<%@ Page Language="VB" %>
<%@ Import Namespace="System" %>
<%@ Import Namespace="System.IO" %>
<%@ Import Namespace="System.Web" %>
<%@ Import Namespace="System.Drawing" %>

<script runat="server">
    'Copyright (C) 2007 Daniele Iunco

    'This program is free software; you can redistribute it and/or modify
    'it under the terms of the GNU General Public License as published by
    'the Free Software Foundation; either version 2 of the License, or
    '(at your option) any later version.

    'This program is distributed in the hope that it will be useful,
    'but WITHOUT ANY WARRANTY; without even the implied warranty of
    'MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    'GNU General Public License for more details.

    'You should have received a copy of the GNU General Public License along
    'with this program; if not, write to the Free Software Foundation, Inc.,
    '51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

    'resizetool.aspx v1.0
    'Author: Daniele Iunco
    'Date: 9th May 2007

    'Limite massimo per l'altezza in pixel
    Private Const MaxHeightSafe As Integer = 400

    'Limite massimo per la larghezza in pixel
    Private Const MaxWidthSafe As Integer = 400

    'Percorso dell'immagine su cui reindirizzare le richieste non valide
    Private Const ErrorImagePath As String = "/error.jpg"

    'Percorso in cui salvare le copie delle immagini, il percorso indicato deve avere i permessi in scrittura
    Private Const ImageCachePath As String = "/public/tempfiles"

    'Salva su disco una copia riutilizzabile delle thumbnails create
    Private Const UseCache As Boolean = True
    
    'Di seguito sono riportati i valori predefiniti che verranno utilizzati quando non vengono specificati parametri
    Private Const DefaultHeight As Integer = 100
    Private Const DefaultWidth As Integer = 100
    Private Const DefaultResizeMode As ResizeMode = ResizeMode.AutoResize

    Private Enum ResizeMode
        AutoResize = 0
        ManualResize = 1
    End Enum

    Private ReadOnly Property Mode() As ResizeMode
        Get
            Dim myReqMode As String = Request("mode")
            If myReqMode Is Nothing OrElse Not IsNumeric(myReqMode) Then Return DefaultResizeMode
            If CInt(myReqMode) = 0 Then Return ResizeMode.AutoResize Else Return ResizeMode.ManualResize
        End Get
    End Property

    Private ReadOnly Property MaxHeight() As Integer
        Get
            Dim myValue As String = Request("height")
            If myValue Is Nothing OrElse Not IsNumeric(myValue) Then Return DefaultHeight
            Dim myIntValue As Integer = CInt(myValue)
            If myIntValue < MaxHeightSafe Then
                Return myIntValue
            Else
                Return MaxHeightSafe
            End If
        End Get
    End Property

    Private ReadOnly Property MaxWidth() As Integer
        Get
            Dim myValue As String = Request("width")
            If myValue Is Nothing OrElse Not IsNumeric(myValue) Then Return DefaultWidth
            Dim myIntValue As Integer = CInt(myValue)
            If myIntValue < MaxWidthSafe Then
                Return myIntValue
            Else
                Return MaxWidthSafe
            End If
        End Get
    End Property

    Private _ImagePath As String
    Private ReadOnly Property ImagePath() As String
        Get
            If Not _ImagePath Is Nothing Then Return _ImagePath
            Dim sRequestPath As String = Request.QueryString("path")

            If sRequestPath Is Nothing Then Return Nothing

            'Rimuovo le doppie / e i doppi . con le espressioni regolari
            sRequestPath = Regex.Replace(sRequestPath, "\/{2,}", "/")
            sRequestPath = Regex.Replace(sRequestPath, "\.{2,}", ".")

