pixelmatch-cpp

A C++ port of pixelmatch, the smallest, simplest and fastest JavaScript pixel-level image comparison library.

This is a header-only library; add include/ to your include path, use it as a CMake subdirectory, or install it and link against mapbox::pixelmatch.

Building & testing

Requires CMake 3.15+ and a C++11 compiler.

cmake -B build
cmake --build build
ctest --test-dir build --output-on-failure

To generate an Xcode project: cmake -B build -G Xcode && open build/pixelmatch.xcodeproj.

API

namespace mapbox {

uint64_t pixelmatch(
    const uint8_t* img1,
    const uint8_t* img2,
    std::size_t width,
    std::size_t height,
    uint8_t* output = nullptr,
    double threshold = 0.1,
    bool includeAA = false
);

}

img1 and img2 must point to buffers of size width * height * 4. The return value is the number of mismatched pixels.

Optional arguments:

• output - If non-null, must point to an output buffer of the same size, which recieves the diff.
• threshold — Matching threshold, ranges from 0 to 1. Smaller values make the comparison more sensitive.
• includeAA — If true, disables detecting and ignoring anti-aliased pixels.