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Add approximatelyEquals function for comparing extents

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This commit is contained in:
Andreas Hocevar
2020-03-31 14:52:02 +02:00
parent 2c7f58dbed
commit cdafc4fa05
3 changed files with 27 additions and 8 deletions
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12
src/ol/extent.js
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@@ -295,6 +295,18 @@ export function equals(extent1, extent2) {
extent1[1] == extent2[1] && extent1[3] == extent2[3]; extent1[1] == extent2[1] && extent1[3] == extent2[3];
} }
/**
* Determine if two extents are approximately equivalent.
* @param {Extent} extent1 Extent 1.
* @param {Extent} extent2 Extent 2.
* @param {number} tolerance Tolerance in extent coordinate units.
* @return {boolean} The two extents differ by less than the tolerance.
*/
export function approximatelyEquals(extent1, extent2, tolerance) {
return Math.abs(extent1[0] - extent2[0]) < tolerance && Math.abs(extent1[2] - extent2[2]) < tolerance &&
Math.abs(extent1[1] - extent2[1]) < tolerance && Math.abs(extent1[3] - extent2[3]) < tolerance;
}
/** /**
* Modify an extent to include another extent. * Modify an extent to include another extent.

14
src/ol/layer/Graticule.js
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@@ -18,7 +18,7 @@ import {
applyTransform, applyTransform,
containsCoordinate, containsCoordinate,
containsExtent, containsExtent,
equals, approximatelyEquals,
getCenter, getCenter,
getHeight, getHeight,
getIntersection, getIntersection,
@@ -481,17 +481,15 @@ class Graticule extends VectorLayer {
*/ */
strategyFunction(extent, resolution) { strategyFunction(extent, resolution) {
// extents may be passed in different worlds, to avoid endless loop we use only one // extents may be passed in different worlds, to avoid endless loop we use only one
const realExtent = extent.slice(); const realWorldExtent = extent.slice();
if (this.projection_ && this.getSource().getWrapX()) { if (this.projection_ && this.getSource().getWrapX()) {
wrapExtentX(realExtent, this.projection_); wrapExtentX(realWorldExtent, this.projection_);
} }
realExtent[0] = Math.round(realExtent[0] * 1e8) / 1e8; if (this.loadedExtent_ && !approximatelyEquals(this.loadedExtent_, realWorldExtent, resolution)) {
realExtent[2] = Math.round(realExtent[2] * 1e8) / 1e8;
if (this.loadedExtent_ && !equals(this.loadedExtent_, realExtent)) {
// we should not keep track of loaded extents // we should not keep track of loaded extents
this.getSource().removeLoadedExtent(this.loadedExtent_); this.getSource().removeLoadedExtent(this.loadedExtent_);
} }
return [realExtent]; return [realWorldExtent];
} }
/** /**
@@ -508,7 +506,7 @@ class Graticule extends VectorLayer {
const layerExtent = this.getExtent() || [-Infinity, -Infinity, Infinity, Infinity]; const layerExtent = this.getExtent() || [-Infinity, -Infinity, Infinity, Infinity];
const renderExtent = getIntersection(layerExtent, extent); const renderExtent = getIntersection(layerExtent, extent);
if (this.renderedExtent_ && equals(this.renderedExtent_, renderExtent)) { if (this.renderedExtent_ && approximatelyEquals(this.renderedExtent_, renderExtent, resolution)) {
return; return;
} }
this.renderedExtent_ = renderExtent; this.renderedExtent_ = renderExtent;

9
test/spec/ol/extent.test.js
View File

@@ -851,4 +851,13 @@ describe('ol.extent', function() {
}); });
describe('approximatelyEquals', function() {
it('returns true when within tolerance', function() {
expect(_ol_extent_.approximatelyEquals([16, 48, 17, 49], [16.09, 48, 17, 49], 0.1)).to.be(true);
});
it('returns false when not within tolerance', function() {
expect(_ol_extent_.approximatelyEquals([16, 48, 17, 49], [16.11, 48, 17, 49], 0.1)).to.be(false);
});
});
}); });