Re: [NTG-context] Use MetaPost to distort images?

5 Sep 2021

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Am 04.09.2021 um 19:06 schrieb Hans Hagen :
On 9/4/2021 2:18 PM, Henning Hraban Ramm via ntg-context wrote:
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I guess it’s on me to write a wiki page about GM.
you can then also add some comparison with im (i.e. what does it offer more than gm)
Oh no...

IM and GM have a history, and I don’t want to get involved.

GM accuses IM of security issues, feature and dependency bloat, bad code quality, inefficiency, frequent API changes, license changes and whatnot.

OTOH IM offers much more features (e.g. the geometric transformations I inquired about), and you can find lots of interesting examples (including the scripts Bruce mentioned). I couldn’t find another CLI tool that can do most of these things, at least not with much more programming.

Dependencies according to MacPorts:

Full Name: GraphicsMagick @1.3.36_1+q8
Library Dependencies: libxml2, bzip2, xz, zlib, libpng, tiff, freetype, libiconv, libtool, lcms2, jasper, libjpeg-turbo, webp

Full Name: ImageMagick @6.9.11-60_1+x11
Library Dependencies: bzip2, djvulibre, xz, jbigkit, libjpeg-turbo, lcms2, libpng, libraw, tiff, webp, zlib, fftw-3, freetype, fontconfig, ghostscript, libiconv, libtool, openjpeg, openexr, expat, libxml2, libheif, pkgconfig, xorg-libX11, xorg-libXext, xorg-libXt
Runtime Dependencies: urw-fonts

It’s probably not wise to run IM in a web server process for security and efficiency reasons, but if I run it only on my own computer there shouldn’t be a problem.

BTW, here’s my script:

#!/bin/bash
#INPUT=$1

OUTPUT=${INPUT/.JPG/.png}
OUTPUT=${OUTPUT/.jpg/.png}
OUTPUT=${OUTPUT/in\//out\/}

# random rotation ±1.5˚
ROTATION=`jot -r 1 -1.5 1.5`
echo $OUTPUT ${ROTATION}˚

# downscale, add a white border and a shadow, rotate, move down, add a piece of tape (tesa1.png), grayscale
convert "$INPUT" \
-auto-orient \
-resize 800x800 \
-bordercolor white -border 10 \
\( +clone -background black -shadow 80x3+2+2 \) +swap \
-background transparent \
-layers merge \
-rotate ${ROTATION} \
+repage  \
-gravity north \
-splice 0x10 \
\( tesa1.png -resize 200x50! \) -compose Multiply -composite \
-colorspace Gray \
"$OUTPUT"

Here are some results:
https://sedna.fiee.net/d/2c3218730f8341aab1fa/

Hraban