iconwriter 1.4.0

A simple solution for encoding common icon file formats.
Documentation

IconWriter

Crate API Minimum rustc version

A simple solution for encoding common icon file formats, such as .ico and .icns. This crate is mostly a wrapper for other libraries, unifying existing APIs into a single, cohesive interface.

Overview

An icon stores a collection of small images of different sizes. Individual images within the icon are bound to a source image, which is rescaled to fit a particular size using a resampling filter.

Resampling filters are represented by functions that take a source image and a size and return a rescaled raw RGBA buffer. This allows the users of this crate to provide their custom resampling filters. Common resampling filters are provided by the resample module.

Examples

General Usage

use iconwriter::*;
 
fn example() -> iconwriter::Result<()> {
    let icon = Ico::new();
    match SourceImage::from_path("image.svg") {
        Some(img) => icon.add_entry(resample::linear, &img, 32),
        None      => Ok(())
    }
}

Writing to a File

use iconwriter::*;
use std::{io, fs::File};
 
fn example() -> io::Result<()> {
    let icon = PngSequence::new();

    /* Process the icon */

    let file = File::create("ou.icns")?;
    icon.write(file)
}

Limitations

There are two main limitations in this crate: both ICNS and SVG are not fully supported. Due to the use of external dependencies, the author of this crate is not able to fully support the formal specifications of those two file formats.

Supported Image Formats

Format Supported?
PNG All supported color types
JPEG Baseline and progressive
GIF Yes
BMP Yes
ICO Yes
TIFF Baseline(no fax support), LZW, PackBits
WEBP Lossy(Luma channel only)
PNM PBM, PGM, PPM, standard PAM
SVG Limited(flat filled shapes only)

ICNS Support

However, the coverage provided by these external dependencies should be more than enought for most use cases.

Icon Writer uses the icns crate for generating .icns files. The supported icon types are specified by the creators of such crate as follows:

OSType Description Supported?
ICON 32×32 1-bit icon No
ICN# 32×32 1-bit icon with 1-bit mask No
icm# 16×12 1-bit icon with 1-bit mask No
icm4 16×12 4-bit icon No
icm8 16×12 8-bit icon No
ics# 16×16 1-bit mask No
ics4 16×16 4-bit icon No
ics8 16x16 8-bit icon No
is32 16×16 24-bit icon Yes
s8mk 16x16 8-bit mask Yes
icl4 32×32 4-bit icon No
icl8 32×32 8-bit icon No
il32 32x32 24-bit icon Yes
l8mk 32×32 8-bit mask Yes
ich# 48×48 1-bit mask No
ich4 48×48 4-bit icon No
ich8 48×48 8-bit icon No
ih32 48×48 24-bit icon Yes
h8mk 48×48 8-bit mask Yes
it32 128×128 24-bit icon Yes
t8mk 128×128 8-bit mask Yes
icp4 16x16 32-bit PNG/JP2 icon PNG only
icp5 32x32 32-bit PNG/JP2 icon PNG only
icp6 64x64 32-bit PNG/JP2 icon PNG only
ic07 128x128 32-bit PNG/JP2 icon PNG only
ic08 256×256 32-bit PNG/JP2 icon PNG only
ic09 512×512 32-bit PNG/JP2 icon PNG only
ic10 512x512@2x "retina" 32-bit PNG/JP2 icon PNG only
ic11 16x16@2x "retina" 32-bit PNG/JP2 icon PNG only
ic12 32x32@2x "retina" 32-bit PNG/JP2 icon PNG only
ic13 128x128@2x "retina" 32-bit PNG/JP2 icon PNG only
ic14 256x256@2x "retina" 32-bit PNG/JP2 icon PNG only

SVG Support

IconWriter uses the nsvg crate to rasterize .svg files. According to the authors of the crate:

Like NanoSVG, the rasterizer only renders flat filled shapes. It is not particularly fast or accurate, but it is a simple way to bake vector graphics into textures.

The author of iconwriter is inclined to search for alternatives to nsvg if inquired to. Help would be appreciated.