Add ol.geom.flat.intersectsextent

Includes functions for testing if an extent and a geometry intersect.

src/ol/geom/flat/intersectsextent.js

@@ -0,0 +1,154 @@
+goog.provide('ol.geom.flat.intersectsextent');
+
+goog.require('goog.asserts');
+goog.require('ol.extent');
+goog.require('ol.geom.flat.contains');
+goog.require('ol.geom.flat.segments');
+
+
+/**
+ * @param {Array.<number>} flatCoordinates Flat coordinates.
+ * @param {number} offset Offset.
+ * @param {number} end End.
+ * @param {number} stride Stride.
+ * @param {ol.Extent} extent Extent.
+ * @return {boolean} True if the geometry and the extent intersect.
+ */
+ol.geom.flat.intersectsextent.lineString =
+    function(flatCoordinates, offset, end, stride, extent) {
+  var coordinatesExtent = ol.extent.extendFlatCoordinates(
+      ol.extent.createEmpty(), flatCoordinates, offset, end, stride);
+  if (!ol.extent.intersects(extent, coordinatesExtent)) {
+    return false;
+  }
+  if (ol.extent.containsExtent(extent, coordinatesExtent)) {
+    return true;
+  }
+  if (coordinatesExtent[0] >= extent[0] &&
+      coordinatesExtent[2] <= extent[2]) {
+    return true;
+  }
+  if (coordinatesExtent[1] >= extent[1] &&
+      coordinatesExtent[3] <= extent[3]) {
+    return true;
+  }
+  return ol.geom.flat.segments.forEach(flatCoordinates, offset, end, stride,
+      /**
+       * @param {ol.Coordinate} point1 Start point.
+       * @param {ol.Coordinate} point2 End point.
+       * @return {boolean} `true` if the segment and the extent intersect,
+       *     `false` otherwise.
+       */
+      function(point1, point2) {
+        return ol.extent.segmentIntersects(extent, point1, point2);
+      });
+};
+
+
+/**
+ * @param {Array.<number>} flatCoordinates Flat coordinates.
+ * @param {number} offset Offset.
+ * @param {Array.<number>} ends Ends.
+ * @param {number} stride Stride.
+ * @param {ol.Extent} extent Extent.
+ * @return {boolean} True if the geometry and the extent intersect.
+ */
+ol.geom.flat.intersectsextent.lineStrings =
+    function(flatCoordinates, offset, ends, stride, extent) {
+  var i, ii;
+  for (i = 0, ii = ends.length; i < ii; ++i) {
+    if (ol.geom.flat.intersectsextent.lineString(
+        flatCoordinates, offset, ends[i], stride, extent)) {
+      return true;
+    }
+    offset = ends[i];
+  }
+  return false;
+};
+
+
+/**
+ * @param {Array.<number>} flatCoordinates Flat coordinates.
+ * @param {number} offset Offset.
+ * @param {number} end End.
+ * @param {number} stride Stride.
+ * @param {ol.Extent} extent Extent.
+ * @return {boolean} True if the geometry and the extent intersect.
+ */
+ol.geom.flat.intersectsextent.linearRing =
+    function(flatCoordinates, offset, end, stride, extent) {
+  if (ol.geom.flat.intersectsextent.lineString(
+      flatCoordinates, offset, end, stride, extent)) {
+    return true;
+  }
+  if (ol.geom.flat.contains.linearRingContainsXY(
+      flatCoordinates, offset, end, stride, extent[0], extent[1])) {
+    return true;
+  }
+  if (ol.geom.flat.contains.linearRingContainsXY(
+      flatCoordinates, offset, end, stride, extent[0], extent[3])) {
+    return true;
+  }
+  if (ol.geom.flat.contains.linearRingContainsXY(
+      flatCoordinates, offset, end, stride, extent[2], extent[1])) {
+    return true;
+  }
+  if (ol.geom.flat.contains.linearRingContainsXY(
+      flatCoordinates, offset, end, stride, extent[2], extent[3])) {
+    return true;
+  }
+  return false;
+};
+
+
+/**
+ * @param {Array.<number>} flatCoordinates Flat coordinates.
+ * @param {number} offset Offset.
+ * @param {Array.<number>} ends Ends.
+ * @param {number} stride Stride.
+ * @param {ol.Extent} extent Extent.
+ * @return {boolean} True if the geometry and the extent intersect.
+ */
+ol.geom.flat.intersectsextent.linearRings =
+    function(flatCoordinates, offset, ends, stride, extent) {
+  goog.asserts.assert(ends.length > 0);
+  if (!ol.geom.flat.intersectsextent.linearRing(
+      flatCoordinates, offset, ends[0], stride, extent)) {
+    return false;
+  }
+  if (ends.length === 1) {
+    return true;
+  }
+  var i, ii;
+  for (i = 1, ii = ends.length; i < ii; ++i) {
+    if (ol.geom.flat.contains.linearRingContainsExtent(
+        flatCoordinates, ends[i - 1], ends[i], stride, extent)) {
+      return false;
+    }
+  }
+  return true;
+};
+
+
+/**
+ * @param {Array.<number>} flatCoordinates Flat coordinates.
+ * @param {number} offset Offset.
+ * @param {Array.<Array.<number>>} endss Endss.
+ * @param {number} stride Stride.
+ * @param {ol.Extent} extent Extent.
+ * @return {boolean} True if the geometry and the extent intersect.
+ */
+ol.geom.flat.intersectsextent.linearRingss =
+    function(flatCoordinates, offset, endss, stride, extent) {
+  goog.asserts.assert(endss.length > 0);
+  var i, ii;
+  for (i = 0, ii = endss.length; i < ii; ++i) {
+    var ends = endss[i];
+    if (ol.geom.flat.intersectsextent.linearRings(
+        flatCoordinates, offset, ends, stride, extent)) {
+      return true;
+    }
+    offset = ends[ends.length - 1];
+  }
+  return false;
+};

