[Tex/LaTex] Get high resolution for bitmap fonts under pdflatex

fontspdftexresolution

I’m using the Boisik font/package, which is not available as Type 1 and so (unless I’ve missed something) is only able to produce bitmapped fonts in the pdf output. By default, the resolution of these is fairly low.

Using a latex → dvips → ps2pdf workflow, I can at least make sure the generated bitmaps are high resolution, by invoking dvips with an option like dvips -D 2400 (as suggested in the Boisik documentation).

Is there any way to do this while using pdflatex?

Best Answer

The parameter to set is \pdfpkresolution that TeX Live (and MiKTeX, I believe) sets to 600 (dpi).

It can be set in the document by

\pdfpkresolution=2400

There is also a token register \pdfpkmode that chooses the Metafont mode for creating the bitmaps, if non empty:

\pdfpkmode={supre}

The supre mode is found in modes.mf and is for a 2400 dpi printer (but it may be not the right one for yours.

Related Solutions

[Tex/LaTex] Can pdflatex (or any tex package) automatically rescale included images which have been reduced in size

I've tried a little black magic with LaTeX, and found out how to do it without external scripts ─ though it still is somewhat dirty and not that easy to use. Basically, you would need to call ImageMagick from inside LaTeX.

To do this, you need to call it with --shell-escape parameter. This allows for using a command named \write18, that executes a parameter passed to it. Then you could add the following code to the preamble:

\newcommand{\doConvert}[2]{\immediate\write18{convert #1 -resample %
  300x300 -resize #2 #1.rs}}
\newcommand{\imgRs}[4]{\doConvert{#1.#2}{#3x#4}%
  \includegraphics[width=#3, height=#4, type=#2, ext=.#2.rs, read=.#2.rs]{#1}%
}

This enables you to call \imgRs{file}{extension}{width_in_pts}{height_in_pts} in order to convert the image to 300 dpi and include it in the document.

Of course you could always specify the dimensions in inches or any other units: you would just have to change the call to \doConvert in imgRs to account for scaling from unit used to points -- and you would have to use the dimensions consistently. It could be possible to actually find out what were the units used, or make some parameters optional, but it's independent of this solution.

[Tex/LaTex] Resolution (dpi) checks for included bitmaps

LaTeX neither knows the resolution nor the final size on the paper:

\includegraphics prints the requested sizes in the .log file with driver pdftex.def:
```
Package pdftex.def Info: foobar.png used on input line 5.
(pdftex.def)             Requested size: 67.0pt x 89.0pt.
```
But \includegraphics can be put inside \scalebox or \resizebox, for example. Thus the final size on the paper is not known, when \includegraphics is executed.
The terminal output and the .log file also contain something like:
```
<foo.png, id=1, 12pt x 34pt>
```
That is printed by the driver part of pdfTeX. It is the natural size of the image that would be the size of the image, if the image is included by pdfTeX without further scaling.
\pdfimageresolution is only considered, if the image does not contain resolution data.

What can be done:

Reading the .log file by a script that takes the natural size, the requested size, the image file name. Then it can calculate the scale factor and can apply it to the resolution. The script gets the resolution by running an external program (e.g. file in Linux) or by analyzing the image. But this method will not detect later scalings.
Package bmpsize analyzes bitmap images. The method there can be used to get the resolution at TeX macro level. The package itself terminates for pdfTeX in PDF mode, originally because it is not needed to calculate the size of the image, that pdfTeX in PDF mode already is able to do itself. Again, later scalings are difficult to track.
Parsing the PDF file directly. Then the settings of the current transfer matrix can be tracked and applied to the resolution of the bitmap image data. Also this method can find images inside PDF Form XObjects, that are missed by the previous methods (pdfTeX can include PDF files that contain bitmap images).

Best Answer

Related Solutions

[Tex/LaTex] Can pdflatex (or any tex package) automatically rescale included images which have been reduced in size

[Tex/LaTex] Resolution (dpi) checks for included bitmaps

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