PAINT.NET COLOR TO ALPHA UPDATE
PAINT.NET COLOR TO ALPHA FULL
PAINT.NET COLOR TO ALPHA CODE

The code in this repo doesn't use this approach because the next section fixes both this and another problem. Search for 'Merging for Exact Colors Count.' I found a CodeProject article by someone who figured out a way to fix this. You'll end up with 253 colors instead of 256. If you have reduced the octree down to 260 leaf nodes and you're now reducing a node that has 8 children, the color count will be reduced by 7. 4) Exact palette size is not always achievedĪ problem with using the standard Octree quantization algorithm is that the Reduce() method, on a per-node basis, is all or nothing. It is probably possible to improve this, maybe by destroying/trimming the histogram while enumerating it, but I didn't think it was worth pursuing. More memory is required for this approach (building and using a histogram), but it's temporary, and is still quite a bit less than the OctreeNodes (see section 6). | (((color.G & mask) > shift) > shift), where Entry is a struct with a ColorBgr24 and a long for the count. Private static int GetColorIndex(ref Rgba32 color, int level) However, it has what is essentially a precision bug that causes colors to land in the wrong leaf nodes: The MSDN code has a GetColorIndex method whose job is to provide the child node index for a color while navigating down the octree. So, here are the changes I've made to ye ol' MSDN quantization code, in order from simple to crazy: 1) Right Shift Bug

ImageSharp's Quantization code, GitHub.

Median Cut (another algorithm often used for palette generation), Wikipedia.

Octree (data structure employed by this code), Wikipedia.

Optimizing Color Quantization for ASP.NET Images, Microsoft - (v=msdn.10).

If you're new to quantization, here is some recommended reading: I've also optimized performance quite a lot, especially the code that maps from colors to palette entries (see section 7 below). I recently dove in and completely gutted this code, making fixes and improvements, and I thought it would be useful to share this with everyone else. Unfortunately, it has a few bugs and quirks that this repository has fixes for. The code in the article has made its way into a number of projects besides Paint.NET, including ImageSharp ( ). Paint.NET's quantization code is based on an old MSDN article from 2003, Optimizing Color Quantization for ASP.NET Images ( (v=msdn.10)).

PAINT.NET COLOR TO ALPHA FULL

Things like IBitmapSource and IImagingFactory, in particular, are mere shadows of their counterparts in the full Paint.NET source code. As such, don't expect the public API surface to be beautiful or amazing, don't expect lots of attention given to Issues or especially Pull Requests. You can do that (as per the license), but the code in this repository is meant for integration, not linking. Please note that this is NOT intended to be used as a library or 'nuget package' that you drop into your app and use as-is. You can also use the Quantize effect (added in 4.2.16) to do this in-place (the image is still 32-bit BGRA, albeit using only up to 256 unique colors). Since images are always stored in-memory at 32-bit color depth (BGRA), quantization is necessary in order to permit saving images at 8-bit (or less) color depths.

This repository has the image quantization code from Paint.NET, along with the supporting utility and helper classes that are used along the way.

PAINT.NET COLOR TO ALPHA UPDATE

codelab filter to turn color into alpha raw gistfile1.NOTE: This is still pre-first draft! I'll update this to say final draft when it's all finished 🙂 4.3 alpha build 7881 Preview Center Forum from

palettes contain 96 colors and are viewable in the colors window.

Paint.net color to alpha