error reported using find function in legend

I'm trying to add a legend to a plot to show which line is plotted. when using find function to get the indexes of plot handles, it report error of " Index exceeds matrix dimensions." I dont know why it failed.

It works fine, if I use somethin like: legend(hp(1:Nms),get(hst(1:Nms),'string'));

Below is my code, any help is appreciated.

 function gui_test
clear all;
fh = figure('Visible','on','position',[50,60, 660, 400]);
hax = axes('Units','pixels','Position',[60,90,400,300],'color','black','ylim',[-1 1]);
hpb1 = uicontrol('Style','pushbutton','String','RUN',...
    'position',[500 200, 80, 40],'Callback',{@run_Callback});
 hst(1)= uicontrol('style','text','string','line1',...
    'units','pix','position',[500 155 55 13]);
hst(2) = uicontrol('style','text','string','line2',...
    'units','pix','position',[500 135 55 13]);
hst(3) = uicontrol('style','text','string','line3',...
    'units','pix','position',[500 115 55 13]);
hst(4) = uicontrol('style','text','string','line4',...
    'units','pix','position',[500 95 55 13]);

 c = zeros(4,3)

    function run_Callback(~,~)

        for i=1:4,
            x=0:0.001:10;
            y = 1.8*sin(i*0.2.*x).*cos(0.3.*x);

            if min(y)> -1
                hold all;
                hp(i)= plot(x,y);

                c(i,3)=1; % flag it if it is plotted

            end
        end

        legend(hp(find(c(:,3))),get(hst((find(c(:,3))),'string')))

    end

 end

Answer 1

[Vivek Selvam]

You had added an extra set of parenthesis:

hst((...),'string') --> hst(...),'string'

Here is the fixed line:

lh = legend(hp(find(c(:,3))),get(hst(find(c(:,3))),'string'))
set(lh,'TextColor','w')         % legend text is white now

[Chong Tao]

Thank you Vivek. it's hard to believe a mistake like that. :) one more question, How can I make the legend text color match line color?

[Vivek Selvam]

Chong Tao, here is the update you asked for:

    lhKids     = get(lh,'Children');
    lhText     = sort(lhKids(strcmp(get(lhKids,'Type'),'text')));
    lineColors = get(hp(find(c(:,3))),'Color');
    set(lhText,{'Color'},lineColors)

[Chong Tao]

Thanks again, Vivek. This is very helpful.