export_fig problem with linebreak in title

I try to export my figure as pdf with export_fig. Some of the titles have linebreaks.

img_sos = rand(64);
img_oar_pixel = rand(64);
img_oar_block = rand(64);

snr_sos = rand(64)*250;
snr_oar_pixel = rand(64)*250;
snr_oar_block = rand(64)*250;
snr_max = ceil(max([snr_sos(:); snr_oar_pixel(:); snr_oar_block(:)]));
snr_max_50 = ceil(snr_max / 50) * 50;

% Layout-Parameter
tile_size_cm = 4.0;         % image size in cm
n_cols = 3;                 
n_rows = 2;                 
padding_cm = 0.8;           
spacing_cm = 0.3;           
colorbar_width_cm = 0.3;    % colorbar width

fig_width_cm  = padding_cm*2 + n_cols*tile_size_cm + (n_cols-1)*spacing_cm + colorbar_width_cm + 0.3; % extra rechts
fig_height_cm = padding_cm*2 + n_rows*tile_size_cm + (n_rows-1)*spacing_cm;

f = figure('Units', 'centimeters', ...
           'Position', [5 5 fig_width_cm fig_height_cm], ...
           'PaperUnits', 'centimeters', ...
           'PaperSize', [fig_width_cm fig_height_cm], ...
           'PaperPositionMode', 'manual', ...
           'PaperPosition', [0 0 fig_width_cm fig_height_cm]);

cm2norm_w = @(x) x / fig_width_cm;
cm2norm_h = @(x) x / fig_height_cm;

imgs1 = {img_sos, img_oar_pixel, img_oar_block};
titles1 = {sprintf('Sum-of-Squares'), ...
           sprintf('Adaptive Kombination\n(Pixelweise)'), ...
           sprintf('Adaptive Kombination\n(Blockweise)')};
clim1 = [0 1];
cmap1 = jet;

for k = 1:3
    row = 2; col = k; % upper row = row 2
    left = cm2norm_w(padding_cm + (col-1)*(tile_size_cm + spacing_cm));
    bottom = cm2norm_h(padding_cm + (n_rows-row)*(tile_size_cm + spacing_cm));

    ax1(k) = axes('Position', [left bottom cm2norm_w(tile_size_cm) cm2norm_h(tile_size_cm)]);
    imagesc(imgs1{k}, clim1);
    axis image off;
    colormap(ax1(k), cmap1);
end

cb1_left   = cm2norm_w(padding_cm + n_cols*tile_size_cm + (n_cols-1)*spacing_cm + 0.1);
cb1_bottom = cm2norm_h(padding_cm + tile_size_cm + spacing_cm);
cb1_height = cm2norm_h(tile_size_cm);
cb1 = colorbar('Position', [cb1_left cb1_bottom cm2norm_w(colorbar_width_cm) cb1_height]);
cb1.Label.String = 'Normierte Signalintensit\"at';
cb1.Label.Interpreter = 'latex';
cb1.Label.FontSize = 10;
cb1.Ticks = 0:0.2:1;

imgs2 = {snr_sos, snr_oar_pixel, snr_oar_block};
clim2 = [0 snr_max_50];
cmap2 = hot;

for k = 1:3
    row = 1; col = k; % bottom row = row 1
    left = cm2norm_w(padding_cm + (col-1)*(tile_size_cm + spacing_cm));
    bottom = cm2norm_h(padding_cm + (n_rows-row)*(tile_size_cm + spacing_cm));

    ax2(k) = axes('Position', [left bottom cm2norm_w(tile_size_cm) cm2norm_h(tile_size_cm)]);
    imagesc(imgs2{k}, clim2);
    axis image off;
    colormap(ax2(k), cmap2);
    
    title_k = titles1(k);
    title(cell2str(title_k), 'FontSize', 10, 'Interpreter', 'latex', ...
        'FontName', 'Latin Modern Roman');
end

cb2_left   = cb1_left;
cb2_bottom = cm2norm_h(padding_cm);
cb2_height = cm2norm_h(tile_size_cm);
cb2 = colorbar('Position', [cb2_left cb2_bottom cm2norm_w(colorbar_width_cm) cb2_height]);
cb2.Label.String = '$\mathrm{SNR}$';
cb2.Label.Interpreter = 'latex';
cb2.Label.FontSize = 10;
cb2.Ticks = 0:50:snr_max_50;

export_fig('Test_Vergleich.pdf', '-pdf', '-transparent');

But when I do this I get the following error:

Error using horzcat
Inconsistent concatenation dimensions because a 1-by-3 'char' array was converted to a 1-by-1 'cell' array. Consider creating arrays of the same type
before concatenating.

