Postcard

Simple Ruby program to compose holiday cards, ready to print, given a digital image.

The intent is not to modify the original image file, but to create a new PDF file with the result.

Installation and options

You need Ruby, which usually comes pre-installed in macOS and Linux. Better if you use one of the last versions (tested up to version 3.4.7).

It requires ImageMagick, which in macOS it can be installed with Homebrew:

brew install imagemagick

The minimum is to download the files:

postcard.rb
Gemfile
Gemfile.lock

The rest can be generated from running that program.

After downloading it, run this command once to install a couple of dependencies (Ruby gems):

bundle

Also find the image file you want to use for your postcards.

Special commad-line options:

-g  Generates a YAML configuration file (`postcard.yml`) and exits (no postcard images generated).
    The file can be used to set several options, like the text to be printed or the target page size

-v  Verbose mode. It could be a bit technical. It gives some details for each of the operations performed.

A few examples

At a Terminal window:

./postcard.rb -g

./postcard.rb

./postcard.rb "My Art Work.png"

./postcard.rb -v 0.artwork_large_sample.png

Some examples of output can be seen in the doc/usage_examples.md file.

November 2025