As far as I can tell from reading various bits of the spec, setting the content attributes change the intrinsic size of the <img>, which should be used as 'sw' and 'sh' by drawImage.

This indeed seems like a non-compliance issue.  Before fixing, let's see if there is a compatibility bug by seeing what all other browsers are doing, then decide whether we want to fix this or modify the spec to reflect existing behavior.

1. The behavior of Firefox and Opera is the same as Chromium. I'll check others.

2. If you set the value of width and height in the img tag, then the image itself is shown properly resized. drawImage uses the original not-resized image. Please see the output and sample code attached.

justin@: When you say they "should be used as 'sw' and 'sh' by drawImage", this doesn't mean a resize is necessary. Would you please clarify? What I expect is to have the image resized to new width and height, and from there it should be behaved like the original image on the disk was resized before loading. Do you expect the same behavior or something else?

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IE 11.1593 and Edge 38.14393 produce the same output for both cases.

'width' and 'height' on <img> are presentational hints (presentation attributes), and has no effect on any intrinsic dimension (which are the dimension of the actual image.)

As for the general issue, this is fairly clear from the spec:

"When a CanvasImageSource object represents an element that is being rendered and that element has been resized, the original image data of the source image must be used, not the image as it is rendered (e.g. width and height attributes on the source element have no effect on how the object is interpreted when rendering the image for CanvasRenderingContext2D APIs)."

https://html.spec.whatwg.org/multipage/canvas.html#image-sources-for-2d-rendering-contexts (third paragraph from the end of the section)

Thanks fs@, that settles it!

zakerinasab@: there is still a bug here, right?  I recall you told me that if the width and height were set in the HTML markup, that had an effect on drawImage, which it should not.

Replying to comment #5: Apparently my statement was not correct. Changing the image dimension in image tag does not affect the drawImage, which is spec compliant behavior.