Files
2017-05-10 16:33:00 +08:00

114 lines
4.2 KiB
JavaScript

'use strict';
Object.defineProperty(exports, "__esModule", {
value: true
});
var _slicedToArray = function () { function sliceIterator(arr, i) { var _arr = []; var _n = true; var _d = false; var _e = undefined; try { for (var _i = arr[Symbol.iterator](), _s; !(_n = (_s = _i.next()).done); _n = true) { _arr.push(_s.value); if (i && _arr.length === i) break; } } catch (err) { _d = true; _e = err; } finally { try { if (!_n && _i["return"]) _i["return"](); } finally { if (_d) throw _e; } } return _arr; } return function (arr, i) { if (Array.isArray(arr)) { return arr; } else if (Symbol.iterator in Object(arr)) { return sliceIterator(arr, i); } else { throw new TypeError("Invalid attempt to destructure non-iterable instance"); } }; }();
var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();
var _intervalTree = require('../vendor/intervalTree');
var _intervalTree2 = _interopRequireDefault(_intervalTree);
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
// Position cache requirements:
// O(log(n)) lookup of cells to render for a given viewport size
// O(1) lookup of shortest measured column (so we know when to enter phase 1)
var PositionCache = function () {
function PositionCache() {
_classCallCheck(this, PositionCache);
this._columnSizeMap = {};
this._intervalTree = (0, _intervalTree2.default)();
this._leftMap = {};
}
// Tracks the height of each column
// Store tops and bottoms of each cell for fast intersection lookup.
// Maps cell index to x coordinates for quick lookup.
_createClass(PositionCache, [{
key: 'estimateTotalHeight',
value: function estimateTotalHeight(cellCount, columnCount, defaultCellHeight) {
var unmeasuredCellCount = cellCount - this.count;
return this.tallestColumnSize + Math.ceil(unmeasuredCellCount / columnCount) * defaultCellHeight;
}
// Render all cells visible within the viewport range defined.
}, {
key: 'range',
value: function range(scrollTop, clientHeight, renderCallback) {
var _this = this;
this._intervalTree.queryInterval(scrollTop, scrollTop + clientHeight, function (_ref) {
var _ref2 = _slicedToArray(_ref, 3),
top = _ref2[0],
_ = _ref2[1],
index = _ref2[2];
return renderCallback(index, _this._leftMap[index], top);
});
}
}, {
key: 'setPosition',
value: function setPosition(index, left, top, height) {
this._intervalTree.insert([top, top + height, index]);
this._leftMap[index] = left;
var columnSizeMap = this._columnSizeMap;
var columnHeight = columnSizeMap[left];
if (columnHeight === undefined) {
columnSizeMap[left] = top + height;
} else {
columnSizeMap[left] = Math.max(columnHeight, top + height);
}
}
}, {
key: 'count',
get: function get() {
return this._intervalTree.count;
}
}, {
key: 'shortestColumnSize',
get: function get() {
var columnSizeMap = this._columnSizeMap;
var size = 0;
for (var i in columnSizeMap) {
var height = columnSizeMap[i];
size = size === 0 ? height : Math.min(size, height);
}
return size;
}
}, {
key: 'tallestColumnSize',
get: function get() {
var columnSizeMap = this._columnSizeMap;
var size = 0;
for (var i in columnSizeMap) {
var height = columnSizeMap[i];
size = Math.max(size, height);
}
return size;
}
}]);
return PositionCache;
}();
exports.default = PositionCache;