Effective/Shadow

Effective Shadow is a powerful, framework-independent library designed to create rich, harmonious shadows for web interfaces. Utilizing a shadow factory based on Bézier curves, this library generates consistent shadow layers from minimal input parameters. It supports both CSS box-shadow and filter-based drop-shadow, ensuring nearly identical visual results across both techniques.

Demo

Take a look at the shadows in our Storybook Demo.

Installation

Install the npm package:

npm install @effective/shadow

Quick Start

Using Predefined Shadows

Effective Shadow provides a set of typical shadow values for quick and easy use. The index position in both arrays corresponds to the effective elevation.

Importing Predefined Shadows

import { boxShadow, dropShadow } from "@effective/shadow"

// Using predefined box-shadow
const firstBoxShadow: string = boxShadow[0]
const secondBoxShadow: string = boxShadow[1]

// Using predefined drop-shadow
const firstDropShadow: string = dropShadow[0]
const secondDropShadow: string = dropShadow[1]

Example Usage

You can directly use these predefined shadow values in your e.g. CSS-in-JS

{
  boxShadow: boxShadow[2]
}

{
  filter: dropShadow[2]
}

Custom Shadows

For more control over shadow creation, you can generate custom shadows using the library's methods.

Generating Shadows

To create a custom shadow set, use the buildShadow function with a partial ShadowConfig object:

import {
  buildShadow,
  toBoxShadow,
  toDropShadow,
  ShadowConfig,
  ShadowSet
} from "@effective/shadow"

const config: Partial<ShadowConfig> = {
  shadowLayers: 3,
  finalOffsetX: 10,
  finalOffsetY: 10,
  offsetEasing: [0.25, 0.1, 0.25, 1.0],
  finalBlur: 20,
  blurEasing: [0.25, 0.1, 0.25, 1.0],
  finalAlpha: 0.8,
  alphaEasing: [0.25, 0.1, 0.25, 1.0],
  reverseAlpha: false
}

const shadowSet: ShadowSet = buildShadow(config)

Converting to CSS Shadows

To convert the generated shadow set to a CSS box-shadow or drop-shadow string, use the respective functions:

const boxShadowString: string = toBoxShadow(shadowSet)
const dropShadowString: string = toDropShadow(shadowSet)

API Reference

Types

EasingValue

An array of four numbers representing a Bézier curve:

export type EasingValue = [number, number, number, number]

ShadowConfig

The configuration object for generating shadows:

export interface ShadowConfig {
  shadowLayers: number
  finalOffsetX: number
  finalOffsetY: number
  offsetEasing: EasingValue
  finalBlur: number
  blurEasing: EasingValue
  finalAlpha: number
  alphaEasing: EasingValue
  reverseAlpha: boolean
}

ShadowValues

An array of four numbers representing a single shadow layer:

export type ShadowValues = [number, number, number, number]

ShadowSet

An array of ShadowValues, representing multiple shadow layers:

export type ShadowSet = ShadowValues[]

Functions

buildShadow

Generates a set of shadow layers based on the provided configuration:

export declare function buildShadow(config: Partial<ShadowConfig>): ShadowSet

toBoxShadow

Converts a ShadowSet to a CSS box-shadow string:

export declare function toBoxShadow(
  shadowSet: ShadowSet,
  precision?: number
): string

toDropShadow

Converts a ShadowSet to a CSS drop-shadow string:

export declare function toDropShadow(
  shadowSet: ShadowSet,
  precision?: number
): string

Constants

boxShadow

An array of predefined box-shadow strings:

export declare const boxShadow: string[]

dropShadow

An array of predefined drop-shadow strings:

export declare const dropShadow: string[]

Examples

Here are some practical examples to get you started:

// Basic usage
const basicConfig: Partial<ShadowConfig> = {
  shadowLayers: 5,
  finalOffsetX: 15,
  finalOffsetY: 15,
  offsetEasing: [0.42, 0, 0.58, 1],
  finalBlur: 30,
  blurEasing: [0.42, 0, 0.58, 1],
  finalAlpha: 0.9,
  alphaEasing: [0.42, 0, 0.58, 1],
  reverseAlpha: true
}

const basicShadowSet = buildShadow(basicConfig)
console.log(toBoxShadow(basicShadowSet))
console.log(toDropShadow(basicShadowSet))

// Using predefined shadows
console.log(boxShadow[3])
console.log(dropShadow[3])

Demo

To see our library in action and explore the possibilities it offers, check out our Storybook demo.

License

Apache License; Version 2.0, January 2004