We have many square EPS images, which we would like to export via script to PNG at very specific formats/sizes, namely
8192x8192, greyscale, no alpha, no anti-aliasing
2048x2048,greyscale, no alpha, anti-aliased.
We have had no luck scripting the "professional" tools Photoshop or Illustrator to do this (although we can do so through the UI, their weak scripting support does not give control over alpha or precise image export size, so we either always get alpha in the large images, or we sometimes get slightly inaccurate image sizes which breaks subsequent algorithms.)
Our first attempt at doing the high resolution version of this was:
gs -sDEVICE=pnggray -o cover.png -dDEVICEWIDTHPOINTS=8192 -dDEVICEHEIGHTPOINTS=8192 -dGraphicsAlphaBits=1 -dPDFFitPage=true cover.eps
However, this does not seem to resize the image to fill the box as expected.
Is there a way, given a square EPS, to get Ghostscript to do what we want?
Your problem with EPS files is that they do not request a media size. That's because EPS files are intended to be included in other PostScript programs, so they need to be resized by the application generating the PostScript.
To that end, EPS files include comments (which are ignored by PostScript interpreters) which define the BoundingBox of the EPS. An application which places EPS can quickly scan the EPS to find this information, then it sets the CTM appropriately in the final PostScript program it is creating and inserts the content of the EPS.
The FitPage switch in Ghostscript relies on having a known media size (and you should set -dFIXEDMEDIA when using this) and a requested media size, figuring out what scale factor to apply to the request in order to make it fit the actual size, and setting up the CTM to apply that scaling.
If you don't ever get a media size request (which you won't with an EPS) then no scaling will take place.
Now Ghostscript does have a different switch, EPSCrop which picks up the comments from the EPS and uses that to set the media size (Ghostscript has mechanisms to permit processing of comments for this reason, amongst others). You could implement a similar mechanism to pick up the BoundingBox comments, and scale the EPS so that it fits a desired target media size.
I could probably knock something up, but I'd have to mess around creating an example file to work from.....
Do not accidentally specify PDFFitPage in the command line above. Specify EPSFitPage when dealing with EPS files. PDFFitPage will silently do nothing.
Related
I am trying to export a figure which includes highlighting of regions - something like this: Highlight parts of matlab plot. Unfortunately, when I export the figures to .eps files the size is of the order of ~10 MB... Thus, when I include them in a tex file, the quality is severely degraded. As expected this problem seems to occur due to the use of the area function for the highlighting. Is there any workaround on this?
You have transparency in your plot which requires the renderer to be OpenGL which causes any EPS to not really be vector graphics but rather bitmaps coerced in some strange way. This is why the file size is much larger than what you would expect for vector graphics. If you open the resulting EPS file with an external editor (Illustrator, Inkscape, etc.) you will see what I am talking about. As a side-note, transparency isn't technically supported in EPS files.
Your options are really to
Save your figures as something else such as TIFF or PNG
You could try saving the figure as an EPS using export_fig from the file exchange but you will likely still have the same issue.
Turn off transparency, save to an EPS, and use Illustrator or an external program to change the transparency and try to save as an EPS file and see if you get better results.
I have managed to read SVG using rsvg and output it to PNG via Cairo, in Python.
Despite there being MANY similar questions, I've not seen any documentation on how to convert SVG into PDF through rsvg & cairo. I am aware of the command-line 'rsvg'/'rsvp-convert' tools, but want to incorporate the functionality into my Python code instead. No launching subprocess either.
For the sake of example, here's basically what I currently use to render PNG:
img = cairo.ImageSurface(cairo.FORMAT_ARGB32, w, h)
ctx = cairo.Context(img)
handler= rsvg.Handle(None, svgstr)
handler.render_cairo(ctx)
img.write_to_png(pngfilepath)
The question is: how would the code be changed to output PDF instead, so that vector format is kept; rasterization must not happen.
Replace your call to cairo.ImageSurface(cairo.FORMAT_ARGB32, w, h) with cairo.PDFSurface(filename, width_in_points, height_in_points). I don't know what the default scaling of the PDF surface is, but hopefully you can continue to use the same width and height values as before.
Since you explicitely mention that rasterization must now happen: Cairo "does its best" not to raster things, but there are combinations where cairo has to fall back to rasterized images. You can control the resolution of this images via the set_fallback_resolution method.
Reasons for rasterization include combinations of operations that cannot be expressed in PDF (sorry, I don't know details) and if some rasterized image is drawn to the PDF surface.
I am looking to export my MATLAB plot as a high quality figure. Specifically, I would like to save it as a vector based file format such as EPS or SVG.
I have tried print and saveas commands:
saveas(h,'myFileName','epsc2');
print('-r150','-depsc2', 'myFilename');
On all occasions this produces poor quality parts of the graph, although the axis-labels are indeed vector. Why does MatLab do some horrible rendering before putting it into an EPS?
