This is WebKit bug https://bugs.webkit.org/show_bug.cgi?id=46319
The workaround is to wrap Canvas render functions with a function that
sets a flush timer. The flush function sets the right margin and then
1ms later sets it back. This triggers the canvas to redraw with the
correct contents.
Two downsides:
- rendering is slower, but only on the busted versions of webkit.
Correct and useful is better than fast and useless.
- There is a barely perceptible jitter of the control buttons because
the canvas size is changing by one pixel.
To support this functionality, we also have to read out the exact
webkit version from the user agent in the render engine detection code
in include/util.js.
- util.js that contains essential functions
- webutils.js that contains the GUI utility function.js
this helps to include noVNC in other project, especially Cappuccino Application
i
- include/util.js: Add type and desc field to conf_default routine.
Make comment descriptions of settings into desc parameters that can
be queried. Also, use set_FOO in conf_default to set or coerce the
current setting so that we always have the right type for the value.
- include/rfb.js, include/default_config.js: add connectTimeout
setting to address situations with slow connections that may need
more than 2 seconds.
Generally, most servers send hextile updates as single updates
containing many rects. Some servers send hextile updates as many small
framebuffer updates with a few rects each (such as QEMU). This latter
cases revealed that shifting off the beginning of the receive queue
(which happens after each hextile FBU) performs poorly.
This change switches to using an indexed receive queue (instead of
actually shifting off the array). When the receive queue has grown to
a certain size, then it is compacted all at once.
The code is not as clean, but this change results in more than 2X
speedup under Chrome for the pessimal case and 10-20% in firefox.
New API:
To use the RFB object, you now must instantiate it (this allows more
than one instance of it on the same page).
rfb = new RFB(settings);
The 'settings' variable is a namespace that contains initial default
settings. These can also be set and read using 'rfb.set_FOO()' and
'rfb.get_FOO()' where FOO is the setting name. The current settings
are (and defaults) are:
- target: the DOM Canvas element to use ('VNC_canvas').
- encrypt: whether to encrypt the connection (false)
- true_color: true_color or palette (true)
- b64encode: base64 encode the WebSockets data (true)
- local_cursor: use local cursor rendering (true if supported)
- connectTimeout: milliseconds to wait for connect (2000)
- updateState: callback when RFB state changes (none)
- clipboardReceive: callback when clipboard data received (none)
The parameters to the updateState callback have also changed. The
function spec is now updateState(rfb, state, oldstate, msg):
- rfb: the RFB object that this state change is for.
- state: the new state
- oldstate: the previous state
- msg: a message associate with the state (not always set).
The clipboardReceive spec is clipboardReceive(rfb, text):
- rfb: the RFB object that this text is from.
- text: the clipboard text received.
Changes:
- The RFB and Canvas namespaces are now more proper objects. Private
implementation is no longer exposed and the public API has been made
explicit. Also, instantiation allows more than one VNC connection
on the same page (to complete this, DefaultControls will also need
this same refactoring).
- Added 'none' logging level.
- Removed automatic stylesheet selection workaround in util.js and
move it to defaultcontrols so that it doesn't interfere with
intergration.
- Also, some major JSLinting.
- Fix input, canvas, and cursor tests to work with new model.
Uses the CSS "scale()" operation. The main problem is that the DOM
container is not rescaled, only the size of the displayed content
within it so there will need to be some sort of mechanism to handle
this better so other elements reflow to the new size. Or it might just
not work and be removed later. The zoom property seems to do the right
behavior, but it's not widely supported. Worth exploring though.
Move the whole RFB object to rfb.js. vnc.js is now just the loader
file. This allows an integrating project to easily replace vnc.js with
an alternate loader mechanism (or just do it directly in the html
file). Thanks for the idea primalmotion (http://github.com/primalmotion).
Also, JSLint the various files.
The following API changes may affect integrators:
- Settings have been moved out of the RFB.connect() call. Each
setting now has it's own setter function: setEncrypt, setBase64,
setTrueColor, setCursor.
- Encrypt and cursor settings now default to on.
- CSS changes:
- VNC_status_bar for input buttons switched to a element class.
- VNC_buttons split into VNC_buttons_right and
VNC_buttons_left
- New id styles for VNC_settings_menu and VNC_setting
Note: the encrypt, true_color and cursor, logging setting can all be
set on load using query string variables (in addition to host, port
and password).
Client cursor (cursor pseudo-encoding) support has been polished and
activated.
The RFB settings are now presented as radio button list items in
a drop-down "Settings" menu when using the default controls.
Also, in the settings menu is the ability to select between alternate
style-sheets.
Cookie and stylesheet selection support added to util.js.
To change the appearance of the cursor, we use the CSS cursor style
and set the url to a data URI scheme. The image data sent via the
cursor pseudo-encoding has to be encoded to a CUR format file before
being used in the data URI.
During Canvas initialization we try and set a simple cursor to see if
the browser has support. Opera is missing support for data URI scheme
in cursor URLs.
Disabled for now until we have a better way of specifying settings
overall (too many settings for control bar now).
Util.Debug, Util.Info, Util.Warn, Util.Error routines instead of
direct calls to console.*. Add "logging=XXX" query variable that sets
the logging level (default is "warn").
Logging values:
debug: code debug logging (many calls in performance path are also
commented for performance reasons).
info: informative messages including timing information.
warn: significant events
error: something has gone wrong
Some basic functions from mootools implemented in util.js.
Also, some more DOM separation. Move clipboard focus logic into
default_controls and canvas and out of vnc.js.
JSLint cleanup.
- All state/status updates go through updateState routine which
updates the status line also.
- Old firefox (and opera) don't support canvas createImageData, so use
getImageData as replacement.
- Add console.warn and console.error stubs so that firefox without
firebug doesn't crap out.
- If no WebSockets then error if no flash or if URL is location (flash
will refuse to load the object for security reasons).
Joel Martin
Antoine Mercadal