[whatwg] [canvas] imageRenderingQuality property

[Ian Hickson]

On Mon, 30 Jun 2008, Vladimir Vukicevic wrote:
> On Jun 11, 2008, at 3:34 AM, Ian Hickson wrote:
> > On Mon, 2 Jun 2008, Vladimir Vukicevic wrote:
> > > 
> > > I'd like to propose adding an imageRenderingQuality property on the 
> > > canvas 2D context to allow authors to choose speed vs. quality when 
> > > rendering images (especially transformed ones).
> > 
> > How can an author know which is appropriate?
> 
> Erm, presumably because they're the author -- it seems quite valid to 
> for an author to be able to say "Just make this happen quickly, I don't 
> care about the quality" or "Take extra time to make this the highest 
> quality you can".

But which of those to pick depends on the hardware at least as much as the 
complexity of the drawing code, as has been noted before.

This table shows what the author would want to pick for a given page:

   2008:                   2008 desktop    2008 mobile
      Complex Graphics     high-quality    high-speed
      Simple Graphics      high-quality    high-quality

   2012:                   2012 desktop    2012 mobile    2008 desktop
      2018-era Graphics    high-quality    high-speed     high-speed
      Complex Graphics     high-quality    high-quality   high-quality
      Simple Graphics      high-quality    high-quality   high-quality

This table shows the same thing again, but this time the desktop machine 
is also doing a massive high-CPU job in the background:

   2008:                   2008 desktop    2008 mobile
      Complex Graphics     high-speed      high-speed
      Simple Graphics      high-speed      high-quality

   2012:                   2012 desktop    2012 mobile    2008 desktop
      2018-era Graphics    high-speed      high-speed     high-speed
      Complex Graphics     high-speed      high-quality   high-speed
      Simple Graphics      high-quality    high-quality   high-speed

How can the author possibly know what the right answer is?

It seems better for the browser to simply detect when the graphics burden 
being placed on the hardware by the page is too much to be done at high 
quality given the current load on the CPU, and for the browser to 
automatically drop down to a lower fidelity, higher speed rendering on the 
fly when appropriate.

-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'