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import {abs, epsilon} from "../math.js";
import clipBuffer from "./buffer.js";
import clipLine from "./line.js";
import clipRejoin from "./rejoin.js";
import {merge} from "d3-array";
var clipMax = 1e9, clipMin = -clipMax;
// TODO Use d3-polygon’s polygonContains here for the ring check?
// TODO Eliminate duplicate buffering in clipBuffer and polygon.push?
export default function clipRectangle(x0, y0, x1, y1) {
function visible(x, y) {
return x0 <= x && x <= x1 && y0 <= y && y <= y1;
}
function interpolate(from, to, direction, stream) {
var a = 0, a1 = 0;
if (from == null
|| (a = corner(from, direction)) !== (a1 = corner(to, direction))
|| comparePoint(from, to) < 0 ^ direction > 0) {
do stream.point(a === 0 || a === 3 ? x0 : x1, a > 1 ? y1 : y0);
while ((a = (a + direction + 4) % 4) !== a1);
} else {
stream.point(to[0], to[1]);
}
}
function corner(p, direction) {
return abs(p[0] - x0) < epsilon ? direction > 0 ? 0 : 3
: abs(p[0] - x1) < epsilon ? direction > 0 ? 2 : 1
: abs(p[1] - y0) < epsilon ? direction > 0 ? 1 : 0
: direction > 0 ? 3 : 2; // abs(p[1] - y1) < epsilon
}
function compareIntersection(a, b) {
return comparePoint(a.x, b.x);
}
function comparePoint(a, b) {
var ca = corner(a, 1),
cb = corner(b, 1);
return ca !== cb ? ca - cb
: ca === 0 ? b[1] - a[1]
: ca === 1 ? a[0] - b[0]
: ca === 2 ? a[1] - b[1]
: b[0] - a[0];
}
return function(stream) {
var activeStream = stream,
bufferStream = clipBuffer(),
segments,
polygon,
ring,
x__, y__, v__, // first point
x_, y_, v_, // previous point
first,
clean;
var clipStream = {
point: point,
lineStart: lineStart,
lineEnd: lineEnd,
polygonStart: polygonStart,
polygonEnd: polygonEnd
};
function point(x, y) {
if (visible(x, y)) activeStream.point(x, y);
}
function polygonInside() {
var winding = 0;
for (var i = 0, n = polygon.length; i < n; ++i) {
for (var ring = polygon[i], j = 1, m = ring.length, point = ring[0], a0, a1, b0 = point[0], b1 = point[1]; j < m; ++j) {
a0 = b0, a1 = b1, point = ring[j], b0 = point[0], b1 = point[1];
if (a1 <= y1) { if (b1 > y1 && (b0 - a0) * (y1 - a1) > (b1 - a1) * (x0 - a0)) ++winding; }
else { if (b1 <= y1 && (b0 - a0) * (y1 - a1) < (b1 - a1) * (x0 - a0)) --winding; }
}
}
return winding;
}
// Buffer geometry within a polygon and then clip it en masse.
function polygonStart() {
activeStream = bufferStream, segments = [], polygon = [], clean = true;
}
function polygonEnd() {
var startInside = polygonInside(),
cleanInside = clean && startInside,
visible = (segments = merge(segments)).length;
if (cleanInside || visible) {
stream.polygonStart();
if (cleanInside) {
stream.lineStart();
interpolate(null, null, 1, stream);
stream.lineEnd();
}
if (visible) {
clipRejoin(segments, compareIntersection, startInside, interpolate, stream);
}
stream.polygonEnd();
}
activeStream = stream, segments = polygon = ring = null;
}
function lineStart() {
clipStream.point = linePoint;
if (polygon) polygon.push(ring = []);
first = true;
v_ = false;
x_ = y_ = NaN;
}
// TODO rather than special-case polygons, simply handle them separately.
// Ideally, coincident intersection points should be jittered to avoid
// clipping issues.
function lineEnd() {
if (segments) {
linePoint(x__, y__);
if (v__ && v_) bufferStream.rejoin();
segments.push(bufferStream.result());
}
clipStream.point = point;
if (v_) activeStream.lineEnd();
}
function linePoint(x, y) {
var v = visible(x, y);
if (polygon) ring.push([x, y]);
if (first) {
x__ = x, y__ = y, v__ = v;
first = false;
if (v) {
activeStream.lineStart();
activeStream.point(x, y);
}
} else {
if (v && v_) activeStream.point(x, y);
else {
var a = [x_ = Math.max(clipMin, Math.min(clipMax, x_)), y_ = Math.max(clipMin, Math.min(clipMax, y_))],
b = [x = Math.max(clipMin, Math.min(clipMax, x)), y = Math.max(clipMin, Math.min(clipMax, y))];
if (clipLine(a, b, x0, y0, x1, y1)) {
if (!v_) {
activeStream.lineStart();
activeStream.point(a[0], a[1]);
}
activeStream.point(b[0], b[1]);
if (!v) activeStream.lineEnd();
clean = false;
} else if (v) {
activeStream.lineStart();
activeStream.point(x, y);
clean = false;
}
}
}
x_ = x, y_ = y, v_ = v;
}
return clipStream;
};
}
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