How to save a MATLAB created by bar function in a right size .pdf?

I save a graphic as .pdf format, but matlab will produce an A4 size to put this small picture in the middle of this A4 size pdf. The problem comes when I import them into my LaTeX file, i only need the picture size, not the whole A4 pdf size. Could anyone tell how to solve this problem?

This is my code

function DisplayGeneral(Conversational,Background,...
                                         Interactive,Streaming,...
                                        NameFunctions)

                                    
max1= max(Conversational(1,:));
max2=max(Background(1,:));
max3=max(Interactive(1,:));
max4=max(Streaming(1,:));
MAX=max(max1, max(max2,max(max3,max4)) );
% This will produce 4 groups of 3 different colored bars
x = [1 2 3 4];


y = [Conversational ;Background; Interactive ;Streaming];
Bar = bar(x,y);  % h will have 3 handles, one for each color of bars

% set 3 display names for the 3 handles
%xtips1 = Bar(1).XEndPoints;

NameFunctions=cellstr(NameFunctions);
set(Bar, {'DisplayName'}, NameFunctions');


% Legend will show names for each color
legend() ;


somenames={'Conversational','Background','Interactive','Streaming'};
set(gca,'xticklabel',somenames)
set(gcf, 'Position',  [100, 100, 800, 450]);

ylabel('Rank Reversal Ratio [%]')
xlabel('Traffic classes')
ylim([0 MAX+30]);


%text(xtips1,ytips1,string( ) ,'HorizontalAlignment','center','VerticalAlignment','bottom')
opts = {'VerticalAlign','middle', 'HorizontalAlign','left', ...
    'FontSize',8, 'Rotation',90};
%title('')


    for k1 = 1:size(Conversational,2)
        ctr(k1,:) = bsxfun(@plus, Bar(k1).XData, Bar(k1).XOffset');       % Note: ‘XOffset’ Is An Undocumented Feature, This Selects The ‘bar’ Centres
        ydt(k1,:) = Bar(k1).YData;                                        % Individual Bar Heights
    end
   
    for k1 = 1:size(ctr,2)
                format short 
        text(ctr(:,k1), ydt(:,k1), sprintfc('%.1f',ydt(:,k1)), 'HorizontalAlignment','center', 'VerticalAlignment','bottom')
    end
end

Answer 1

[Rahim Rahim]

I need your help