            If sRequestPath.Substring(0, 1) = "/" Then sRequestPath = sRequestPath.Substring(1)
            _ImagePath = sRequestPath

            Return _ImagePath
        End Get
    End Property

    Sub Page_Load(ByVal Sender As Object, ByVal e As System.EventArgs)
        Dim LocalImageFilePath As String
        Dim LocalThumbnailCacheFilePath As String

        LocalImageFilePath = Server.MapPath("/" & ImagePath)
        If Not File.Exists(LocalImageFilePath) Then
            Response.Redirect(ErrorImagePath)
            Exit Sub
        End If

        Dim TempFilePath As String = Server.MapPath(ImageCachePath)
        LocalThumbnailCacheFilePath = Path.Combine(TempFilePath, ImagePath.Replace("/", "_")) & "_" & Int(Mode) & "_" & Int(MaxWidth) & "_" & Int(MaxWidth) & ".thumb"

        Dim mySourceFile As New System.IO.FileInfo(LocalImageFilePath)

        If UseCache Then
            If File.Exists(LocalThumbnailCacheFilePath) Then
                Dim myDestFile As System.IO.FileInfo
                myDestFile = New System.IO.FileInfo(LocalThumbnailCacheFilePath)
                'Se il file della thumbnail è stato modificato dopo il file sorgente
                'allora è valido e uso quello
                If myDestFile.LastWriteTime.CompareTo(mySourceFile.LastWriteTime) = 1 Then
                    'Il file esiste e va bene
                    Response.ContentType = "image/jpeg"
                    Response.WriteFile(myDestFile.FullName)
                    Response.End()
                    Exit Sub
                Else
                    'Il file esiste ma è vecchio e va sostituito
                    myDestFile.Delete()
                End If
            End If
        End If
        
        Dim orginalimg, thumb As System.Drawing.Image

        Try
            orginalimg = System.Drawing.Image.FromFile(mySourceFile.FullName)
        Catch
            Response.Redirect(ErrorImagePath)
            Exit Sub
        End Try

        Dim ThumbnailWidth, ThumbnailHeight As Integer
        Select Case Mode
            Case ResizeMode.AutoResize
                ' ResizeMode.AutoResize: Ridimensiona l'immagine per restare nei limiti impostati, mantenendo le proporzioni
                Dim myRatio As Double = orginalimg.Width / orginalimg.Height

                If myRatio > 1 Then 'La larghezza è maggiore dell'altezza, quindi fisso l'altezza e calcolo il resto
                    ThumbnailHeight = MaxHeight
                    ThumbnailWidth = orginalimg.Width / orginalimg.Height * MaxHeight
                ElseIf myRatio < 1 Then 'L'altezza è maggiore della larghezza, quindi fisso la larghezza e calcolo il resto
                    ThumbnailWidth = MaxWidth
                    ThumbnailHeight = orginalimg.Height / orginalimg.Width * MaxWidth
                ElseIf myRatio = 1 Then 'Larghezza = Altezza
                    ThumbnailWidth = MaxWidth
                    ThumbnailHeight = MaxHeight
                End If
            Case ResizeMode.ManualResize
                ' ResizeMode.ManualResize: Ridimensiona con le misure indicate nei parametri
                ThumbnailWidth = MaxWidth
                ThumbnailHeight = MaxHeight
        End Select

        Response.ContentType = "image/jpeg"

        'Creo l'immagine con le misure calcolate, in formato Jpeg
        thumb = orginalimg.GetThumbnailImage(ThumbnailWidth, ThumbnailHeight, Nothing, IntPtr.Zero)

        If UseCache Then
            Dim myS As New IO.FileStream(LocalThumbnailCacheFilePath, IO.FileMode.CreateNew)
            thumb.Save(myS, System.Drawing.Imaging.ImageFormat.Jpeg)
            myS.Close()
            orginalimg.Dispose()
            thumb.Dispose()
            Response.WriteFile(LocalThumbnailCacheFilePath)
        Else
            thumb.Save(Response.OutputStream, Imaging.ImageFormat.Jpeg)
            thumb.Dispose()
        End If
    End Sub
</script>