test/spec/ol/geom/flat/intersectsextentflatgeom.test.js

@@ -0,0 +1,92 @@
+goog.provide('ol.test.geom.flat.intersectsextent');
+
+describe('ol.geom.flat.intersectsextent', function() {
+
+  describe('ol.geom.flat.intersectsextent.lineString', function() {
+    var flatCoordinates;
+    beforeEach(function() {
+      flatCoordinates = [0, 0, 1, 1, 2, 2];
+    });
+    describe('linestring envelope does not intersect the extent', function() {
+      it('returns false', function() {
+        var extent = [3, 3, 4, 4];
+        var r = ol.geom.flat.intersectsextent.lineString(
+            flatCoordinates, 0, flatCoordinates.length, 2, extent);
+        expect(r).to.be(false);
+      });
+    });
+    describe('linestring envelope within the extent', function() {
+      it('returns true', function() {
+        var extent = [-1, -1, 3, 3];
+        var r = ol.geom.flat.intersectsextent.lineString(
+            flatCoordinates, 0, flatCoordinates.length, 2, extent);
+        expect(r).to.be(true);
+      });
+    });
+    describe('linestring envelope bisected by an edge of the extent',
+        function() {
+          it('returns true', function() {
+            var extent = [-0.1, 0.1, 2.1, 0.1];
+            var r = ol.geom.flat.intersectsextent.lineString(
+                flatCoordinates, 0, flatCoordinates.length, 2, extent);
+            expect(r).to.be(true);
+          });
+        });
+    describe('a segment intersects the extent', function() {
+      it('returns true', function() {
+        var extent = [-0.5, -0.5, 0.5, 0.5];
+        var r = ol.geom.flat.intersectsextent.lineString(
+            flatCoordinates, 0, flatCoordinates.length, 2, extent);
+        expect(r).to.be(true);
+      });
+    });
+    describe('no segments intersect the extent', function() {
+      it('returns false', function() {
+        var extent = [0.5, 1.5, 1, 1.75];
+        var r = ol.geom.flat.intersectsextent.lineString(
+            flatCoordinates, 0, flatCoordinates.length, 2, extent);
+        expect(r).to.be(false);
+      });
+      it('returns false', function() {
+        var extent = [1, 0.25, 1.5, 0.5];
+        var r = ol.geom.flat.intersectsextent.lineString(
+            flatCoordinates, 0, flatCoordinates.length, 2, extent);
+        expect(r).to.be(false);
+      });
+    });
+  });
+
+  describe('ol.geom.flat.intersectsextent.linearRing', function() {
+    var flatCoordinates;
+    beforeEach(function() {
+      flatCoordinates = [0, 0, 1, 1, 2, 0, 1, -1, 0, 0];
+    });
+    describe('boundary intersects the extent', function() {
+      it('returns true', function() {
+        var extent = [1.5, 0.0, 2.5, 1.0];
+        var r = ol.geom.flat.intersectsextent.linearRing(
+            flatCoordinates, 0, flatCoordinates.length, 2, extent);
+        expect(r).to.be(true);
+      });
+    });
+    describe('boundary does not intersect the extent and ring does not ' +
+        'contain a corner of the extent', function() {
+          it('returns false', function() {
+            var extent = [2.0, 0.5, 3, 1.5];
+            var r = ol.geom.flat.intersectsextent.linearRing(
+                flatCoordinates, 0, flatCoordinates.length, 2, extent);
+            expect(r).to.be(false);
+          });
+        });
+    describe('ring contains the extent', function() {
+      it('returns true', function() {
+        var extent = [0.75, -0.25, 1.25, 0.25];
+        var r = ol.geom.flat.intersectsextent.linearRing(
+            flatCoordinates, 0, flatCoordinates.length, 2, extent);
+        expect(r).to.be(true);
+      });
+    });
+  });
+});
+
+goog.require('ol.geom.flat.intersectsextent');