function out = pdezoom(varargin)
%PDEZOOM   Zoom in and out on a 2-D plot.
%   Note: special version of ZOOM for the PDE Toolbox
%   preserves the WindowButtonMotion-callback.
%
%   PDEZOOM with no arguments toggles the zoom status.
%   PDEZOOM ON turns zoom on for the current axis.
%   PDEZOOM OFF turns zoom off in the current axis.
%   PDEZOOM OUT returns the plot to its initial (full) zoom.
%   PDEZOOM XON or PDEZOOM YON turns zoom on for the x or y axis only.
%   PDEZOOM RESET clears the zoom out point
%
%   When zoom is on, click the left mouse button to zoom in on the
%   point under the mouse.  Click the right mouse button to zoom out
%   (shift-click on the Macintosh).  Each time you click, the axes
%   limits will be changed by a factor of 2 (in or out).  You can also
%   click and drag to zoom into an area.  Double clicking zooms out to
%   the point at which zoom was first turned for this figure.  Note
%   that turning zoom on, then off does not reset the zoom point.
%   This may be done explicitly with PDEZOOM RESET.
%
%   PDEZOOM(FIG,OPTION) or PDEZOOM(FIG) applies the zoom command to the
%   figure specified by FIG. OPTION can be any of the above arguments.

%   Clay M. Thompson 1-25-93
%   Revised 11 Jan 94 by Steven L. Eddins
%   PDEZOOM add's: M Ringh 07-26-94, MR 10-01-96.
%   Copyright 1994-2016 The MathWorks, Inc.

%   Note: pdezoom uses the userdata of the zlabel of the axis and
%   the figure buttondown and buttonmotion functions
%
%   PDEZOOM XON zooms x-axis only
%   PDEZOOM YON zooms y-axis only

switch nargin

  %%%%%%%%%%%%%%%%%%%%%%%%%%
  %%% No Input Arguments %%%
  %%%%%%%%%%%%%%%%%%%%%%%%%%
  case 0
    fig=get(0,'currentfigure');
    if isempty(fig), return, end
    zoomCommand='toggle';

  %%%%%%%%%%%%%%%%%%%%%%%%%%
  %%% One Input Argument %%%
  %%%%%%%%%%%%%%%%%%%%%%%%%%
  case 1

    % If the argument is a string, the argument is a zoom command
    % (i.e. (on, off, down, xdown, etc.).  Otherwise, the argument is
    % assumed to be a figure handle, in which case all we do is
    % toggle the zoom status.

    if ischar(varargin{1})
      fig=get(0,'currentfigure');
      if isempty(fig), return, end

      zoomCommand=varargin{1};
    else
      scale_factor=varargin{1};
      zoomCommand='scale';
      fig = gcf;
    end % if

  %%%%%%%%%%%%%%%%%%%%%%%%%%%
  %%% Two Input Arguments %%%
  %%%%%%%%%%%%%%%%%%%%%%%%%%%
  case 2
    fig=varargin{1};
    zoomCommand=varargin{2};

  otherwise
    narginchk(0, 2);

end % switch nargin

%
% handle 'off' commands first
%
if strcmp(zoomCommand,'off')
  %
  % turn off zoom, and take a hike
  %
  fcns = getappdata(fig,'ZOOMFigureFcns');
  if ~isempty(fcns)
    set(fig,'windowbuttondownfcn',fcns.wbdf,'windowbuttonupfcn',fcns.wbuf,...
            'windowbuttonmotionfcn',fcns.wbmf,'buttondownfcn',fcns.bdf);
    rmappdata(fig,'ZOOMFigureFcns');
  end
  return
end % if

ax = findobj(get(fig,'Children'),'flat','Tag','PDEAxes');
if isempty(ax), error(message('pde:pdezoom:NoAxis')), end

rbbox_mode = 0;
zoomx = 1; zoomy = 1; % Assume no constraints

zoomCommand=lower(zoomCommand);

if any(get(ax,'view')~=[0 90]) && ~(strcmp(zoomCommand,'scale') || strcmp(zoomCommand,'fill'))
  return % Do nothing
end

if strcmp(zoomCommand,'toggle')
  fcns = getappdata(fig,'ZOOMFigureFcns');
  if isempty(fcns)
    pdezoom(fig,'on');
  else
    pdezoom(fig,'off');
  end
  return
end % if

