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Accept resolution or zoom related options for constrained views

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Any of minResolution, maxResolution, minZoom, or maxZoom can be used to constrain the view resolutions.  Resolution options are given precedence over zoom options.
This commit is contained in:
Tim Schaub
2014-05-15 16:43:27 -06:00
parent 3384ba07e3
commit 815f5b38c8
3 changed files with 269 additions and 28 deletions
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43
externs/olx.js
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@@ -351,7 +351,9 @@ olx.ProjectionOptions.prototype.global;
* constrainRotation: (boolean|number|undefined),
* enableRotation: (boolean|undefined),
* extent: (ol.Extent|undefined),
* minResolution: (number|undefined),
* maxResolution: (number|undefined),
* minZoom: (number|undefined),
* maxZoom: (number|undefined),
* projection: ol.proj.ProjectionLike,
* resolution: (number|undefined),
@@ -400,23 +402,48 @@ olx.View2DOptions.prototype.extent;
/**
* The maximum resolution used to determine the resolution constraint. It is
* used together with `maxZoom` and `zoomFactor`. If unspecified it is
* calculated in such a way that the projection's validity extent fits in a
* 256x256 px tile. If the projection is Spherical Mercator (the default) then
* `maxResolution` defaults to `40075016.68557849 / 256 = 156543.03392804097`.
* used together with `minResolution` (or `maxZoom`) and `zoomFactor`. If
* unspecified it is calculated in such a way that the projection's validity
* extent fits in a 256x256 px tile. If the projection is Spherical Mercator
* (the default) then `maxResolution` defaults to `40075016.68557849 / 256 =
* 156543.03392804097`.
* @type {number|undefined}
*/
olx.View2DOptions.prototype.maxResolution;
/**
* The minimum resolution used to determine the resolution constraint. It is
* used together with `maxResolution` (or `minZoom`) and `zoomFactor`. If
* unspecified it is calculated assuming 29 zoom levels (with a factor of 2).
* If the projection is Spherical Mercator (the default) then `minResolution`
* defaults to `40075016.68557849 / 256 / Math.pow(2, 28) =
* 0.0005831682455839253`.
* @type {number|undefined}
*/
olx.View2DOptions.prototype.minResolution;
/**
* The maximum zoom level used to determine the resolution constraint. It is
* used together with `maxResolution` and `zoomFactor`. Default is `28`.
* used together with `minZoom` (or `maxResolution`) and `zoomFactor`. Default
* is `28`. Note that if `minResolution` is also provided, it is given
* precedence over `maxZoom`.
* @type {number|undefined}
*/
olx.View2DOptions.prototype.maxZoom;
/**
* The minimum zoom level used to determine the resolution constraint. It is
* used together with `maxZoom` (or `minResolution`) and `zoomFactor`. Default
* is `0`. Note that if `maxResolution` is also provided, it is given
* precedence over `minZoom`.
* @type {number|undefined}
*/
olx.View2DOptions.prototype.minZoom;
/**
* The projection. Default is `EPSG:3857` (Spherical Mercator).
* @type {ol.proj.ProjectionLike}
@@ -436,7 +463,8 @@ olx.View2DOptions.prototype.resolution;
/**
* Resolutions to determine the resolution constraint. If set the
* `maxResolution`, `maxZoom` and `zoomFactor` options are ignored.
* `maxResolution`, `minResolution`, `minZoom`, `maxZoom`, and `zoomFactor`
* options are ignored.
* @type {Array.<number>|undefined}
*/
olx.View2DOptions.prototype.resolutions;
@@ -460,8 +488,7 @@ olx.View2DOptions.prototype.zoom;
/**
* The zoom factor used to determine the resolution constraint. Used together
* with `maxResolution` and `maxZoom`. Default is `2`.
* The zoom factor used to determine the resolution constraint. Default is `2`.
* @type {number|undefined}
*/
olx.View2DOptions.prototype.zoomFactor;

75
src/ol/view2d.js
View File

@@ -657,30 +657,65 @@ ol.View2D.createResolutionConstraint_ = function(options) {
resolutionConstraint = ol.ResolutionConstraint.createSnapToResolutions(
resolutions);
} else {
// TODO: move these to be ol constants
// see https://github.com/openlayers/ol3/issues/2076
var defaultMaxZoom = 28;
var defaultMinZoom = 0;
var defaultZoomFactor = 2;
// calculate the default min and max resolution
var projection = options.projection;
var extent = ol.proj.createProjection(projection, 'EPSG:3857').getExtent();
var size = goog.isNull(extent) ?
// use an extent that can fit the whole world if need be
360 * ol.proj.METERS_PER_UNIT[ol.proj.Units.DEGREES] /
ol.proj.METERS_PER_UNIT[projection.getUnits()] :
Math.max(ol.extent.getWidth(extent), ol.extent.getHeight(extent));
var defaultMaxResolution = size / ol.DEFAULT_TILE_SIZE / Math.pow(
defaultZoomFactor, defaultMinZoom);
var defaultMinResolution = defaultMaxResolution / Math.pow(
defaultZoomFactor, defaultMaxZoom - defaultMinZoom);
var minZoom = goog.isDef(options.minZoom) ?
options.minZoom : defaultMinZoom;
var maxZoom = goog.isDef(options.maxZoom) ?
options.maxZoom : defaultMaxZoom;
var zoomFactor = goog.isDef(options.zoomFactor) ?
options.zoomFactor : defaultZoomFactor;
// user provided maxResolution takes precedence
maxResolution = options.maxResolution;
if (!goog.isDef(maxResolution)) {
var projection = options.projection;
var projectionExtent = ol.proj.createProjection(projection, 'EPSG:3857')
.getExtent();
var size = goog.isNull(projectionExtent) ?
// use an extent that can fit the whole world if need be
360 * ol.proj.METERS_PER_UNIT[ol.proj.Units.DEGREES] /
ol.proj.METERS_PER_UNIT[projection.getUnits()] :
Math.max(projectionExtent[2] - projectionExtent[0],
projectionExtent[3] - projectionExtent[1]);
maxResolution = size / ol.DEFAULT_TILE_SIZE;
if (goog.isDef(maxResolution)) {
minZoom = 0;
} else {
maxResolution = defaultMaxResolution / Math.pow(zoomFactor, minZoom);
}
var maxZoom = options.maxZoom;
if (!goog.isDef(maxZoom)) {
maxZoom = 28;
// user provided minResolution takes precedence
minResolution = options.minResolution;
if (!goog.isDef(minResolution)) {
if (goog.isDef(options.maxZoom)) {
if (goog.isDef(options.maxResolution)) {
minResolution = maxResolution / Math.pow(zoomFactor, maxZoom);
} else {
minResolution = defaultMaxResolution / Math.pow(zoomFactor, maxZoom);
}
} else {
minResolution = defaultMinResolution;
}
}
var zoomFactor = options.zoomFactor;
if (!goog.isDef(zoomFactor)) {
zoomFactor = 2;
}
minResolution = maxResolution / Math.pow(zoomFactor, maxZoom);
// given discrete zoom levels, minResolution may be different than provided
maxZoom = minZoom + Math.floor(
Math.log(maxResolution / minResolution) / Math.log(zoomFactor));
minResolution = maxResolution / Math.pow(zoomFactor, maxZoom - minZoom);
resolutionConstraint = ol.ResolutionConstraint.createSnapToPower(
zoomFactor, maxResolution, maxZoom);
zoomFactor, maxResolution, maxZoom - minZoom);
}
return {constraint: resolutionConstraint, maxResolution: maxResolution,
minResolution: minResolution};

179
test/spec/ol/view2d.test.js
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@@ -58,6 +58,185 @@ describe('ol.View2D', function() {
});
});
describe('with zoom related options', function() {
var defaultMaxRes = 156543.03392804097;
function getConstraint(options) {
return ol.View2D.createResolutionConstraint_(options).constraint;
}
it('works with only maxZoom', function() {
var maxZoom = 10;
var constraint = getConstraint({
maxZoom: maxZoom
});
expect(constraint(defaultMaxRes, 0, 0)).to.roughlyEqual(
defaultMaxRes, 1e-9);
expect(constraint(0, 0, 0)).to.roughlyEqual(
defaultMaxRes / Math.pow(2, maxZoom), 1e-9);
});
it('works with only minZoom', function() {
var minZoom = 5;
var constraint = getConstraint({
minZoom: minZoom
});
expect(constraint(defaultMaxRes, 0, 0)).to.roughlyEqual(
defaultMaxRes / Math.pow(2, minZoom), 1e-9);
expect(constraint(0, 0, 0)).to.roughlyEqual(
defaultMaxRes / Math.pow(2, 28), 1e-9);
});
it('works with maxZoom and minZoom', function() {
var minZoom = 2;
var maxZoom = 11;
var constraint = getConstraint({
minZoom: minZoom,
maxZoom: maxZoom
});
expect(constraint(defaultMaxRes, 0, 0)).to.roughlyEqual(
