = [m+'_r' for m in brewer]
gist = ['gist_ncar','gist_rainbow',
'gist_stern','gist_earth',
'gist_gray','gist_heat',
#'gist_yarg', # Seems to be a reverse of gray
]
gist_r = [m+'_r' for m in gist]
return gist + [None] + mlab + [None] + brewer
def event_callback(callback, **kw):
"""
Add keyword arguments to the event callback.
"""
return lambda evt: callback(evt,**kw)
class CMapMenu(wx.Menu):
"""
Menu tree binding to a list of colormaps.
"""
def __init__(self, window,
mapper=None, canvas=None, callback=None):
"""
Define a context menu for selecting colormaps.
Need a window to use as the event handler.
If mapper is defined, it will be updated with the new colormap.
If canvas is defined, it will update on idle.
"""
wx.Menu.__init__(self)
# OS X needs 16x16 icons; Windows and Linux can be longer
bar_length = 32 if not sys.platform in ['darwin'] else 16
bar_height = 16
self.mapper,self.canvas,self.callback = mapper,canvas,callback
self.selected = None
self.mapid = {}
for name in grouped_colormaps():
if name is None:
self.AppendSeparator()
else:
item = wx.MenuItem(self, wx.ID_ANY, name)
map = cm.get_cmap(name)
icon = colorbar_bitmap(map,bar_length,thickness=bar_height)
item.SetBitmap(icon)
self.AppendItem(item)
window.Bind(wx.EVT_MENU,
event_callback(self._OnSelect, name=name),
id=item.GetId())
def _OnSelect(self, event, name=None):
"""
When selected, record the name and call the subclass OnSelect method.
"""
self.selected = name
if self.mapper:
self.mapper.set_cmap(cm.get_cmap(name))
if self.canvas:
self.canvas.draw_idle()
if self.callback:
self.callback(name)
def demo():
from matplotlib.image import FigureImage
from matplotlib.figure import Figure
from matplotlib.backends.backend_wxagg import FigureCanvasWxAgg as Canvas
class Frame(wx.Frame):
def __init__(self):
wx.Frame.__init__(self, parent=None, title="Colourmap Selection")
self.figure = Figure(dpi=80, figsize=(2,2))
self.canvas = Canvas(self, -1, self.figure)
self.axes = self.figure.gca()
x = y = numpy.linspace(-3,3,80)
X,Y = numpy.meshgrid(x,y)
V = numpy.sin(Y**2+X**2)
self.mapper = FigureImage(self.figure)
im = self.axes.pcolor(x,y,V,shading='flat')
self.mapper.add_observer(im)
sizer = wx.BoxSizer(wx.VERTICAL)
sizer.Add(self.canvas,1,wx.EXPAND)
self.SetSizer(sizer)
self.canvas.Bind(wx.EVT_RIGHT_DOWN, self.OnContext)
def OnContext(self, evt):
popup = wx.Menu()
item = popup.Append(wx.ID_ANY,'&Grid on/off', 'Toggle grid lines')
wx.EVT_MENU(self, item.GetId(), self.OnGridToggle)
cmapmenu = CMapMenu(self, callback = self.OnColormap,
mapper=self.mapper, canvas=self.canvas)
item = popup.AppendMenu(wx.ID_ANY, "Colourmaps", cmapmenu)
self.PopupMenu(popup, evt.GetPositionTuple())
def OnColormap(self, name):
print "Selected colormap",name
def OnGridToggle(self, event):
self.axes.grid()
self.canvas.draw_idle()
app = wx.App(redirect=False)
Frame().Show()
app.MainLoop()
if __name__ == "__main__": demo()
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