% Catch constrained zoom
if strcmp(zoomCommand,'xdown')
  zoomy = 0; zoomCommand = 'down'; % Constrain y
elseif strcmp(zoomCommand,'ydown')
  zoomx = 0; zoomCommand = 'down'; % Constrain x
end

if strcmp(zoomCommand,'down')
  % Activate main axis if it is clicked in; else return
  ZOOM_found = 0;
  ZOOM_Pt1 = get(ax,'CurrentPoint');
  xlim = get(ax,'xlim');
  ylim = get(ax,'ylim');
  if (xlim(1) <= ZOOM_Pt1(1,1) && ZOOM_Pt1(1,1) <= xlim(2) && ...
      ylim(1) <= ZOOM_Pt1(1,2) && ZOOM_Pt1(1,2) <= ylim(2))
    ZOOM_found = 1;
    set(fig,'currentaxes',ax);
  end % if

  if ZOOM_found==0, return, end

  % Check for selection type
  selection_type = get(fig,'SelectionType');
  if (strcmp(selection_type, 'normal'))
    % Zoom in
    m = 1;
    scale_factor = 2; % the default zooming factor
  elseif (strcmp(selection_type, 'open'))
    % Zoom all the way out
    pdezoom(fig,'out');
    return;
  else
    % Zoom partially out
    m = -1;
    scale_factor = 2;
  end

  ZOOM_Pt1 = get_currentpoint(ax);
  ZOOM_Pt2 = ZOOM_Pt1;
  center = ZOOM_Pt1;

  if (m == 1)
    % Zoom in
    units = get(fig,'units'); set(fig,'units','pixels')
    rbbox([get(fig,'currentpoint') 0 0],get(fig,'currentpoint'));
    ZOOM_Pt2 = get_currentpoint(ax);
    set(fig,'units',units)

    % Note the currentpoint is set by having a non-trivial up function.
    if min(abs(ZOOM_Pt1-ZOOM_Pt2)) >= ...
       min(.01*[diff(get_xlim(ax)) diff(get_ylim(ax))])
      % determine axis from rbbox
      a = [ZOOM_Pt1;ZOOM_Pt2]; a = [min(a);max(a)];

      % Undo the effect of get_currentpoint for log axes
      if strcmp(get(ax,'XScale'),'log')
        a(1:2) = 10.^a(1:2);
      end
      if strcmp(get(ax,'YScale'),'log')
        a(3:4) = 10.^a(3:4);
      end
      rbbox_mode = 1;
    end
  end
  limits = pdezoom(fig,'getlimits');

elseif strcmp(zoomCommand,'scale')
  if all(get(ax,'view')==[0 90]) % 2D zooming with scale_factor

    % Activate axis that is clicked in
    ZOOM_found = 0;
    ax = gca;
    xlim = get(ax,'xlim');
    ylim = get(ax,'ylim');
    ZOOM_Pt1 = [sum(xlim)/2 sum(ylim)/2];
    ZOOM_Pt2 = ZOOM_Pt1;
    center = ZOOM_Pt1;

    if (xlim(1) <= ZOOM_Pt1(1,1) && ZOOM_Pt1(1,1) <= xlim(2) && ...
          ylim(1) <= ZOOM_Pt1(1,2) && ZOOM_Pt1(1,2) <= ylim(2))
      ZOOM_found = 1;
    end % if

    if ZOOM_found==0, return, end

    if (scale_factor >= 1)
      m = 1;
    else
      m = -1;
    end

  else % 3D
    old_CameraViewAngle = get(ax,'CameraViewAngle')*pi/360;
    ncva = atan(tan(old_CameraViewAngle)*(1/scale_factor))*360/pi;
    set(ax,'CameraViewAngle',ncva);
    return;
  end

  limits = pdezoom(fig,'getlimits');

elseif strcmp(zoomCommand,'on')
  fcns = getappdata(fig,'ZOOMFigureFcns');
  if isempty(fcns)
    fcns.wbdf = get(fig,'windowbuttondownfcn');
    fcns.wbuf = get(fig,'windowbuttonupfcn');
    fcns.wbmf = get(fig,'windowbuttonmotionfcn');
    fcns.bdf  = get(fig,'buttondownfcn');
    setappdata(fig,'ZOOMFigureFcns',fcns);
  end
  set(fig,'windowbuttondownfcn','pdezoom down', ...
          'windowbuttonupfcn','ones;', ...
          'buttondownfcn','', ...
          'interruptible','on');
  set(ax,'interruptible','on')
  return

