Node.js GM negative() Function

The negative() function is an inbuilt function in the GraphicsMagick library which is used to replace every pixel with its complementary color. The function returns the true value on success.
Syntax:

negative()

Parameters: This function does not accept any parameter.
Return Value: This function returns the GraphicsMagick object.
Example 1:

javascript

// Include gm library
var gm = require('gm');

// Import the image
gm('1.png')

// Invoke Negative function
.negative()

// Process and Write the image
.write("negative1.png", function (err) {
  if (!err) console.log('done');
});

Output:

Example 2:

javascript

// Include gm library
var gm = require('gm');

// Import the image
gm(600, 300, 'white')

// Set the color for the stroke
.stroke("green", 3)

// Set the font
.font("Helvetica.ttf", 60)

// Call to drawText Function
.drawText(100, 280, "GeeksforGeeks!")

// Invoke borderColor() function
// and set border color to green
.borderColor("Green")

// Invoke border function
.border(62, 32)

// Invoke negative function
.negative()

// Process and write the image
.write("negative2.png", function (err) {
  if (!err) console.log('done');
});

Output:

Example 3:

javascript

// Include gm library
var gm = require('gm');
gm('1.png')

// Include another image
.composite('operator-noise-multiplicative1.png')

// Shift the image using geometry function
.geometry('+10+50')

// Invoke compose function with 'plus' Argument
.compose('plus')

// Include another image
.composite('randomThreshold1.png')

// Shift the image using geometry function
.geometry('+20+70')

// Invoke compose function with 'plus' argument
.compose('plus')

// Invoke negative function
.negative()

// Process and write the image
.write('negative3.png', function(err) {
    if(!err) console.log("Written composite image.");
});

Output:

Reference:

• http://www.graphicsmagick.org/GraphicsMagick.html#details-negate
• https://www.npmjs.com/package/gm