python - Can I force my enable Container to redraw from a traitsui Handler? -

i have employed traitsui.api.handler catch , handle events traitsui.api.view, view includes button, behavior remove plot container containing multiple plots. container's components list accessed when remove button used, pop() method called, , plot removed. however, view not redraw, , plot appears remain in place. resizing window through dragging corner force redraw, confirming pop()

the question is: how can force redraw programmatically ?

it seems me right place in handler's setattr method, after pop()-ing plot.

# major library imports  numpy import linspace scipy.special import jn  # enthought library imports enable.api import container, componenteditor traits.api import hastraits, instance, button, int, str traitsui.api import item, hgroup, view, vsplit, uitem, instanceeditor, handler  # chaco imports chaco.api import arrayplotdata, gridcontainer, plot  # =============================================================================== # attributes use plot view. size = (1000, 800)  color_palette = [     (0.65098039, 0.80784314, 0.89019608, 1.0),     (0.12156863, 0.47058824, 0.70588235, 1.0),     (0.69803922, 0.8745098, 0.54117647, 1.0),     (0.2, 0.62745098, 0.17254902, 1.0),     (0.98431373, 0.60392157, 0.6, 1.0),     (0.89019608, 0.10196078, 0.10980392, 1.0),     (0.99215686, 0.74901961, 0.43529412, 1.0),     (1., 0.49803922, 0., 1.0),     (0.79215686, 0.69803922, 0.83921569, 1.0), ]   class instanceuitem(uitem):     """convenience class including instance in view"""     style = str('custom')     editor = instance(instanceeditor, ())    # =============================================================================== # # managerhandler view's handler #=============================================================================== class managerhandler(handler):     def setattr(self, info, object, name, value):         handler.setattr(self, info, object, name, value)         info.ui.context['pgrid'].plots_container.components.pop()         #at point, container not redraw, , so, while no longer         #contains last plot in components collection, plot still         # visible  # =============================================================================== # # plotsgrid class used demo #=============================================================================== class plotsgrid(hastraits):     plots_container = instance(container)     rows = int(3)     cols = int(3)      #===============================================================================     # # create plots, adapted chaco gridcontainer demo     #===============================================================================     def _plots_container_default(self):         # create gridcontainer hold of our plots         container = gridcontainer(padding=20, fill_padding=true,                                   bgcolor="lightgray", use_backbuffer=true,                                   shape=(self.rows, self.cols), spacing=(20, 20))          # create initial series of data         x = linspace(-5, 15.0, 100)         pd = arrayplotdata(index=x)          # plot bessel functions , add plots our container         in range(self.rows * self.cols):             pd.set_data("y" + str(i), jn(i, x))             plot = plot(pd)             plot.plot(("index", "y" + str(i)),                       color=tuple(color_palette[i]), line_width=2.0,                       bgcolor="white", border_visible=true)              container.add(plot)         return container    # =============================================================================== # # controls hastraits provides button used wire in desired behavior #=============================================================================== class controls(hastraits):     rem_plot = button("remove ...")      def _rem_plot_changed(self):         print "rem plot changed"    # =============================================================================== # # manager_view provides view , defines layout #=============================================================================== manager_view = view(     vsplit(         hgroup(             item('controls.rem_plot', height=32)         ),         item('pgrid.plots_container', editor=componenteditor(size=size), show_label=false),         show_border=true     ),     handler=managerhandler(),     resizable=true )  grid = plotsgrid() ctrl = controls()  if __name__ == "__main__":     ctrl.configure_traits(view=manager_view, context={'pgrid': grid, 'controls': ctrl}) 

the simplest way working call invalidate_and_redraw on plot container after popping plot. in case, modify call pop like:

plots_container = info.ui.context['pgrid'].plots_container plots_container.components.pop() plots_container.invalidate_and_redraw() 

longer discussion:

ideally, handled chaco. part of problem container wasn't designed have components list modified directly. instead, (i'm guessing) intention have user call plots_container.remove on item in components list.

that said, that doesn't seem work either. turns out remove invalidates current state, doesn't request redraw. (my guess chaco/enable doesn't automatically redraw since there may many cache-invalidating operations in row; e.g. if remove plots container, you'd want redraw after calls remove, not after each one.)

so use alternative method, write like:

plot = plots_container.components[-1] plots_container.remove(plot) plots_container.request_redraw()