matlab 坐标軸居中,MATLAB 把坐标軸(X Y軸)移到坐标原點

某位PKU前輩的工作，很贊。移動坐标軸就先隐藏之前的坐标軸，再用axis('position')屬性重新生成新軸，很巧妙。

function new_fig_handle = shift_axis_to_origin( fig_handle )

% 本函數目的是把 matlab 做的圖坐标軸移到圖形的中間部分去(與數學的做圖習慣一緻)

% 2008.10.10 in pku

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figure('Name','shift_axis_to_origin','NumberTitle','off')                         % Create a new figure

% 拷貝圖形到一個新的視窗

new_fig_handle = copyobj( fig_handle , gcf );

xL=xlim ;

yL=ylim ;

xt=get(gca,'xtick') ;

yt=get(gca,'ytick') ;

set(gca,'XTick',[],'XColor','w') ;

set(gca,'YTick',[],'YColor','w') ;

% 把 x 和 y 坐标軸的兩個方向各延長 10% (為了視覺上好看)

extend_x = ( xL(2)-xL(1) ) * 0.1 ;

extend_y = ( yL(2)-yL(1) ) * 0.1 ;

xxL = xL + [ -extend_x extend_x] ;

yyL = yL + [ -extend_y extend_y] ;

set(gca,'xlim', xxL) ;

set(gca,'ylim', yyL) ;

pos = get(gca,'Position') ;

box off;

x_shift = abs( yyL(1)/(yyL(2)-yyL(1)) ) ;

y_shift = abs( xxL(1)/(xxL(2)-xxL(1)) ) ;

temp_1 = axes( 'Position', pos + [ 0 , pos(4) * x_shift , 0 , - pos(4)* x_shift*0.99999 ] ) ;

xlim(xxL) ;

box off ;

set(temp_1,'XTick',xt,'Color','None','YTick',[]) ;

set(temp_1,'YColor','w') ;

temp_2 = axes( 'Position', pos + [ pos(3) * y_shift , 0 , -pos(3)* y_shift*0.99999 , 0 ] ) ;

ylim(yyL) ;

box off ;

set(temp_2,'YTick',yt,'Color','None','XTick',[]) ;

set(temp_2,'XColor','w') ;

Base_pos = get(new_fig_handle,'Position') ;

arrow_pos_in_x_dircetion = Base_pos(2) - Base_pos(4) * yyL(1)/(yyL(2)-yyL(1)) ;

arrow_pos_in_y_dircetion = Base_pos(1) - Base_pos(3) * xxL(1)/(xxL(2)-xxL(1)) ;

annotation('arrow',[Base_pos(1) , Base_pos(1)+Base_pos(3)] , [arrow_pos_in_x_dircetion , arrow_pos_in_x_dircetion ] , 'Color','k');

annotation('arrow',[arrow_pos_in_y_dircetion , arrow_pos_in_y_dircetion ] , [Base_pos(2) , Base_pos(2)+Base_pos(4)] , 'Color','k');

end

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下面是一個例子：

% 本程式目的是把 matlab 做的圖坐标軸移到圖形的中間部分去(與數學的做圖習慣一緻)

% 2008.10.08

%

clc;clear;close all;

t=linspace(-2,8,100);

a1=axes;

plot(t,cos(t));

% xt=get(gca,'xtick');

% set(gca,'XTick',[],'XColor','w');

% xL=xlim;

% p=get(gca,'Position');

% box off;

% a2=axes('Position',p+[0,p(4)/2,0,-p(4)/2]);

% xlim(xL);box off;

% set(gca,'XTick',xt,'Color','None','YTick',[]);

new_fig_handle = shift_axis_to_origin( gca ) ;

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此例子的實作效果如下兩個圖所示：