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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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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};