[whatwg] Adding the imageSmoothingEnabled back into 2dContext Level 2 spec.

Tue Feb 12 09:49:55 PST 2013

Is there an implementation report on this?
If browsers stabilized on this feature, it might be time to drop the prefix.

On Tue, Feb 12, 2013 at 7:30 AM, Ashley Gullen <ashley at scirra.com> wrote:

> I would re-emphasise this is important for many game applications.  Here's
> an image showing the effect it can have from a recent blog post I wrote:
> https://www.scirra.com/images/sampling-point-linear.png
> For a game in this style it is essential to be able to force
> nearest-neighbour.  Games in that "retro" style are often unplayable
> because they look so awful if they get bilinear interpolation forced on
> them.  On the other hand, modern hi-res style games which intend to use
> bilinear interpolation only look marginally worse if they get
> nearest-neighbour.  So I think the existing spec was fine as it was:
> imageSmoothingEnabled = false means "require nearest-neighbour
> interpolation", imageSmoothingEnabled = true means "any smoothing
> algorithm, or nearest-neighbour".
>
> I would also emphasise this should definitely also apply to patterns, for
> the same reason: games are likely to use a pattern to render tiles, and
> those should be rendered with the same interpolation as everything else.
>
> Ashley
>
>
>
> On 8 February 2013 12:25, Rik Cabanier <cabanier at gmail.com> wrote:
>
>> I agree we should bring it back.
>>
>> Personally, it would be nice that have a more formal definition of what
>> smoothing actually means so user agents can implement it similarly.
>>
>> Rik
>>
>> On Tue, Feb 5, 2013 at 7:14 AM, Jay Munro <jaymunro at microsoft.com> wrote:
>>
>> > For CR, we took the imageSmoothingEnable feature out because it hadn't
>> > been given a chance to be discussed by the working group. For level 2,
>> I'm
>> > adding it back in, but asking for any discussion that needs to be made
>> > first.
>> >
>> > Silence will be taken to mean there is no objection, but positive
>> > responses are encouraged.  If I don't hear any objections by Monday Feb
>> 11,
>> > I'll check it in.
>> >
>> > The following is the pending check in:
>> >
>> >
>> > @@ -40677,6 +40677,10 @@ dictionary <dfn>TrackEventInit</dfn> :
>> > <span>EventInit</span> {
>> >    // compositing
>> >             attribute unrestricted double <span
>> > title="dom-context-2d-globalAlpha">globalAlpha</span>; // (default 1.0)
>> >             attribute DOMString <span
>> >
>> title="dom-context-2d-globalCompositeOperation">globalCompositeOperation</span>;
>> > // (default source-over)
>> > +
>> > +  // image smoothing
>> > +           attribute boolean <span
>> >
>> title="dom-context-2d-imageSmoothingEnabled">imageSmoothingEnabled</span>;
>> > // (default true)
>> > +
>> >  <!--
>> >    // v7 we've also received requests for:
>> >    - turning off antialiasing to avoid seams when patterns are painted
>> > next to each other
>> > @@ -40945,7 +40949,8 @@ interface <dfn>Path</dfn> {
>> >
>> >
>> title="dom-context-2d-globalCompositeOperation">globalCompositeOperation</code>,
>> > <code
>> >     title="dom-context-2d-font">font</code>, <code
>> >     title="dom-context-2d-textAlign">textAlign</code>, <code
>> > -   title="dom-context-2d-textBaseline">textBaseline</code>.</li>
>> > +   title="dom-context-2d-textBaseline">textBaseline</code>, <code
>> > +
>> >
>> title="dom-context-2d-imageSmoothingEnabled">imageSmoothingEnabled</code>.</li>
>> >    </ul>
>> >
>> >    <p class="note">The <span>current default path</span> and the
>> > @@ -43416,10 +43421,16 @@ try {
>> >
>> >    <p>If the original image data is a bitmap image, the value painted
>> >    at a point in the area of the repetitions is computed by filtering
>> > -  the original image data. The user agent may use any filtering
>> > +  the original image data. If the <code
>> > +
>> >
>>  title="dom-context-2d-imageSmoothingEnabled">imageSmoothingEnabled</code>
>> > +  then the user agent may use any filtering
>> >    algorithm (for example bilinear interpolation or nearest-neighbor).
>> > -  When the filtering algorithm requires a pixel value from outside the
>> > -  original image data, it must instead use the value from wrapping the
>> > +  If the <code
>> > +
>> >
>>  title="dom-context-2d-imageSmoothingEnabled">imageSmoothingEnabled</code>
>> > +  attribute is set to false, the image must be rendered using
>> > +  nearest-neighbor interpolation. When such the filtering algorithm
>> > +  requires a pixel value from outside the original image data, it
>> > +  must instead use the value from wrapping the
>> >    pixel's coordinates to the original image's dimensions. (That is,
>> >    the filter uses 'repeat' behavior, regardless of the value of
>> >    <var title="">repetition</var>.)
>> > @@ -44539,6 +44550,18 @@ v6DVT (also check for '- -' bits in the part
>> > above) -->
>> >    <p class="note">This specification does not define the algorithm to
>> >    use when scaling the image, if necessary.</p>
>> >
>> > +  <p>If the <code
>> > +
>> >
>>  title="dom-context-2d-imageSmoothingEnabled">imageSmoothingEnabled</code>
>> > +  attribute is set to true, then the user agent should attempt to
>> > +  apply a smoothing algorithm to the image data when it is scaled.
>> > +  Otherwise, the image must be rendered using nearest-neighbor
>> > +  interpolation.</p>
>> > +
>> > +  <p class="note">This specification does not define the precise
>> > +  algorithm to use when scaling an image when the <code
>> > +
>> >
>>  title="dom-context-2d-imageSmoothingEnabled">imageSmoothingEnabled</code>
>> > +  attribute is set to true.</p>
>> > +
>> >    <p class="note">When a canvas is drawn onto itself, the <span>drawing
>> >    model</span> requires the source to be copied before the image is
>> drawn
>> >    back onto the canvas, so it is possible to copy parts of a canvas
>> > @@ -46040,6 +46063,36 @@ function AddCloud(data, x, y) { ... }</pre>
>> >
>> >    </div>
>> >
>> > +  <h6>Image smoothing</h6>
>> > +
>> > +  <dl class="domintro">
>> > +
>> > +   <dt><var title="">context</var> . <code
>> >
>> title="dom-context-2d-imageSmoothingEnabled">imageSmoothingEnabled</code> [
>> > = <var title="">value</var> ]</dt>
>> > +
>> > +   <dd>
>> > +
>> > +    <p>Returns whether pattern fills and the <code
>> > +    title="dom-context-2d-drawImage">drawImage()</code> method will
>> > +    attempt to smooth images if they have to rescale them (as opposed
>> > +    to just rendering the images with "big pixels").</p>
>> > +
>> > +    <p>Can be set, to change whether images are smoothed (true) or not
>> > +    (false).</p>
>> > +
>> > +   </dd>
>> > +
>> > +  </dl>
>> > +
>> > +  <div class="impl">
>> > +
>> > +  <p>The <dfn
>> > +
>> >
>>  title="dom-context-2d-imageSmoothingEnabled"><code>imageSmoothingEnabled</code></dfn>
>> > +  attribute, on getting, must return the last value it was set to. On
>> > +  setting, it must be set to the new value. When the
>> > +  <code>CanvasRenderingContext2D</code> object is created, the
>> > +  attribute must be set to true.</p>
>> > +
>> > +  </div>
>> >
>> >
>> >
>> >
>> >
>> >
>> >
>>
>
>