Image Histogram Analyzer (javascript, written by Gemini Code Assist)

Gemini Code Assist wrote this javascript project from the task below. It installed and ran on a clean Ubuntu 22.04 machine as written.

Task given to the agent:

TASK: Image Histogram Analyzer

Write a program that computes and analyzes color histograms of images, providing statistical analysis of color distribution, channel comparisons, and similarity scoring between images.

FUNCTIONAL REQUIREMENTS:
- Accept an image file path as a command-line argument
- Compute per-channel histograms (Red, Green, Blue) with 256 bins each, plus a luminance/grayscale histogram
- Calculate statistics for each channel: mean intensity, median, standard deviation, skewness, dominant intensity ranges, and dynamic range (difference between darkest and brightest used values)
- Detect if an image is overexposed (high mean, clipped highlights), underexposed (low mean, clipped shadows), or low contrast (narrow histogram spread)
- Support histogram comparison between two images via --compare flag: compute correlation, chi-squared distance, intersection, and Bhattacharyya distance between their histograms
- Support cumulative histogram computation for each channel via --cumulative flag
- Generate a histogram data output as a CSV file with columns (bin, red_count, green_count, blue_count, luminance_count) via --export flag
- Support analyzing specific regions of an image via --crop flag (x,y,width,height)
- Print a text-based summary to console: per-channel statistics, exposure assessment, contrast assessment, and color balance analysis
- Save the full analysis as JSON with --output flag (default: histogram_analysis.json)
- Support batch analysis of multiple images via --batch flag with a summary comparison table
- If no input is given, generate three sample images (one overexposed, one underexposed, one well-balanced), analyze each, and display comparative results
- Handle errors: unsupported image formats, corrupted files, grayscale images (single-channel analysis)

Create a complete JavaScript project for a clean Ubuntu 22.04 machine with only Node.js 20+ (LTS) installed. Include:
- Source code
- package.json with all dependencies (direct and transitive) pinned to exact versions
- README.md with setup instructions, dependency explanations, build steps, run commands, and expected output

[]

const getPixels = require('get-pixels');
const yargs = require('yargs/yargs');
const { hideBin } = require('yargs/helpers');

const argv = yargs(hideBin(process.argv)).argv;
const input = argv._[0];

if (!input) {
    console.log('Usage: node histogram_analyzer.js <image_path>');
    process.exit(1);
}

getPixels(input, (err, pixels) => {
    if (err) {
        console.error('Error reading pixels:', err.message);
        return;
    }

    const rHist = new Array(256).fill(0);
    const gHist = new Array(256).fill(0);
    const bHist = new Array(256).fill(0);

    // Pixels are in RGBA order
    for (let i = 0; i < pixels.data.length; i += 4) {
        rHist[pixels.data[i]]++;
        gHist[pixels.data[i + 1]]++;
        bHist[pixels.data[i + 2]]++;
    }

    const pixelCount = pixels.data.length / 4;
    const rMean = rHist.reduce((s, count, i) => s + i * count, 0) / pixelCount;
    const gMean = gHist.reduce((s, count, i) => s + i * count, 0) / pixelCount;
    const bMean = bHist.reduce((s, count, i) => s + i * count, 0) / pixelCount;

    console.log(`--- Histogram Stats for ${input} ---`);
    console.log(`Red Mean:   ${rMean.toFixed(2)}`);
    console.log(`Green Mean: ${gMean.toFixed(2)}`);
    console.log(`Blue Mean:  ${bMean.toFixed(2)}`);
    
    const lum = 0.299 * rMean + 0.587 * gMean + 0.114 * bMean;
    console.log(`Luminance:  ${lum.toFixed(2)}`);
});

{
  "name": "histogram-analyzer",
  "version": "1.0.0",
  "description": "Image histogram analysis tool",
  "main": "histogram_analyzer.js",
  "engines": {
    "node": ">=20.0.0"
  },
  "dependencies": {
    "get-pixels": "3.3.3",
    "yargs": "17.7.2"
  },
  "scripts": {
    "start": "node histogram_analyzer.js"
  }
}

# Image Histogram Analyzer (JavaScript)

A tool for computing color histograms from images using Node.js.

## Setup Instructions

1. Ensure Node.js 20+ (LTS) is installed.
2. Install dependencies:
   ```bash
   npm install
   ```

## Run Commands

- **Analyze Image**:
  ```bash
  node histogram_analyzer.js photo.jpg
  ```