wolffd@0: function out = centeraxes(ax,opt)
wolffd@0: % out = centeraxes(ax,opt)
wolffd@0: %==========================================================================
wolffd@0: % Center the coordinate axes of a plot so that they pass through the 
wolffd@0: % origin.
wolffd@0: %
wolffd@0: % Input: 0, 1 or 2 arguments
wolffd@0: %        0: Moves the coordinate axes of 'gca', i.e. the currently active 
wolffd@0: %           axes.
wolffd@0: %        1: ax, a handle to the axes which should be moved.
wolffd@0: %        2: ax, opt, where opt is a struct with further options
wolffd@0: %                opt.fontsize = 'size of axis tick labels'
wolffd@0: %                opt.fontname = name of axis tick font.
wolffd@0: %
wolffd@0: % If the opt struct is ommitted, the current values for the axes are used.
wolffd@0: %
wolffd@0: % Output: stuct out containing handles to all line objects created by this
wolffd@0: %         function.
wolffd@0: %
wolffd@0: %==========================================================================
wolffd@0: % Version: 1.1
wolffd@0: % Created: October 1, 2008, by Johan E. Carlson
wolffd@0: % Last modified: November 21, 2009, by Johan E. Carlson
wolffd@0: %==========================================================================
wolffd@0: 
wolffd@0: if nargin < 2,
wolffd@0:     fontsize = get(ax,'FontSize');
wolffd@0:     fontname = get(ax,'FontName');
wolffd@0: end
wolffd@0: if nargin < 1,
wolffd@0:     ax = gca;
wolffd@0: end
wolffd@0: 
wolffd@0: if nargin == 2,
wolffd@0:     if isfield(opt,'fontsize'),
wolffd@0:         fontsize = opt.fontsize;
wolffd@0:     else
wolffd@0:         fontsize = get(ax,'FontSize');
wolffd@0:     end;
wolffd@0:     if isfield(opt,'fontname'),
wolffd@0:         fontname = opt.fontname;
wolffd@0:     else
wolffd@0:         fontname = get(ax,'FontName');
wolffd@0:     end
wolffd@0: end
wolffd@0: 
wolffd@0: axes(ax);
wolffd@0: set(gcf,'color',[1 1 1]);
wolffd@0: xtext = get(get(ax,'xlabel'),'string');
wolffd@0: ytext = get(get(ax,'ylabel'),'string');
wolffd@0: 
wolffd@0: %--------------------------------------------------------------------------
wolffd@0: % Check if the current coordinate system include the origin. If not, change
wolffd@0: % it so that it does!
wolffd@0: %--------------------------------------------------------------------------
wolffd@0: xlim = 1.1*get(ax,'xlim');
wolffd@0: ylim = 1.1*get(ax,'ylim');
wolffd@0: set(ax,'xlim',xlim);
wolffd@0: set(ax,'ylim',ylim);
wolffd@0: 
wolffd@0: if xlim(1)>0,
wolffd@0:     xlim(1) = 0;
wolffd@0: end
wolffd@0: 
wolffd@0: if ylim(1)>0,
wolffd@0:     ylim(1) = 0;
wolffd@0: end
wolffd@0: 
wolffd@0: if xlim(2) < 0,
wolffd@0:     xlim(2) = 0;
wolffd@0: end
wolffd@0: 
wolffd@0: if ylim(2) < 0,
wolffd@0:     ylim(2) = 0;
wolffd@0: end;
wolffd@0: 
wolffd@0: set(ax,'xlim',xlim,'ylim',ylim);
wolffd@0: 
wolffd@0: 
wolffd@0: % -------------------------------------------------------------------------
wolffd@0: % Caculate size of the "axis tick marks"
wolffd@0: % -------------------------------------------------------------------------
wolffd@0: axpos = get(ax,'position');
wolffd@0: figpos = get(gcf,'position');
wolffd@0: aspectratio = axpos(4) / (axpos(3));
wolffd@0: xsize = xlim(2) - xlim(1);
wolffd@0: ysize = ylim(2) - ylim(1);
wolffd@0: xticksize = ysize/figpos(4)*12;
wolffd@0: yticksize = xsize*aspectratio/figpos(3)*12;
wolffd@0: 
wolffd@0: % -------------------------------------------------------------------------
wolffd@0: % Store old tick values and tick labels
wolffd@0: % -------------------------------------------------------------------------
wolffd@0: ytick = get(ax,'YTick');
wolffd@0: xtick = get(ax,'XTick');
wolffd@0: xticklab = get(ax,'XTickLabel');
wolffd@0: yticklab = get(ax,'YTickLabel');
wolffd@0: 
wolffd@0: % -------------------------------------------------------------------------
wolffd@0: % Draw new coordinate system
wolffd@0: % -------------------------------------------------------------------------
wolffd@0: 
wolffd@0: yax = line([0; 0],[ylim(1)-1; ylim(2)]);
wolffd@0: xax = line([xlim(1); xlim(2)],[0; 0]);
wolffd@0: set(xax,'color',[0 0 0])
wolffd@0: set(yax,'color',[0 0 0])
wolffd@0: 
wolffd@0: % Draw x-axis ticks
wolffd@0: for k = 1:length(xtick),
wolffd@0:     newxtick(k) = line([xtick(k); xtick(k)],[-xticksize/2; xticksize/2]);
wolffd@0:     if (xtick(k)~=0),
wolffd@0:         newxticklab(k) = text(xtick(k),-1.5*xticksize, strtrim(xticklab(k,:)));
wolffd@0:         set(newxticklab(k),'HorizontalAlignment','center',...
