Solution to problem : [Seaside] serve jpg image files from form
martin.schubert at informatik.uni-ulm.de
Thu Jun 1 23:49:57 UTC 2006
Hello out there,
finally after hours on end i finally found (with the help of mb) the
solution to the problem :
i subclassed Form with FormXTD and overwrote the method
#asMIMEDocument with the following method:
| aStream |
aStream _ (RWBinaryOrTextStream on: '').
JPEGReadWriter2 putForm: (self asFormOfDepth: self depth) onStream:
^MIMEDocument contentType: 'image/jpeg' content: aStream contents.
but this didn`t work. than i realized that the new method was never
called but only the original method in Form. because the construct :
FormXTD fromFileNamed: 'x.jpeg' created an instance of Form and not
of FormXTD because the class method is invoked on Form class and not
inherited to FormXTD. so i will finally restart learning the
inheritance mechanism in smalltalk. so for a quick hack, just take
the previous method and substitute the Form>>asMIMEDocument method
> Martin Schubert a écrit :
>> i want to serve a jpg-file which is stored in a Form object.
>> so i do : aForm _ (Form fromFileNamed: 'wave.jpg')
> Method #fromFileNamed: is smart enough to decode various picture
> and turn them into bitmaps. That's why it can understand your jpeg
> file. However
> after this was executed, the knowledge that its source was jpeg is
> Not so smart.
>> this doesn`t work, and when i am acceptin the following, seaside
>> seems to convert the jpg file to gif or wracks up the picture
>> file somehow :
>> html imageWithDocument: aForm
>> mimeType: 'image/jpeg'
>> fileName: root name,'Picture', '.jpg'.
> The above creates a document handler. When invoked for the
> rendering, this document handler
> needs to encode the bitmap into a MIME document. For some reason,
> the GIF encoding
> is selected by Seaside. See Form>>asMIMEDocument.
> A possible solution would be to subclass Form so that it remembers
> the encoding of
> its source, re-implementing #asMIMEDocument to take this into account.
> Another solution may be to use the Canvas api, where the image tag
> is handled quite
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