vasturiano/.block

## .block
license: gpl-3.0
height: 600
border: no

## README.md

      
    Raw
  

              README.md
            
          
    Updated version of Mike Bostock's Versor Dragging to include zoom interaction.
This combo behavior is also available for convenience as the d3-geo-zoom plugin module.

  
## index.html
<!DOCTYPE html>
<canvas width="960" height="600"></cavnas>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://unpkg.com/topojson-client@2"></script>
<script src="versor.js"></script>
<script>

var canvas = d3.select("canvas"),
    width = canvas.property("width"),
    height = canvas.property("height"),
    context = canvas.node().getContext("2d");

var projection = d3.geoOrthographic()
    .scale((height - 10) / 2)
    .translate([width / 2, height / 2])
    .precision(0.1);

var path = d3.geoPath()
    .projection(projection)
    .context(context);

canvas.call(d3.zoom()
    .on("start", zoomstarted)
    .on('zoom', zoomed));

var render = function() {},
    v0, // Mouse position in Cartesian coordinates at start of drag gesture.
    r0, // Projection rotation as Euler angles at start.
    q0; // Projection rotation as versor at start.

function zoomstarted() {
    v0 = versor.cartesian(projection.invert(d3.mouse(this)));
    r0 = projection.rotate();
    q0 = versor(r0);
}

function zoomed() {
    projection.scale(d3.event.transform.k * (height - 10) / 2);

    var v1 = versor.cartesian(projection.rotate(r0).invert(d3.mouse(this))),
        q1 = versor.multiply(q0, versor.delta(v0, v1)),
        r1 = versor.rotation(q1);
    projection.rotate(r1);

    render();
}

d3.json("https://unpkg.com/world-atlas@1/world/110m.json", function(error, world) {
  if (error) throw error;

  var sphere = {type: "Sphere"},
      land = topojson.feature(world, world.objects.land);

  render = function() {
    context.clearRect(0, 0, width, height);
    context.beginPath(), path(sphere), context.fillStyle = "#fff", context.fill();
    context.beginPath(), path(land), context.fillStyle = "#000", context.fill();
    context.beginPath(), path(sphere), context.stroke();
  };

  render();
});

</script>

## preview.png

      
    Raw
  

              preview.png
            
          
## thumbnail.png

      
    Raw
  

              thumbnail.png
            
          
## versor.js
// Version 0.0.0. Copyright 2017 Mike Bostock.
(function(global, factory) {
  typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
  typeof define === 'function' && define.amd ? define(factory) :
  (global.versor = factory());
}(this, (function() {'use strict';

var acos = Math.acos,
    asin = Math.asin,
    atan2 = Math.atan2,
    cos = Math.cos,
    max = Math.max,
    min = Math.min,
    PI = Math.PI,
    sin = Math.sin,
    sqrt = Math.sqrt,
    radians = PI / 180,
    degrees = 180 / PI;

// Returns the unit quaternion for the given Euler rotation angles [λ, φ, γ].
function versor(e) {
  var l = e[0] / 2 * radians, sl = sin(l), cl = cos(l), // λ / 2
      p = e[1] / 2 * radians, sp = sin(p), cp = cos(p), // φ / 2
      g = e[2] / 2 * radians, sg = sin(g), cg = cos(g); // γ / 2
  return [
    cl * cp * cg + sl * sp * sg,
    sl * cp * cg - cl * sp * sg,
    cl * sp * cg + sl * cp * sg,
    cl * cp * sg - sl * sp * cg
  ];
}

// Returns Cartesian coordinates [x, y, z] given spherical coordinates [λ, φ].
versor.cartesian = function(e) {
  var l = e[0] * radians, p = e[1] * radians, cp = cos(p);
  return [cp * cos(l), cp * sin(l), sin(p)];
};

// Returns the Euler rotation angles [λ, φ, γ] for the given quaternion.
versor.rotation = function(q) {
  return [
    atan2(2 * (q[0] * q[1] + q[2] * q[3]), 1 - 2 * (q[1] * q[1] + q[2] * q[2])) * degrees,
    asin(max(-1, min(1, 2 * (q[0] * q[2] - q[3] * q[1])))) * degrees,
    atan2(2 * (q[0] * q[3] + q[1] * q[2]), 1 - 2 * (q[2] * q[2] + q[3] * q[3])) * degrees
  ];
};

// Returns the quaternion to rotate between two cartesian points on the sphere.
versor.delta = function(v0, v1) {
  var w = cross(v0, v1), l = sqrt(dot(w, w));
  if (!l) return [1, 0, 0, 0];
  var t = acos(max(-1, min(1, dot(v0, v1)))) / 2, s = sin(t); // t = θ / 2
  return [cos(t), w[2] / l * s, -w[1] / l * s, w[0] / l * s];
};

// Returns the quaternion that represents q0 * q1.
versor.multiply = function(q0, q1) {
  return [
    q0[0] * q1[0] - q0[1] * q1[1] - q0[2] * q1[2] - q0[3] * q1[3],
    q0[0] * q1[1] + q0[1] * q1[0] + q0[2] * q1[3] - q0[3] * q1[2],
    q0[0] * q1[2] - q0[1] * q1[3] + q0[2] * q1[0] + q0[3] * q1[1],
    q0[0] * q1[3] + q0[1] * q1[2] - q0[2] * q1[1] + q0[3] * q1[0]
  ];
};

function cross(v0, v1) {
  return [
    v0[1] * v1[2] - v0[2] * v1[1],
    v0[2] * v1[0] - v0[0] * v1[2],
    v0[0] * v1[1] - v0[1] * v1[0]
  ];
}

