Re: [evolution-patches] Plugin for resizing inline attachments (images)

[Not Zed <notzed novell com>]

Only had a very quick look at this, sorry, but a few comments about this
sequence of code below.

Yeah it works, etc, but its not very efficient, copying whole images
around from memory to memory to memory.

You should create a new stream class, which writes to the pixbuf loader.
Then you just 'deocde to stream' to that stream, and you end up with a
decoded image!  That way you dont need to generate all these
intermediate copies of the binary data.  You will still need to write
out a memory stream for the output though.  You could alsoimplement it
as a 'stream filter' and do some pipelined processing on it (ok maybe
not).

Also note that camel_stream_mem_new() can't fail, so dont bother
checking for null.

Other issues - dont put inline_disposition on the type!  This will cause
all attachments to be expanded all the time, which overrides the current
behaviour.

The other massive problem with this code - actually i dont know how it
is even working - is that the format handler runs in another thread.
You simply can't call any gtk+ stuff from this thread, NONE, about all
you can do - and you should have at least looked at what the existing
code does, which is nothing like this - is insert an <img> tag, and set
a callback for when the streamed content of that tag is requested.

Then when it is requested you then create the stream from the part, and
output it directly to the html stream (thus, saving the need for another
temporary full-copy of the data).

Still - it wont handle resizing, you can't override the scaling, and you
can't do anything useful with the image (i dont know, do you get the
original still as an attachment you can play with?).  But these are more
cosmetic, the details above are serious.

Another approach would be to create a gtkimage and feed that the data
(it MUST be from a 'pobject' callback), that way it could resize, but on
the other hand then you'd have to re-implement the
em-format-html-display popup menu somehow, since it wont know anything
about it.

On Tue, 2005-06-14 at 11:39 +0530, Srinivasa Ragavan wrote:
> +       out = camel_stream_mem_new ();
> +       if (out == NULL)
> +               goto fail;
> +       
> +       content = camel_medium_get_content_object((CamelMedium
> *)t->part);
> +       if (content == NULL)
> +               goto fail;
> +       if (camel_data_wrapper_decode_to_stream(content, out) == -1
> +           || camel_stream_flush(out) == -1) {
> +               goto fail;
> +       }
> +       camel_stream_reset (out);
> +       
> +       loader = gdk_pixbuf_loader_new();
> +       do {
> +               len = camel_stream_read(out, buffer, sizeof (buffer));
> +               if (len > 0) 
> +                       gdk_pixbuf_loader_write(loader, buffer, len,
> NULL);
> +       } while (len>0);
> +       
> +       camel_object_unref(out);
> +       out = NULL;