Published
Edited
Dec 31, 2020
md`# sector`
{
let startAngle = 10
let endAngle = 20
let width = 800
let height = 800
let cx = width / 2
let cy = height / 2
let radius = 10
let degree_offset = 1
let context = DOM.context2d(width, height)
d3.select(context.canvas).call(
d3.zoom()
.scaleExtent([1/4, 4])
.on("zoom", render)
);
function render(transform = d3.zoomTransform(context.canvas)) {
context.clearRect(0, 0, width, height);
for(let i = 40; i >= 1; i = i - 1) {
for(let j = 360; j >= 0; j -= degree_offset) {
drawSector(context,
color(j / i / 360 * 17),
transform.applyX(cx),
transform.applyY(cy),
radius * transform.k * i,
(j - 10) / 180 * PI ,
j / 180 * PI)
}
}
// context.save()
}
render()
return context.canvas
}
md`## 等密度圆 覆盖方式`
{
let startAngle = 10
let endAngle = 20
let width = 800
let height = 800
let cx = width / 2
let cy = height / 2
let radius = 30
let degree_offset = 1
let context = DOM.context2d(width, height)
d3.select(context.canvas).call(
d3.zoom()
.scaleExtent([1/4, 4])
.on("zoom", render)
);
function render(transform = d3.zoomTransform(context.canvas)) {
context.clearRect(0, 0, width, height);
for(let i = 40; i >= 1; i = i - 1) {
for(let j = 360; j >= 0; j -= degree_offset) {
drawSector(context,
color(i / 360 * 17),
transform.applyX(cx),
transform.applyY(cy),
radius * transform.k * Math.sqrt(i),
(j - 10) / 180 * PI ,
j / 180 * PI)
}
}
// context.save()
}
render()
return context.canvas
}
{
// let context = DOM.context2d(600, 600)
let startAngle = 310 / 180 * PI
let endAngle = 320 / 180 * PI
let radius = 50
let width = 800
let height = 800
let cx = width / 2
let cy = height / 2
// let radius = 10
let degree_offset = 10
let context = DOM.context2d(width, height)
d3.select(context.canvas).call(
d3.zoom()
.scaleExtent([1/2, 2])
.on("zoom", render)
);
function render(transform = d3.zoomTransform(context.canvas)) {
context.clearRect(0, 0, width, height);
drawSector(context, color(0.2), transform.applyX(cx), transform.applyY(cy), radius * transform.k, startAngle, endAngle)
drawSector(context, color(0.1), transform.applyX(cx), transform.applyY(cy), (radius - 20) * transform.k, startAngle, endAngle)
}
render()
return context.canvas
}
function drawSector(ctx, color, cx, cy, radius, startAngle, endAngle, transform) {
ctx.beginPath();
ctx.moveTo(cx,cy);
ctx.arc(cx,cy, radius, startAngle, endAngle);
ctx.lineTo(cx,cy);
ctx.fillStyle = color
ctx.fill()
// ctx.save()
}
function drawRingSector(ctx, color, cx, cy, innerRadius, outRadius, startAngle, endAngle, transform) {
ctx.beginPath();
ctx.arc(cx,cy, innerRadius, startAngle, endAngle);
ctx.arc(cx,cy, outRadius, startAngle, endAngle);
// ctx.moveTo(cx + innerRadius * cos(startAngle), cy + innerRadius * sin(startAngle));
// ctx.lineTo(cx + outRadius * cos(startAngle),cy + outRadius * sin(startAngle));
// ctx.moveTo(cx + outRadius*cos(endAngle), cy + outRadius*sin(endAngle));
ctx.lineTo(cx + innerRadius * cos(endAngle), cy + innerRadius*sin(endAngle));
// ctx.moveTo(cx + innerRadius * cos(startAngle), cy + innerRadius * sin(startAngle));
ctx.lineTo(cx + outRadius * cos(startAngle),cy + outRadius * sin(startAngle));
// ctx.arc(cx,cy, innerRadius, startAngle, endAngle);
// ctx.arc(cx,cy, outRadius, startAngle, endAngle);
ctx.fillStyle = color
ctx.fill()
// ctx.strokeStyle = 'steelblue'
// ctx.stroke()
// ctx.save()
}
{
// let context = DOM.context2d(600, 600)
let startAngle = 310 / 180 * PI
let endAngle = 360 / 180 * PI
let radius = 50
let cx = width / 2
let cy = height / 2
// let radius = 10
let context = DOM.context2d(width, height)
d3.select(context.canvas).call(
d3.zoom()
.scaleExtent([1/2, 4])
.on("zoom", render)
);
function render(transform = d3.zoomTransform(context.canvas)) {
context.clearRect(0, 0, width, height);
drawRingSector(context, color(0.2), transform.applyX(cx), transform.applyY(cy), (radius - 20) * transform.k, radius * transform.k, startAngle, endAngle)
}
render()
return context.canvas
}
{
let width = 800
let height = 800
let cx = width / 2
let cy = height / 2
let radius = 10
let degree_offset = 1
let context = DOM.context2d(width, height)
d3.select(context.canvas).call(
d3.zoom()
.scaleExtent([1/4, 4])
.on("zoom", render)
);
function render(transform = d3.zoomTransform(context.canvas)) {
context.clearRect(0, 0, width, height);
// context.save()
for(let i = 0; i < 40; i++) {
for(let j = 360; j >= 10; j -= degree_offset) {
// if( j / 20 === 0 ) {
drawRingSector(context,
color(j / i / 360 * 17),
transform.applyX(cx),
transform.applyY(cy),
radius * transform.k * i,
radius * transform.k * (i + 1),
(j - 10) / 180 * PI ,
j / 180 * PI)
// }
}
}
// context.save()
}
render()
return context.canvas
}
{
let width = 800
let height = 800
let cx = width / 2
let cy = height / 2
let radius = 40
let degree_offset = 1
let context = DOM.context2d(width, height)
d3.select(context.canvas).call(
d3.zoom()
.scaleExtent([1/4, 4])
.on("zoom", render)
);
function render(transform = d3.zoomTransform(context.canvas)) {
context.clearRect(0, 0, width, height);
// context.save()
for(let i = 0; i < 40; i++) {
for(let j = 360; j >= 10; j -= degree_offset) {
// if( j / 20 === 0 ) {
drawRingSector(context,
color(i / 360 * 17),
transform.applyX(cx),
transform.applyY(cy),
radius * transform.k * Math.sqrt(i),
radius * transform.k * Math.sqrt(i + 1),
(j - 10) / 180 * PI ,
j / 180 * PI)
// }
}
}
// context.save()
}
render()
return context.canvas
}
color = d3.interpolateHslLong("red", "blue")
PI = Math.PI
cos = Math.cos
sin = Math.sin
width = 800
height = 800
d3 = require('d3@5')
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