On Wed, Apr 3, 2013 at 9:04 AM, Gregg Tavares <g...@google.com> wrote:
> On Wed, Apr 3, 2013 at 8:41 AM, Stephen White <senorbla...@chromium.org > >wrote: > > > Would Mozilla (or other browser vendors) be interested in implementing > the > > hint as Gregg described above? > > > > If so, we could break out the LCD text issue from canvas opacity, and > > consider the latter on its own merits, since it has benefits apart from > LCD > > text (i.e., performance). Regarding that, if I'm reading correctly, > > Vladimir Vukicevic has expressed support on webkit-dev for the > > ctx.getContext('2d', { alpha: false }) proposal (basically, a syntactic > > rewrite of <canvas opaque>). Does this indeed have traction with other > > browser vendors? > > > > As for naming, I would prefer that it be something like ctx.fontSmoothing > > or ctx.fontSmoothingHint, to align more closely with canvas's > > ctx.imageSmoothingEnabled and webkit's -webkit-font-smoothing CSS > property. > > -webkit-font-smoothing has "none", "antialiased" and > > "subpixel-antialiased" as options. I think it's ok to explicitly call out > > subpixel antialiasing, even if the platform (or UA) does not support it, > > especially if the attribute explicitly describes itself as a hint. > > > > > Why call it "Font" smoothing? Shouldn't a UA be able to also render paths > using the same hint? > I have not heard of anyone using sub-pixel antialiasing for vector art. It might look weird... > > > > > > Stephen > > > > > > On Sun, Mar 17, 2013 at 11:17 PM, Gregg Tavares <g...@google.com> wrote: > > > >> On Sun, Mar 17, 2013 at 1:40 PM, Robert O'Callahan < > rob...@ocallahan.org > >> >wrote: > >> > >> > On Sat, Mar 16, 2013 at 5:52 PM, Gregg Tavares <g...@google.com> > wrote: > >> > > >> >> Let me ask again in a different way ;-) Specifically about LCD style > >> >> antialiasing. > >> >> > >> >> What about a context attribute "antialiasRenderingQualityHint" for > now > >> >> with > >> >> 2 settings "default" and "displayDependent" > >> >> > >> >> context.antialiasRenderingQualityHint = "displayDependent" > >> >> > >> > > >> > How would this interact with canvas opacity? E.g. if the author uses > >> > displayDependent and then draws text over transparent pixels in the > >> canvas, > >> > what is the UA supposed to do? > >> > > >> > >> Whatever the UA wants. It's a hint. From my POV, since the spec doesn't > >> say > >> anything about anti-aliasing then it really doesn't matter. > >> > >> My preference, if I was programming a UA, would be if the user sets > >> "displayDependent" and the UA is running on a lo-dpi machine I'd > >> unconditionally render LCD-AA with the assumption that the canvas is > >> composited on white. If they want some other color they'd fill the > canvas > >> with as solid color first. Personally I don't think that needs to be > >> specced, but it would be my suggestion. As I mentioned, even without > this > >> hint the spec doesn't prevent a UA from unconditionally using LCD-AA. > >> > >> Very few developers are going to run into issues. Most developers that > use > >> canvas aren't going to set the hint. Most developers that use canvas > dont' > >> make it transparent nor do they CSS rotate/scale them. For those few > >> developers that do happen to blend and/or rotate/scale AND set the hint > >> they'll get probably get some fringing but there (a) there was no > >> guarantee > >> they wouldn't already have that problem since as pointed out, the spec > >> doesn't specify AA nor what kind, and (b) if they care they'll either > stop > >> using the hint or they'll search for "why is my canvas fringy" and the > >> answer will pop up on stackoverlow and they can choose one of the > >> solutions. > >> > >> > >> > >> > > >> > Rob > >> > -- > >> > Wrfhf pnyyrq gurz gbtrgure naq fnvq, “Lbh xabj gung gur ehyref bs gur > >> > Tragvyrf ybeq vg bire gurz, naq gurve uvtu bssvpvnyf rkrepvfr > nhgubevgl > >> > bire gurz. Abg fb jvgu lbh. Vafgrnq, jubrire jnagf gb orpbzr terng > nzbat > >> > lbh zhfg or lbhe freinag, naq jubrire jnagf gb or svefg zhfg or lbhe > >> fynir > >> > — whfg nf gur Fba bs Zna qvq abg pbzr gb or freirq, ohg gb freir, naq > gb > >> > tvir uvf yvsr nf n enafbz sbe znal.” [Znggurj 20:25-28] > >> > > >> > > > > >