Implementation for SWS scale

[Cacsjep]

Hi

I am starting with implementation sws scale, hope we can start here as a draft so that we add this to go-astiv =)

br

[asticode]

Let me know when your draft is done so that I know when to start reviewing it 👍

[Cacsjep]

done it works for my application gg, hope its fit to your needs =)

[Cacsjep]

I did some improvments based on your feedback on my hw_context pr :)

Br

[Cacsjep]

ok this was a lot, hope i dont miss anything

[Cacsjep]

I think it would also be cool to have one setter for width and height, because most of time user would be change both, currently we would call updateContext twice.

func (ssc *SoftwareScaleContext) SetSourceResolution(w int, h int) error {
    ssc.srcW = C.int(w)
    ssc.srcH = C.int(h)
    return ssc.updateContext()
}

func (ssc *SoftwareScaleContext) SetDestinationResolution(w int, h int) error {
    ssc.dstW = C.int(w)
    ssc.dstH = C.int(h)
    return ssc.updateContext()
}

I think its better to have this and not calling it twice so i add it and let me know if this ok for you =)

[Cacsjep]

ok done lets go to next round ;)

[asticode]

Great, I'll merge the PR and make minor adjustments 👍

[Cacsjep]

Perfect, thank you for letting me contribute =)