Creare le immagini thumbnail usando LS in Notes/Domino 6

In questo esempio viene utilizzato un agente richiamato nella WebQuerySave di una FORM. L'agente e' scritto in LS, controlla se il documento contiene file immagini ed in caso venga trovato, crea un file thumbnail e lo allega al documento. E' possibile creare un agente per il client Notes che fa esattamente la stessa cosa.

La parte piu' importante dell'agente e' la chiamata al metodo che genera il file thumbnail. Questo metodo (thumbnailObject.ThumbnailThis nell'esempio sotto riportato) riceve i seguenti parametri:

• Il nome del file sorgente sul quale verra' applicato il filtro thumbnail.
• Il nome del file di uscita che si vorra' ottenere.
• La larghezza massima dell'immagine.
• L'altezza massima dell'immagine.

Nel database e' stato inserito un agente con il seguente codice:

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'Options
Option Public
Option Declare
Uselsx "*javacon" 'Which lets you use Java from Lotusscript
Use "ThumbNail" ' A Java library that holds a function to do Thumbnailing

'Initialize
Sub Initialize
Dim session As New NotesSession
Dim CurDB As NotesDatabase
Dim curDoc As NotesDocument
Dim fileList As Variant
Dim expression As String, serverName As String, thumbnailPrefix As String
Dim fileType As String, fileNameExcludingType As String
Dim sourceFilePath As String, thumbFilePath As String
Dim notesEmbeddedObject As NotesEmbeddedObject
Dim bodyItem As NotesRichTextItem

Dim js As JAVASESSION
Dim thumbnailClass As JAVACLASS
Dim thumbnailObject As JavaObject
Set js = New JAVASESSION
Set thumbnailClass = js.GetClass("ThumbNail")
Set thumbnailObject = thumbnailClass.CreateObject

Dim workingDir As String
Dim maxX As Integer, maxY As Integer
Dim returnCode As String
workingDir = "c:\temp\" 'Hard coding - you should change this
maxX = 100 'Maximum width of thumbnail in pixels
maxY = 100 'Maximum height of thumbnail in pixels
thumbnailPrefix = "t_" 'The prefix we will use for thumbnails

Set curDb = session.CurrentDatabase
servername = curDb.Server

On Error Goto ErrorHandling

expression = "@AttachmentNames"
Set curDoc = session.DocumentContext
Set bodyItem = curDoc.GetFirstItem("Body")
If curDoc.HasEmbedded Then
fileList = Evaluate(expression, curDoc) 'Contains an array of attachmentnames
Forall fileName In fileList
 fileType = Lcase(Strrightback(Cstr(fileName), "."))
 If (fileType = "jpeg" Or fileType = "jpg" Or fileType = "gif") And (Left$(fileName, 2) <> thumbnailPrefix)
Then 'The code only works with these image types, and we exclude old thumbnails
  fileNameExcludingType = Strleft(fileName, ".")
  Set notesEmbeddedObject = curDoc.GetAttachment( fileName ) 'We get a handle to the file that is to be the
source of a thumbnail
  sourceFilePath = workingDir & fileName 'The file name of the file - on disk
  thumbFilePath = workingDir & thumbnailPrefix &  fileNameExcludingType & "." & fileType 'The file name for
the thumbnail
  Call notesEmbeddedObject.ExtractFile(workingDir & fileName) 'Writing the source file to disk
  returnCode = thumbnailObject.ThumbnailThis(sourceFilePath, ThumbFilePath , maxX, maxY) 'Calling the
thumbnailfunction
  If returnCode = "OK" Then 'If thumbnail creation was OK
   Set notesEmbeddedObject = bodyItem.EmbedObject(EMBED_ATTACHMENT, "",thumbFilePath) 'Attaching
the thumbnail
   Call curDoc.Save(True, True, True) 'We only save if we modify the document
  End If 'If returnCode = "OK" Then
  Kill sourceFilePath 'Deleting temporary files
  Kill thumbFilePath
 End If 'If fileType = "jpeg" Or fileType = "jpg" Or fileType = "gif" Then
End Forall 'Forall fileName In fileList
End If 'If curDoc.HasEmbedded Then

Exit Sub

ErrorHandling:
Print " Error (" & Err & ") - line: " & Erl
Exit Sub
End Sub

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Ora e' necessario creare la Java Library con il metodo per generare la thumbnail.

Per fare cio' e' necessario andare  Shared code->Script Libraries, cliccare su New Java Library e sostituire il codice generato con il seguente:

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import com.sun.image.codec.jpeg.*;
import java.awt.*;
import java.awt.image.*;
import java.io.*;
import java.util.*;

public class ThumbNail {
public String thumbNailThis(String inputFilePath, String outputFilePath, int maxX, int maxY) {

try {
  int thumbHeight;
  int thumbWidth;
   
  // load source image file
  Image image = Toolkit.getDefaultToolkit().getImage(inputFilePath);
  MediaTracker mediaTracker = new MediaTracker(new Container());
  mediaTracker.addImage(image, 0);
  mediaTracker.waitForAll();

  int imageWidth = image.getWidth(null);
  int imageHeight = image.getHeight(null);
 
  double imageRatio = (double)imageWidth / (double)imageHeight;
 
  if (imageRatio<1) {
   thumbHeight = maxY;
   thumbWidth = (int)(maxY*imageRatio);
  } else {
   thumbWidth = maxX;
   thumbHeight = (int)(maxX/imageRatio);
  }
       
  resizeImage(image,outputFilePath,thumbWidth,thumbHeight,100);

} catch(Exception e) {
 e.printStackTrace();
}

return "OK";
}

private void resizeImage(Image pImage, String pstFileName, int piWidth, int piHeight, int piQuality) {
try {
  // draw original image to thumbnail image object and
  // scale it to the new size on-the-fly
  BufferedImage thumbImage = new BufferedImage(piWidth, piHeight, BufferedImage.TYPE_INT_RGB);
  Graphics2D graphics2D = thumbImage.createGraphics();
  graphics2D.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BILINEAR);
  graphics2D.drawImage(pImage, 0, 0, piWidth, piHeight, null);
   
  // save thumbnail image to OUTFILE
  BufferedOutputStream out = new BufferedOutputStream(new FileOutputStream(pstFileName));
  JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(out);
  JPEGEncodeParam param = encoder.getDefaultJPEGEncodeParam(thumbImage);

  param.setQuality((float)piQuality / 100.0f, false);
  encoder.setJPEGEncodeParam(param);
  encoder.encode(thumbImage);
   
  out.close();
} catch(Exception e) {
 e.printStackTrace();
}
}

}

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Questo articolo e' stato tradotto da SearchDomino