Minor fix to color XY calculation

[visualage]

The color XY uint16 representation in zigbee spec is in s15Fixed16Number format per ICC spec (https://www.color.org/specification/ICC1v43_2010-12.pdf). It is actually a 16-bit fixed-point number. If we don't consider negative numbers, it is exactly the integer divide by 65536 instead of 65535. Minor, but better to get it according to spec.

[Koenkk]

Thanks!

[TheJulianJES]

It looks like this change wasn't made in all places. Shouldn't cause any major issues, but it would be nice to have it correct everywhere.

If I'm right, it should also be changed in these places (and likely others):

zigbee-herdsman-converters/converters/fromZigbee.js

Lines 588 to 591 in aa44881

	result.color.x = mapNumberRange(msg.data['currentX'], 0, 65535, 0, 1, 4);
	}
	if (msg.data.hasOwnProperty('currentY')) {
	result.color.y = mapNumberRange(msg.data['currentY'], 0, 65535, 0, 1, 4);

zigbee-herdsman-converters/converters/toZigbee.js

Lines 1041 to 1042 in aa44881

	zclData.colorx = utils.mapNumberRange(xy.x, 0, 1, 0, 65535);
	zclData.colory = utils.mapNumberRange(xy.y, 0, 1, 0, 65535);

zigbee-herdsman-converters/converters/toZigbee.js

Line 2023 in aa44881

value = {x: utils.mapNumberRange(colorXY.x, 0, 1, 0, 65535), y: utils.mapNumberRange(colorXY.y, 0, 1, 0, 65535)};

zigbee-herdsman-converters/converters/toZigbee.js

Lines 5549 to 5564 in aa44881

	const xScaled = utils.mapNumberRange(xy.x, 0, 1, 0, 65535);
	const yScaled = utils.mapNumberRange(xy.y, 0, 1, 0, 65535);
	extensionfieldsets.push({'clstId': 768, 'len': 4, 'extField': [xScaled, yScaled]});
	state['color_mode'] = constants.colorMode[2];
	state['color_temp'] = val;
	} else if (attribute === 'color') {
	try {
	val = JSON.parse(val);
	} catch (e) {
	e;
	}
	const newColor = libColor.Color.fromConverterArg(val);
	if (newColor.isXY()) {
	const xScaled = utils.mapNumberRange(newColor.xy.x, 0, 1, 0, 65535);
	const yScaled = utils.mapNumberRange(newColor.xy.y, 0, 1, 0, 65535);

zigbee-herdsman-converters/converters/toZigbee.js

Lines 5590 to 5591 in aa44881

	const xScaled = utils.mapNumberRange(colorXY.x, 0, 1, 0, 65535);
	const yScaled = utils.mapNumberRange(colorXY.y, 0, 1, 0, 65535);