Error in print2eps (line 605)
        fstrm = regexprep(fstrm, '(%%Title:)[^\n]*\n', ['$1 ' title_str '\n']);
                                                        ^^^^^
Error in export_fig (line 1146)
                print2eps(tmp_nam, fig, options, printArgs{:}); %winopen(tmp_nam)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error in Copy_of_Vergleich_Mehrkanalkombination (line 99)
export_fig('Test_Vergleich.pdf', '-pdf', '-transparent');
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Without linebreak it works.

[Matt J]

I get a different error,

Warning: Error in state of SceneNode.
String scalar or character vector must have valid interpreter syntax:
Normierte Signalintensit\\"at
 
> In defaulterrorcallback (line 12)
In matlab.graphics.illustration/ColorBar/get.Label
In test (line 55) 
Unrecognized function or variable 'cell2str'.

Error in test (line 74)
    title(cell2str(title_k), 'FontSize', 10, 'Interpreter', 'latex', ...
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[Rik]

Unfortunately, this code can't run online either, even with a cell2str stub function.

img_sos = rand(64);
img_oar_pixel = rand(64);
img_oar_block = rand(64);

snr_sos = rand(64)*250;
snr_oar_pixel = rand(64)*250;
snr_oar_block = rand(64)*250;
snr_max = ceil(max([snr_sos(:); snr_oar_pixel(:); snr_oar_block(:)]));
snr_max_50 = ceil(snr_max / 50) * 50;

% Layout-Parameter
tile_size_cm = 4.0;         % image size in cm
n_cols = 3;                 
n_rows = 2;                 
padding_cm = 0.8;           
spacing_cm = 0.3;           
colorbar_width_cm = 0.3;    % colorbar width

fig_width_cm  = padding_cm*2 + n_cols*tile_size_cm + (n_cols-1)*spacing_cm + colorbar_width_cm + 0.3; % extra rechts
fig_height_cm = padding_cm*2 + n_rows*tile_size_cm + (n_rows-1)*spacing_cm;

f = figure('Units', 'centimeters', ...
           'Position', [5 5 fig_width_cm fig_height_cm], ...
           'PaperUnits', 'centimeters', ...
           'PaperSize', [fig_width_cm fig_height_cm], ...
           'PaperPositionMode', 'manual', ...
           'PaperPosition', [0 0 fig_width_cm fig_height_cm]);

cm2norm_w = @(x) x / fig_width_cm;
cm2norm_h = @(x) x / fig_height_cm;

imgs1 = {img_sos, img_oar_pixel, img_oar_block};
titles1 = {sprintf('Sum-of-Squares'), ...
           sprintf('Adaptive Kombination\n(Pixelweise)'), ...
           sprintf('Adaptive Kombination\n(Blockweise)')};
clim1 = [0 1];
cmap1 = jet;

for k = 1:3
    row = 2; col = k; % upper row = row 2
    left = cm2norm_w(padding_cm + (col-1)*(tile_size_cm + spacing_cm));
    bottom = cm2norm_h(padding_cm + (n_rows-row)*(tile_size_cm + spacing_cm));

    ax1(k) = axes('Position', [left bottom cm2norm_w(tile_size_cm) cm2norm_h(tile_size_cm)]);
    imagesc(imgs1{k}, clim1);
    axis image off;
    colormap(ax1(k), cmap1);
end

cb1_left   = cm2norm_w(padding_cm + n_cols*tile_size_cm + (n_cols-1)*spacing_cm + 0.1);
cb1_bottom = cm2norm_h(padding_cm + tile_size_cm + spacing_cm);
cb1_height = cm2norm_h(tile_size_cm);
cb1 = colorbar('Position', [cb1_left cb1_bottom cm2norm_w(colorbar_width_cm) cb1_height]);
cb1.Label.String = 'Normierte Signalintensit\"at';
cb1.Label.Interpreter = 'latex';
cb1.Label.FontSize = 10;
cb1.Ticks = 0:0.2:1;

imgs2 = {snr_sos, snr_oar_pixel, snr_oar_block};
clim2 = [0 snr_max_50];
cmap2 = hot;

