Getting transparency in a vector plot

Hi,

The following creates a plot that uses transparency to render otherwise obscured data visible ...

tval = 1980:1:2009;
figure(1); clf;
hold on;
h1 = area(x, y1); set(h1, 'FaceColor', [0.9 0.8 0.8], 'EdgeColor', [0.9 0.8 0.8]); h1b = get(h1, 'Children'); set(h1b, 'FaceAlpha', 0.5);
h2 = area(x, y2); set(h2, 'FaceColor', [0.8 0.8 0.9], 'EdgeColor', [0.8 0.8 0.9]); h2b = get(h2, 'Children'); set(h2b, 'FaceAlpha', 0.5); plot (tval, ann_data_sst, 'r-', tval, ann_nemo_sst, 'b-'); axis ([1980 2009 17.8 19.4]); axis square; xlabel ('Time [year]'); ylabel ('SST [{\circ}C]'); title ('Sea surface temperature');
paper; orient portrait;
print -depsc2 -painters future_1980_2009_phys

... And I'm quite pleased with the result, at least as it appears on the screen. However, when I try to print it to an EPS file, all I get is a flat plot with no transparency. Obscured data remains annoyingly obscured.

From poking around the MathWorks website, it looks like this loss of transparency may be a fundamental limitation of printing to EPS in vector format. If I drop the -painters option or use OpenGL instead (while still writing to an EPS file), I get the transparency but with hideous bitmap fonts, etc. A colleague suggested switching to PDF, but I find I get the same results with this - so long as I'm printing in vector format, transparency seems a no-go.

Has anyone here ever done anything like this successfully (or better) before? Alternatively, does anyone have any tips for how I could plot such a set of data to achieve something like the transparency effect that I'm aiming for?

Apologies for having such a woolly question.

Best regards,

Andrew.

P.S. I can try to post up images of what I mean if it's not obvious.

P.P.S. For reference ...

-------------------------------------------------------------------------------------
MATLAB Version 7.8.0.347 (R2009a)
MATLAB License Number: ••••••
Operating System: Linux 2.6.32.12-0.7-default #1 SMP 2010-05-20 11:14:20 +0200 x86_64
Java VM Version: Java 1.6.0_04-b12 with Sun Microsystems Inc. Java HotSpot(TM) 64-Bit Server VM mixed mode
-------------------------------------------------------------------------------------
MATLAB                                                Version 7.8        (R2009a)
Image Processing Toolbox                              Version 6.3        (R2009a)
MATLAB Compiler                                       Version 4.10       (R2009a)
M_Map - mapping toolbox (Author: [e-mail])     Version 1.4c       9       
Mapping Toolbox                                       Version 2.7.2      (R2009a)
Neural Network Toolbox                                Version 6.0.2      (R2009a)
Optimization Toolbox                                  Version 4.2        (R2009a)
Partial Differential Equation Toolbox                 Version 1.0.14     (R2009a)
Signal Processing Toolbox                             Version 6.11       (R2009a)
Simulink 3D Animation                                 Version 5.0        (R2009a)
Spline Toolbox                                        Version 3.3.6      (R2009a)
Statistics Toolbox                                    Version 7.1        (R2009a)
Symbolic Math Toolbox                                 Version 5.2        (R2009a)
Wavelet Toolbox                                       Version 4.4        (R2009a)

Answer 1

[Jan]

Transparency requires the OpenGL renderer. The OpenGL renderer can export bitmap images only. This is a fundamental limitation.

FEX: ExportSVG might be a workaround.

[K E]

If using ExportSVG, this tutorial on getting the resulting plot into Word might help.

[Luis J Gilarranz]

Do we know if in 2019 this is still a fundamental limitation?

[Petr Dohnalik]

Yes, transparency is a fundamental limitation of .eps format also in 2022.

If you use other software, you can run into similar problem, see this thread on Wolfram Mathematica, R, or Adobe Ilustrator. However, you can print .svg formats from Matlab by now, see "formattype" in print help.

Answer 2

[Andrew Yool]

Hi Jan,

Thanks for getting back to me. That's more or less what I thought was the case from poking around here. But it's very useful to have it confirmed - it'll certainly save me from chasing a mirage ...

... That said, your SVG suggestion appears to work a charm. While I've yet to work out how best to handle the resulting SVG file (i.e. whether I can import it to LaTeX, etc.), it's just about perfect. That's a brilliant suggestion! And it worked first time - no messing about getting the new libraries to work.

Best regards,

Andrew.