diff options
Diffstat (limited to 'extlib/leaflet/src/geometry/LineUtil.js')
| -rw-r--r-- | extlib/leaflet/src/geometry/LineUtil.js | 159 |
1 files changed, 0 insertions, 159 deletions
diff --git a/extlib/leaflet/src/geometry/LineUtil.js b/extlib/leaflet/src/geometry/LineUtil.js deleted file mode 100644 index 72a80855..00000000 --- a/extlib/leaflet/src/geometry/LineUtil.js +++ /dev/null @@ -1,159 +0,0 @@ -/*
- * L.LineUtil contains different utility functions for line segments
- * and polylines (clipping, simplification, distances, etc.)
- */
-
-L.LineUtil = {
- /*
- * Simplify polyline with vertex reduction and Douglas-Peucker simplification.
- * Improves rendering performance dramatically by lessening the number of points to draw.
- */
- simplify: function(/*Point[]*/ points, /*Number*/ tolerance) {
- if (!tolerance) return points.slice();
-
- // stage 1: vertex reduction
- points = this.reducePoints(points, tolerance);
-
- // stage 2: Douglas-Peucker simplification
- points = this.simplifyDP(points, tolerance);
-
- return points;
- },
-
- // distance from a point to a segment between two points
- pointToSegmentDistance: function(/*Point*/ p, /*Point*/ p1, /*Point*/ p2) {
- return Math.sqrt(this._sqPointToSegmentDist(p, p1, p2));
- },
-
- // Douglas-Peucker simplification, see http://en.wikipedia.org/wiki/Douglas-Peucker_algorithm
- simplifyDP: function(points, tol) {
- var maxDist2 = 0,
- index = 0,
- t2 = tol * tol;
-
- for (var i = 1, len = points.length, dist2; i < len - 1; i++) {
- dist2 = this._sqPointToSegmentDist(points[i], points[0], points[len - 1]);
- if (dist2 > maxDist2) {
- index = i;
- maxDist2 = dist2;
- }
- }
-
- if (maxDist2 >= t2) {
- var part1 = points.slice(0, index),
- part2 = points.slice(index),
- simplifiedPart1 = this.simplifyDP(part1, tol).slice(0, len - 2),
- simplifiedPart2 = this.simplifyDP(part2, tol);
-
- return simplifiedPart1.concat(simplifiedPart2);
- } else {
- return [points[0], points[len - 1]];
- }
- },
-
- // reduce points that are too close to each other to a single point
- reducePoints: function(points, tol) {
- var reducedPoints = [points[0]],
- t2 = tol * tol;
-
- for (var i = 1, prev = 0, len = points.length; i < len; i++) {
- if (this._sqDist(points[i], points[prev]) < t2) continue;
- reducedPoints.push(points[i]);
- prev = i;
- }
- if (prev < len - 1) {
- reducedPoints.push(points[len - 1]);
- }
- return reducedPoints;
- },
-
- /*
- * Cohen-Sutherland line clipping algorithm.
- * Used to avoid rendering parts of a polyline that are not currently visible.
- */
- clipSegment: function(a, b, bounds, useLastCode) {
- var min = bounds.min,
- max = bounds.max;
-
- var codeA = useLastCode ? this._lastCode : this._getBitCode(a, bounds),
- codeB = this._getBitCode(b, bounds);
-
- // save 2nd code to avoid calculating it on the next segment
- this._lastCode = codeB;
-
- while (true) {
- // if a,b is inside the clip window (trivial accept)
- if (!(codeA | codeB)) {
- return [a, b];
- // if a,b is outside the clip window (trivial reject)
- } else if (codeA & codeB) {
- return false;
- // other cases
- } else {
- var codeOut = codeA || codeB,
- p = this._getEdgeIntersection(a, b, codeOut, bounds),
- newCode = this._getBitCode(p, bounds);
-
- if (codeOut == codeA) {
- a = p;
- codeA = newCode;
- } else {
- b = p;
- codeB = newCode;
- }
- }
- }
- },
-
- _getEdgeIntersection: function(a, b, code, bounds) {
- var dx = b.x - a.x,
- dy = b.y - a.y,
- min = bounds.min,
- max = bounds.max;
-
- if (code & 8) { // top
- return new L.Point(a.x + dx * (max.y - a.y) / dy, max.y);
- } else if (code & 4) { // bottom
- return new L.Point(a.x + dx * (min.y - a.y) / dy, min.y);
- } else if (code & 2){ // right
- return new L.Point(max.x, a.y + dy * (max.x - a.x) / dx);
- } else if (code & 1) { // left
- return new L.Point(min.x, a.y + dy * (min.x - a.x) / dx);
- }
- },
-
- _getBitCode: function(/*Point*/ p, bounds) {
- var code = 0;
-
- if (p.x < bounds.min.x) code |= 1; // left
- else if (p.x > bounds.max.x) code |= 2; // right
- if (p.y < bounds.min.y) code |= 4; // bottom
- else if (p.y > bounds.max.y) code |= 8; // top
-
- return code;
- },
-
- // square distance (to avoid unnecessary Math.sqrt calls)
- _sqDist: function(p1, p2) {
- var dx = p2.x - p1.x,
- dy = p2.y - p1.y;
- return dx * dx + dy * dy;
- },
-
- // square distance from point to a segment
- _sqPointToSegmentDist: function(p, p1, p2) {
- var x2 = p2.x - p1.x,
- y2 = p2.y - p1.y;
-
- if (!x2 && !y2) return this._sqDist(p, p1);
-
- var dot = (p.x - p1.x) * x2 + (p.y - p1.y) * y2,
- t = dot / this._sqDist(p1, p2);
-
- if (t < 0) return this._sqDist(p, p1);
- if (t > 1) return this._sqDist(p, p2);
-
- var proj = new L.Point(p1.x + x2 * t, p1.y + y2 * t);
- return this._sqDist(p, proj);
- }
-};
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