HalCanary/imagediff

Image Diff: Provides a metric for measuring the difference between two PNG images. Prints out a single floating-point number between 0.0 and 1.0; 0 means that the images are identical; 1 means that each pixel is maximally different in each channel. A non-zero return value indicates that something went wrong.

Image Diff

Provides a metric for measuring the difference between two PNG images.

Prints out a single floating-point number between 0 and 1.

• 0 means that the images are identical.
• 1 means that each pixel is maximally different in each channel.

A non-zero return value indicates that something went wrong.

This program is intended for use in scripts to sort pairs of images by sameness.

Build

On Posix systems with libpng 1.6+ installed in standard locations:

git clone https://github.com/HalCanary/imagediff.git
cd imagediff
make
./imgdiff FILE1.png FILE2.png

On MacOS with Homebrew:

brew install libpng
git clone https://github.com/HalCanary/imagediff.git
cd imagediff
./maker.sh "$(brew --prefix)"
./imgdiff FILE1.png FILE2.png

On Posix system without libpng1.6+ already installed:

# Download source to libpng version 1.6+...
md5sum ~/Downloads/libpng-1.6.29.tar.xz
# verify checksum
cd /tmp
tar xf ~/Downloads/libpng-1.6.29.tar.xz
cd libpng-1.6.29
PREFIX=~/local
./configure --prefix="$PREFIX" && make && make install
cd /tmp
git clone https://github.com/HalCanary/imagediff.git
cd imagediff
./maker.sh "$PREFIX"
./imgdiff FILE1.png FILE2.png