彩色圖片轉為黑白圖片
Introduction
本篇的主旨在於介紹如何把圖片轉為黑白照片。欲把彩色圖片轉為黑白圖片，我們可以把圖片上的每個像素都設為灰階值。灰階值的取得可套用下面公式。
灰階值 = (R+G+B)/3
範例程式
VB.NET
'|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||'Author: Larry Nung'Date: 2009/6/2'File: 'Memo: '|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||''' <summary>''' ''' </summary>''' <remarks></remarks>Public Class Form1
'***************************************************************************
'Author: Larry Nung
'Date: 2009/6/2
'Purpose:
'Memo:
'***************************************************************************
''' <summary>
''' Handles the Click event of the Button1 control.
''' </summary>
''' <param name="sender">The source of the event.</param>
''' <param name="e">The <see cref="System.EventArgs" /> instance containing the event data.</param>
''' <remarks></remarks>
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
If OpenFileDialog1.ShowDialog = Windows.Forms.DialogResult.OK Then
Me.PictureBox1.Image = GetGrayBitmap(OpenFileDialog1.FileName)
End If
End Sub
'***************************************************************************
'Author: Larry Nung
'Date: 2009/6/2
'Purpose:
'Memo:
'***************************************************************************
''' <summary>
''' Gets the gray image.
''' </summary>
''' <param name="file">The file.</param>
''' <returns></returns>
''' <remarks></remarks>
Private Function GetGrayBitmap(ByVal file As String) As Bitmap
Dim bmp As Bitmap = New Bitmap(file)
For x As Integer = 0 To bmp.Width - 1
For y As Integer = 0 To bmp.Height - 1
Dim color As Color = bmp.GetPixel(x, y)
Dim gray As Integer = (CInt(color.R) + CInt(color.G) + CInt(color.B)) \ 3
bmp.SetPixel(x, y, color.FromArgb(gray, gray, gray))
Next
Next
Return bmp
End FunctionEnd Class
C#
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 WindowsFormsApplication1
{
//|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
//Author: Larry Nung
//Date: 2009/6/2
//File:
//Memo:
//|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
/// <summary>
///
/// </summary>
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
//***************************************************************************
//Author: Larry Nung
//Date: 2009/6/2
//Purpose:
//Memo:
//***************************************************************************
/// <summary>
/// Handles the Click event of the button1 control.
/// </summary>
/// <param name="sender">The source of the event.</param>
/// <param name="e">The <see cref="System.EventArgs"/> instance containing the event data.</param>
private void button1_Click(object sender, EventArgs e)
{
if (openFileDialog1.ShowDialog() == DialogResult.OK)
{
pictureBox1.Image = GetGrayBitmap(openFileDialog1.FileName);
}
}
//***************************************************************************
//Author: Larry Nung
//Date: 2009/6/2
//Purpose:
//Memo:
//***************************************************************************
/// <summary>
/// Gets the gray bitmap.
/// </summary>
/// <param name="file">The file.</param>
/// <returns></returns>
private Bitmap GetGrayBitmap(string file)
{
Bitmap bmp = new Bitmap(file);
for (int x=0; x < bmp.Width; x++)
{
for (int y=0; y < bmp.Height; y++)
{
Color color = bmp.GetPixel(x, y);
int gray = (color.R + color.G + color.B) / 3;
bmp.SetPixel(x, y, Color.FromArgb(gray, gray, gray));
}
}
return bmp;
}
}}
執行結果：
