%'keyboard_callback:' function activated when a key is pressed on the keyboard
%-----------------------------------
function keyboard_callback(hObject,eventdata,handleshaxes)
cur_axes=get(hObject,'CurrentAxes');%current plotting axes of the figure with handle hObject
xx=double(get(hObject,'CurrentCharacter')); %get the keyboard character
switch xx
    case {29,28,30,31}    %arrows for displacement
        if ~isempty(cur_axes)
            xlimit=get(cur_axes,'XLim');
            ylimit=get(cur_axes,'Ylim');
            dx=(xlimit(2)-xlimit(1))/10;
            dy=(ylimit(2)-ylimit(1))/10;
            if isequal(xx,29)%move arrow right
                xlimit=xlimit+dx;
            elseif isequal(xx,28)%move arrow left
                xlimit=xlimit-dx;
            elseif isequal(xx,30)%move arrow up
                ylimit=ylimit+dy;
            elseif isequal(xx,31)%move arrow down
                ylimit=ylimit-dy;
            end
            set(cur_axes,'XLim',xlimit)
            set(cur_axes,'YLim',ylimit)
            hfig=hObject; %master figure
            AxeData=get(cur_axes,'UserData');
            if isfield(AxeData,'ParentRect')% update the position of the parent rectangle representing the field
                hparentrect=AxeData.ParentRect;
                rect([1 2])=[xlimit(1) ylimit(1)];
                rect([3 4])=[xlimit(2)-xlimit(1) ylimit(2)-ylimit(1)];
                set(hparentrect,'Position',rect)
                hfig=get(hparentrect,'parent');
                hfig=get(hfig,'parent');
            elseif isfield(AxeData,'LimEditBox')&& isequal(AxeData.LimEditBox,1)% update display of the GUI containing the axis (uvmat or view_field)
                hh=guidata(hfig);
                if isfield(hh,'MinX')
                    set(hh.MinX,'String',num2str(xlimit(1)))
                    set(hh.MaxX,'String',num2str(xlimit(2)))
                    set(hh.MinY,'String',num2str(ylimit(1)))
                    set(hh.MaxY,'String',num2str(ylimit(2)))
                end
            end
        end
    case {8, 127} %if the delete or suppr key is pressed, delete the current object 
        currentobject=gco;
        huvmat=findobj(allchild(0),'tag','uvmat');
        hlist_object=findobj(huvmat,'Tag','list_object_1');
        ObjIndex=get(hlist_object,'Value');
        if ObjIndex>1 
            delete_object(ObjIndex)
        end
        if ishandle(currentobject)
            tag=get(currentobject,'Tag');%tag of the current selected object
            if isequal(tag,'proj_object')
                delete_object(currentobject)
            end
        end
    case 112%  key 'p'
        uvmat('runplus_Callback',hObject,eventdata,handleshaxes)
    case 109%  key 'm'
        uvmat('runmin_Callback',hObject,eventdata,handleshaxes)
end

