Mega Code Archive
Use Color Matrix to gray the image
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using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Drawing.Imaging;
public class Form1 : System.Windows.Forms.Form
{
public Form1()
{
InitializeComponent();
}
private void InitializeComponent()
{
this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
this.ClientSize = new System.Drawing.Size(292, 273);
this.Text = "";
this.Resize += new System.EventHandler(this.Form1_Resize);
this.Paint += new System.Windows.Forms.PaintEventHandler(this.Form1_Paint);
}
static void Main()
{
Application.Run(new Form1());
}
private void Form1_Paint(object sender, System.Windows.Forms.PaintEventArgs e)
{
Graphics g = e.Graphics;
Bitmap bmp = new Bitmap("winter.jpg");
g.FillRectangle(Brushes.White, this.ClientRectangle);
// Create a color matrix
// The value 0.6 in row 4, column 4 specifies the alpha value
float[][] matrixItems = {
new float[] {1, 0, 0, 0, 0},
new float[] {0, 1, 0, 0, 0},
new float[] {0, 0, 1, 0, 0},
new float[] {0, 0, 0, 0.6f, 0},
new float[] {0, 0, 0, 0, 1}};
ColorMatrix colorMatrix = new ColorMatrix(matrixItems);
// Create an ImageAttributes object and set its color matrix
ImageAttributes imageAtt = new ImageAttributes();
imageAtt.SetColorMatrix(
colorMatrix,
ColorMatrixFlag.Default,
ColorAdjustType.Bitmap);
// Now draw the semitransparent bitmap image.
g.DrawImage(bmp, this.ClientRectangle, 0.0f, 0.0f, bmp.Width, bmp.Height,
GraphicsUnit.Pixel, imageAtt);
imageAtt.Dispose();
}
private void Form1_Resize(object sender, System.EventArgs e)
{
Invalidate();
}
}
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