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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -1 +1,2 @@ | ||
| export {default as contours} from "./src/contours"; | ||
| export {default as contourDensity} from "./src/density"; |
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,43 @@ | ||
| // TODO Optimize edge cases. | ||
| // TODO Optimize index calculation. | ||
| // TODO Optimize arguments. | ||
| export function blurX(source, target, r) { | ||
| var n = source.width, | ||
| m = source.height, | ||
| w = (r << 1) + 1; | ||
| for (var j = 0; j < m; ++j) { | ||
| for (var i = 0, sr = 0; i < n + r; ++i) { | ||
| if (i < n) { | ||
| sr += source.data[i + j * n]; | ||
| } | ||
| if (i >= r) { | ||
| if (i >= w) { | ||
| sr -= source.data[i - w + j * n]; | ||
| } | ||
| target.data[i - r + j * n] = sr / Math.min(i + 1, n - 1 + w - i, w); | ||
| } | ||
| } | ||
| } | ||
| } | ||
|
|
||
| // TODO Optimize edge cases. | ||
| // TODO Optimize index calculation. | ||
| // TODO Optimize arguments. | ||
| export function blurY(source, target, r) { | ||
| var n = source.width, | ||
| m = source.height, | ||
| w = (r << 1) + 1; | ||
| for (var i = 0; i < n; ++i) { | ||
| for (var j = 0, sr = 0; j < m + r; ++j) { | ||
| if (j < m) { | ||
| sr += source.data[i + j * n]; | ||
| } | ||
| if (j >= r) { | ||
| if (j >= w) { | ||
| sr -= source.data[i + (j - w) * n]; | ||
| } | ||
| target.data[i + (j - r) * n] = sr / Math.min(j + 1, m - 1 + w - j, w); | ||
| } | ||
| } | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
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| @@ -0,0 +1,123 @@ | ||
| import {max, range, tickStep} from "d3-array"; | ||
| import {slice} from "./array"; | ||
| import {blurX, blurY} from "./blur"; | ||
| import constant from "./constant"; | ||
| import contours from "./contours"; | ||
|
|
||
| function defaultX(d) { | ||
| return d[0]; | ||
| } | ||
|
|
||
| function defaultY(d) { | ||
| return d[1]; | ||
| } | ||
|
|
||
| export default function() { | ||
| var x = defaultX, | ||
| y = defaultY, | ||
| dx = 960, | ||
| dy = 500, | ||
| r = 20, // blur radius | ||
| k = 2, // log2(grid cell size) | ||
| o = r * 3, // grid offset, to pad for blur | ||
| n = (dx + o * 2) >> k, // grid width | ||
| m = (dy + o * 2) >> k, // grid height | ||
| threshold = constant(20); | ||
|
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| function density(data) { | ||
| var values0 = new Float32Array(n * m), | ||
| values1 = new Float32Array(n * m); | ||
|
|
||
| data.forEach(function(d, i, data) { | ||
| var xi = (x(d, i, data) + o) >> k, | ||
| yi = (y(d, i, data) + o) >> k; | ||
| if (xi >= 0 && xi < n && yi >= 0 && yi < m) { | ||
| ++values0[xi + yi * n]; | ||
| } | ||
| }); | ||
|
|
||
| // TODO Optimize. | ||
| blurX({width: n, height: m, data: values0}, {width: n, height: m, data: values1}, r >> k); | ||
| blurY({width: n, height: m, data: values1}, {width: n, height: m, data: values0}, r >> k); | ||
| blurX({width: n, height: m, data: values0}, {width: n, height: m, data: values1}, r >> k); | ||
| blurY({width: n, height: m, data: values1}, {width: n, height: m, data: values0}, r >> k); | ||
| blurX({width: n, height: m, data: values0}, {width: n, height: m, data: values1}, r >> k); | ||
| blurY({width: n, height: m, data: values1}, {width: n, height: m, data: values0}, r >> k); | ||
|
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| var tz = threshold(values0); | ||
|
|
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| // Convert number of thresholds into uniform thresholds. | ||
| if (!Array.isArray(tz)) { | ||
| var stop = max(values0); | ||
| tz = tickStep(0, stop, tz); | ||
| tz = range(0, Math.floor(stop / tz) * tz, tz); | ||
| tz.shift(); | ||
| } | ||
|
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||
| return contours() | ||
| .thresholds(tz) | ||
| .size([n, m]) | ||
| (values0) | ||
| .map(transform); | ||
| } | ||
|
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||
| function transform(geometry) { | ||
| geometry.value *= Math.pow(2, -2 * k); // Density in points per square pixel. | ||
| geometry.coordinates.forEach(transformPolygon); | ||
| return geometry; | ||
| } | ||
|
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| function transformPolygon(coordinates) { | ||
| coordinates.forEach(transformRing); | ||
| } | ||
|
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| function transformRing(coordinates) { | ||
| coordinates.forEach(transformPoint); | ||
| } | ||
|
|
||
| // TODO Optimize. | ||
| function transformPoint(coordinates) { | ||
| coordinates[0] = coordinates[0] * Math.pow(2, k) - o; | ||
| coordinates[1] = coordinates[1] * Math.pow(2, k) - o; | ||
| } | ||
|
|
||
| function resize() { | ||
| o = r * 3; | ||
| n = (dx + o * 2) >> k; | ||
| m = (dy + o * 2) >> k; | ||
| return density; | ||
| } | ||
|
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||
| density.x = function(_) { | ||
| return arguments.length ? (x = typeof _ === "function" ? _ : constant(+_), density) : x; | ||
| }; | ||
|
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| density.y = function(_) { | ||
| return arguments.length ? (y = typeof _ === "function" ? _ : constant(+_), density) : y; | ||
| }; | ||
|
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| density.size = function(_) { | ||
| if (!arguments.length) return [dx, dy]; | ||
| var _0 = Math.ceil(_[0]), _1 = Math.ceil(_[1]); | ||
| if (!(_0 >= 0) && !(_0 >= 0)) throw new Error("invalid size"); | ||
| return dx = _0, dy = _1, resize(); | ||
| }; | ||
|
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| density.cellSize = function(_) { | ||
| if (!arguments.length) return 1 << k; | ||
| if (!((_ = +_) >= 1)) throw new Error("invalid cell size"); | ||
| return k = Math.floor(Math.log(_) / Math.LN2), resize(); | ||
| }; | ||
|
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| density.thresholds = function(_) { | ||
| return arguments.length ? (threshold = typeof _ === "function" ? _ : Array.isArray(_) ? constant(slice.call(_)) : constant(_), density) : threshold; | ||
| }; | ||
|
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| density.bandwidth = function(_) { | ||
| if (!arguments.length) return Math.sqrt(r * (r + 1)); | ||
| if (!((_ = +_) >= 0)) throw new Error("invalid bandwidth"); | ||
| return r = Math.round((Math.sqrt(4 * _ * _ + 1) - 1) / 2), resize(); | ||
| }; | ||
|
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||
| return density; | ||
| } |