openlayers
Version:
Build tools and sources for developing OpenLayers based mapping applications
67 lines (61 loc) • 2.19 kB
JavaScript
goog.provide('ol.ResolutionConstraint');
goog.require('ol.array');
goog.require('ol.math');
/**
* @param {Array.<number>} resolutions Resolutions.
* @return {ol.ResolutionConstraintType} Zoom function.
*/
ol.ResolutionConstraint.createSnapToResolutions = function(resolutions) {
return (
/**
* @param {number|undefined} resolution Resolution.
* @param {number} delta Delta.
* @param {number} direction Direction.
* @return {number|undefined} Resolution.
*/
function(resolution, delta, direction) {
if (resolution !== undefined) {
var z =
ol.array.linearFindNearest(resolutions, resolution, direction);
z = ol.math.clamp(z + delta, 0, resolutions.length - 1);
var index = Math.floor(z);
if (z != index && index < resolutions.length - 1) {
var power = resolutions[index] / resolutions[index + 1];
return resolutions[index] / Math.pow(power, z - index);
} else {
return resolutions[index];
}
} else {
return undefined;
}
});
};
/**
* @param {number} power Power.
* @param {number} maxResolution Maximum resolution.
* @param {number=} opt_maxLevel Maximum level.
* @return {ol.ResolutionConstraintType} Zoom function.
*/
ol.ResolutionConstraint.createSnapToPower = function(power, maxResolution, opt_maxLevel) {
return (
/**
* @param {number|undefined} resolution Resolution.
* @param {number} delta Delta.
* @param {number} direction Direction.
* @return {number|undefined} Resolution.
*/
function(resolution, delta, direction) {
if (resolution !== undefined) {
var offset = -direction / 2 + 0.5;
var oldLevel = Math.floor(
Math.log(maxResolution / resolution) / Math.log(power) + offset);
var newLevel = Math.max(oldLevel + delta, 0);
if (opt_maxLevel !== undefined) {
newLevel = Math.min(newLevel, opt_maxLevel);
}
return maxResolution / Math.pow(power, newLevel);
} else {
return undefined;
}
});
};