openlayers
Version:
Build tools and sources for developing OpenLayers based mapping applications
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JavaScript
goog.provide('ol.interaction.PinchZoom');
goog.require('ol');
goog.require('ol.View');
goog.require('ol.functions');
goog.require('ol.interaction.Interaction');
goog.require('ol.interaction.Pointer');
/**
* @classdesc
* Allows the user to zoom the map by pinching with two fingers
* on a touch screen.
*
* @constructor
* @extends {ol.interaction.Pointer}
* @param {olx.interaction.PinchZoomOptions=} opt_options Options.
* @api stable
*/
ol.interaction.PinchZoom = function(opt_options) {
ol.interaction.Pointer.call(this, {
handleDownEvent: ol.interaction.PinchZoom.handleDownEvent_,
handleDragEvent: ol.interaction.PinchZoom.handleDragEvent_,
handleUpEvent: ol.interaction.PinchZoom.handleUpEvent_
});
var options = opt_options ? opt_options : {};
/**
* @private
* @type {boolean}
*/
this.constrainResolution_ = options.constrainResolution || false;
/**
* @private
* @type {ol.Coordinate}
*/
this.anchor_ = null;
/**
* @private
* @type {number}
*/
this.duration_ = options.duration !== undefined ? options.duration : 400;
/**
* @private
* @type {number|undefined}
*/
this.lastDistance_ = undefined;
/**
* @private
* @type {number}
*/
this.lastScaleDelta_ = 1;
};
ol.inherits(ol.interaction.PinchZoom, ol.interaction.Pointer);
/**
* @param {ol.MapBrowserPointerEvent} mapBrowserEvent Event.
* @this {ol.interaction.PinchZoom}
* @private
*/
ol.interaction.PinchZoom.handleDragEvent_ = function(mapBrowserEvent) {
ol.DEBUG && console.assert(this.targetPointers.length >= 2,
'length of this.targetPointers should be 2 or more');
var scaleDelta = 1.0;
var touch0 = this.targetPointers[0];
var touch1 = this.targetPointers[1];
var dx = touch0.clientX - touch1.clientX;
var dy = touch0.clientY - touch1.clientY;
// distance between touches
var distance = Math.sqrt(dx * dx + dy * dy);
if (this.lastDistance_ !== undefined) {
scaleDelta = this.lastDistance_ / distance;
}
this.lastDistance_ = distance;
if (scaleDelta != 1.0) {
this.lastScaleDelta_ = scaleDelta;
}
var map = mapBrowserEvent.map;
var view = map.getView();
var resolution = view.getResolution();
// scale anchor point.
var viewportPosition = map.getViewport().getBoundingClientRect();
var centroid = ol.interaction.Pointer.centroid(this.targetPointers);
centroid[0] -= viewportPosition.left;
centroid[1] -= viewportPosition.top;
this.anchor_ = map.getCoordinateFromPixel(centroid);
// scale, bypass the resolution constraint
map.render();
ol.interaction.Interaction.zoomWithoutConstraints(
map, view, resolution * scaleDelta, this.anchor_);
};
/**
* @param {ol.MapBrowserPointerEvent} mapBrowserEvent Event.
* @return {boolean} Stop drag sequence?
* @this {ol.interaction.PinchZoom}
* @private
*/
ol.interaction.PinchZoom.handleUpEvent_ = function(mapBrowserEvent) {
if (this.targetPointers.length < 2) {
var map = mapBrowserEvent.map;
var view = map.getView();
view.setHint(ol.View.Hint.INTERACTING, -1);
if (this.constrainResolution_) {
var resolution = view.getResolution();
// Zoom to final resolution, with an animation, and provide a
// direction not to zoom out/in if user was pinching in/out.
// Direction is > 0 if pinching out, and < 0 if pinching in.
var direction = this.lastScaleDelta_ - 1;
ol.interaction.Interaction.zoom(map, view, resolution,
this.anchor_, this.duration_, direction);
}
return false;
} else {
return true;
}
};
/**
* @param {ol.MapBrowserPointerEvent} mapBrowserEvent Event.
* @return {boolean} Start drag sequence?
* @this {ol.interaction.PinchZoom}
* @private
*/
ol.interaction.PinchZoom.handleDownEvent_ = function(mapBrowserEvent) {
if (this.targetPointers.length >= 2) {
var map = mapBrowserEvent.map;
this.anchor_ = null;
this.lastDistance_ = undefined;
this.lastScaleDelta_ = 1;
if (!this.handlingDownUpSequence) {
map.getView().setHint(ol.View.Hint.INTERACTING, 1);
}
return true;
} else {
return false;
}
};
/**
* @inheritDoc
*/
ol.interaction.PinchZoom.prototype.shouldStopEvent = ol.functions.FALSE;