108 lines
2.0 KiB
JavaScript
108 lines
2.0 KiB
JavaScript
'use strict';
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var $ = require('jquery');
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var _ = require('lodash');
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function MoveCanvas(events, canvas) {
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var THRESHOLD = 20;
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function init(element) {
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var context = {};
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function getPosition(e) {
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return { x: e.clientX, y: e.clientY };
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}
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function getDelta(p1, p2) {
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return {
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x: p1.x - p2.x,
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y: p1.y - p2.y
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};
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}
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function isThresholdReached(delta) {
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return Math.abs(delta.x) > THRESHOLD || Math.abs(delta.y) > THRESHOLD;
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}
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function cursor(value) {
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var current = document.body.style.cursor || '';
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if (value !== undefined) {
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document.body.style.cursor = value;
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}
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return current;
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}
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function handleMove(event) {
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var position = getPosition(event);
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if (!context.dragging && isThresholdReached(getDelta(context.start, position))) {
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context.dragging = true;
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context.cursor = cursor('move');
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}
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if (context.dragging) {
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var lastPos = context.last || context.start;
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var delta = getDelta(position, lastPos);
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canvas.scroll({
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dx: delta.x,
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dy: delta.y
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});
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context.last = position;
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}
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// prevent select
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event.preventDefault();
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}
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function handleEnd(event) {
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$(element).off('mousemove', handleMove);
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$(document).off('mouseup', handleEnd);
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if (context) {
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cursor(context.cursor);
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}
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// prevent select
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event.preventDefault();
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}
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function handleStart(event) {
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var position = getPosition(event);
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context = {
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start: position
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};
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$(element).on('mousemove', handleMove);
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$(document).on('mouseup', handleEnd);
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// prevent select
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event.preventDefault();
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}
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$(element).on('mousedown', handleStart);
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}
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events.on('canvas.init', function(e) {
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init(e.paper.node);
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});
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}
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MoveCanvas.$inject = [ 'eventBus', 'canvas' ];
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module.exports = MoveCanvas; |