MATLAB: Centering annotation over subplot

annotation;figure

I'm trying to center a textbox annotation over a subplot. I have a 2×2 subplot and I want titles over the columns, centered for each column. I don't want to just use title() because it shrinks the axes of the upper plots, so they are not the same as the axes on the bottom row.

I've tried using the x position of the upper subplot like so:

figure();

hLF1 = subplot(2,2,1); bxA = boxplot([1:10;1:10]','labels',{'On','Off'}); ylabel('LabelY')

annot_LF_pos = [mean(hLF1.Position([1,3])), 0.775, 0.3, 0.2];

annotation('textbox',annot_LF_pos,'String','Title','EdgeColor','none',…

'FontSize',22,'HorizontalAlignment', 'center')

But that didn't really center it. I know I can hack around with numbers, but I'm hoping for a better solution.

I'm not tied to using an annotation, so any other suggestions are welcome!

Thanks!

Best Answer

You could try to use text instead and use the x and y limits instead of the axis position, see below:

text((max(hLF1.XLim)-min(hLF1.XLim))/2+min(hLF1.XLim),max(hLF1.YLim),'Title','EdgeColor','none',...
    'FontSize',22,'HorizontalAlignment', 'center','VerticalAlignment','Bottom')

Related Solutions

MATLAB: Add titles over rows in subplots

Create one centered title per row of subplots

Two methods are included

For an odd number of subplots per row (simpler)
For and even or odd number of subplots per row

For an odd number of suplots per row

Add the title to the middle subplot

Demo:

figure()
subplotLayout = [3,3];
ax = gobjects(fliplr(subplotLayout));
for i = 1:prod(subplotLayout)
    ax(i) = subplot(subplotLayout(1),subplotLayout(2),i); 
end
ax = ax'; % now axis handles are same shape as subplot layout

% list all titles in order (top to bottom)

titles = {'Row 1 title', 'Row 2 title', 'Row 3 title'};  
% Get handles to center subplots
centerSubHandles = ax(:,ceil(subplotLayout(2)/2));
for i = 1:numel(centerSubHandles)
    % get center subplot handle
    title(centerSubHandles(i), titles{i})
end

For an even or odd number of suplots per row

Compute the upper position of each row of subplots in normalized units and the center position across the first row of subplots (assuming the center position is the same for all rows of subplots). Then use annotation to set the title position.

Demo:

figure()
subplotLayout = [3,4];
ax = gobjects(fliplr(subplotLayout));
for i = 1:prod(subplotLayout)
    ax(i) = subplot(subplotLayout(1),subplotLayout(2),i);
end
set(ax,'Units','Normalize') % this is typically the default
ax = ax'; % now axis handles are same shape as subplot layout
% Reduce vertical space of axes just a bit to make room for "titles"
axPos = cell2mat(get(ax, 'Position'));
axPos(:,4) = axPos(:,4).*.96; % reduces vert space to 96% of height
set(ax, {'Position'}, mat2cell(axPos, ones(numel(ax),1), 4))
% Get upper position of each row of axes, normalized coordinates
axPos = cell2mat(get(ax(:,1), 'Position'));
axUpperPos = sum(axPos(:,[2,4]),2);  %upper pos.
% Get center position for 1st row (assumes all rows have same center)
axPos = cell2mat(get(ax(1,[1,end]),'Position'));
axCenterPos = mean([axPos(1,1), sum(axPos(2,[1,3]))]);
% list all titles in order (top to bottom)
titles = {'Row 1 title', 'Row 2 title', 'Row 3 title'};  
% Set annotation for each row of subplots
titleHandles = gobjects(numel(titles),1); 
for i = 1:numel(titles)
    titleHandles = annotation('textbox','String',titles{i}, ...
        'Position', [axCenterPos, axUpperPos(i), 0, 0], ... 
        'HorizontalAlignment', 'center','VerticalAlignment','bottom',...
        'LineStyle','none','FitBoxToText','on', ...
        'FontWeight',ax(1).Title.FontWeight, ... % matches title property
        'FontSize', ax(1).Title.FontSize, ...    % matches title property
        'FontName', ax(1).Title.FontName, ...    % matches title property
        'Color', ax(1).Title.Color);             % matches title property
end

MATLAB: Multiple subplots with one dynamic super title using annotation

annotation doesn't have the facilities of sprintf, etc., you've got to build the string

annotation('textbox', [0 0.85 1 0.1],'String',...
   num2str(i,'Test text Number=%d'),'EdgeColor', 'none','HorizontalAlignment', 'center')

Best Answer

Related Solutions

MATLAB: Add titles over rows in subplots

MATLAB: Multiple subplots with one dynamic super title using annotation

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