function dot(v0, v1) {
  return v0[0] * v1[0] + v0[1] * v1[1] + v0[2] * v1[2];
}

return versor;
})));
	<!DOCTYPE html>
	<canvas width="960" height="600"></cavnas>
	<script src="https://d3js.org/d3.v4.min.js"></script>
	<script src="https://unpkg.com/topojson-client@2"></script>
	<script src="versor.js"></script>
	<script>

	var canvas = d3.select("canvas"),
	width = canvas.property("width"),
	height = canvas.property("height"),
	context = canvas.node().getContext("2d");

	var projection = d3.geoOrthographic()
	.scale((height - 10) / 2)
	.translate([width / 2, height / 2])
	.precision(0.1);

	var path = d3.geoPath()
	.projection(projection)
	.context(context);

	canvas.call(d3.zoom()
	.on("start", zoomstarted)
	.on('zoom', zoomed));

	var render = function() {},
	v0, // Mouse position in Cartesian coordinates at start of drag gesture.
	r0, // Projection rotation as Euler angles at start.
	q0; // Projection rotation as versor at start.

	function zoomstarted() {
	v0 = versor.cartesian(projection.invert(d3.mouse(this)));
	r0 = projection.rotate();
	q0 = versor(r0);
	}

	function zoomed() {
	projection.scale(d3.event.transform.k * (height - 10) / 2);

	var v1 = versor.cartesian(projection.rotate(r0).invert(d3.mouse(this))),
	q1 = versor.multiply(q0, versor.delta(v0, v1)),
	r1 = versor.rotation(q1);
	projection.rotate(r1);

	render();
	}

	d3.json("https://unpkg.com/world-atlas@1/world/110m.json", function(error, world) {
	if (error) throw error;

	var sphere = {type: "Sphere"},
	land = topojson.feature(world, world.objects.land);

	render = function() {
	context.clearRect(0, 0, width, height);
	context.beginPath(), path(sphere), context.fillStyle = "#fff", context.fill();
	context.beginPath(), path(land), context.fillStyle = "#000", context.fill();
	context.beginPath(), path(sphere), context.stroke();
	};

	render();
	});

	</script>
	// Version 0.0.0. Copyright 2017 Mike Bostock.
	(function(global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
	typeof define === 'function' && define.amd ? define(factory) :
	(global.versor = factory());
	}(this, (function() {'use strict';

	var acos = Math.acos,
	asin = Math.asin,
	atan2 = Math.atan2,
	cos = Math.cos,
	max = Math.max,
	min = Math.min,
	PI = Math.PI,
	sin = Math.sin,
	sqrt = Math.sqrt,
	radians = PI / 180,
	degrees = 180 / PI;

	// Returns the unit quaternion for the given Euler rotation angles [λ, φ, γ].
	function versor(e) {
	var l = e[0] / 2 * radians, sl = sin(l), cl = cos(l), // λ / 2
	p = e[1] / 2 * radians, sp = sin(p), cp = cos(p), // φ / 2
	g = e[2] / 2 * radians, sg = sin(g), cg = cos(g); // γ / 2
	return [
	cl * cp * cg + sl * sp * sg,
	sl * cp * cg - cl * sp * sg,
	cl * sp * cg + sl * cp * sg,
	cl * cp * sg - sl * sp * cg
	];
	}

	// Returns Cartesian coordinates [x, y, z] given spherical coordinates [λ, φ].
	versor.cartesian = function(e) {
	var l = e[0] * radians, p = e[1] * radians, cp = cos(p);
	return [cp * cos(l), cp * sin(l), sin(p)];
	};

	// Returns the Euler rotation angles [λ, φ, γ] for the given quaternion.
	versor.rotation = function(q) {
	return [
	atan2(2 * (q[0] * q[1] + q[2] * q[3]), 1 - 2 * (q[1] * q[1] + q[2] * q[2])) * degrees,
	asin(max(-1, min(1, 2 * (q[0] * q[2] - q[3] * q[1])))) * degrees,
	atan2(2 * (q[0] * q[3] + q[1] * q[2]), 1 - 2 * (q[2] * q[2] + q[3] * q[3])) * degrees
	];
	};

	// Returns the quaternion to rotate between two cartesian points on the sphere.
	versor.delta = function(v0, v1) {
	var w = cross(v0, v1), l = sqrt(dot(w, w));
	if (!l) return [1, 0, 0, 0];
	var t = acos(max(-1, min(1, dot(v0, v1)))) / 2, s = sin(t); // t = θ / 2
	return [cos(t), w[2] / l * s, -w[1] / l * s, w[0] / l * s];
	};

	// Returns the quaternion that represents q0 * q1.
	versor.multiply = function(q0, q1) {
	return [
	q0[0] * q1[0] - q0[1] * q1[1] - q0[2] * q1[2] - q0[3] * q1[3],
	q0[0] * q1[1] + q0[1] * q1[0] + q0[2] * q1[3] - q0[3] * q1[2],
	q0[0] * q1[2] - q0[1] * q1[3] + q0[2] * q1[0] + q0[3] * q1[1],
	q0[0] * q1[3] + q0[1] * q1[2] - q0[2] * q1[1] + q0[3] * q1[0]
	];
	};

	function cross(v0, v1) {
	return [
	v0[1] * v1[2] - v0[2] * v1[1],
	v0[2] * v1[0] - v0[0] * v1[2],
	v0[0] * v1[1] - v0[1] * v1[0]
	];
	}

	function dot(v0, v1) {
	return v0[0] * v1[0] + v0[1] * v1[1] + v0[2] * v1[2];
	}

	return versor;
	})));