https://github.com/cdown/icopng

Directly embed PNGs into ICO files without reencoding.
https://github.com/cdown/icopng

command-line command-line-tool ico image-processing png rust rust-lang

Last synced: 2 months ago
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Directly embed PNGs into ICO files without reencoding.

• Host: GitHub
• URL: https://github.com/cdown/icopng
• Owner: cdown
• License: other
• Created: 2021-12-30T04:55:15.000Z (about 3 years ago)
• Default Branch: master
• Last Pushed: 2024-10-26T19:08:20.000Z (3 months ago)
• Last Synced: 2024-10-26T21:12:54.389Z (3 months ago)
• Topics: command-line, command-line-tool, ico, image-processing, png, rust, rust-lang
• Language: Rust
• Homepage:
• Size: 17.6 KB
• Stars: 7
• Watchers: 3
• Forks: 1
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# icopng | [![Tests](https://img.shields.io/github/actions/workflow/status/cdown/icopng/ci.yml?branch=master)](https://github.com/cdown/icopng/actions?query=branch%3Amaster)

icopng stores a PNG inside an ico, without converting to the traditional bitmap

with alpha channel. This saves a lot of space, since PNGs can be compressed and

there are tools to highly optimise them. Embedding PNG data inside a

favicon.ico file is well supported by browsers, as well.

Compared to using GIMP, ImageMagick, or ICOEncoder, the resulting file can be

an order of magnitude smaller with an optimised input PNG due to avoiding

re-encoding. For example, with [this](tests/data/favicon.png) input image,

icopng's output is ~30% smaller than GIMP's re-encoded PNG, and ~900% smaller

than traditional bitmap with alpha channel:

| Engine           | Embedded format | Size   |

|------------------|-----------------|--------|

| icopng           | PNG             | 1.2KiB |

| GIMP             | PNG             | 1.7KiB |

| ImageMagick/GIMP | BMP             | 17KiB  |

## Usage

Here's an example of converting a traditional bitmap ico file to a PNG, and

then into a PNG embedded into an ico file with this tool.

    # `convert' is from ImageMagick

    convert favicon-old.ico favicon.png

    # Optional: Shrink the png further

    pngquant --skip-if-larger --strip -f --ext .png favicon.png

    optipng favicon.png

    # Embed into new favicon.ico

    icopng favicon.png favicon.ico

## Why not just use...?

### image::ico::ICOEncoder, or the ico crate

The image and ico crates _do_ export PNGs inside ICO files (nice!), but they

will re-encode them, thus losing all the benefits of things like

optipng/pngquant.

### ImageMagick

Tools like imagemagick can convert from PNG to ico, but they convert to bitmap

with alpha instead of just putting the PNG into an ico container, which means

the files are very large.

### GIMP

GIMP can also export as a PNG inside an ICO by exporting as ICO and selecting

"Compressed (PNG)", however then you don't get the benefits of

pngquant/optipng.