Working on circles for http://1wheel.github.io/swoopy-drag/
Last active
August 22, 2016 02:33
-
-
Save 1wheel/dabdb5bd3eabf8e2da752fee31bbec14 to your computer and use it in GitHub Desktop.
circle-arc-drag
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
<!DOCTYPE html> | |
<meta charset="utf-8"> | |
<style> | |
body{ | |
background: black; | |
} | |
circle{ | |
fill: green; | |
fill-opacity: .3; | |
stroke: white; | |
stroke-width: 5; | |
cursor: pointer; | |
} | |
path{ | |
fill: none; | |
stroke: green; | |
stroke-width: 3; | |
} | |
</style> | |
<script src="https://d3js.org/d3.v3.min.js" charset="utf-8"></script> | |
<script src='script.js'></script> |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
function translate(sel, pos){ | |
sel.attr('transform', function(d){ | |
var posStr = typeof(pos) == 'function' ? pos(d) : pos | |
return 'translate(' + posStr + ')' | |
}) | |
} | |
function ƒ(str){ return function(d){ return str ? d[str] : d } } | |
d3.selection.prototype.appendMany = function(data, name){ | |
return this.selectAll(name).data(data).enter().append(name) | |
} | |
var width = 960, | |
height = 500; | |
var svg = d3.select('html') | |
.append('svg') | |
.attr('width', width) | |
.attr('height', height) | |
var g = svg.append('g') | |
var path = svg.append('path') | |
var circles = [ | |
[100, 300], | |
[400, 100], | |
[800, 200], | |
] | |
var drag = d3.behavior.drag() | |
.on('dragstart', function(d){}) | |
.on('drag', function(d){ | |
d[0] = d3.event.x | |
d[1] = d3.event.y | |
d3.select(this).call(translate, ƒ()) | |
calcPath() | |
}) | |
.origin(function(d){ return {x: d[0], y: d[1]} }) | |
var circleSel = svg.appendMany(circles, 'circle') | |
.attr('r', 10) | |
.call(translate, ƒ()) | |
.call(drag) | |
function calcPath(){ | |
var a = circles[0] | |
var b = circles[2] | |
var c = circles[1] | |
var A = dist(b, c) | |
var B = dist(c, a) | |
var C = dist(a, b) | |
var angle = Math.acos((A*A + B*B - C*C)/(2*A*B)) | |
//calc radius of circle | |
var K = .5*A*B*Math.sin(angle) | |
var r = A*B*C/4/K | |
//large arc flag | |
var laf = +(Math.PI/2 > angle) | |
//sweep flag | |
var saf = +((b[0] - a[0])*(c[1] - a[1]) - (b[1] - a[1])*(c[0] - a[0]) < 0) | |
path.attr('d', ['M', a, 'A', r, r, 0, laf, saf, b].join(' ')) | |
} | |
function parsePath(str){ | |
var path = svg.append('path').attr('d', str) | |
var l = path.node().getTotalLength() | |
circles = [0, .5, 1].map(function(d){ | |
var p = path.node().getPointAtLength(d*l) | |
console.log(d, p) | |
return [p.x, p.y] | |
}) | |
circleSel.data(circles).call(translate, ƒ()) | |
calcPath() | |
} | |
parsePath('M 622,449 A 263 263 0 1 0 146,382') | |
function slope(a, b){ | |
return (a[1] - b[1])/(a[0] + b[0]) | |
} | |
function mid(a, b){ | |
return [(a[0] + b[0])/2, (a[1] + b[1])/2] | |
} | |
function dist(a, b){ | |
return Math.sqrt( | |
Math.pow(a[0] - b[0], 2) + | |
Math.pow(a[1] - b[1], 2)) | |
} |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment