XeNote/.yarn/unplugged/sharp-npm-0.26.2-a42331601c/node_modules/sharp/lib/colour.js
canburaks b23e3ff508 ...
2021-05-17 04:16:19 +03:00

124 lines
3.3 KiB
JavaScript

'use strict';
const color = require('color');
const is = require('./is');
/**
* Colourspaces.
* @private
*/
const colourspace = {
multiband: 'multiband',
'b-w': 'b-w',
bw: 'b-w',
cmyk: 'cmyk',
srgb: 'srgb'
};
/**
* Tint the image using the provided chroma while preserving the image luminance.
* An alpha channel may be present and will be unchanged by the operation.
*
* @param {string|Object} rgb - parsed by the [color](https://www.npmjs.org/package/color) module to extract chroma values.
* @returns {Sharp}
* @throws {Error} Invalid parameter
*/
function tint (rgb) {
const colour = color(rgb);
this.options.tintA = colour.a();
this.options.tintB = colour.b();
return this;
}
/**
* Convert to 8-bit greyscale; 256 shades of grey.
* This is a linear operation. If the input image is in a non-linear colour space such as sRGB, use `gamma()` with `greyscale()` for the best results.
* By default the output image will be web-friendly sRGB and contain three (identical) color channels.
* This may be overridden by other sharp operations such as `toColourspace('b-w')`,
* which will produce an output image containing one color channel.
* An alpha channel may be present, and will be unchanged by the operation.
* @param {Boolean} [greyscale=true]
* @returns {Sharp}
*/
function greyscale (greyscale) {
this.options.greyscale = is.bool(greyscale) ? greyscale : true;
return this;
}
/**
* Alternative spelling of `greyscale`.
* @param {Boolean} [grayscale=true]
* @returns {Sharp}
*/
function grayscale (grayscale) {
return this.greyscale(grayscale);
}
/**
* Set the output colourspace.
* By default output image will be web-friendly sRGB, with additional channels interpreted as alpha channels.
* @param {string} [colourspace] - output colourspace e.g. `srgb`, `rgb`, `cmyk`, `lab`, `b-w` [...](https://github.com/libvips/libvips/blob/master/libvips/iofuncs/enumtypes.c#L568)
* @returns {Sharp}
* @throws {Error} Invalid parameters
*/
function toColourspace (colourspace) {
if (!is.string(colourspace)) {
throw is.invalidParameterError('colourspace', 'string', colourspace);
}
this.options.colourspace = colourspace;
return this;
}
/**
* Alternative spelling of `toColourspace`.
* @param {string} [colorspace] - output colorspace.
* @returns {Sharp}
* @throws {Error} Invalid parameters
*/
function toColorspace (colorspace) {
return this.toColourspace(colorspace);
}
/**
* Update a colour attribute of the this.options Object.
* @private
* @param {string} key
* @param {string|Object} value
* @throws {Error} Invalid value
*/
function _setBackgroundColourOption (key, value) {
if (is.defined(value)) {
if (is.object(value) || is.string(value)) {
const colour = color(value);
this.options[key] = [
colour.red(),
colour.green(),
colour.blue(),
Math.round(colour.alpha() * 255)
];
} else {
throw is.invalidParameterError('background', 'object or string', value);
}
}
}
/**
* Decorate the Sharp prototype with colour-related functions.
* @private
*/
module.exports = function (Sharp) {
Object.assign(Sharp.prototype, {
// Public
tint,
greyscale,
grayscale,
toColourspace,
toColorspace,
// Private
_setBackgroundColourOption
});
// Class attributes
Sharp.colourspace = colourspace;
Sharp.colorspace = colourspace;
};