Pandoc can easily render the same source file to html or LaTeX and then pdf. In many cases, I'd like to use different versions of the same image file depending on which backend is being used: When the original "image" is a vector figure, possibly containing text (e.g. PostScript, PDF, maybe SVG), I'd like to use that version to generate LaTeX and PDF, so there's not loss of quality. But browsers don't generally render those well, so I'd like to generate and use a raster (e.g. PNG) image when generating HTML.
Is there any way to do this in Pandoc? What I was hoping would "just work" was something like the \includegraphics{} LaTeX macro where, if you provide the filename with no extension, it identifies all the image files matching that stem and applies some heuristic to pick the best option.
You could call pandoc with --default-image-extension=png when generating html, and --default-image-extension=pdf (or whichever other extension you use) when generating the pdf. See
https://pandoc.org/MANUAL.html#reader-options
Related
I'm trying to create a small PDF file, embedding one optimized PNG image displayed as a header and footer on a 3 page PDF (same image must appear 6x in the PDF)
My optimized PNG image is only 2.3KB. It looks very sharp.
Failed with libreoffice
When I insert just one instance of the 2.3KB PNG image into a Libreoffice Writer doc containing only text, then export as PDF I can see that the image gets re-compressed to JPG and the resulting PDF file grows by about 40KB after adding the image. It also loses quality, the PNG also gets JPG fuzzy edges.
If I right click the image and select compression, there is no way to disable recompressing the image (it's already optimized better than libreoffice could do it) I've tried setting a compression level of 0,1,9 etc. Choosing JPG, no resize, lossless, etc but there was no improvement.
Failed with wkhtmltopdf
I also tried making a test page and used wkhtml2pdf but it did the same thing. Adding the low quality flag made no difference.
PDF Spec suggests PNG is supported?
From skimming the PDF spec, it looks like PNG images are supported.
Even plain text PDF files are surprisingly large
The disappointing thing is also when I take a 7KB HTML file which is basically just <html><body><p>foo...</p><p>bar...</p> (only about 15 paragraphs) with no CSS. The resulting 2 page PDF file is 30KB. Why should a 7kb (almost plain text) file become 30kb as a PDF?
Suggestions?
Can someone please suggest how to make a small PDF file in Linux?
I need to include 7KB of text and repeat one PNG image 6 times.
Manually or programatically. I'll take whatever I can get at this point.
PDF Spec suggests PNG is supported?
PNG isn't supported per se; PDF allows embedding JPEG images as-is, but not PNG images. PDF does borrow a set of features of the PNG format, however.
rinohtype (full disclosure: I'm the author) tries to embed as much as possible from PNG images as-is into the PDF. This does involve some bit-juggling to separate the alpha channel from the color data for example, but no reencoding of the image is performed. It does not (yet) support interlaced PNGs.
rinohtype should be able to do what you want to achieve. But please note that it currently is in a beta stage, so you might encounter some bugs.
Even plain text PDF files are surprisingly large
To keep the PDF size as small as possible, make sure not to embed/subset any of the fonts. Use only the fonts from the base 14 PDF fonts which are provided by PDF readers.
What you want is certainly achievable. Regarding the image quality, I would recommend making your image twice the size that you want it to actually display at in the PDF to keep it looking sharp.
As to the size, I've just modified a test in my PDF writer module (WIP..) to include a 7.2K png, 200px x 70px, in a PDF twice and the PDF came out at 6.8K 8). There's not much text included, but more text will only add what it's worth + a small percentage.
You can see the module and original test here.. https://github.com/DoccaPDF/docca-pdf-writer/blob/master/src/tests/writer.js#L40
That test adds ~112K of images to the PDF and results in a 103K PDF.
Of course not all images are created equal so you milage may vary..
*the images are only actually added to the PDF once, but are displayed multiple time.
Is there any way to stamp or overlap a tiff image on a existing PDF file and output the result using Ghostscript?
I have two PDF which i want to merge in a result PDF with one over the other using ghostscript. I want to know if this can be done and how, or if it may work with one PDF as tiff image on top of the base PDF.
Can ghostscript make this stamp using layers in the PDF?
Thank you for your answers
The pdfwrite device in Ghostscript doesn't really support layers, so you can't use that. Also its unclear why you think layers would help.
TIFF isn't part of PostScript (or PDF), so you can't directly read a TIFF file into GS. I have elsewhere posted a PostScript program which reads TIFF files and renders them for output. You could use that to read a TIFF file.
However, you would have to mess about with either the PDF interpreter or a custom EndPage procedure in order to read and render the TIFF file. And unless you take specific kinds of action, it will be opaque, which may well not be what you want.
The Ghostscript PDF interpreter doesn't really lend itself to this kind of manipulation, have you considered using pdftk instead ?
How do I convert an svg file to an image using Go ?