elseif strcmp(zoomCommand, 'reset')
  hZlabel = get(ax, 'Zlabel');
  ZlabelUserData = get(hZlabel, 'UserData');

  if IsZoomData(ZlabelUserData)
    set(hZlabel, 'UserData', []);
  end
  return

elseif strcmp(zoomCommand,'xon')
  pdezoom(fig,'on') % Set up userprop
  set(fig,'windowbuttondownfcn','pdezoom xdown', ...
          'windowbuttonupfcn','ones;', ...
          'buttondownfcn','',...
          'interruptible','on');
  set(ax,'interruptible','on')
  return

elseif strcmp(zoomCommand,'yon')
  pdezoom(fig,'on') % Set up userprop
  set(fig,'windowbuttondownfcn','pdezoom ydown', ...
          'windowbuttonupfcn','ones;', ...
          'buttondownfcn','',...
          'interruptible','on');
  set(ax,'interruptible','on')
  return

elseif strcmp(zoomCommand,'out')
  limits = pdezoom(fig,'getlimits');
  center = [sum(get_xlim(ax))/2 sum(get_ylim(ax))/2];
  m = -inf; % Zoom totally out

elseif strcmp(zoomCommand,'getlimits') % Get axis limits
  limits = get(get(ax,'ZLabel'),'UserData');
  % Do simple checking of userdata
  if size(limits,2)==4 && size(limits,1)<=2
    if all(limits(1,[1 3])<limits(1,[2 4]))
      getlimits = 0; out = limits(1,:); return   % Quick return
    else
      getlimits = -1; % Don't munge data
    end
  else
    if isempty(limits), getlimits = 1; else getlimits = -1; end
  end

  % If I've made it to here, we need to compute appropriate axis
  % limits.

  if isempty(get(get(ax,'ZLabel'),'userdata'))
    % Use quick method if possible
    xlim = get_xlim(ax); xmin = xlim(1); xmax = xlim(2);
    ylim = get_ylim(ax); ymin = ylim(1); ymax = ylim(2);

  elseif strcmp(get(ax,'xLimMode'),'auto') && ...
         strcmp(get(ax,'yLimMode'),'auto')
    % Use automatic limits if possible
    xlim = get_xlim(ax); xmin = xlim(1); xmax = xlim(2);
    ylim = get_ylim(ax); ymin = ylim(1); ymax = ylim(2);

  else
    % Use slow method only if someone else is using the userdata
    h = get(ax,'Children');
    xmin = inf; xmax = -inf; ymin = inf; ymax = -inf;
    for i=1:length(h)
      t = get(h(i),'Type');
      if ~strcmp(t,'text')
        if strcmp(t,'image') % Determine axis limits for image
          x = get(h(i),'Xdata'); y = get(h(i),'Ydata');
          x = [min(min(x)) max(max(x))];
          y = [min(min(y)) max(max(y))];
          [ma,na] = size(get(h(i),'Cdata'));
          if na>1, dx = diff(x)/(na-1); else dx = 1; end
          if ma>1, dy = diff(y)/(ma-1); else dy = 1; end
          x = x + [-dx dx]/2; y = y + [-dy dy]/2;
        end
        xmin = min(xmin,min(min(x)));
        xmax = max(xmax,max(max(x)));
        ymin = min(ymin,min(min(y)));
        ymax = max(ymax,max(max(y)));
      end
    end

    % Use automatic limits if in use (override previous calculation)
    if strcmp(get(ax,'xLimMode'),'auto')
      xlim = get_xlim(ax); xmin = xlim(1); xmax = xlim(2);
    end
    if strcmp(get(ax,'yLimMode'),'auto')
      ylim = get_ylim(ax); ymin = ylim(1); ymax = ylim(2);
    end
  end

  limits = [xmin xmax ymin ymax];
  if getlimits~=-1 % Don't munge existing userdata.
    % Store limits in ZLabel userdata
    set(get(ax,'ZLabel'),'UserData',limits);
  end

  out = limits;
  return

elseif strcmp(zoomCommand,'getconnect') % Get connected axes
  limits = get(get(ax,'ZLabel'),'UserData');
  if all(size(limits)==[2 4]) % Do simple checking
    out = limits(2,[1 2]);
  else
    out = [ax ax];
  end
  return