for k = 1:3
    row = 1; col = k; % bottom row = row 1
    left = cm2norm_w(padding_cm + (col-1)*(tile_size_cm + spacing_cm));
    bottom = cm2norm_h(padding_cm + (n_rows-row)*(tile_size_cm + spacing_cm));

    ax2(k) = axes('Position', [left bottom cm2norm_w(tile_size_cm) cm2norm_h(tile_size_cm)]);
    imagesc(imgs2{k}, clim2);
    axis image off;
    colormap(ax2(k), cmap2);
    
    title_k = titles1(k);
    title(cell2str(title_k), 'FontSize', 10, 'Interpreter', 'latex', ...
        'FontName', 'Latin Modern Roman');
end

cb2_left   = cb1_left;
cb2_bottom = cm2norm_h(padding_cm);
cb2_height = cm2norm_h(tile_size_cm);
cb2 = colorbar('Position', [cb2_left cb2_bottom cm2norm_w(colorbar_width_cm) cb2_height]);
cb2.Label.String = '$\mathrm{SNR}$';
cb2.Label.Interpreter = 'latex';
cb2.Label.FontSize = 10;
cb2.Ticks = 0:50:snr_max_50;

export_fig('Test_Vergleich.pdf', '-pdf', '-transparent');

For professional Matlab assistance, please contact https://UndocumentedMatlab.com/consulting

Warning: You are using version 3.50 of export_fig. A newer version (3.51) is available, with the following improvements/fixes:
* Fixed: figure with non-default colormap exported with default colormap in some cases (issue #389)
A change-log of recent releases is available here; the complete change-log is included at the top of the export_fig.m file.
You can download the new version from GitHub or Matlab File Exchange, or run export_fig('-update') to install it directly.

Warning: In Matlab R2020a+ you can also use exportgraphics(hFigure,filename,'BackgroundColor','none','ContentType','vector') for simple file export, which could also improve image vectorization, solving rasterization/pixelization problems.

●

export_fig error. Please ensure:
 * that the function you used (/users/mss.system.zxvbr/export_fig.m) version 3.5 is from the expected location
 * and that you did not made a mistake in export_fig's expected input arguments
 * and that ghostscript is properly installed in 

Exporting to vector format (EPS, PDF etc.) requires the Ghostscript utility from http://ghostscript.com

Warning: Error in state of SceneNode.
String scalar or character vector must have valid interpreter syntax:
$\mathrm{SNR}$

Error using questdlg (line 71)
Creating dialog boxes that block execution is not supported when MATLAB is in a configuration that is non-interactive or disables window display.

Error in export_fig>selectUtilityPath (line 1633)
answer = questdlg(msg,utilName,'Use local installation','Go to website','Cancel','Cancel');
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error in export_fig (line 1584)
selectUtilityPath('Ghostscript',url,'Exporting to vector format (EPS, PDF etc.)');
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Error in export_fig (line 517)
[imageData, alpha] = export_fig(varargin{:});
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

function s=cell2str(c)
%placeholder function to make the rest of the code run
s=cell2mat(reshape(c,1,[]));
end

Answer 1

[Ronit]

Hello @Dominik,

You can replace 'cell2str' with direct access to the cell array like:

title(titles1{k}, 'FontSize', 10, 'Interpreter', 'latex', ...
        'FontName', 'Latin Modern Roman');

Additionally, the function 'export_fig' is not a built-in MATLAB function, it is a third-party add-on. I would recommend using the following alternative functions:

• 'exportgraphics': Available for MATLAB R2020a and newer versions.

exportgraphics(f, 'Test_Vergleich.pdf', 'ContentType', 'vector', 'BackgroundColor', 'none');

• 'print': Exports figures to PDF in vector format.

print(f, 'Test_Vergleich.pdf', '-dpdf', '-vector');

