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jasondaviesjasondavies
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First stab at d3.geo.clipView.
This is a simple stream transformation for the moment. Note that the clip region points should be specified in counterclockwise order as required by d3.geom.polygon, and unlike GeoJSON, the first and last points should not be coincident.
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Lines changed: 179 additions & 4 deletions

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‎Makefile‎

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@@ -194,6 +194,7 @@ d3.geo.js: \
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src/geo/clip.js \
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src/geo/clip-antimeridian.js \
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src/geo/clip-circle.js \
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src/geo/clip-view.js \
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src/geo/compose.js \
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src/geo/equirectangular.js \
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src/geo/gnomonic.js \

‎d3.js‎

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@@ -6052,6 +6052,84 @@ d3 = function() {
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return d3_geo_spherical(q);
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}
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}
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d3.geo.clipView = function d3_geo_clipView(coordinates) {
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var clipPolygon = d3.geom.polygon(coordinates).clip;
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return function(listener) {
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var clip = {
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point: point,
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lineStart: lineStart,
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lineEnd: lineEnd,
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polygonStart: function() {
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clip.lineStart = ringStart;
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clip.lineEnd = ringEnd;
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clip.point = ringPoint;
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},
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polygonEnd: function() {
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clip.point = point;
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clip.lineEnd = lineEnd;
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clip.lineStart = lineStart;
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}
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};
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function visible(x, y) {
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var p = [ x, y ], i = -1, n = coordinates.length, a = coordinates[n - 1];
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while (++i < n) {
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b = coordinates[i];
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if (!d3_geom_polygonInside(p, a, b)) return false;
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a = b;
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}
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return true;
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}
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function point(x, y) {
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if (visible(x, y)) {
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listener.point(x, y);
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}
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}
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var x0, y0, v0, first;
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function lineStart() {
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clip.point = linePoint;
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first = true;
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v0 = false;
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}
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function lineEnd() {
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clip.point = point;
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if (v0) listener.lineEnd();
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}
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function linePoint(x, y) {
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var v = visible(x, y);
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if (v) {
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if (first) listener.lineStart(); else if (v !== v0) {
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listener.lineStart();
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}
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listener.point(x, y);
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} else if (v0) {
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listener.lineEnd();
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}
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first = false;
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x0 = x, y0 = y, v0 = v;
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}
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var ring;
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function ringStart() {
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ring = [];
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}
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function ringEnd() {
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ring.pop();
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ring = clipPolygon(ring);
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var n = ring.length;
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if (n) {
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listener.lineStart();
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for (var i = 0, n = ring.length, p; i < n; ++i) {
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listener.point((p = ring[i])[0], p[1]);
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}
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listener.point(ring[0][0], ring[0][1]);
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listener.lineEnd();
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}
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}
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function ringPoint(x, y) {
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ring.push([ x, y ]);
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}
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return clip;
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};
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};
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function d3_geo_compose(a, b) {
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function compose(x, y) {
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return x = a(x, y), b(x[0], x[1]);

‎d3.min.js‎

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‎src/geo/clip-view.js‎

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d3.geo.clipView = function d3_geo_clipView(coordinates) {
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var clipPolygon = d3.geom.polygon(coordinates).clip;
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return function(listener) {
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var clip = {
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point: point,
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lineStart: lineStart,
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lineEnd: lineEnd,
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polygonStart: function() {
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clip.lineStart = ringStart;
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clip.lineEnd = ringEnd;
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clip.point = ringPoint;
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},
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polygonEnd: function() {
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clip.point = point;
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clip.lineEnd = lineEnd;
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clip.lineStart = lineStart;
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}
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};
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function visible(x, y) {
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var p = [x, y],
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i = -1,
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n = coordinates.length,
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a = coordinates[n - 1];
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while (++i < n) {
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b = coordinates[i];
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if (!d3_geom_polygonInside(p, a, b)) return false;
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a = b;
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}
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return true;
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}
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function point(x, y) {
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if (visible(x, y)) {
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listener.point(x, y);
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}
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}
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var x0, y0, v0, first;
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function lineStart() {
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clip.point = linePoint;
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first = true;
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v0 = false;
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}
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function lineEnd() {
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clip.point = point;
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if (v0) listener.lineEnd();
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}
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function linePoint(x, y) {
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var v = visible(x, y);
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if (v) {
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if (first) listener.lineStart();
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else if (v !== v0) {
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listener.lineStart();
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// TODO intersect
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}
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listener.point(x, y);
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} else if (v0) {
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// TODO intersect
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listener.lineEnd();
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}
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first = false;
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x0 = x, y0 = y, v0 = v;
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}
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var ring;
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function ringStart() {
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ring = [];
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}
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function ringEnd() {
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ring.pop();
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ring = clipPolygon(ring);
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var n = ring.length;
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if (n) {
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listener.lineStart();
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for (var i = 0, n = ring.length, p; i < n; ++i) {
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listener.point((p = ring[i])[0], p[1]);
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}
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listener.point(ring[0][0], ring[0][1]);
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listener.lineEnd();
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}
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}
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function ringPoint(x, y) {
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ring.push([x, y]);
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}
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return clip;
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};
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}

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