about image data transmission in V2 whiteboard, thanks:)

[sunng]

hi

I am here to disturb you about a question :

in the V2 whiteboard, if I import a image, does it mean that the data
of the image is send to participant via the jabber server?

thanks:)

[larry sherrill]

Hi Sunng,

Yes, image data is sent through the server similar to a normal
message. We base64 encode the bytes with: Base64.encodeBytes(bytes)
and enclose the bytes in an <image> tag. The receiver of the message
decodes it with : Base64.decode(new String(bytes))

Good question.

Larry

[sunng]

hi larry, ryan

if the data of image is transmitted via the server, then, if there is
more and more users do image operations, the stress of the server will
be diger and biger.

how to deal with this situation?

sunng

[larry sherrill]

HI Sunng,

Any middleware server can be theoretically overwhelmed given enough
traffic. We could compress the jpeg bytes before sending but that
would only delay the problem. We could also send the image data out of
band but that would be a major change in the architecture of the
whiteboard. Other solutions would be the typical solutions for a large
jabber site: faster machines, clustering, client connection managers.

Has your site hit a limit yet?

Larry

[sunng]

hi

I have not hit the limit yet, I'm just worry about that:)

and, another jabber client which supports whiteboard uses adifferent
way to process image operations, it's called coccinella, the way is to
send command instead of data, the other clients only process the
command.

how do you think about this methord?

> > sunng- 隐藏被引用文字 -
>
> - 显示引用的文字 -

[larry sherrill]

Hi Sunng,

The V2 Whiteboard is vector based, which means we send small vector
commands for all graphics primitives except the jpeg images. After the
image is transmitted and we need to move it to a different spot, then
we only send the coordinates specifying the move, that is, we only
send the image once.

As far as optimization regarding images, we will keep our ears open in
case it becomes a problem. But I think it would be a mistake at this
point to optimize something that isn't a problem for anyone. One
solution might be to post the jpeg file in a public place, and then
use a special attribute in the image command to tell whiteboard
clients where to retrieve the image.

Larry