jsoneditor/app/web/splitter.js

139 lines
4.0 KiB
JavaScript

/**
* A splitter control.
* Turns an existing HTML element into an horizontal splitter control.
* @constructor Splitter
* @param {Object} params Available parameters:
* {Element} container HTML container representing
* the splitter
* {function} [change] Callback method called when
* the splitter value has changed.
* The callback is called with
* the new value as parameter
*/
function Splitter (params) {
if (!params || !params.container) {
throw new Error('params.container undefined in Splitter constructor');
}
var me = this;
JSONEditor.util.addEventListener(params.container, "mousedown", function (event) {
me.onMouseDown(event);
});
this.container = params.container;
this.onChange = (params.change) ? params.change : function () {};
this.params = {};
}
/**
* Handle mouse down event. Start dragging the splitter.
* @param {Event} event
* @private
*/
Splitter.prototype.onMouseDown = function (event) {
var me = this;
var leftButtonDown = event.which ? (event.which == 1) : (event.button == 1);
if (!leftButtonDown) {
return;
}
if (!this.params.mousedown) {
this.params.mousedown = true;
this.params.mousemove =
JSONEditor.util.addEventListener(document, 'mousemove', function (event) {
me.onMouseMove(event);
});
this.params.mouseup =
JSONEditor.util.addEventListener(document, 'mouseup', function (event) {
me.onMouseUp(event);
});
this.params.screenX = event.screenX;
this.params.value = this.getValue();
}
JSONEditor.util.preventDefault(event);
};
/**
* Handle on mouse move event. Used to drag the splitter
* @param {Event} event
* @private
*/
Splitter.prototype.onMouseMove = function (event) {
var width = (window.innerWidth || document.body.offsetWidth ||
document.documentElement.offsetWidth);
var diff = event.screenX - this.params.screenX;
var value = this.params.value + diff / width;
value = this.setValue(value);
this.onChange(value);
JSONEditor.util.preventDefault(event);
};
/**
* Handle on mouse up event
* @param {Event} event
* @private
*/
Splitter.prototype.onMouseUp = function (event) {
if (this.params.mousedown) {
JSONEditor.util.removeEventListener(document, 'mousemove', this.params.mousemove);
JSONEditor.util.removeEventListener(document, 'mouseup', this.params.mouseup);
this.params.mousemove = undefined;
this.params.mouseup = undefined;
this.params.mousedown = false;
}
JSONEditor.util.preventDefault(event);
};
/**
* Set a value for the splitter (UI is not adjusted)
* @param {Number} value A number between 0.1 and 0.9
* @return {Number} value The stored value
*/
Splitter.prototype.setValue = function (value) {
value = Number(value);
if (value < 0.1) {
value = 0.1;
}
if (value > 0.9) {
value = 0.9;
}
this.value = value;
try {
localStorage['splitterValue'] = value;
}
catch (e) {
console.log(e);
}
return value;
};
/**
* Get the splitter value from local storage
* @return {Number} value A value between 0.1 and 0.9
*/
Splitter.prototype.getValue = function () {
var value = this.value;
if (value == undefined) {
// read from localStorage once
try {
if (localStorage['splitterValue'] != undefined) {
value = Number(localStorage['splitterValue']); // read
value = this.setValue(value); // verify and store
}
}
catch (e) {
console.log(e);
}
}
if (value == undefined) {
value = this.setValue(0.5);
}
return value;
};