I found the amazing svgo library and would like to use it to generate a custom set of playing cards. The idea is to store the text and layout of a card in a text file and then read and process it with go. This would be a huge improvement of my current workflow where I use gimp to edit each individual card. The problem is that I need to have an image of the card for printing. Preferably png since the printing script so far only works with that format. But I could easily adapt it to accept jpeg, too.
Unfortunately svgo doesn't seem to offer export functionality. Can you recommend a go library to convert svg to png ?
One possible strategy is to write your SVG to files and invoke an external tool to convert them. For example, ImageMagick and its related GraphicsMagick will both convert SVG to PNG via command-line options. You would need to use the convert verb, possibly within their batch support if you're converting lots of images at once.
GraphicsMagick has bindings for C and Go and other languages that you could use directly from your Go scripts, although I've not tried this myself.
I can't find a native Go library to do it, but there seems to be a way to convert an HTML canvas element to PNG quite simply in Javascript.
You can therefore output SVG to an HTML canvas element, and then use JS to export to SVG.
See this answer for details.
I include several images of eps format in latex. After latex command, there are some of the images missing in the dvi file. Not sure if it is related to the image size, most of the images missing have size around 83kB while those shown up have a size less than 40kB. After conversion from dvi to ps, the images are all back. Just wonder what is the reason causing the images missing in dvi file?
Thanks and regards!
As far as I can remember, a dvi viewer cannot show eps file. Just use pdflatex as the front-end instead of latex and view the resulting pdf file.
Checking man xdvi reveals this:
Xdvi can show PostScript specials
by any of three methods. It will try
first to use Display PostScript,
then NeWS, then it will try to
use Ghostscript to render the images. All of these options
depend on additional software to work
properly; moreover, some of them may
not be compiled into this copy of xdvi.
So it would appear to be platform- and/or implementation-dependent.
What is the preferred way to convert various images, bitmap and vector, for use in a LaTeX and PDFLaTeX document?
There are many ways to do this, some make use of standard inclusions in the various LaTeX packages, others give better results.
You can include a PDF image directly into a LaTeX document if you want to produce your final output using pdflatex, but not if you want to produce a dvi file.
pdflatex can use PDF, PNG, and JPEG
latex/dvips can use PS, EPS
See more details:
Including images in LaTeX files
Watch what you name graphics files in LaTeX
I convert bitmaps into PNG, and vector graphics (e.g. SVG) into PDF. pdflatex understand both PNG and PDF.
If you have an image "as PDF", and you don't want to include it as pdf, you may want to extract the complete image data first with pdfimages. Other conversions may render the image only with reduced resolution.
My current preferred way is using bmeps and epstopdf included in MikTeX. For the generation of pdf and eps versions of a png.
In a file called convertimage.bat,
bmeps -p3 -c -e8f -tpng %1.png > %1.eps
epstopdf %1.eps
Use by including in the path and writing convertimage.bat filenameminusextension
Include in the documents using,
\begin{figure}[h]
\begin{center}
\includegraphics[scale=0.25]{path/to/fileminuxextension}
\caption{My caption here}
\label{somelabelforreference}
\end{center}
\end{figure}
I only use Encapsulated PostScript (.eps) figures (converting bitmaps with NetPBM first), since I always use dvips + ps2pdf anyway, and then I do \includegraphics{file}.
As John D. Cook says, your available image formats depend on whether you are using latex or pdflatex.
I find ImageMagick a useful tool for converting images between formats. Handles bitmap images, plus ps/pdf/eps (with ghostscript) and a zillion others. Available through apt, macports, etc.
I use a mac so I use GraphicConverter to load images and export as PDFs.
When I draw diagrams, I use Omnigraffle which lets me export as PDFs.
On windows I used to use Visio which supported EPSs which I also had no problems embedding.
The basic issues are that a) you want to handle raster and vector images differently and b) this introduces potential pitfalls.
The "right" thing to do depends a bit on your final output.
If your final output is going to be a .pdf file, and you don't need pstricks or anything else that these days you're probably better off just using pdflatex to directly produce the file.
In this case:
store all vector figures as .pdf
store all raster figures as .png (or jpeg if they were originally jpeg)
use graphicx package and \includegraphics{filename-without-suffix}
If you don't do the above, your raster figures will be converted to jpegs and may gain compression artifacts. png is the best bet if you can choose output.
If you are headed for .dvi file you're going to want .eps for everything. (You can gzip these files as long as you generate a bounding box file).
If you're careful you can do both. I store all vector figures as (compressed) .eps because there are a few things .pdf can't do that .eps can. I store all raster figures as .png. Using make, I can have temporary copies of these canonical versions generated on the fly for .dvi or .pdf output as needed.
Someone above pointed out the filename issue. You want to avoid "." in the file names, and avoid suffixes always in your latex file itself.
I always include images in PNG format.
If you compile your code with pdflatex, then you also can use the \includegraphics to include images in pdf (you have to include the package graphix