flocon/lib/default.nix

55 lines
1.4 KiB
Nix

let
# convert rrggbb hex to rgba(r, g, b, a)
rgba = lib: color: opacity: let
r = toString (hexToDec lib (builtins.substring 0 2 color));
g = toString (hexToDec lib (builtins.substring 2 2 color));
b = toString (hexToDec lib (builtins.substring 4 2 color));
in "rgba(${r}, ${g}, ${b}, ${opacity})";
hexToDec = lib: v: let
# Map of hex characters to their decimal values
hexToInt = {
"0" = 0;
"1" = 1;
"2" = 2;
"3" = 3;
"4" = 4;
"5" = 5;
"6" = 6;
"7" = 7;
"8" = 8;
"9" = 9;
"a" = 10;
"b" = 11;
"c" = 12;
"d" = 13;
"e" = 14;
"f" = 15;
"A" = 10;
"B" = 11;
"C" = 12;
"D" = 13;
"E" = 14;
"F" = 15;
};
# Remove any leading `#` from the input
cleanHex =
if lib.strings.substring 0 1 v == "#"
then lib.strings.substring 1 (builtins.stringLength v - 1) v
else v;
# Convert the cleaned string into characters
chars = lib.strings.stringToCharacters cleanHex;
in
# Fold over the characters to calculate the decimal value
builtins.foldl' (acc: char: acc * 16 + hexToInt."${char}") 0 chars;
blurImage = pkgs: path:
pkgs.runCommand "${builtins.baseNameOf path}-blurred" {
buildInputs = [pkgs.imagemagick];
}
''
magick ${path} -gaussian-blur 0x12 "$out"
'';
in {
inherit blurImage rgba;
}