Image Processing in C#

Question

What I want to do is as in the following.
1. Load image from jpg/bmp file and display on the PictureBox or any other image control keeping image ratio
2. Perform Image Processing, for example, zoom in/zoom out, change brightness/contrast
Does any .NET class supports this? or should I implement it with my own code?
If I should make my own code, is the PictureBox optimal control?

Answer 1

Hmm.  If you don't know where to start then maybe the do-it-yourself approach is not going to work for you.
Here's code for a simple control you can use to display an image with a transform matrix and a color matrix.
using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Windows.Forms;
class ImageControl : Control
public Image Image
get
return image;
set
image = value;
Invalidate();
private Image image;
public Matrix Transform
get
return transform;
set
transform = value;
Invalidate();
private Matrix transform = new Matrix();
public ColorMatrix ColorMatrix
get
return colorMatrix;
set
colorMatrix = value;
Invalidate();
private ColorMatrix colorMatrix = new ColorMatrix();
protected override void OnResize( EventArgs e )
Invalidate();
public ImageControl()
this.DoubleBuffered = true;
protected override void OnPaint( PaintEventArgs e )
if( image == null ) return;
e.Graphics.ResetTransform();
e.Graphics.Transform = transform;
ImageAttributes imageAttributes = new ImageAttributes();
imageAttributes.SetColorMatrix(
colorMatrix,
ColorMatrixFlag.Default,
ColorAdjustType.Bitmap );
e.Graphics.DrawImage(
image,
new Rectangle( 0, 0, image.Width, image.Height),
0, 0, image.Width, image.Height,
GraphicsUnit.Pixel,
imageAttributes );
You can set a transformation matrix to do the zooming, panning, etc.  And set a color matrix to do simple contrast brightness adjustments.
// Some example matrices
float[][] colorMatrixElements = {
new float[] {2, 0, 0, 0, 0}, // red scaling factor of 2
new float[] {0, 1, 0, 0, 0}, // green scaling factor of 1
new float[] {0, 0, 1, 0, 0}, // blue scaling factor of 1
new float[] {0, 0, 0, 1, 0}, // alpha scaling factor of 1
new float[] {.2f, .2f, .2f, 0, 1}}; // three translations of 0.2
ColorMatrix colorMatrix = new ColorMatrix( colorMatrixElements );
Matrix transform = new Matrix(
1.5f, 0.0f, // horizontal scale of 1.5, 0
0.0f, 0.5f, // 0, vertical scale of 0.5
20.0f, 40.0f, // horizontal offset of 20, vertical offset of 40
Contrast and brightness are performed together in a single matrix.  Contrast scales the output range and brightness is the offset.
Zooming is just scale and offset.