function deletepz(Editor,varargin)
%DELETEPZ  Deletes pole or zero graphically.

%   Author(s): Bora Eryilmaz
%   Revised:
%   Copyright 1986-2002 The MathWorks, Inc. 
%   $Revision: 1.11 $  $Date: 2002/04/10 05:04:53 $

EditModel = Editor.EditedObject;
% Return if nothing to delete
if isempty(EditModel.PZGroup)  
  return
end

% Data and handles
PZViews = Editor.EditedPZ;
PlotAxes = getaxes(Editor.Axes);
EventMgr = Editor.EventManager;
Ts = EditModel.Ts;

% Acquire current mouse position 
CP = get(PlotAxes, 'CurrentPoint');
Xm = CP(1,1);
Ym = CP(1,2);

% Get positions of compensator poles and zeros
hPZ = [get(PZViews, {'Zero'}) ; get(PZViews, {'Pole'})];
hPZ = cat(1, hPZ{:});
X = get(hPZ, {'Xdata'});  X = cat(1, X{:});
Y = get(hPZ, {'Ydata'});  Y = cat(1, Y{:});

% Adjust for X and Y scales (distance measured in pixels, not data units)
Lims = get(PlotAxes, {'Xlim', 'Ylim'});
IsLogY = strcmpi(get(PlotAxes, 'YScale'), 'log');
if IsLogY
  Lims{2} = log2(Lims{2});   Ym = log2(Ym);
  ispos = (Y > 0);
  Y(ispos,:)  = log2(Y(ispos,:));   
  Y(~ispos,:) = -Inf;   
end

% Determine nearest match
[distmin, imin] = ...
    min(abs(((Xm-X) / diff(Lims{1})).^2 + ((Ym-Y) / diff(Lims{2})).^2));

if distmin < 0.03^2,
    % Identify selected group and get its description
    SelectedGroup = get(getappdata(hPZ(imin), 'PZVIEW'), 'GroupData');
    isel = find(EditModel.PZGroup == SelectedGroup);
    Description = EditModel.PZGroup(isel).describe(Ts);
    
    % Start transaction
    T = ctrluis.transaction(Editor.LoopData,'Name',sprintf('Delete %s', Description{1}),...
        'OperationStore','on','InverseOperationStore','on');
    
    % Delete selected group from list of compensator PZ groups
    delete(EditModel.PZGroup(isel));
    EditModel.PZGroup = EditModel.PZGroup([1:isel-1, isel+1:end], :);
    
    % Register transaction
    EventMgr.record(T);
    
    % Notify peers of deletion
    Editor.LoopData.dataevent('all');
    
    % Notify status and history listeners
    Status = sprintf('Deleted %s',Description{2});
    EventMgr.newstatus(Status);
    EventMgr.recordtxt('history',Status);
end