如何用vb编程将彩色图像转换为黑白

我昨天刚用过，效果很好，速度也快

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（代码在下面地址的7楼）

一个用API来完成的例子, 速度比GetPixel快n倍

Option Explicit

'图像处理的一个例子

'Powered by Jadeluo , 2004/02/21

'EMail: Jadeluo@sina.com

Private Type BITMAP

bmType As Long

bmWidth As Long

bmHeight As Long

bmWidthBytes As Long

bmPlanes As Integer

bmBitsPixel As Integer

bmBits As Long

End Type

Private Declare Function GetObject Lib "gdi32" Alias "GetObjectA" (ByVal hObject As Long, ByVal nCount As Long, lpObject As Any) As Long

Private Declare Function GetBitmapBits Lib "gdi32" (ByVal hBitmap As Long, ByVal dwCount As Long, lpBits As Any) As Long

Private Declare Function SetBitmapBits Lib "gdi32" (ByVal hBitmap As Long, ByVal dwCount As Long, lpBits As Any) As Long

Private Sub Form_Load()

picShow.BorderStyle = vbBSNone

picShow.Move 0, 0

End Sub

Private Sub cmdLoad_Click()

On Error Resume Next

With CommonDialog1

.Filter = "Picture(*.BMP;*.JPG;*.GIF;*.ICO)|*.BMP;*.JPG;*.GIF;*.ICO|All Files(*.*)|*.*"

.CancelError = True

.ShowOpen

If Err.Number = 0 Then

picShow.AutoSize = True

picShow.Picture = LoadPicture(.FileName)

End If

End With

On Error GoTo 0

End Sub

Private Sub cmdGray_Click()

Dim PicBits() As Byte, PicInfo As BITMAP, BytesPerPixel As Long

Dim R As Byte, G As Byte, B As Byte, Gray As Byte, i As Long

With picShow

.AutoRedraw = True

GetObject .Image, Len(PicInfo), PicInfo

BytesPerPixel = PicInfo.bmBitsPixel \ 8

ReDim PicBits(1 To PicInfo.bmWidth * PicInfo.bmHeight * BytesPerPixel)

GetBitmapBits .Image, UBound(PicBits), PicBits(1)

For i = 0 To UBound(PicBits) \ BytesPerPixel - 1

B = PicBits(i * BytesPerPixel + 1)

G = PicBits(i * BytesPerPixel + 2)

R = PicBits(i * BytesPerPixel + 3)

Gray = R * 0.39 + G * 0.5 + B * 0.11

'下面这一句是将灰度值换算成二值

' If Gray 127 Then Gray = 255 Else Gray = 0

PicBits(i * BytesPerPixel + 1) = Gray

PicBits(i * BytesPerPixel + 2) = Gray

PicBits(i * BytesPerPixel + 3) = Gray

Next i

SetBitmapBits .Image, UBound(PicBits), PicBits(1)

.Refresh

End With

End Sub

vb.net怎么使图像灰度化再输出

在web上可以使用HTML5的特效实现。

在windows forms里面可以直接修改设置图片的属性。

Try

' 图片位置初始化一个image1

Dim image1 As New Bitmap(

"C:\Documents and Settings\All Users\Documents\My Music\music.bmp",

True)

Dim x, y As Integer

' Loop through the images pixels to reset color.

For x = 0 To image1.Width - 1

For y = 0 To image1.Height - 1

Dim pixelColor As Color = image1.GetPixel(x, y)

Dim newColor As Color =

Color.FromArgb(pixelColor.R, 0, 0)

image1.SetPixel(x, y, newColor)

Next

Next

' Set the PictureBox to display the image.

PictureBox1.Image = image1

' Display the pixel format in Label1.

Label1.Text = "Pixel format: " + image1.PixelFormat.ToString()

Catch ex As ArgumentException

MessageBox.Show("There was an error." _

"Check the path to the image file.")

End Try

vb.net 打印问题

可以将打印机默认打印设置改为黑白打印，如果打印对象是RGB配色，打印机驱动转换为CMYK颜色时，黑色都是由彩色墨水组成的

2.可以试一下图片从一个标准灰度图片格式化而来，这样图片自身只有黑白色，也许可以

VB.net 旋转图像时，如何指定填充色

绘制线条采用Draw开头的方法，颜色参数用Pen类；

绘制有填充色的封闭图形采用Fill开头的方法，颜色参数用Brush类；

例如：

'绘制一个实心圆，该圆在：直线x=200，y=200，x=200+100，y=200+100所划矩形区域内

Me.CreateGraphics.FillEllipse(New SolidBrush(Color.Orange), 200, 200, 100, 100)

'绘制一个空心圆，该圆在：直线x=200，y=200，x=200+100，y=200+100所划矩形区域内

Me.CreateGraphics.DrawEllipse(New Pen(Color.Black), 200, 200, 100, 100)

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