Check out Symmetric Chess, our featured variant for March, 2024.

Enter Your Reply

The Comment You're Replying To
🕸Fergus Duniho wrote on Sat, Apr 30, 2022 09:51 PM UTC in reply to H. G. Muller from 08:55 PM:

But the anti-aliasing causes pixels on the boundary of the black outline and the colored interior to be darker versions of the interior color, by mixing in the black. So simply looking for an exact match of the original color fails to replace the boundary pixels.

I already took that into consideration.

This problem can be solved, though: you could test every pixel for the value of the brightest RGB component, and deduce from that by which factor it is darkened compared to the interior color. And then darken the replacement color by the same factor.

Here's what I'm doing. I collect all the color indexes. For each color index with a non-zero alpha value, I make a determination of whether it belongs to the outline of a piece or to its coloring. I do that with this conditional:

if (color_diff(array($cv["red"], $cv["green"], $cv["blue"]), $original) 
<= color_diff(array($cv["red"], $cv["green"], $cv["blue"]), "black")*2) {

The color_diff function returns the greatest difference between one color's minimum component value and the other one's maximum component value. I added the *2 to prevent some errors, and that part now seems to be working well. If it belongs to its coloring, I recolor each RGB component with this function:

function recolor_component_as ($originalvalue, $currentvalue, $newvalue) {
    if ($originalvalue == 0)
        return $newvalue;
    return min(255,round($newvalue*($currentvalue/$originalvalue)));
}

One remaining problem is that when I try to color the Black pieces white, I get an aquamarine fringe around the Black Motif pieces. In this case, $originalvalue will be 255 for the red component and 0 for the green and blue components, and $newvalue will be 255 for all three components. So, it recolors some edge pixels with positive values for green and blue but with 0 for red, resulting in aquamarine. So, I might have to factor in the value of each component when deciding how to recolor each component. But when I tried that earlier, I got some undesirable results.


Edit Form

Comment on the page Game Courier

Quick Markdown Guide

By default, new comments may be entered as Markdown, simple markup syntax designed to be readable and not look like markup. Comments stored as Markdown will be converted to HTML by Parsedown before displaying them. This follows the Github Flavored Markdown Spec with support for Markdown Extra. For a good overview of Markdown in general, check out the Markdown Guide. Here is a quick comparison of some commonly used Markdown with the rendered result:

Top level header: <H1>

Block quote

Second paragraph in block quote

First Paragraph of response. Italics, bold, and bold italics.

Second Paragraph after blank line. Here is some HTML code mixed in with the Markdown, and here is the same <U>HTML code</U> enclosed by backticks.

Secondary Header: <H2>

  • Unordered list item
  • Second unordered list item
  • New unordered list
    • Nested list item

Third Level header <H3>

  1. An ordered list item.
  2. A second ordered list item with the same number.
  3. A third ordered list item.
Here is some preformatted text.
  This line begins with some indentation.
    This begins with even more indentation.
And this line has no indentation.

Alt text for a graphic image

A definition list
A list of terms, each with one or more definitions following it.
An HTML construct using the tags <DL>, <DT> and <DD>.
A term
Its definition after a colon.
A second definition.
A third definition.
Another term following a blank line
The definition of that term.