Labeling data points in plotyy

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Mark
Mark on 27 Feb 2012
I need to plot two bar series in different scales and thus I am using the plotyy function as in the example below. I'm trying to show the values of the data points I plot with the bar function. The issue is that the labels I draw are not very well positioned for the series in the second axis (please see the example)
My question is: How can I make the text function correctly draw the text for the data points of the series in the right axis?
Thanks in advance
Just in case, I cannot put the first series in the second axes, and the second series in the first axes, the solution needs not to depend on such an order.
%%%%%%%%%%%%%%%%%
x = 15;
y = {rand(x, 1) * 100; (-0:(0.8)/(x-1):0.8)'};
fn1 = @(x, y) bar(x, y, 0.3, 'FaceColor', 'blue');
fn2 = @(x, y) bar(x, y, 0.3, 'FaceColor', 'red');
figure;
[ax, hbar1, hbar2] = plotyy( [1:x]-1, y{1}, [1:x]+1, y{2}, fn1, fn2);
hbars = [hbar1, hbar2];
angle = 67.5;
for i=1:length(hbars)
hbar = hbars(i);
x = get(get(hbar,'children'), 'xdata');
rot = angle;
while rot>360, rot=rot-360; end
while rot<0, rot=rot+360; end
if rot>=180, strDir='right'; else, strDir='left'; end
caDataLabels = strread(sprintf(' %.3g\n', y{i}), '%s', 'delimiter', sprintf('\n'), 'whitespace', '');
th=text(mean(x,1)', y{i}, caDataLabels, 'HorizontalAlignment', strDir, 'rotation', rot, 'FontSize', 8, 'VerticalAlignment', 'middle');
end

Accepted Answer

Jiro Doke
Jiro Doke on 27 Feb 2012
You can specify the axes in which to place the text. For example, specify ax(2) for the right axes.
Notice below, I specified the Parent property for the text command. Also, to distinguish the labels, I specified the colors.
clr = {'blue', 'red'};
x = 15;
y = {rand(x, 1) * 100; (-0:(0.8)/(x-1):0.8)'};
fn1 = @(x, y) bar(x, y, 0.3, 'FaceColor', clr{1});
fn2 = @(x, y) bar(x, y, 0.3, 'FaceColor', clr{2});
figure;
[ax, hbar1, hbar2] = plotyy( [1:x]-1, y{1}, [1:x]+1, y{2}, fn1, fn2);
hbars = [hbar1, hbar2];
angle = 67.5;
for i=1:length(hbars)
hbar = hbars(i);
x = get(get(hbar,'children'), 'xdata');
rot = angle;
while rot>360, rot=rot-360; end
while rot<0, rot=rot+360; end
if rot>=180, strDir='right'; else, strDir='left'; end
caDataLabels = strread(sprintf(' %.3g\n', y{i}), '%s', ...
'delimiter', sprintf('\n'), 'whitespace', '');
th=text(mean(x,1)', y{i}, caDataLabels, 'Parent', ax(i), ...
'Color', clr{i}, 'HorizontalAlignment', strDir, ...
'rotation', rot, 'FontSize', 8, 'VerticalAlignment', 'middle');
end

More Answers (1)

Mark
Mark on 27 Feb 2012
For reference, here's another solution I just found:
%%Set the current axes
set(gcf(), 'CurrentAxes', ax(i));
%%Draw the text
th=text(mean(x,1)', y{i}, caDataLabels, 'HorizontalAlignment', strDir, 'rotation', rot, 'FontSize', 8, 'VerticalAlignment', 'middle');

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