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). This is modeled on
the SVG image-rendering property, at http://www.w3.org/TR/SVG/painting.html#ImageRenderingProperty
attribute string imageRenderingQuality;
'auto' (default): The user agent shall make appropriate tradeoffs to
balance speed and quality, but quality shall be given more importance
'optimizeQuality': Emphasize quality over rendering speed.
'optimizeSpeed': Emphasize speed over rendering quality.
No specific image sampling algorithm is specified for any of these
properties, with the exception that, at a minimum, nearest-neighbour
resampling should be used. One alternative is to specify 'best',
'good', 'fast', with "good" being the default, as opposed to the SVG
names; I think those names are more descriptive, but there might be
value in keeping the names consistent with SVG, especially if that
property bubbles up into general CSS usage.