[whatwg] Challenging canvas.supportsContext

Glenn Maynard glenn at zewt.org
Thu Jun 20 18:40:28 PDT 2013

On Thu, Jun 20, 2013 at 10:22 AM, Boris Zbarsky <bzbarsky at mit.edu> wrote:

> On 6/19/13 5:27 PM, Paul Irish wrote:
>> I agree that supportsContext is only useful if it's more accurate that
>> !!window.WebGLRenderingContext.
> So that's an interesting question.  Should UAs simply not have
> window.WebGLRenderingContext in situations in which supportsContext would
> return false?

I've suggested that in the past, and the response was that it's harder to
do (don't recall in which engine, probably WebKit).  It would seem pretty
weird if the interface appears and disappears from window over the life of
the page, as WebGL support comes and goes (eg. the driver blacklist or
system graphics drivers are updated).

Also, supportsContext() takes arguments, so you can find out if context
creation would fail with a particular set of options.  You can't do that by
hiding or displaying an interface.

Glenn Maynard

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