adds an extra all-255 alpha channel dest == src is legal img_n must be 1 or 3

create the png data from post-deflated data

this function is designed to support animated gifs, although stb_image doesn't support it two back is the image from two frames ago, used for a very s

decode one 64-entry block--

get some unsigned bits

returns 1 if "a*b + add" has no negative terms/factors and doesn't overflow

returns 1 if the product of two ints fits in a signed short, 0 on overflow.

set up the kernels

read 16bit value and convert to 24bit RGB

* write generated template to dir, * returns 1 on success */

if user provided OFFSET value, apply it to color */

calculate the average color of a given pixel range in an image */

convert bin indices to an rgb color */

* blend two colors together based on a blend factor, * bright mode - leave little color accent on white surface */

check Euclidean distance between two colors to ensure diversity */

Calculates the contrast ratio between two colors. * * See WCAG standards: * - [Technique G18](https://www.w3.org/WAI/WCAG21/Techniques/general/G18)

if wallpaper was previously computed, if so, just load it */

Compares every color in the palette against the background and checks their * contrast ratio. If it is too low, increases the contrast by lightening

compare luminance of two RGB colors * returns 1 if a > b * returns -1 if a < b * returns 0 if a == b */

* prints to stderr formatted output and exits with EXIT_FAILURE, * also prints hellwal_usage() */

return array of TEMPLATE structure of files in directory */

Convert HSL to RGB */

free all allocated stuff in IMG */

Load image file using stb, return IMG structure */

ensure that new color is not too similar to existing colors in the palette */

* check in directory for theme with provided name, * if not exist, try to open it as a path */

perform median cut to partition the color space */

cache wallpaper color palette */

part of median algo */

prints current terminal colors

* reads content of all given and found templates paths, * and writes to specified or default output folder. */

make sure that buffer does not * start or ends with space, and * only occurs once between characters */

function to reverse the palette, used when light mode is specified */

Convert RGB to HSL */

run script from given path */

set given arguments */

* overides default terminal color variables from PALETTE * This works thanks to this (and chatgpt): * - https://github.com/dylanaraps/paleta * - ht

build a table that decodes both magnitude and value of small ACs in one go.

decode image to YCbCr format

@OPTIMIZE: store non-zigzagged during the decode passes, and only de-zigzag when dequantizing