86 lines
2.7 KiB
JavaScript
86 lines
2.7 KiB
JavaScript
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import clipRectangle from "../clip/rectangle.js";
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import identity from "../identity.js";
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import {transformer} from "../transform.js";
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import {fitExtent, fitSize, fitWidth, fitHeight} from "./fit.js";
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import {cos, degrees, radians, sin} from "../math.js";
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export default function() {
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var k = 1, tx = 0, ty = 0, sx = 1, sy = 1, // scale, translate and reflect
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alpha = 0, ca, sa, // angle
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x0 = null, y0, x1, y1, // clip extent
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kx = 1, ky = 1,
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transform = transformer({
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point: function(x, y) {
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var p = projection([x, y])
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this.stream.point(p[0], p[1]);
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}
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}),
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postclip = identity,
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cache,
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cacheStream;
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function reset() {
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kx = k * sx;
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ky = k * sy;
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cache = cacheStream = null;
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return projection;
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}
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function projection (p) {
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var x = p[0] * kx, y = p[1] * ky;
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if (alpha) {
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var t = y * ca - x * sa;
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x = x * ca + y * sa;
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y = t;
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}
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return [x + tx, y + ty];
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}
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projection.invert = function(p) {
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var x = p[0] - tx, y = p[1] - ty;
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if (alpha) {
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var t = y * ca + x * sa;
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x = x * ca - y * sa;
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y = t;
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}
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return [x / kx, y / ky];
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};
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projection.stream = function(stream) {
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return cache && cacheStream === stream ? cache : cache = transform(postclip(cacheStream = stream));
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};
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projection.postclip = function(_) {
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return arguments.length ? (postclip = _, x0 = y0 = x1 = y1 = null, reset()) : postclip;
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};
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projection.clipExtent = function(_) {
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return arguments.length ? (postclip = _ == null ? (x0 = y0 = x1 = y1 = null, identity) : clipRectangle(x0 = +_[0][0], y0 = +_[0][1], x1 = +_[1][0], y1 = +_[1][1]), reset()) : x0 == null ? null : [[x0, y0], [x1, y1]];
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};
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projection.scale = function(_) {
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return arguments.length ? (k = +_, reset()) : k;
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};
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projection.translate = function(_) {
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return arguments.length ? (tx = +_[0], ty = +_[1], reset()) : [tx, ty];
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}
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projection.angle = function(_) {
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return arguments.length ? (alpha = _ % 360 * radians, sa = sin(alpha), ca = cos(alpha), reset()) : alpha * degrees;
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};
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projection.reflectX = function(_) {
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return arguments.length ? (sx = _ ? -1 : 1, reset()) : sx < 0;
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};
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projection.reflectY = function(_) {
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return arguments.length ? (sy = _ ? -1 : 1, reset()) : sy < 0;
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};
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projection.fitExtent = function(extent, object) {
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return fitExtent(projection, extent, object);
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};
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projection.fitSize = function(size, object) {
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return fitSize(projection, size, object);
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};
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projection.fitWidth = function(width, object) {
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return fitWidth(projection, width, object);
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};
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projection.fitHeight = function(height, object) {
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return fitHeight(projection, height, object);
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};
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return projection;
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}
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