BlazeDiff vs odiff

@blazediff/core-native is ~2.5x faster than odiff over our 34 fixtures, with image decode and diff PNG writing included. Both are native binaries with a Node API, and both return the same kind of result, so most code moves over with a changed import.

odiff is a SIMD image diff written in Zig, popular in visual testing tools. It decodes many image formats and has a server mode that keeps one process alive between comparisons. BlazeDiff runs a block-based Rust kernel with SIMD on ARM and x86, and it reads file paths or encoded bytes.

At a glance

Benchmarks

odiff runs through ODiffServer, its server mode, so process start-up is not counted against it. “BlazeDiff Next” is the same binary with the blazediff-png codec turned on through BLAZEDIFF_PNG_ENABLED=1.

Switching

The result is a discriminated union in both libraries: match, then a reason of layout-diff, pixel-diff or file-not-exists, with diffCount and diffPercentage on a pixel diff.

// Before
import { compare } from "odiff-bin";
// After
import { compare } from "@blazediff/core-native";
 
const result = await compare("baseline.png", "current.png", "diff.png", {
  threshold: 0.1,
  antialiasing: true,
});
 
if (!result.match && result.reason === "pixel-diff") {
  console.log(`${result.diffCount} pixels differ`);
}

When to keep odiff

• You compare WebP, TIFF or BMP files, or a JPEG against a PNG.
• You depend on ignoreRegions or on the changed-line output.
• You use a tool that already integrates odiff, for example Argos or Lost Pixel.

Related

• Pixel comparison in native Node
• @blazediff/core-native API
• BlazeDiff vs honeydiff
• All benchmarks