VB.NET写的一个图片处理组件,用于在ASP中处理图片,缩放图片,成比例缩放,有固定比例背景的缩放,加半透明LOGO小图标等功能.

dImage.vb


Imports System
Imports System.Drawing
<ComClass(dImage.ClassId, dImage.InterfaceId, dImage.EventsId)> _
Public Class dImage

#Region "COM GUIDs"
' 这些 GUID 提供该类的 COM 标识及其 COM 接口。
' 如果您更改它们，现有的客户端将再也无法
' 访问该类。
Public Const ClassId As String = "29641F37-8FA4-4ED9-9118-9DA8EFA306B9"
Public Const InterfaceId As String = "06E4B037-2461-4F83-96BE-2A5D1CAAB0CE"
Public Const EventsId As String = "802EBB14-2D4D-416E-BA26-E8ADCD480E26"
#End Region

' 可创建的 COM 类必须具有不带参数的
' Public Sub New()，否则，该类将不会注册到 COM 注册表中，
' 而且不能通过 CreateObject
' 来创建。
Private myImage As Drawing.Bitmap
Private syimg As Drawing.Bitmap
Private syok As Boolean = False
Private myok As Boolean = False
Public Sub New()
MyBase.New()
End Sub
Public WriteOnly Property bigImage() As String
Set(ByVal Value As String)
Try
myImage = New Bitmap(Value)
myok = True
Catch e As IO.IOException
myok = False
End Try
End Set
End Property
Public WriteOnly Property LogoImage() As String
Set(ByVal Value As String)
Try
syimg = New Bitmap(Value)
syok = True
Catch ex As Exception
syok = False
End Try
End Set
End Property
Public Function SaveAs(ByVal ToFile As String, ByVal nWidth As Integer, ByVal nHeight As Integer, ByVal nLogo As Boolean) As String
Try
If myok = False Then
Return "err0"
Exit Function
End If
Dim newbmp As Bitmap = New Bitmap(nWidth, nHeight, Imaging.PixelFormat.Format16bppArgb1555)
Dim iX As Integer
Dim iY As Integer
Dim xMax As Integer
Dim yMax As Integer
For iX = 0 To nWidth - 1
For iY = 0 To nHeight - 1
newbmp.SetPixel(iX, iY, Color.White)
Next
Next
If nWidth < myImage.Width Or nHeight < myImage.Height Then
If myImage.Width / myImage.Height > nWidth / nHeight Then
xMax = nWidth
yMax = myImage.Height * nWidth \ myImage.Width
Else
yMax = nHeight
xMax = myImage.Width * nHeight \ myImage.Height
End If
Else
xMax = myImage.Width
yMax = myImage.Height
End If
Dim tembmp As Bitmap = New Bitmap(myImage, xMax, yMax)
xMax = (newbmp.Width - tembmp.Width) \ 2
yMax = (newbmp.Height - tembmp.Height) \ 2
For iX = 0 To tembmp.Width - 1
For iY = 0 To tembmp.Height - 1
newbmp.SetPixel(iX + xMax, iY + yMax, tembmp.GetPixel(iX, iY))
Next
Next
If syok And nLogo Then
Dim cob As Color
Dim coc As Color
xMax = newbmp.Width - syimg.Width - 4
yMax = newbmp.Height - syimg.Height - 3
For iX = 0 To syimg.Width - 1
For iY = 0 To syimg.Height - 1
cob = syimg.GetPixel(iX, iY)
coc = newbmp.GetPixel(iX + xMax, iY + yMax)
newbmp.SetPixel(iX + xMax, iY + yMax, getnewco(cob, coc))