elseif strcmp(zoomCommand,'fill')
  old_view = get(ax,'view');
  view(45,45);
  set(ax,'CameraViewAngleMode','auto');
  set(ax,'CameraViewAngle',get(ax,'CameraViewAngle'));
  view(old_view);
  return

else
  error(message('pde:pdezoom:InvalidOption', zoomCommand));
end

%
% Actual zoom operation
%

if ~rbbox_mode
  xmin = limits(1); xmax = limits(2);
  ymin = limits(3); ymax = limits(4);

  if m==(-inf)
    dx = xmax-xmin;
    dy = ymax-ymin;
  else
    dx = diff(get_xlim(ax))*(scale_factor.^(-m-1)); dx = min(dx,xmax-xmin);
    dy = diff(get_ylim(ax))*(scale_factor.^(-m-1)); dy = min(dy,ymax-ymin);
  end

  % Limit zoom.
  center = max(center,[xmin ymin] + [dx dy]);
  center = min(center,[xmax ymax] - [dx dy]);
  a = [max(xmin,center(1)-dx) min(xmax,center(1)+dx) ...
       max(ymin,center(2)-dy) min(ymax,center(2)+dy)];

  % Check for log axes and return to linear values.
  if strcmp(get(ax,'XScale'),'log')
    a(1:2) = 10.^a(1:2);
  end
  if strcmp(get(ax,'YScale'),'log')
    a(3:4) = 10.^a(3:4);
  end

end

% Check for v4-type equal
fillequal = strcmp(get(ax,'plotboxaspectratiomode'),'manual') & ...
            strcmp(get(ax,'dataaspectratiomode'),'manual');
pbar = get(ax,'plotboxaspectratio');
% Update circular list of connected axes
list = pdezoom(fig,'getconnect'); % Circular list of connected axes.
if zoomx
  if a(1)==a(2), return, end % Short circuit if zoom is moot.
  if fillequal && (pbar(1) < pbar(2))
    set(ax,'xlimmode','auto')
  else
    set(ax,'xlim',a(1:2))
  end
  h = list(1);
  while h ~= ax
    if fillequal && zoomx && zoomy && (pbar(1) < pbar(2))
      set(h,'xlimmode','auto')
    else
      set(h,'xlim',a(1:2))
        end
    % Get next axes in the list
    next = get(get(h,'ZLabel'),'UserData');
    if all(size(next)==[2 4]), h = next(2,1); else h = ax; end
  end
end
if zoomy
  if a(3)==a(4), return, end % Short circuit if zoom is moot.
  if fillequal && (pbar(1) >= pbar(2))
    set(ax,'ylimmode','auto')
  else
    set(ax,'ylim',a(3:4))
  end
  h = list(2);
  while h ~= ax
    if fillequal && zoomx && zoomy && (pbar(1) >= pbar(2))
      set(h,'ylimmode','auto')
    else
      set(h,'ylim',a(3:4))
    end
    % Get next axes in the list
    next = get(get(h,'ZLabel'),'UserData');
    if all(size(next)==[2 4]), h = next(2,2); else h = ax; end
  end
end

function bZoomData = IsZoomData(data)
% Return 1 if the data represents zoom data
% Return 0 if someone else is using user data

if size(data,2)==4 && size(data,1)<=2
    if all(data(1,[1 3])<data(1,[2 4]))
      bZoomData = 1;
    else
      bZoomData = 0;
    end
else
  bZoomData = 0;
end

function p = get_currentpoint(ax)
%GET_CURRENTPOINT Return equivalent linear scale current point
p = get(ax,'currentpoint'); p = p(1,1:2);
if strcmp(get(ax,'XScale'),'log')
  p(1) = log10(p(1));
end
if strcmp(get(ax,'YScale'),'log')
  p(2) = log10(p(2));
end

function xlim = get_xlim(ax)
%GET_XLIM Return equivalent linear scale xlim
xlim = get(ax,'xlim');
if strcmp(get(ax,'XScale'),'log')
  xlim = log10(xlim);
end

function ylim = get_ylim(ax)
%GET_YLIM Return equivalent linear scale ylim
ylim = get(ax,'ylim');
if strcmp(get(ax,'YScale'),'log')
  ylim = log10(ylim);
end

