When extracting the data URI info, much more efficient in firefox to
iterate and push onto an array, then to generate the whole array at
once using the map function.
Chrome is mostly unaffected by this change (might be slightly better).
Move DOM manipulation into include/default_controls.js and update
vnc.html to use it.
Add an example vnc_auto.html which automatically connects using
parameters from the query string and doesn't use default_controls.js.
Reorder functions in vnc.js to put external interface functions at the
top of the RFB namespace.
In colourMap mode there are 256 colours in a colour palette sent from
the server via the SetColourMapEntries message. This reduces the
bandwidth by about 1/4. However, appearance can be somewhat less than
ideal (pinks instead of gray, etc).
It also increases client side rendering performance especially on
firefox. Rendering a full 800x600 update takes about 950ms in
firefox on my system compared to about 1400ms. Round-trip time for
a full frame buffer update is even better on firefox (due to
performance of the flash WebSocket emulator). Reduced from about
1800ms to 1100ms on firefox (for 800x600 full update).
Also add a wsencoding test client/server program to test send a set of
values between client and server and vice-versa to test encodings.
Not turned on by default.
Add support for encode/decode of UTF-8 in the proxy. This leverages
the browser for decoding the WebSocket stream directly instead of
doing base64 decode in the browser itself.
Unfortunately, in Chrome this has negligible impact (round-trip time
is increased slightly likely due to extra python processing).
In firefox, due to the use of the flash WebSocket emulator the
performance is even worse. This is because it's really annoying to get
the flash WebSocket emulator to properly decode a UTF-8 bytestream.
The problem is that the readUTFBytes and readMultiByte methods of an
ActionScript ByteArray don't treat 0x00 correctly. They return
a string that ends at the first 0x00, but the index into the ByteArray
has been advanced by however much you requested.
This is very silly for two reasons: ActionScript (and Javascript)
strings can contain 0x00 (they are not null terminated) and second,
UTF-8 can legitimately contain 0x00 values. Since UTF-8 is not
constant width there isn't a great way to determine if those methods
in fact did encounter a 0x00 or they just read the number of bytes
requested.
Doing manual decoding using readUTFByte one character at a time slows
things down quite a bit. And to top it all off, those methods don't
support the alternate UTF-8 encoding for 0x00 ("\xc0\x80"). They also
just treat that encoding as the end of string too.
So to get around this, for now I'm encoding zero as 256 ("\xc4\x80")
and then doing mod 256 in Javascript. Still doesn't result in much
benefit in firefox.
But, it's an interesting approach that could use some more exploration
so I'm leaving in the code in both places.
The purpose of the code is to be incorporated into other web projects
(whether those are free or not). AGPL prevents combination with other
HTML and javascript that is under a weaker (or proprietary) license.
Better would be a lesser AGPL, but there is not GNU standard for that.
So LGPL-3 meets most of my requirements. If somebody modifies the
actual client code and conveys it, then they must release the changes
under LGPL-3 also.
Add some implementation notes in docs/notes.
- By dereferencing the 'data' field of the imageData object before the
loop, the hextile performance on Chrome is down to 140ms or so for
a full 800x600 update. Still have to fall back to Canvas operations
for firefox.
- Fix RQ empty after reorder bug.
Fixes:
- Make sure that failed state messages stay around until next connect.
- Get status message font colors working.
- Clear RQ_reorder list on re-connect.
- For webkit engines, do array manipulation for each tile subrectangle
and only use the array for putImageData after rendering is finished.
In Chrome 5.0.375.29 beta, the time to render a full 800x600 hextile
image dropped from 500ms to 250ms or so. Firefox 3.5.3 rendering of
a full 800x600 hextile image is about 2300ms.
Joel Martin
Joel Martin