Select brushX or brushY based on mouse direction ? about d3-brush

[Shravya-Siluveru]

@mbostock Thank you for getting back to me. I implemented single directional zoom based on mouse direction. This works perfect for my requirement, Here is the block https://bl.ocks.org/Shravya-Siluveru/d958edfcbd6333e1a07054c15060ebd9/a6907c80f62202136ec2201cf15b776374e27732

[mbostock]

This is essentially what happens when you hold down Shift; the brush sets the internal lockX or lockY flag based on the subsequent movement of the mouse.

d3-brush/src/brush.js

Lines 361 to 364 in c8fe9fa

	if (shifting && !lockX && !lockY) {
	if (Math.abs(point1[0] - point[0]) > Math.abs(point1[1] - point[1])) lockY = true;
	else lockX = true;
	}

I can’t think of an obvious way of triggering this behavior programmatically (meaning without requiring Shift to be held down), but, maybe it’s possible? I think the ideal would be some way of overriding the logic that determines which mode the brush is in during interaction. But there are a lot of different modes, so I’m not sure how to do that elegantly. The quickest path to implementing this is probably to fork the code and modify the internal logic.