Prompted by a question in the forums, I searched around and didn't find a good example of this technique, so here's a sample of confirming that a rich text field contains exactly one image, with restrictions on the dimensions.
Dim doc As NotesDocument
On Error Goto oops
Source.Refresh True ' update rich text data into back end.
Set doc = Source.Document
Dim session As New NotesSession
Dim stream As NotesStream
Dim dxle As NotesDXLExporter
Dim domp As NotesDOMParser
Dim domd As NotesDOMDocumentNode
Dim nl As NotesDOMNodeList
Set stream = session.CreateStream
Set dxle = session.CreateDXLExporter(doc, stream)
dxle.RestrictToItemNames = "Body"
' at this point you might want to set additional properties for efficiency, e.g. to omit attachments
' please note that if you want to disallow certain types of content, you can use a Rich Text Lite field,
' so this is not the preferrred way to block users from adding an image.
dxle.Process
Set domp = session.CreateDOMParser(stream)
domp.Parse
Set domd = domp.Document
Set nl = domd.GetElementsByTagName("picture")
If nl.NumberOfEntries <> 1 Then
Msgbox "You must have exactly one image in the Body field."
Continue = False
Exit Sub
End If
Dim picture As NotesDOMElementNode
Set picture = nl.GetItem(1)
Dim picX As Long, picY As Long
picX = Clng("0"+Strleft(picture.GetAttribute("width"), "px"))
picY = Clng("0"+Strleft(picture.GetAttribute("height"), "px"))
If picX > 400 Or picY > 400 Then
Msgbox "The image may not exceed 400x400 pixels."
Continue = False
Exit Sub
End If
If stream.Bytes > 160000 Then
Msgbox "The image is too large. Please IMPORT the image from a GIF or JPEG file; do not paste graphics or import a BMP file. Thanks."
Continue = False
Exit Sub
End If
' else: success!
Exit Sub
oops:
' if a validation failure don't bother to display the error because user already saw one.
If Err <> 4412 Then Msgbox "Error " & Err & " in Querysave line " & Erl & ": " & Error
Continue = False
Exit Sub
End Sub
Please note that the width and height properties refer to the dimensions before scaling; if the user drags the picture bigger or smaller these values will not change, but scaling values will be added to the DXL, so you might need to look at those in addition/instead.
I've done a crude size check by checking stream.Bytes; the user could exceed this limit by other things than having a too-large graphic. For instance, if the field contained a lot of text in addition to the image. To more precisely check the image size, you would have to check the length of the base64-encoded character node which is a second-level descendant of the
R0lGODlhCAAIAKIAAP///9HHx8m+vpiHh4p4eFQAADoDAy4BASH5BAkIAAAALAAAAAAIAAgAAAMa
CEqkLueIZ6qZ5JhSzGEa5zWCdT3R5ACMkwAAOw==
Andre Guirard | 9 September 2009 09:25:56 AM ET | Home, Plymouth, MN, USA | Comments (3)
