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? > > 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] >> > >> > >