Add DPI Converter extension

[Qualigraphe]

Description

DPI Converter is a utility extension that converts between pixels, centimeters, millimeters, and inches with customizable DPI support.

Features:

• Convert single or dual dimensions (width × height)
• Support for pixels (px), centimeters (cm), millimeters (mm), inches (in)
• Customizable DPI resolution (default: 300 DPI)
• Detailed step-by-step calculations
• Quick copy actions with keyboard shortcuts

Use Cases:
Perfect for designers, publications editors and printing houses who need to convert units for print design (A4, US Letter…). This extension allows them, for example, to know how many pixels are the minimum required to print at a good resolution.

Screencast

Screenshots are included in the metadata/ folder showing:

1. The conversion form with input fields
2. The detailed calculation results with all unit conversions

Checklist

• I read the extension guidelines
• I read the documentation about publishing
• I ran npm run build and tested this distribution build in Raycast
• I checked that files in the assets folder are used by the extension itself
• I checked that assets used in the README are located outside the metadata folder if they were not generated with our metadata

[raycastbot]

Congratulations on your new Raycast extension! 🚀

Due to our current reduced availability, the initial review may take up to 10-15 business days.

Once the PR is approved and merged, the extension will be available on our Store.

[greptile-apps]

Greptile Overview

Greptile Summary

This PR adds a new DPI Converter extension that converts between pixels, centimeters, millimeters, and inches with customizable DPI support. The extension provides both single and dual dimension conversion capabilities with detailed step-by-step calculations.

Key Features:

• Form-based interface for entering dimensions with unit specifications
• Support for px, cm, mm, and in units
• Customizable DPI resolution with default of 300
• Detailed calculation display in results view
• Copy actions with keyboard shortcuts

Implementation Quality:
The extension follows Raycast patterns well with proper use of Form and Detail components. The conversion math is correct, and the code structure is clean. However, there are a few issues that should be addressed:

1. Critical: DPI validation doesn't prevent negative values, which could cause incorrect calculations
2. The package.json includes an unused dependency (@raycast/utils)
3. Minor grammatical errors in descriptions

The extension includes proper metadata screenshots and follows the standard extension structure. Overall, this is a useful utility extension with solid functionality that just needs minor fixes to the validation logic.

Confidence Score: 4/5

• This PR is mostly safe to merge with one logical issue to address
• Score of 4 reflects that the extension is well-structured and follows Raycast patterns correctly, with accurate conversion math. The main concern is the DPI validation issue that allows negative values, which is a logic bug but won't cause crashes. The unused dependency and grammatical errors are minor style issues. After fixing the DPI validation, this would be a solid 5.
• Pay close attention to convert-to-px-cm-mm-in.tsx line 54 for the DPI validation fix

Important Files Changed

File Analysis

Filename	Score	Overview
extensions/dpi-converter/src/convert-to-px-cm-mm-in.tsx	3/5	Main converter logic with DPI validation issue allowing negative values
extensions/dpi-converter/package.json	4/5	Configuration has unused dependency and minor grammatical errors in descriptions

[greptile-apps]

_{4 files reviewed, 4 comments}

_{Edit Code Review Agent Settings | Greptile}

[greptile-apps]

The DPI validation here doesn't handle negative numbers. When parseInt(values.dpi) returns a negative number like -10, the || 300 fallback won't trigger because -10 is truthy. This will cause incorrect calculations with negative DPI values.

Consider adding proper validation:

Suggested change

	const dpiValue = parseInt(values.dpi) || 300;
	const dpiValue = Math.max(1, parseInt(values.dpi) || 300);

This ensures DPI is always at least 1, preventing division by negative numbers or very small values that could cause precision issues.

[greptile-apps]

@raycast/utils is listed as a dependency but is never imported or used anywhere in the extension code. This adds unnecessary weight to the bundle.

Suggested change

	"@raycast/utils": "^1.17.0"
	"dependencies": {
	"@raycast/api": "^1.104.1"
	},

Remove this unused dependency to reduce bundle size.

[greptile-apps]

The description has grammatical errors: "Convert pixels in centimeters, millimeter and inches" should use "to" instead of "in", "millimeters" should be plural, and there should be a comma before "and".

Suggested change

	"description": "Convert pixels in centimeters, millimeter and inches, and vice-versa! Useful for printers.",
	"description": "Convert pixels to centimeters, millimeters, and inches, and vice-versa! Useful for printers.",

[greptile-apps]

Same grammatical issue as the main description: "Convert px in cm" should be "Convert px to cm".

Suggested change

	"description": "Convert px in cm, mm, in, and vice-versa.",
	"description": "Convert px to cm, mm, in, and vice-versa.",

[0xdhrv]

Thanks for your contribution @Qualigraphe 🔥

We already have core calculator which deals with this.

• Calculator

If there are unique features or workflows you’re aiming to add, we’d love to hear them as feedback and see if they can be integrated into one of these to avoid duplication and improve discoverability.

This would help avoid duplication and keep related functionality consolidated in one place.
As mentioned in our extension guidelines here ↗

[Qualigraphe]

Hi @0xdhrv,

Thank you so much for taking the time to review my contribution and for your feedback! 🙏 I really appreciate the thoughtful response and completely understand the concern about avoiding duplication.

I'd love to clarify why I believe DPI Converter addresses a specific workflow gap that Calculator doesn't currently cover, based on my daily work with designers and print professionals.

Real-World Use Cases

As a designer and trainer working daily with print professionals, these are critical daily workflows:

Example 1: Large Format Print

• Print shop needs a banner: "400cm × 300cm" (4m × 3m banner viewed from distance)
• Designer asks: "How many pixels do I need at 75 DPI for outdoor signage?"
• Answer: 11,811 × 8,858 px
• Formula used: px = (cm / 1 inch) × DPI

Example 2: Video Screenshot to Print

• Designer has a video screenshot: "1920 × 1080 px"
• Client asks: "What's the maximum print size at 300 DPI for good quality?"
• Answer: 16.26 × 9.14 cm (approximately 6.4 × 3.6 inches)
• Formula used: cm = pixels × (1 inch / DPI)

​These examples demonstrate why DPI context is essential – you need different pixel dimensions based on viewing distance and print technology, and you need to know printable dimensions from existing pixel assets.
​

Why This is Unique to DPI Converter

This is a unique capability that Calculator does not currently offer. Calculator handles standard unit conversions excellently, but it has no mechanism to perform resolution-dependent conversions where the relationship between pixels and physical units depends on a third parameter (DPI). Queries like those in the example above simply cannot be resolved without knowing the target resolution.

Potential Integration into Calculator

If Calculator could support this syntax natively, that would be ideal. Maybe by typing something like this (though I'm concerned it might become too complicated for the syntax):

• 1024 px to cm @300dpi
• ​4m to px at 75dpi

If no DPI is specified, defaulting to 300 DPI makes sense because it's the universal standard for commercial printers, photo labs, and professional print houses.

• 1920 px to cm → defaults to 300 DPI

​