After making the above changes:

img_sos = rand(64);
img_oar_pixel = rand(64);
img_oar_block = rand(64);
snr_sos = rand(64)*250;
snr_oar_pixel = rand(64)*250;
snr_oar_block = rand(64)*250;
snr_max = ceil(max([snr_sos(:); snr_oar_pixel(:); snr_oar_block(:)]));
snr_max_50 = ceil(snr_max / 50) * 50;
% Layout-Parameter
tile_size_cm = 4.0;         % image size in cm
n_cols = 3;                 
n_rows = 2;                 
padding_cm = 0.8;           
spacing_cm = 0.3;           
colorbar_width_cm = 0.3;    % colorbar width
fig_width_cm  = padding_cm*2 + n_cols*tile_size_cm + (n_cols-1)*spacing_cm + colorbar_width_cm + 0.3; % extra rechts
fig_height_cm = padding_cm*2 + n_rows*tile_size_cm + (n_rows-1)*spacing_cm;
f = figure('Units', 'centimeters', ...
           'Position', [5 5 fig_width_cm fig_height_cm], ...
           'PaperUnits', 'centimeters', ...
           'PaperSize', [fig_width_cm fig_height_cm], ...
           'PaperPositionMode', 'manual', ...
           'PaperPosition', [0 0 fig_width_cm fig_height_cm]);
cm2norm_w = @(x) x / fig_width_cm;
cm2norm_h = @(x) x / fig_height_cm;
imgs1 = {img_sos, img_oar_pixel, img_oar_block};
titles1 = {sprintf('Sum-of-Squares'), ...
           sprintf('Adaptive Kombination\n(Pixelweise)'), ...
           sprintf('Adaptive Kombination\n(Blockweise)')};
clim1 = [0 1];
cmap1 = jet;
for k = 1:3
    row = 2; col = k; % upper row = row 2
    left = cm2norm_w(padding_cm + (col-1)*(tile_size_cm + spacing_cm));
    bottom = cm2norm_h(padding_cm + (n_rows-row)*(tile_size_cm + spacing_cm));
    ax1(k) = axes('Position', [left bottom cm2norm_w(tile_size_cm) cm2norm_h(tile_size_cm)]);
    imagesc(imgs1{k}, clim1);
    axis image off;
    colormap(ax1(k), cmap1);
end
cb1_left   = cm2norm_w(padding_cm + n_cols*tile_size_cm + (n_cols-1)*spacing_cm + 0.1);
cb1_bottom = cm2norm_h(padding_cm + tile_size_cm + spacing_cm);
cb1_height = cm2norm_h(tile_size_cm);
cb1 = colorbar('Position', [cb1_left cb1_bottom cm2norm_w(colorbar_width_cm) cb1_height]);
cb1.Label.String = 'Normierte Signalintensit\"at';
cb1.Label.Interpreter = 'latex';
cb1.Label.FontSize = 10;
cb1.Ticks = 0:0.2:1;
imgs2 = {snr_sos, snr_oar_pixel, snr_oar_block};
clim2 = [0 snr_max_50];
cmap2 = hot;
for k = 1:3
    row = 1; col = k; % bottom row = row 1
    left = cm2norm_w(padding_cm + (col-1)*(tile_size_cm + spacing_cm));
    bottom = cm2norm_h(padding_cm + (n_rows-row)*(tile_size_cm + spacing_cm));
    ax2(k) = axes('Position', [left bottom cm2norm_w(tile_size_cm) cm2norm_h(tile_size_cm)]);
    imagesc(imgs2{k}, clim2);
    axis image off;
    colormap(ax2(k), cmap2);
    
    title(titles1{k}, 'FontSize', 10, 'Interpreter', 'latex', ...
        'FontName', 'Latin Modern Roman');
end
cb2_left   = cb1_left;
cb2_bottom = cm2norm_h(padding_cm);
cb2_height = cm2norm_h(tile_size_cm);
cb2 = colorbar('Position', [cb2_left cb2_bottom cm2norm_w(colorbar_width_cm) cb2_height]);
cb2.Label.String = '$\mathrm{SNR}$';
cb2.Label.Interpreter = 'latex';
cb2.Label.FontSize = 10;
cb2.Ticks = 0:50:snr_max_50;
% print(f, 'Test_Vergleich.pdf', '-dpdf', '-vector');
exportgraphics(f, 'Test_Vergleich.pdf', 'ContentType', 'vector', 'BackgroundColor','none');

Warning: Error in state of SceneNode.
String scalar or character vector must have valid interpreter syntax:
$\mathrm{SNR}$

Please refer to the following documentation pages for more information about the functions:

• 'exportgraphics': https://www.mathworks.com/help/matlab/ref/exportgraphics.html
• 'print': https://www.mathworks.com/help/matlab/ref/print.html

I hope the above recommendations help you resolve the query.