[whatwg] [canvas] imageRenderingQuality property

Oliver Hunt oliver at apple.com
Mon Jun 2 12:25:32 PDT 2008

Um, could you actually give some kind of reasoning for these?  I am  
not aware of any significant performance issues in Canvas that cannot  
be almost directly attributed to JavaScript itself rather than the  


On Jun 2, 2008, at 12:19 PM, 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).  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 than speed.
> '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.
>    - Vlad

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