Fix for IE11 IndexSizeError for negative source crops

[CaptEmulation]

This codepen will not render on IE11 https://codepen.io/captemulation/pen/PXPORb (copy to your own codepen and replace pen with debug to view on IE11)

In IE11, if a negative number is passed in for sx or sy when using the 9 argument version of drawImage an IndexSizeError exception will be thrown. This can occur with rounding errors making a number just past 0, e.g. -2.4e-12.

Negative numbers do not really make sense here.

[asturur]

@CaptEmulation eventually also the source width/height must be at max the naturalWidth/naturalHeight ( width/height ) of the element we are about to draw.
That is source of another indexSizeError.

Can you fix that too?

[CaptEmulation]

Can you fix that too?

Taking a looksee

[CaptEmulation]

Add the additional boundary check and added a test. Could not follow test style because I could not run anything in image test suite (timeout). IDE also picked up on some reformatting.

[asturur]

Suggested change

	sW = Math.min(elementToDraw.naturalWidth || elementToDraw.width, w * this._filterScalingX),
	sW = Math.min(elementToDraw.naturalWidth || elementToDraw.width, w) * this._filterScalingX,

we want to limit the source area, this._filterScaling apply anyway

[asturur]

Suggested change

	sH = Math.min(elementToDraw.naturalHeight || elementToDraw.height, h * this._filterScalingY),
	sH = Math.min(elementToDraw.naturalHeight || elementToDraw.height, h) * this._filterScalingY,

[asturur]

Thanks for the test too.
Can you checkout away the changes to dist folder?

i usually do git checkout master dist and i rest them.

[CaptEmulation]

Understood. Thanks and will do!

[asturur]

ok we broke something.
i probably suggested something wrong?

[asturur]

oh well if there is a filter scaling, the elementToDraw is already resized to the right dimension of width * filterScalingX. So as you did in the first version, the code was right, with filterScaling inside the parenthesis.