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Implement pointer handling #239

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Implement pointer handling #239

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104 changes: 99 additions & 5 deletions src/zoom.js
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Original file line number Diff line number Diff line change
@@ -1,7 +1,7 @@
import {dispatch} from "d3-dispatch";
import {dragDisable, dragEnable} from "d3-drag";
import {interpolateZoom} from "d3-interpolate";
import {event, customEvent, select, mouse, touch} from "d3-selection";
import {event, customEvent, select, mouse, touch, clientPoint} from "d3-selection";
import {interrupt} from "d3-transition";
import constant from "./constant.js";
import ZoomEvent from "./event.js";
Expand Down Expand Up @@ -49,6 +49,14 @@ function defaultConstrain(transform, extent, translateExtent) {
);
}

function pointable() {
return "onpointerdown" in this;
}

function unpointable() {
return !pointable.call(this)
}

export default function() {
var filter = defaultFilter,
extent = defaultExtent,
Expand All @@ -64,15 +72,24 @@ export default function() {
touchending,
touchDelay = 500,
wheelDelay = 150,
clickDistance2 = 0;
clickDistance2 = 0,
pointers = [];

function zoom(selection) {
selection
const a = selection
.property("__zoom", defaultTransform)
.on("wheel.zoom", wheeled)
.on("wheel.zoom", wheeled);
const ptb = a.filter(pointable)
.on("pointerdown.zoom", pointdowned)
.on("pointermove.zoom", pointmoved)
.on("pointerup.zoom", pointupped)
.on("pointercancel.zoom", pointupped)
.style("touch-action", "none")
.style("-webkit-tap-highlight-color", "rgba(0,0,0,0)");
const upb = a.filter(unpointable)
.on("mousedown.zoom", mousedowned)
.on("dblclick.zoom", dblclicked)
.filter(touchable)
.filter(touchable)
.on("touchstart.zoom", touchstarted)
.on("touchmove.zoom", touchmoved)
.on("touchend.zoom touchcancel.zoom", touchended)
Expand Down Expand Up @@ -291,6 +308,83 @@ export default function() {
else select(this).call(zoom.transform, t1);
}

function pointdowned() {
if (!filter.apply(this, arguments)) return;
var g = gesture(this, arguments, pointers.length === 0),
i = event.pointerId,
started, p;

event.preventDefault();
pointers.push(i);
p = clientPoint(this, event);
p = [p, this.__zoom.invert(p), i];
if (!g.touch0) g.touch0 = p, started = true, g.taps = 1 + !!touchstarting;
else if (!g.touch1 && g.touch0[2] !== p[2]) g.touch1 = p, g.taps = 0;

if (touchstarting) touchstarting = clearTimeout(touchstarting);

if (started) {
if (g.taps < 2) touchstarting = setTimeout(function() { touchstarting = null; }, touchDelay);
interrupt(this);
g.start();
}
}

function pointmoved() {
if (!this.__zooming) return;
var g = gesture(this, arguments),
i = event.pointerId,
t, p, l;

event.preventDefault();
if (touchstarting) touchstarting = clearTimeout(touchstarting);
g.taps = 0;
p = clientPoint(this, event);

if (g.touch0 && g.touch0[2] === i) g.touch0[0] = p;
else if (g.touch1 && g.touch1[2] === i) g.touch1[0] = p;

t = g.that.__zoom;
if (g.touch1) {
var p0 = g.touch0[0], l0 = g.touch0[1],
p1 = g.touch1[0], l1 = g.touch1[1],
dp = (dp = p1[0] - p0[0]) * dp + (dp = p1[1] - p0[1]) * dp,
dl = (dl = l1[0] - l0[0]) * dl + (dl = l1[1] - l0[1]) * dl;
t = scale(t, Math.sqrt(dp / dl));
p = [(p0[0] + p1[0]) / 2, (p0[1] + p1[1]) / 2];
l = [(l0[0] + l1[0]) / 2, (l0[1] + l1[1]) / 2];
}
else if (g.touch0) p = g.touch0[0], l = g.touch0[1];
else return;
g.zoom("touch", constrain(translate(t, p, l), g.extent, translateExtent));
}

function pointupped() {
if (!this.__zooming) return;
var g = gesture(this, arguments),
i = event.pointerId,
x;

event.preventDefault();
if (x = pointers.indexOf(i)) delete pointers[x];
if (touchending) clearTimeout(touchending);
touchending = setTimeout(function() { touchending = null; }, touchDelay);

if (g.touch0 && g.touch0[2] === i) delete g.touch0;
else if (g.touch1 && g.touch1[2] === i) delete g.touch1;

if (g.touch1 && !g.touch0) g.touch0 = g.touch1, delete g.touch1;
if (g.touch0) g.touch0[1] = this.__zoom.invert(g.touch0[0]);
else {
g.end();
// If this was a dbltap, reroute to the (optional) dblclick.zoom handler.
if (g.taps === 2) {
var p = select(this).on("dblclick.zoom");
if (p) p.apply(this, arguments);
}
}
}

function touchstarted() {
if (!filter.apply(this, arguments)) return;
var touches = event.touches,
Expand Down