Canvas Widget

[dankurka]

Originally reported on Google Code with ID 1534

Please add Canvas Widget support to GWT. Now we are trying to use  
http://gwt.components.googlepages.com/canvas, but it doesn't work in 
hosted mode browser.

Reported by m.zdila on 2007-08-21 15:22:13

[dankurka]

+1 for standardized graphics api for GWT 

Reported by ivar%oobik.com@gtempaccount.com on 2007-12-06 23:43:29

[dankurka]

Reported by bruce+personal@google.com on 2008-10-21 21:58:16

• Labels removed: priority-medium

[dankurka]

Is this incubator widget sufficient?

http://code.google.com/p/google-web-toolkit-incubator/wiki/GWTCanvas

Reported by acc%google.com@gtempaccount.com on 2008-12-04 05:03:35

• Status changed: NeedsInfo
• Labels added: Type-Enhancement, Category-UI
• Labels removed: Type-Defect

[dankurka]

Reported by acc%google.com@gtempaccount.com on 2008-12-12 01:24:41

[dankurka]

Any chance we can get the GWTCanvas widget from the incubator updated and promoted to

GWT core? Seems like canvas support will be a must for browsers providing HTML 5 
support.

Reported by sumitchandel+legacy@google.com on 2009-06-04 21:47:17

• Status changed: New

[dankurka]

The problem is that the canvas widget can't be made to work decently on IE, so it's
really not a viable candidate for trunk. Assigning this to Joel, though, as he has
been making rumblings about how we'll deal with HTML5

Reported by rjrjr+personal@google.com on 2009-06-04 21:53:46

[dankurka]

Hi

I have used gwtcanvas in IE6+ and firefox to draw piecharts. It works very well for
this purpose.

/Flemming

Reported by flemming.boller on 2009-07-09 19:52:51

[dankurka]

We have been working on developing GWTCanvas and if there is interest would like to

be able to contribute patches back.

In particular we have added text support and is working in IE6, FF (3.5+), and 
Chrome.

Support for FF 3.0 should not be too hard.

We are looking into adding more support as meets our needs, but before we commit more

resource I would like to hear more on "the canvas widget can't be made to work 
decently on IE".

Reported by vineet%architexa.com@gtempaccount.com on 2009-08-14 03:40:09

[dankurka]

Assigning to Dan, who's looked into this. Might be a while before any of us have time
to look into it further, 
though.

Reported by jgw@google.com on 2010-03-16 13:23:38

• Status changed: Accepted

[dankurka]

Hey guys. Sorry for jumping on this thread so late.  What we mean regarding IE is that
an imperative style 
graphics API like the one Canvas exposes will have drastically different performance
and memory 
characteristics on IE since we emulate the API using VML which is declarative.

Essentially, we are hesitant to promote GWTCanvas to trunk since the expectation will
be that anything you 
can do with GWTCanvas should work reasonably in all browsers. Since we use VML to support
IE, that means 
that we will have some legitimate use cases that "should" be fast, but happen to create
large number of VML 
tags and runs orders of magnitude slower on IE.

That being said, there is a large set of practical use cases for which GWTCanvas works
perfectly on IE. 

The alternative approach that we have been thinking about going with was to develop
an SVG/VML graphics 
API that was entirely declarative in nature. That should behave almost identically
in all browsers. Dan has done 
some work on such an API.

@vineet: I would definitely be interested in seeing any patches you have for GWTCanvas.
I think that enough 
people have been using it to warrant it getting some more love.

Reported by jaimeyap@google.com on 2010-03-16 15:21:22

[dankurka]

I stumbled across this ticket while trying to figure out this issue myself. There's
a large demand for this feature evidenced by the plethora of GWT canvas/graphics projects
scattered around Google code. Unfortunately, these types of one-off projects seem to
spring up when a developer needs them, then they move into disrepair after their maintainer
looses interest. The argument "IE is slow, so we should have a fragmented set of api's
of varying code quality scattered around google code and sourceforge for a frequent-use-case
feature" just doesn't make much sense.

@jaime, @r There's a sort-of declarative/object oriented api in http://code.google.com/p/gwt-graphics/
which may be a better fit for VML. Users have reported enhanced performance by removing
GWTCanvas's "custom" IE canvas and simply inserting the Google ExplorerCanvas http://code.google.com/p/explorercanvas/
.

Reported by ekohlwey on 2010-06-11 13:56:07

[dankurka]

Reported by rjrjr@google.com on 2011-01-13 03:11:50

• Labels added: Type-Feature
• Labels removed: Type-Enhancement

[dankurka]

The canvas in 2.2.0+ is awesome. I have some notes on it here:
http://code.google.com/p/gwt-examples/wiki/gwt_hmtl5

Brandon Donnelson
http://gwt-examples.googlecode.com
http://c.gawkat.com

Reported by branflake2267 on 2011-03-26 14:08:36

[dankurka]

Reported by rjrjr@google.com on 2011-10-04 16:28:50

• Status changed: Fixed
• Labels added: Milestone-2_2