defaultMaxRes / Math.pow(2, minZoom), 1e-9);
expect(constraint(0, 0, 0)).to.roughlyEqual(
defaultMaxRes / Math.pow(2, maxZoom), 1e-9);
});
it('works with maxZoom, minZoom, and zoomFactor', function() {
var minZoom = 4;
var maxZoom = 8;
var zoomFactor = 3;
var constraint = getConstraint({
minZoom: minZoom,
maxZoom: maxZoom,
zoomFactor: zoomFactor
});
expect(constraint(defaultMaxRes, 0, 0)).to.roughlyEqual(
defaultMaxRes / Math.pow(zoomFactor, minZoom), 1e-9);
expect(constraint(0, 0, 0)).to.roughlyEqual(
defaultMaxRes / Math.pow(zoomFactor, maxZoom), 1e-9);
});
});
describe('with resolution related options', function() {
var defaultMaxRes = 156543.03392804097;
function getConstraint(options) {
return ol.View2D.createResolutionConstraint_(options).constraint;
}
it('works with only maxResolution', function() {
var maxResolution = 10e6;
var constraint = getConstraint({
maxResolution: maxResolution
});
expect(constraint(maxResolution * 3, 0, 0)).to.roughlyEqual(
maxResolution, 1e-9);
var minResolution = constraint(0, 0, 0);
var defaultMinRes = defaultMaxRes / Math.pow(2, 28);
expect(minResolution).to.be.greaterThan(defaultMinRes);
expect(minResolution / defaultMinRes).to.be.lessThan(2);
});
it('works with only minResolution', function() {
var minResolution = 100;
var constraint = getConstraint({
minResolution: minResolution
});
expect(constraint(defaultMaxRes, 0, 0)).to.roughlyEqual(
defaultMaxRes, 1e-9);
var constrainedMinRes = constraint(0, 0, 0);
expect(constrainedMinRes).to.be.greaterThan(minResolution);
expect(constrainedMinRes / minResolution).to.be.lessThan(2);
});
it('works with minResolution and maxResolution', function() {
var constraint = getConstraint({
maxResolution: 500,
minResolution: 100
});
expect(constraint(600, 0, 0)).to.be(500);
expect(constraint(500, 0, 0)).to.be(500);
expect(constraint(400, 0, 0)).to.be(500);
expect(constraint(300, 0, 0)).to.be(250);
expect(constraint(200, 0, 0)).to.be(250);
expect(constraint(100, 0, 0)).to.be(125);
expect(constraint(0, 0, 0)).to.be(125);
});
it('accepts minResolution, maxResolution, and zoomFactor', function() {
var constraint = getConstraint({
maxResolution: 500,
minResolution: 1,
zoomFactor: 10
});
expect(constraint(1000, 0, 0)).to.be(500);
expect(constraint(500, 0, 0)).to.be(500);
expect(constraint(100, 0, 0)).to.be(50);
expect(constraint(50, 0, 0)).to.be(50);
expect(constraint(10, 0, 0)).to.be(5);
expect(constraint(1, 0, 0)).to.be(5);
});
});
describe('overspecified options (prefers resolution)', function() {
var defaultMaxRes = 156543.03392804097;
function getConstraint(options) {
return ol.View2D.createResolutionConstraint_(options).constraint;
}
it('respects maxResolution over minZoom', function() {
var maxResolution = 10e6;
var minZoom = 8;
var constraint = getConstraint({
maxResolution: maxResolution,
minZoom: minZoom
});
expect(constraint(maxResolution * 3, 0, 0)).to.roughlyEqual(
maxResolution, 1e-9);
var minResolution = constraint(0, 0, 0);
var defaultMinRes = defaultMaxRes / Math.pow(2, 28);
expect(minResolution).to.be.greaterThan(defaultMinRes);
expect(minResolution / defaultMinRes).to.be.lessThan(2);
});
it('respects minResolution over maxZoom', function() {
var minResolution = 100;
var maxZoom = 50;
var constraint = getConstraint({
minResolution: minResolution,
maxZoom: maxZoom
});
expect(constraint(defaultMaxRes, 0, 0)).to.roughlyEqual(
defaultMaxRes, 1e-9);
var constrainedMinRes = constraint(0, 0, 0);
expect(constrainedMinRes).to.be.greaterThan(minResolution);
expect(constrainedMinRes / minResolution).to.be.lessThan(2);
});
});
});
describe('create rotation constraint', function() {