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"use strict"
/**
* DOM object observers
*/
define(
[],
function() {
var MutationObserver = window.MutationObserver;
// more portable version: var MutationObserver =
// window.MutationObserver ||
// window.WebKitMutationObserver;
/**
* observe SVG object's translate attribute (x,y values), measure
* change rate & invoke on_slowdown_threshold_reached() upon
* reaching change slowdown threshold.
*
* Caller is responsible to disconnect observer.
*/
function Mutation_Handler__on_dxy_slowdown(
on_slowdown_threshold_reached) {
var x_cur, y_cur, d, dx, dy, avg_d = 0;
this.on_slowdown_threshold_reached = on_slowdown_threshold_reached;
/**
* handle observer mutation
*/
this.handle_mutation = function(m) {
if ('transform' != m.attributeName || null == m.oldValue) {
return;
}
/*
* parsed txt example:
* "translate(173.6007550157428,275.43228723527193)"
*/
var rgx_m = m.oldValue.match(/\((\d+.\d+),(\d+.\d+)\)/);
x_cur = rgx_m[1];
y_cur = rgx_m[2];
if (undefined == this.x_prv) {
this.x_prv = x_cur;
this.y_prv = y_cur;
return;
}
dx = x_cur - this.x_prv;
dy = y_cur - this.y_prv;
var d = Math.sqrt(dx * dx + dy * dy);
// average across last samples
avg_d = (1.0 - this.most_recent_sample_weight) * avg_d
+ this.most_recent_sample_weight * d;
// debug
// console.log({
// 'dx' : dx,
// 'dy' : dy,
// 'd' : d,
// 'avg_d' : avg_d,
// });
if (avg_d < this.slowdown_threshold) {
// slowdown threshold reached
if (this.on_slowdown_threshold_reached) {
this.on_slowdown_threshold_reached();
}
}
this.x_prv = x_cur;
this.y_prv = y_cur;
}
}
function new_Mutation_Handler__on_dxy_slowdown(
on_slowdown_threshold_reached, slowdown_threshold,
most_recent_sample_weight) {
if (undefined == slowdown_threshold) {
slowdown_threshold = 0.07;
}
if (undefined == most_recent_sample_weight) {
most_recent_sample_weight = 0.3;
}
var ret = new Mutation_Handler__on_dxy_slowdown(
on_slowdown_threshold_reached);
ret.slowdown_threshold = slowdown_threshold;
ret.most_recent_sample_weight = most_recent_sample_weight;
return ret;
}
function new_MutationObserver(handler) {
/*
* FIXME implemente with inheritence - currently triggers
* 'illegal invocation', possibly due to some interaction with
* requirejs
*/
// var o = new
// window.MutationObserver(Mutation_Observer.handler);
// var ret = Object.create(o);
// ret. = undefined;
// return ret;
var for_each_mutaion = function(m_set) {
m_set.forEach(function(m) {
handler.handle_mutation(m);
})
};
return new MutationObserver(for_each_mutaion);
}
return {
new_MutationObserver : new_MutationObserver,
new_Mutation_Handler__on_dxy_slowdown : new_Mutation_Handler__on_dxy_slowdown,
};
});
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