# Sizing Rules

This page explains how `s`, `w`, and `h` translate into output dimensions, including the default downscale and edge cases.

## Computation

Given an original of width `W` and height `H`, every target is capped at the original dimensions; images are **never upscaled**.

| Parameters | Landscape (`W > H`) | Portrait or square (`W ≤ H`) |
|---|---|---|
| `s` | height = `min(s, H)`, width proportional | width = `min(s, W)`, height proportional |
| `w` and `h` | width = `min(w, W)`, height = `min(h, H)`, center-cropped with sharp's default `cover` | Same |
| Only `w` | width = `min(w, W)`, height proportional | Same |
| Only `h` | height = `min(h, H)`, width proportional | Same |
| None, and `min(W, H) > 1024` | width = 1024, height proportional | height = 1024, width proportional |
| None, and `min(W, H) ≤ 1024` | Original size | Original size |

The proportional edge is rounded down with `Math.floor`.

## Examples

| Original | Parameters | Output |
|---|---|---|
| 4000×3000 | none | 1024×768 |
| 3000×800 | none | 3000×800 (short edge not above 1024) |
| 4000×3000 | `s=480` | 640×480 |
| 4000×3000 | `w=800` | 800×600 |
| 4000×3000 | `w=400&h=400` | 400×400 (cropped) |
| 600×400 | `w=1200` | 600×400 (no upscale) |