ConstrainImg

ConstrainImg is a command-line or progammatic tool for resizing multiple images so that they do not exceed a specified width and height.

Command Line

Installation

You must have GraphicsMagick installed on your machine. In Mac OS X, you can use Homebrew:

brew install graphicsmagick

Then, to install ConstrainImg:

npm install constrain-img -g

Usage

constrainImg [<source_dir>] [<out_dir>] [<width>] [<height>] [<options>] [options]

Example:

  constrainImg myimages newimages 200 100

This will copy the images in the folder myimages to the folder newimages and resize them so that the width of any image does not exceed 200 pixels and the height of any image does not exceed 100.

Or more explicitly:

  constrainImg -s myimages -o newimages -w 200 -h 100

More compact syntaxes:

• constraingImg 50 -f: (One argument) Constrain all images in current directory to 50 width and 50 height.
• constrainImg 50 75 -f: (Two arguments) Constrain all images in current directory to 50 width and 75 height.

Options

• -s, --source: The source folder. Defaults to the current working directory.
• -o, --out: The out (export) destination. Defaults to the current working directory.
• -w, --width: Mandatory. The constraining width.
• -h, --height: Mandatory. The constraining height.
• --suffix: A suffix to append to each filename on export.
• --prefix: A prefix to prepend to each filename on export.
• --quiet: Prevent log messages from printing.
• -q, --quality: Quality of compression. 0 is minimum, 100 is maximum. Defaults to 100.
• -f, --force: Allow source files to be overwritten.

Programmatic

The package exports a function that takes two arguments: a dictionary of options and an optional callback.

The available options match the command line options listed above.

The callback function is node-style; its first argument is an error or null if no error occurred. There are no subsequent arguments.

The function returns a promise.

Installation

npm install constrain-img

Usage

var constrainImg = require('constrain-img');
constrainImg({
  source: 'myimages',
  out: 'newimages',
  width: 200,
  height: 100
  suffix: '_new',
  prefix: 'myprefix_',
  quiet: true
})
.then(function(){
  // done!
});