openmct/platform/features/layout/src/FixedDragHandle.js
Victor Woeltjen 10863514cb [Licenses] Add license headers
WTD-1051.
2015-05-13 16:43:30 -07:00

117 lines
4.2 KiB
JavaScript

/*****************************************************************************
* Open MCT Web, Copyright (c) 2014-2015, United States Government
* as represented by the Administrator of the National Aeronautics and Space
* Administration. All rights reserved.
*
* Open MCT Web is licensed under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* http://www.apache.org/licenses/LICENSE-2.0.
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
* Open MCT Web includes source code licensed under additional open source
* licenses. See the Open Source Licenses file (LICENSES.md) included with
* this source code distribution or the Licensing information page available
* at runtime from the About dialog for additional information.
*****************************************************************************/
/*global define*/
define(
[],
function () {
'use strict';
// Drag handle dimensions
var DRAG_HANDLE_SIZE = [ 6, 6 ];
/**
* Template-displayable drag handle for an element in fixed
* position mode.
* @constructor
*/
function FixedDragHandle(elementHandle, gridSize, update, commit) {
var self = {},
dragging;
// Generate ng-style-appropriate style for positioning
function getStyle() {
// Adjust from grid to pixel coordinates
var x = elementHandle.x() * gridSize[0],
y = elementHandle.y() * gridSize[1];
// Convert to a CSS style centered on that point
return {
left: (x - DRAG_HANDLE_SIZE[0] / 2) + 'px',
top: (y - DRAG_HANDLE_SIZE[1] / 2) + 'px',
width: DRAG_HANDLE_SIZE[0] + 'px',
height: DRAG_HANDLE_SIZE[1] + 'px'
};
}
// Begin a drag gesture
function startDrag() {
// Cache initial x/y positions
dragging = { x: elementHandle.x(), y: elementHandle.y() };
}
// Reposition during drag
function continueDrag(delta) {
if (dragging) {
// Update x/y positions (snapping to grid)
elementHandle.x(
dragging.x + Math.round(delta[0] / gridSize[0])
);
elementHandle.y(
dragging.y + Math.round(delta[1] / gridSize[1])
);
// Invoke update callback
if (update) {
update();
}
}
}
// Conclude a drag gesture
function endDrag() {
// Clear cached state
dragging = undefined;
// Mark change as complete
if (commit) {
commit("Dragged handle.");
}
}
return {
/**
* Get a CSS style to position this drag handle.
* @returns CSS style object (for `ng-style`)
*/
style: getStyle,
/**
* Start a drag gesture. This should be called when a drag
* begins to track initial state.
*/
startDrag: startDrag,
/**
* Continue a drag gesture; update x/y positions.
* @param {number[]} delta x/y pixel difference since drag
* started
*/
continueDrag: continueDrag,
/**
* End a drag gesture. This should be callled when a drag
* concludes to trigger commit of changes.
*/
endDrag: endDrag
};
}
return FixedDragHandle;
}
);