Possible simplification in create/sines.c

[andreas-kupries]

Looking at

libvips/libvips/create/sines.c

Lines 99 to 102 in 65c9921

	theta = sines->hfreq == 0.0 ?
	VIPS_PI / 2.0 : atan( sines->vfreq / sines->hfreq );
	factor = sqrt( sines->hfreq * sines->hfreq +
	sines->vfreq * sines->vfreq );

I believe that this may be simpler written as

theta = atan2( sines->vfreq, sines->hfreq );
factor = hypot( sines->hfreq, sines->vfreq);

[jcupitt]

Hi @andreas-kupries,

You're right, that's some crusty old code left over from before atan2 and hypot became a thing. We still work on platforms without these functions, so we'd need ifdefs around them.

arithmetic/complex.c defines wrapper functions, perhaps these should be exported and reused.

https://github.com/libvips/libvips/blob/master/libvips/arithmetic/complex.c#L134-L167