Icon Shadow Adder

Uploads an icon PNG, decodes it onto an off-screen canvas, builds a blurred, offset silhouette tinted with a chosen shadow color behind the icon's opaque content, and composites the original icon on top, then lets you download the result. A free online tool from Staaarter, right in your browser.

Runs locallyUpdated 2026-07-26

Overview

Introduction

This tool adds a drop shadow behind an icon, entirely in your browser, giving flat icon artwork a sense of depth.

It's the same shadow-compositing operation used by the site's general PNG shadow adder, applied here to icon-sized assets.

What Is Icon Shadow Adder?

A client-side icon shadow generator that reads an uploaded icon's pixel data, builds a blurred and offset copy of its silhouette tinted with a chosen color, and alpha-composites the original icon back on top of that shadow layer.

It supports both hard-edged shadows (blur radius 0) and soft, blurred shadows for a more realistic elevated look.

How Icon Shadow Adder Works

The tool first builds a same-shaped silhouette of the icon's opaque pixels tinted with the shadow color, scaling the shadow's alpha by each source pixel's own alpha so partially-transparent edges cast a proportionally lighter shadow.

That silhouette is blurred by the chosen radius, offset by the chosen X/Y amount, and the original icon is composited on top using standard alpha-over blending.

When To Use Icon Shadow Adder

Use it to give a flat app icon or logo mark a subtle sense of elevation for a card, button, or hero section.

It's also useful for making a light-colored icon stand out against a busy or similarly-light background.

Features

Advantages

  • Runs entirely client-side; the uploaded icon is never sent to a server.
  • Shadow follows the icon's actual silhouette rather than a bounding-box rectangle.
  • Fully adjustable offset, blur radius, and shadow color/alpha.

Limitations

  • Large blur radii on large icons can take a moment to process, since blurring is computed pixel by pixel.
  • Very small offset/blur combinations may produce a shadow that's barely visible behind the icon itself; increase the offset for a clearer separation.

Examples

Add a soft shadow to a flat icon

Input

A 128x128 icon PNG, offset (4, 4), blur 4, color rgba(0,0,0,0.6)

Output

A larger PNG with a soft dark shadow offset below-right of the icon

The blur radius softens the shadow's edge for a natural, elevated look.

Add a hard-edged shadow

Input

A 64x64 icon PNG, offset (2, 2), blur 0, color rgba(0,0,0,1)

Output

A PNG with a crisp, unblurred silhouette shadow offset by 2px

A blur radius of 0 skips the blur pass entirely for a sharp comic-style shadow.

Best Practices & Notes

Best Practices

  • Keep offset and blur proportional to the icon's size — small icons need subtler shadows.
  • Lower the shadow color's alpha for a softer, more realistic effect than a fully opaque shadow.

Developer Notes

The pure shadow-compositing math lives in a lib function that thinly re-exports the shared drop-shadow function (also used by the general-purpose PNG shadow adder) under this icon-specific name, since an icon is just a PNG once uploaded and the underlying blur/composite pipeline is identical.

Icon Shadow Adder Use Cases

  • Adding depth to a flat app icon for a marketing page
  • Making a light icon readable against a light background
  • Creating a consistent shadow style across a set of icons

Common Mistakes

  • Setting the blur radius so high relative to the icon size that the shadow overwhelms the icon itself.
  • Forgetting the output canvas is larger than the input, which can surprise a pipeline expecting the original dimensions.

Tips

  • Start with a small offset and blur, then increase gradually until the depth effect reads clearly at the icon's intended display size.
  • Use a lower shadow alpha (150-180) for a subtler, more natural-looking shadow than full opacity.

References

Frequently Asked Questions