[Tex/LaTex] Command(s) which would render a LaTeX document into a PNG on Mac

png

I am using TexShop on a Mac, which handles all of the rendering for me, but have been asked by a colleague to find the command(s) that would render the LaTex document as a PNG instead of PDF.

By way of example, on linux it would be

$ pdflatex file.tex
$ gs -sDEVICE=pnggray -sOutputFile=card.png -dNOPAUSE -r1200 file.pdf quit.ps

(Note: the -r1200 will generate an image 4x larger than used, since it will be scaled down to produce an anti-aliased image).

Thank you & kind regards.

Best Answer

The Mac OS is Unix-based, so at the Terminal

pdflatex <filename> && gs -sDEVICE=pnggray -sBATCH -sOutputFile=<filename>.png -dNOPAUSE -r1200 <filename>.pdf

should work just fine. (Fill in your <filename>, of course.)

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[Tex/LaTex] From inside a LaTeX article, I want to render several parts of the code into a separate png (a “render pass”)

You can use the TikZ external library to automatically generate PNGs of your tikzpictures.

The style

\tikzset{
    png export/.style={
        external/system call={
            pdflatex \tikzexternalcheckshellescape -halt-on-error -interaction=batchmode -jobname "\image" "\texsource";
            convert -density 300 -transparent white "\image.pdf" "\image.png"
        }
    }
}

specifies that after the tikzpicture is compiled using pdflatex, ImageMagick (convert) is used for generating a PNG from the PDF. This requires pdflatex to be called with -shell-escape.

Here's a complete example:

\documentclass[11pt]{article}
\usepackage{tikz}
\usetikzlibrary{external}
\tikzset{
    png export/.style={
        external/system call={
            pdflatex \tikzexternalcheckshellescape -halt-on-error -interaction=batchmode -jobname "\image" "\texsource";
            convert -density 300 -transparent white "\image.pdf" "\image.png"
        }
    }
}
\tikzexternalize
\tikzset{png export}

\begin{document}

\tikzset{external/force remake}
\begin{tikzpicture}
\node [orange,scale=10] {1};
\end{tikzpicture}
\begin{tikzpicture}
\node [cyan,scale=10] {2};
\end{tikzpicture}
\end{document}

[Tex/LaTex] PNG and JPG quality loss inserting webpage screenshot into LaTeX document

LaTeX graphics packages

LaTeX and its graphics packages do not touch the image data. TeX does not even provide the reading of binary data. Thus LaTeX passes the image as file name reference to the driver. Also most of the drivers are not image processing programs. They only move the image data in a form appropriate for the output format. For example, dvips only copies the PostScript file into the output PostScript file. Also pdfTeX often do not need to unpack the image data and can copy the data to the PDF structures. Some PNG files are uncompressed and compressed. But this process does not change the image data.

Driver issues Very view drivers are able to resize an image, AFAIK Acrobat Distiller and GhostScript does some obscure things with images like using JPEG compression for PNG images. I do not know how this can be turned off. The related options given in Ps2pdf.htm seems to have no effect.

But you are using pdflatex that does not change the image data. This can be tested. Take a PNG image and convert it to PPM. Also embed the image in a LaTeX document and run pdflatex. The program pdfimages (xpdf) extract the image in PPM format.

convert image.png image.ppm
pdflatex test.tex
pdfimages test.pdf t
diff t-000.ppm image.ppm

The files t-000.ppm and image.ppm should be identical, if the PPM format is the same (there is a binary and an ASCII variant).

** Different viewing programs** However the programs to view the images are different. The image viewer and the PDF viewer are usually different programs that uses different methods for viewing. For example, a program might use anti-aliasing, …

Scaling vs. resizing

There are no problems in scaling images in LaTeX independent of its method:

Option scale
Options width, height
\scalebox
…

Only the place that the image uses on the page differs, the image data remains the same.

A different term is the resizing of an image. Then the actual number of pixels change. Of course, an image processing program cannot invent missing details if the image is enlarged. It can only use better or worse methods to limit the artefacts of resizing.

Screenshots

Screens have low resolutions comparing to printed media and are usually stupid bitmap images of the pixels on the screen even if the original data were high quality vector data (non-pixel fonts, vector drawings).

Some hints to get better quality:

In some cases a vector screenshot program might be available, e.g. gtk-vector-screenshot.
A special case are web pages. They could be converted to PDF by printing or there are programs/sites that perform the conversion. But caution, PDF, especially PDFs from screenshot programs might contain bitmap data instead.
Higher screen resolution with larger font/symbol settings or using settings for visually impaired people.
A large monitor helps that allows large windows for the screenshot programs that can only catch the pixels inside the screen.
And it can make sense to turn off anti-aliasing and similar (ClearType) to get clean pixel data. Thus that a black line is displayed by black pixels and not by many gray levels at its edges. That makes it easier to optimize the image for the final media.

Best Answer

Related Solutions

[Tex/LaTex] From inside a LaTeX article, I want to render several parts of the code into a separate png (a “render pass”)

[Tex/LaTex] PNG and JPG quality loss inserting webpage screenshot into LaTeX document

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