How to convert a color image into a negative image in C# using Visual Studio

C# Project

In this project we are learning to convert a color image into negative image.

Requirement

For this project we will need Microsoft Visual Studio

Introduction

Converting a color image into negative is very simple. All we have to do is repeat 3 simple steps for each pixels of the image.

1. Get the RGB value of the pixel.
2. Calculate the new RGB value as shown below.

R = 255 – R
G = 255 – G
B = 255 – B

3. Save the new RGB value in the pixel.

Example:

Consider a color pixel with the following values

A = 255

R = 100

G = 150

B = 200

Where A, R, G and B represents the Alpha, Red, Green and Blue value of the pixel.

Remember! ARGB will have an integer value in the range 0 to 255.

So, to convert the color pixel into negative we will subtract the value of R, G and B from 255.

R = 255 - 100 = 155

G = 255 - 150 = 105

B = 255 - 200 = 55

So, the new ARGB value will be:

A = 255

R = 155

G = 105

B = 55

Note! We don't have to change the alpha value because it only controls the transparency of the pixel.

Form1.cs

``````
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace NegativeImage
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private void Form1_Load(object sender, EventArgs e)
{
Bitmap bmp = new Bitmap("D:\\Image\\Taj.jpg");

pictureBox1.Image = Image.FromFile("D:\\Image\\Taj.jpg");

//get image dimension
int width = bmp.Width;
int height = bmp.Height;

//negative
for (int y = 0; y < height; y++)
{
for (int x = 0; x < width; x++)
{
//get pixel value
Color p = bmp.GetPixel(x, y);

//extract ARGB value from p
int a = p.A;
int r = p.R;
int g = p.G;
int b = p.B;

//find negative value
r = 255 - r;
g = 255 - g;
b = 255 - b;

//set new ARGB value in pixel
bmp.SetPixel(x, y, Color.FromArgb(a, r, g, b));
}
}

pictureBox2.Image = bmp;

//save negative image
bmp.Save("D:\\Image\\Negative.png");
}
}
}
``````

Form1.Designer.cs

``````
namespace NegativeImage
{
partial class Form1
{
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.IContainer components = null;

/// <summary>
/// Clean up any resources being used.
/// </summary>
/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}

#region Windows Form Designer generated code

/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.pictureBox1 = new System.Windows.Forms.PictureBox();
this.pictureBox2 = new System.Windows.Forms.PictureBox();
this.label1 = new System.Windows.Forms.Label();
this.label2 = new System.Windows.Forms.Label();
((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
((System.ComponentModel.ISupportInitialize)(this.pictureBox2)).BeginInit();
this.SuspendLayout();
//
// pictureBox1
//
this.pictureBox1.Location = new System.Drawing.Point(12, 12);
this.pictureBox1.Name = "pictureBox1";
this.pictureBox1.Size = new System.Drawing.Size(297, 343);
this.pictureBox1.SizeMode = System.Windows.Forms.PictureBoxSizeMode.Zoom;
this.pictureBox1.TabIndex = 0;
this.pictureBox1.TabStop = false;
//
// pictureBox2
//
this.pictureBox2.Location = new System.Drawing.Point(329, 12);
this.pictureBox2.Name = "pictureBox2";
this.pictureBox2.Size = new System.Drawing.Size(297, 343);
this.pictureBox2.SizeMode = System.Windows.Forms.PictureBoxSizeMode.Zoom;
this.pictureBox2.TabIndex = 1;
this.pictureBox2.TabStop = false;
//
// label1
//
this.label1.AutoSize = true;
this.label1.Font = new System.Drawing.Font("Microsoft Sans Serif", 14.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.label1.Location = new System.Drawing.Point(122, 368);
this.label1.Name = "label1";
this.label1.Size = new System.Drawing.Size(75, 24);
this.label1.TabIndex = 2;
this.label1.Text = "Original";
//
// label2
//
this.label2.AutoSize = true;
this.label2.Font = new System.Drawing.Font("Microsoft Sans Serif", 14.25F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
this.label2.Location = new System.Drawing.Point(431, 368);
this.label2.Name = "label2";
this.label2.Size = new System.Drawing.Size(84, 24);
this.label2.TabIndex = 3;
this.label2.Text = "Negative";
//
// Form1
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(638, 410);
this.Name = "Form1";
this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
this.Text = "Negative";
((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
((System.ComponentModel.ISupportInitialize)(this.pictureBox2)).EndInit();
this.ResumeLayout(false);
this.PerformLayout();

}

#endregion

private System.Windows.Forms.PictureBox pictureBox1;
private System.Windows.Forms.PictureBox pictureBox2;
private System.Windows.Forms.Label label1;
private System.Windows.Forms.Label label2;
}
}
``````