replace-color
v2.3.0
Published
Replace color with another one pixel by pixel.
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Replace Color
replace-color
replaces color with another one pixel by pixel. Especially this will be helpful if you want to remove the watermarks from the images. This package is built on top of Jimp.
Install
npm install --save replace-color
Basic usage
replace-color
supports both Node.js error-first callbacks and promises. The package returns a Jimp's instance which you can use to execute some other image manipulations methods or save it with Jimp's write
method.
Node.js error-first callback example
const replaceColor = require('replace-color')
replaceColor({
image: './input.jpg',
colors: {
type: 'hex',
targetColor: '#FF0000',
replaceColor: '#FFFFFF'
}
}, (err, jimpObject) => {
if (err) return console.log(err)
jimpObject.write('./output.jpg', (err) => {
if (err) return console.log(err)
})
})
Promise example
const replaceColor = require('replace-color')
replaceColor({
image: './input.jpg',
colors: {
type: 'hex',
targetColor: '#FF0000',
replaceColor: '#FFFFFF'
}
})
.then((jimpObject) => {
jimpObject.write('./output.jpg', (err) => {
if (err) return console.log(err)
})
})
.catch((err) => {
console.log(err)
})
API
replaceColor(options, [callback])
options
Object (required) - the options.image
Buffer | Object | String (required) - an image being processed. It can be a buffer, Jimp's instance, a path to an image on your host machine or a URL address to an image on the internet. Please, take a look at the tests to understand all these options.colors
Object (required) - the colors.type
String (required) - atargetColor
andreplaceColor
type. Supported values arehex
andrgb
.targetColor
String | Array (required) - a color you want to replace. A 7-symbol string in case ofhex
type (e.g.#000000
,#FFFFFF
). An array of3
integers from0
to255
in case ofrgb
type (e.g.[0, 0, 0]
,[255, 255, 255]
).replaceColor
String | Array (required) - a new color which will be used instead of atargetColor
color. A 7-symbol string in case ofhex
type (e.g.#000000
,#FFFFFF
). An array of3
integers from0
to255
in case ofrgb
type (e.g.[0, 0, 0]
,[255, 255, 255]
). You can also define a transparent channel for areplaceColor
color. To achieve this, you can use a 9-symbol string in case ofhex
type (e.g.#00000000
,#FFFFFFFF
). Based on this Stack Overflow answer, an alpha channel is controlled by the first pair of digits in a hex code (e.g.,00
means fully transparent,7F
means 50%,FF
means fully opaque). Also, you can use an array of4
integers in case ofrgb
type. The first3
integers must be from0
to255
and the last one must be from0
to1
(e.g.,0
means fully transparent,0.5
means 50%,1
means fully opaque).
formula
String (optional) - one of the three formulas to calculate the color difference. Supported values areE76
,E94
andE00
. The default value isE00
(the best algorithm).deltaE
Number (optional) - adeltaE
value which corresponds to a JND. The default value is2.3
. Please, read more aboutdeltaE
here. Generaly speaking, if the processed by thereplace-color
package image still has the watermarks, you should increase thedeltaE
value.
callback
Function (optional) - a Node.js error-first callback.
Examples
Remove a watermark
Let's try to remove a watermark from this picture.
const replaceColor = require('replace-color')
replaceColor({
image: 'https://i.imgur.com/XqNTuzp.jpg',
colors: {
type: 'hex',
targetColor: '#FFB3B7',
replaceColor: '#FFFFFF'
},
deltaE: 20
})
.then((jimpObject) => {
jimpObject.write('./output.jpg', (err) => {
if (err) return console.log(err)
})
})
.catch((err) => {
console.log(err)
})
Result
Change a background color from a green to a blue one
Let's try to change a background color for this picture.
const replaceColor = require('replace-color')
replaceColor({
image: 'https://i.imgur.com/aCxZpaq.png',
colors: {
type: 'hex',
targetColor: '#66AE74',
replaceColor: '#63A4FF'
},
deltaE: 10
})
.then((jimpObject) => {
jimpObject.write('./output.png', (err) => {
if (err) return console.log(err)
})
})
.catch((err) => {
console.log(err)
})
Result
Change a background color from a green to a transparent one (using hex
type)
Let's try to change a background color for this picture.
const replaceColor = require('replace-color')
replaceColor({
image: 'https://i.imgur.com/aCxZpaq.png',
colors: {
type: 'hex',
targetColor: '#66AE74',
replaceColor: '#00000000'
},
deltaE: 10
})
.then((jimpObject) => {
jimpObject.write('./output.png', (err) => {
if (err) return console.log(err)
})
})
.catch((err) => {
console.log(err)
})
Result
Change a background color from a green to a 50% transparent green (using rgb
type)
Let's try to change a background color for this picture.
const replaceColor = require('replace-color')
replaceColor({
image: 'https://i.imgur.com/aCxZpaq.png',
colors: {
type: 'rgb',
targetColor: [102, 174, 116],
replaceColor: [102, 174, 116, 0.5]
},
deltaE: 10
})
.then((jimpObject) => {
jimpObject.write('./output.png', (err) => {
if (err) return console.log(err)
})
})
.catch((err) => {
console.log(err)
})
Result
Error handling
To indicate the replace-color
's errors you should use the err instanceof replaceColor.ReplaceColorError
class.
replaceColor({}, (err, jimpObject) => {
if (err instanceof replaceColor.ReplaceColorError) {
// A replace-color's error occurred.
} else if (err) {
// An unknown error occurred.
}
// Everything went fine.
})
A replace-color
's error
instance has the code
and field
properties. For now, the package has two codes: PARAMETER_INVALID
and PARAMETER_REQUIRED
. The field
property shows which exact property was not passed or is invalid using the glob notation (e.g. options.colors.type
). Please, take a look at the tests to see all the possible cases.