diff

Compare two screenshots and output difference metrics.

No Bridge Required

This command operates on local image files — no bridge or running Tauri app needed.

Usage

tauri-agent-tools diff <image1> <image2> [options]

Options

Option	Description	Default
`<image1>`	First image path	(required)
`<image2>`	Second image path	(required)
`-o, --output <path>`	Write a visual diff image to this path	—
`--threshold <percent>`	Fail (exit code 1) if difference exceeds this percentage	—
`--json`	Output structured JSON	—

Examples

Basic comparison

tauri-agent-tools diff /tmp/before.png /tmp/after.png

Pixels different: 1500
Total pixels:     2073600
Difference:       0.072%

Generate a diff image

tauri-agent-tools diff /tmp/before.png /tmp/after.png -o /tmp/diff.png

Threshold gating (CI use)

# Fail if more than 1% of pixels differ
tauri-agent-tools diff /tmp/expected.png /tmp/actual.png --threshold 1
echo $?  # 0 = pass, 1 = threshold exceeded

JSON output

tauri-agent-tools diff /tmp/a.png /tmp/b.png --json

{
  "pixelsDifferent": 1500,
  "totalPixels": 2073600,
  "percentDifferent": 0.07233,
  "diffImage": null
}

Requirements

Requires ImageMagick installed on the system. Both v6 (compare, identify) and v7 (magick compare, magick identify) are supported automatically. The --threshold option requires identify to compute image dimensions.