matlab中如何得到图像的坐标

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function crossget
  ezplot('sin(x)');
  set(gcf,'pointer','crosshair'); 
  set(gcf,'WindowButtonMotionFcn',@tempfcn2); 

function tempfcn2(hObject, eventdata, handles) 
  p=get(gca,'currentpoint'); 
  if(isempty(findobj('tag','htext'))) 
     ht=text('tag','htext','string',sprintf('  (%g, %g)', p(1), p(3)),'position',[p(1)  +0.5,p(3)]); 
  else 
     ht = findobj('tag','htext'); 
     set(ht,'string',sprintf('(%g, %g)', p(1), p(3)),'position',[p(1)+0.5,p(3)]); 
  end

%也可以响应鼠标点击取点，例如:
function crosshair 
  ezplot('sin(x)');
  set(gcf,'Pointer','crosshair');
  set(gcf,'WindowButtonDownFcn',@myfcn); 
  flag=1; 
  xlim=get(gca,'xlim'); 
  xlim=[xlim(2)-xlim(1)]*0.025; 
  ylim=get(gca,'ylim'); 
  ylim=[ylim(2)-ylim(1)]*0.03; 
  set(gcf,'userdata',[flag,xlim,ylim]); 

%----------------
function myfcn(hObject, eventdata, handles);
  pt=get(gca,'currentpoint');
  pt_show=[pt(1,1),pt(1,2)]    
  temp=get(gcf,'userdata'); 
  if iscell(temp) 
      H=temp{2}; 
      temp=temp{1}; 
  end 
  flag=temp(1);xlim=temp(2);ylim=temp(3); 
      
  if flag==1 
      H.xline=line([pt(1,1)-xlim,pt(1,1)+xlim],[pt(1,2),pt(1,2)]); 
      H.yline=line([pt(1,1),pt(1,1)],[pt(1,2)-ylim,pt(1,2)+ylim]); 
      flag=0; 
   else 
      set(H.xline,'xdata',[pt(1,1)-xlim,pt(1,1)+xlim]); 
      set(H.xline,'ydata',[pt(1,2),pt(1,2)]); 
      set(H.yline,'xdata',[pt(1,1),pt(1,1)]); 
      set(H.yline,'ydata',[pt(1,2)-ylim,pt(1,2)+ylim]); 
   end 
set(gcf,'userdata',{[flag,xlim,ylim],H});

%以上响应鼠标点击取点，是在matlab窗口中显示坐标值，也是我在论坛中搜索并整理的。实际上，根据不同的需要，只要稍加改动，就可以实现不同功能，如要在图形上记录坐标只需如下改动：

function crosshair 
  ezplot('sin(x)');
  set(gcf,'Pointer','crosshair');
  set(gcf,'WindowButtonDownFcn',@myfcn); 
  flag=1; 
  xlim=get(gca,'xlim'); 
  xlim=[xlim(2)-xlim(1)]*0.025; 
  ylim=get(gca,'ylim'); 
  ylim=[ylim(2)-ylim(1)]*0.03; 
  set(gcf,'userdata',[flag,xlim,ylim]); 

function myfcn(hObject, eventdata, handles);
  pt=get(gca,'currentpoint');
  text('string',sprintf('(%g, %g)', pt(1),  pt(3)),'position',[pt(1)+0.5,pt(3)]);
   
  temp=get(gcf,'userdata'); 
  if iscell(temp) 
      H=temp{2}; 
      temp=temp{1}; 
  end 
  flag=temp(1);xlim=temp(2);ylim=temp(3); 
      
  if flag==1 
      H.xline=line([pt(1,1)-xlim,pt(1,1)+xlim],[pt(1,2),pt(1,2)]); 
      H.yline=line([pt(1,1),pt(1,1)],[pt(1,2)-ylim,pt(1,2)+ylim]); 
      flag=0; 
   else 
      set(H.xline,'xdata',[pt(1,1)-xlim,pt(1,1)+xlim]); 
      set(H.xline,'ydata',[pt(1,2),pt(1,2)]); 
      set(H.yline,'xdata',[pt(1,1),pt(1,1)]); 
      set(H.yline,'ydata',[pt(1,2)-ylim,pt(1,2)+ylim]); 
   end 
%-----------------------
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