Crate exoquant [−] [src]
Exoquant is a very high quality image quantization library featuring code for basic color quantization, K-Means palette optimization and remapping and dithering with Floyd-Steinberg and ordered ditherers.
This version of the library is a much improved rewrite of a C library of the same name written back in 2004.
Basic API:
For simple use cases, there is a convenience function that simply takes true color image data + a few options as input and returns the palette and indexed image data as output:
use exoquant::*; let image = testdata::test_image(); let (palette, indexed_data) = convert_to_indexed(&image.pixels, image.width, 256, &optimizer::KMeans, &ditherer::FloydSteinberg::new());
Low-Level API:
The low-level API gives you full control over the quantization workflow. It allows for use-cases like:
- only create a palette and do the remapping in your own custom code
- remap images to an existing palette or one created with a different library
- generating a single palette for multiple input images (or, say, frames of a GIF)
- implement your own custom ditherer (also usable with the basic API)
Using the low-level API to quantize an image looks like this:
use exoquant::*; use exoquant::optimizer::Optimizer; let image = testdata::test_image(); let histogram = image.pixels.iter().cloned().collect(); let colorspace = SimpleColorSpace::default(); let optimizer = optimizer::KMeans; let mut quantizer = Quantizer::new(&histogram, &colorspace); while quantizer.num_colors() < 256 { quantizer.step(); // very optional optimization, !very slow! // you probably only want to do this every N steps, if at all. if quantizer.num_colors() % 64 == 0 { quantizer = quantizer.optimize(&optimizer, 4); } } let palette = quantizer.colors(&colorspace); // this optimization is more useful than the above and a lot less slow let palette = optimizer.optimize_palette(&colorspace, &palette, &histogram, 16); let ditherer = ditherer::FloydSteinberg::new(); let remapper = Remapper::new(&palette, &colorspace, &ditherer); let indexed_data = remapper.remap(&image.pixels, image.width);
Modules
ditherer |
Dithered remapping |
optimizer |
K-Means optimization |
Structs
Color |
A RGBA8 color used for both the input image data and the palette output. |
ColorCount |
A single float color in quantization color space with the number of times it occurs in the input image data. |
ColorMap |
A data structure for fast nearest color lookups in a palette. |
Colorf |
A color with floating point channel components. |
Histogram |
A histogram that counts the number of times each color occurs in the input image data. |
Quantizer |
The main color quantizer state. |
Remapper |
A helper type to very slightly simplify remapping images using a |
SimpleColorSpace |
The default colorspace implementation. |
Traits
ColorSpace |
Defines the colorspaces in which to do quantization and remapping |
Functions
convert_to_indexed |
A convenience function to simply quantize an image with sensible defaults. |
generate_palette |
A convenience function to just generate a palette from a historam with sensible defaults. |
sort_palette |
Sort neighboring colors in the image to be neighbors in the palette as well. |