水印+微图图

Imports System.IO
Imports System.Drawing
Imports System.web
Imports System.Web.SessionState
Imports System.Web.UI
Imports System
Public Class uploadimg
    ' filePath是客户文件的完全路径，savepath是保存在服务器的文件夹名，imgname是文件更名后的名字，包括后缀名，size是图片缩微的实际大小
    '这是缩微图形成
    Public Sub uploadSmallImg(ByVal filePath As String, ByVal savepath As String, ByVal ImgName As String, ByVal size As Int16)
        Dim Img As System.Drawing.Image = System.Drawing.Image.FromFile(filePath)
        Dim ImgOutput As Bitmap
        Dim neww, newh As Integer '考虑压缩失真问题，按比例保存
        If Img.Height <= Size And Img.Width <= Size Then '直接保存
            neww = Img.Height
            newh = Img.Width

        ElseIf Img.Width > Img.Height Then '按照width的比例保存
            neww = Size
            newh = Size * Img.Height / Img.Width
        Else '按照高度比例保存
            newh = Size
            neww = Size * Img.Width / Img.Height
        End If
        ImgOutput = New Bitmap(Img, neww, newh) '形成缩微图
        Img.Dispose()
        '图片上传到服务器文件
        Call savetofolder(ImgOutput, savepath + "s" + ImgName.ToLower)

    End Sub
    '保存原图，没有添加别的东西
    ' filePath是文件的完全路径，savepath是保存在服务器的文件夹名，imgname是文件更名后的名字，包括后缀名
    Public Sub uploadbigimg(ByVal filepath As String, ByVal savepath As String, ByVal imgname As String)

        Dim imgoutput As Bitmap = New Bitmap(filepath)
        '图片上传到服务器文件
        Call savetofolder(imgoutput, savepath + imgname.ToLower)
     
    End Sub
    ' 由时间形成的新的文件名称，包括了后缀名称，精确到毫秒的文件名称

    ' 因为jpg的图片最小，都考虑用jpg的格式

    Public Function newfilename() As String
        '精确到毫秒的文件名称,包括了后缀了， 以防上传文件同名
        Dim nowtime As DateTime = DateTime.Now
        Dim changefilename As String = nowtime.ToString("yyyyMMddHHmmss") + nowtime.Millisecond.ToString + ".jpg" '+ ImageExtensionName
        Return (changefilename.ToString)
      
    End Function
    '添加图片水印字符，然后上传
    ' filePath是客户文件的完全路径，savepath是保存在服务器的文件夹名，imgname是文件更名后的名字，包括后缀名，addstr是要填加的水印内容

    Public Sub addwatermark(ByVal filepath As String, ByVal savepath As String, ByVal imgname As String) ', ByVal addstr As String)
        '转换为位图
        Dim bmp As Bitmap = New Bitmap(filepath)
        Dim g As Graphics = Graphics.FromImage(bmp)
        Dim fontsize As Int16
        Dim addstr As String
        '考虑图的大小，定义水印字体的大小
        If bmp.Width < 120 Or bmp.Height < 120 Then
            fontsize = 10
            addstr = "--Cyt--" '图片太小添加--Cyt--
        Else : fontsize = 20
            addstr = "www.Caiyt.com" '图片比较大时添加www.Caiyt.com
        End If
        '定义画笔和字体
        Dim f As Font = New Font("Arial Black", fontsize, FontStyle.Italic)
        Dim b As Brush = New SolidBrush(Color.FromArgb(198, Color.Black)) '透明度100%
        '添加水印，取中间值添加
        g.DrawString(addstr, f, b, bmp.Width / 2, bmp.Height / 2)

        '保存添加了水印的图片，选择保存格式
        Call savetofolder(bmp, savepath + imgname.ToLower)
        g.Dispose()
    End Sub
    '添加水印图片，上传
    Public Sub addwatermarkimg(ByVal filepath As String, ByVal savepath As String, ByVal imgname As String, ByVal watermarkpath As String)
        Dim bmp As Bitmap = New Bitmap(filepath)
        Dim g As Graphics = Graphics.FromImage(bmp)

        '考虑图的大小，定义水印字体的大小
        If bmp.Width < 120 Or bmp.Height < 120 Then
            Dim fontsize As Int16
            Dim addstr As String
            fontsize = 10
            addstr = "--Cyt--" '图片太小添加--Cyt--,不添加图片
            Dim f As Font = New Font("Arial Black", fontsize, FontStyle.Italic)
            Dim b As Brush = New SolidBrush(Color.FromArgb(198, Color.Silver)) '透明度100%
            '添加水印，取中间值添加
            g.DrawString(addstr, f, b, bmp.Width / 2, bmp.Height / 2)
            '图片比较大时添加图片
        Else
            Dim markimg As Bitmap = New Bitmap(watermarkpath)
            'Rectangle(X,Y,width,height)
            '放在图片的左上角
            g.DrawImage(markimg, New Rectangle(10, 10, markimg.Width, markimg.Height), 0, 0, markimg.Width, markimg.Height, GraphicsUnit.Pixel)
        End If
        '定义画笔和字体

        '保存添加了水印的图片，选择保存格式
        Call savetofolder(bmp, savepath + imgname.ToLower)
        g.Dispose()
    End Sub
    Public Sub savetofolder(ByVal bmp As Bitmap, ByVal path As String)
        '按照给定的路径保存，统一按照jpg的格式保存

        '必须要求有上载的文件的格式，要不然不知道服务器是什么
        bmp.Save(path, System.Drawing.Imaging.ImageFormat.Jpeg)
        bmp.Dispose()
    End Sub

End Class