wolffd@0:             'Fontsize',fontsize,'FontName',fontname);
wolffd@0:     end
wolffd@0: end
wolffd@0: set(newxtick,'color',[0 0 0]);
wolffd@0: 
wolffd@0: % Draw y-axis ticks
wolffd@0: for k = 1:length(ytick),
wolffd@0:     newytick(k) = line([-yticksize/2; yticksize/2],[ytick(k); ytick(k)]);
wolffd@0:     if (ytick(k)~=0),
wolffd@0:         newyticklab(k) = text(-.8*yticksize,ytick(k), yticklab(k,:));
wolffd@0:         set(newyticklab(k),'HorizontalAlignment','right',...
wolffd@0:             'FontSize',fontsize,'FontName',fontname);
wolffd@0:     end
wolffd@0: end
wolffd@0: set(newytick,'color',[0 0 0]);
wolffd@0: 
wolffd@0: %--------------------------------------------------------------------------
wolffd@0: % Move xlabels
wolffd@0: %--------------------------------------------------------------------------
wolffd@0: newxlabel = text(xlim(2),-1.5*xticksize,xtext);
wolffd@0: set(newxlabel,'HorizontalAlignment','center',...
wolffd@0:     'FontWeight','demi','FontSize',fontsize+2,'FontName',fontname);
wolffd@0: 
wolffd@0: newylabel = text(-yticksize,ylim(2)*1.02,ytext);
wolffd@0: set(newylabel,'HorizontalAlignment','right','VerticalAlignment','top',...
wolffd@0:     'FontWeight','demi','FontSize',fontsize+2,'FontName',fontname);
wolffd@0: 
wolffd@0: %--------------------------------------------------------------------------
wolffd@0: % Create arrowheads
wolffd@0: %--------------------------------------------------------------------------
wolffd@0: x = [0; -yticksize/4; yticksize/4];
wolffd@0: y = [ylim(2); ylim(2)-xticksize; ylim(2)-xticksize];
wolffd@0: patch(x,y,[0 0 0])
wolffd@0: 
wolffd@0: x = [xlim(2); xlim(2)-yticksize; xlim(2)-yticksize];
wolffd@0: y = [0; xticksize/4; -xticksize/4];
wolffd@0: patch(x,y,[0 0 0])
wolffd@0: 
wolffd@0: axis off;
wolffd@0: box off;
wolffd@0: 
wolffd@0: %--------------------------------------------------------------------------
wolffd@0: % Create output struct
wolffd@0: %--------------------------------------------------------------------------
wolffd@0: 
wolffd@0: if nargout > 0,
wolffd@0:     out.xaxis = xax;
wolffd@0:     out.yaxis = yax;
wolffd@0:     out.xtick = newxtick;
wolffd@0:     out.ytick = newytick;
wolffd@0:     out.xticklabel = newxticklab;
wolffd@0:     out.yticklabel = newyticklab;
wolffd@0:     out.newxlabel = newxlabel;
wolffd@0:     out.newylabel = newylabel;
wolffd@0: end;