Example of poor quality plot here:
http://users.ox.ac.uk/~pemb2372/myFileName.eps
Edit:
It is also worth noting that if you use a Mac viewing an EPS file from Matlab, 'Preview' app may render inner graph content rasterized and poor quality, while leaving the axis and labels vectorized and high quality. This is very misleading but when you open said EPS file in, for example, Inkscape, the quality is actually vector and quite high.
Edit 2:
My university hosting account has expired, so you can no longer view the figure. Suffice it to say that it showed a poor quality raster-style plot within high quality beautiful axis lines, ticks and labels.
I thought I would share the issue I had, and how I overcame it...
I was getting terrible results because I had the wrong renderer set to default. In my startup.m, I had the zbuffer renderer enabled. This is an example eps output.
I made that eps output with: print(gcf,'-depsc2','filename.eps'). This eps is so OBVIOUSLY rasterised. It makes me angry at matlab. Then, I had a brainwave - perhaps my default renderer zbuffer is interfering with the image save process. So, adding the line:
set(gcf,'renderer','painters')
and running the print command as before, here is the output:
Note that I just took screenshots of the eps output files at 100%. And I can confirm the second image is actually vector. Here is a good question/explanation on choosing Renderers in MATLAB.
Matlab can export to pdf with better quality than EPS, but with its own caveats of setting decent margins and font sizes.
edit:
Examples are similar to the EPS case as explained in the help of e.g. print:
saveas(gcf,'filename.pdf')
or
print('-dpdf','filename.pdf')
You might also want to take a look at the PaperSize, PaperPosition and PaperUnits properties of your figure (by means of the set and get functions).
edit: Another option is to use one of the functions available on FileExchange such as the ones mentioned by #user664303 below. My personal favorite for use with LaTeX is matlab2tikz for which the latest version can be gotten from GitHub. Together with the external library of TikZ, I think this delivers some of the most nicest graphs around.
Probably it's also best to mention that I have been actively involved in the matlab2tikz project since 2012.
The export_fig function on the MATLAB file exchange is a reasonably reliable way of accurately exporting figures to eps and pdf (as well as bitmap formats) in MATLAB.
The plot2svg function, also from the file exchange, allows you to export in svg format. It provides some additional benefits, such as being able to export translucent patch objects in vector format.
A comparison of exporting methods is given in this blog post.
I always acquire the final plots (those which are supposed to be inserted into papers and publications) by matplotlib library of python.
You can bet on the amazing quality of the generated plots, both .pdf and .eps formats.
I have a 2D color-map plot created with imagesc and want to export it as a .eps file using
print -depsc.
The problem is that the "original" image data is from a rather small matrix (131 x 131). When I view the image in the matlab figure window, I can see all the individual pixels if I zoom a bit closer.
When I export to eps, however, there seems to be some interpolation or anti-aliasing going on, in that neighboring pixels get blurred/blended into each other. I don't get the problem if I export a high-resolution tiff, but that format is not an option (as demanded by a publisher).
How can I obtain an eps that preserves the pixely structure of my image without applying interpolation or anti-aliasing?
The blurring actually depends on the rendering software your viewer application or printer uses. To get good results all the time, make each pixel in your image an 8x8 block of pixels of the same color. The blurring then only affects the pixels at the edge of each block. 8x8 blocks are best as they compress without nasty artifacts using DCT compression (sometimes used in eps files).
Old question, but highly ranked in Google, so here is my answer:
Open the .eps-file with a text editor, search for "Interpolate" and change the following "true" to "false". Repeat that step for all Interpolate-statements.
It might also depend on the viewer you're using, but probably just because some viewers ignore the "Interpolate"s...
Had the same problem using plot2svg in Matlab and exporting from Inkscape to eps.
How do I change the resolution of my MATLAB graphs? The default seems to be 96x96 PPI.
You can save using the print command; here's how:
h1=figure;
your plotting commands here
print(h1,'-djpeg','-r150','filename')
The -r150 argument sets the resolution to 150 DPI. you can set it higher or lower depending on your need. This is assuming you're saving as a JPEG. If not, there are other options such as -dpng for PNG, -dbmp for 24-bit bitmap, etc. more can be found in the help section for print.
That said, if your plot consists only of lines, I would recommend using -depsc which saves it as an EPS file, which is scalable and lossless. You also won't have to define a resolution, so you can simply do
print(h1,'-depsc','filename')
You can convert this EPS file to PDF and retain the same resolution, yet have portability between applications and platforms. I wouldn't recommend saving to PDF directly as MATLAB puts additional white spaces around the plot, wheras the EPS bounding box is tight, and looks neat.
Changing a Figure's Settings: Setting the resolution