imgdiff

A command-line tool that combines two pictures into a single, larger one, and opens a GUI window (provided by the Python Imaging Library) or an external image viewer.

You could use it with a version control tool, e.g. ::

bzr diff *.png --using=imgdiff

or ::

bzr diff *.png --using='imgdiff --eog -H'

Installation

pip install imgdiff or download it from PyPI <https://pypi.python.org/pypi/imgdiff>_.

Usage

Run imgdiff --help to see this help message::

Usage: imgdiff [options] image1 image2

Compare two images side-by-side

Options:
  -h, --help            show this help message and exit
  -o OUTFILE            write the combined image to a file
  --viewer=COMMAND      use an external image viewer (default: builtin)
  --eog                 use Eye of Gnome (same as --viewer eog)
  --grace=SECONDS       seconds to wait before removing temporary file when
                        using an external viewer (default: 1.0)
  -H, --highlight       highlight differences (EXPERIMENTAL)
  -S, --smart-highlight
                        highlight differences in a smarter way (EXPERIMENTAL)
  --opacity=OPACITY     minimum opacity for highlighting (default 64)
  --timeout=TIMEOUT     skip highlighting if it takes too long (default: 10
                        seconds)
  --auto                pick orientation automatically (default)
  --lr, --left-right    force orientation to left-and-right
  --tb, --top-bottom    force orientation to top-and-bottom
  --bgcolor=RGB         background color (default: fff)
  --sepcolor=RGB        separator line color (default: ccc)
  --spacing=N           spacing between images (default: 3 pixels)
  --border=N            border around images (default: 0 pixels)

Output Examples

First example::

imgdiff set1/42.png set3/

.. figure:: https://pythonhosted.org/imgdiff/example1.png :alt: example #1

Here the images are wide and short, so imgdiff decided to put them one above the other.

Same example, with highlighting enabled::

imgdiff set1/42.png set3/ -H

.. figure:: https://pythonhosted.org/imgdiff/example2.png :alt: example #2

You can see that it doesn't work very well, although it can produce nice results in simpler cases::

imgdiff set1/42.png set2/ -H

.. figure:: https://pythonhosted.org/imgdiff/example3.png :alt: example #3

Support and Development

The source code can be found in this Git repository: https://github.com/mgedmin/imgdiff.

To check it out, use git clone https://github.com/mgedmin/imgdiff.

Report bugs at https://github.com/mgedmin/imgdiff/issues.

Changes

1.7.1 (2019-04-23)

• Claim Python 3.6 and 3.7 support (no code changes required).

• Drop Python 3.3 and 3.4 support.

1.7.0 (2016-09-17)

• Clarify the help message for the --opacity option.

• Add Python 3.5 support.

• Drop Python 2.6 and 3.2 support.

1.6.0 (2014-12-01)

• Add Python 3 support.

• Make the --timeout option actually work.

• Drop the --selftest option. Add a real test suite with 100% coverage (which actually means little, since these are smoke tests that don't inspect the results for correctness.)

1.5.0 (2013-08-11)

• Suppress progress output if stderr is not a terminal.

• Make it possible to abort --highligh/--smart-highlight logic by pressing ^C.

• Abort --highlight/--smart-highlight logic if it takes longer than 10 seconds (timeout changeable with --timeout; use 0 to turn it off).

1.4.1 (2013-08-09)

• Depend on Pillow instead of PIL.

• Moved to GitHub.

1.4.0 (2010-12-19)

• Accepts directory names: imgdiff dir1/img.png dir2/.

• Centers images relative to each other if they have different width/height.

• Automatic orientation (--auto) uses the golden ratio (1:1.618) as its goal for desired height:width instead of a 1:1 square.

• New experimental options: --highlight (-H) and --smart-highlight (-S). These highlight areas that are different and fade out areas that are similar. Or at least they try.

• New options for tweaking the output: --bgcolor, --sepcolor, --spacing, --border, --opacity.

• New option: --eog as alias for --viewer eog, but shorter. Guess what desktop environment I'm using. ;-)

• A puny "test suite", runnable with imgdiff --selftest.

• Better source code documentation via docstrings.

1.3.0 (2010-12-18)

• First public release. Options supported: -o, --viewer, --grace, --auto, --lr, --tb, --help.