128 lines
3.3 KiB
JavaScript
128 lines
3.3 KiB
JavaScript
/**
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* @private
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*/
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Ext.define('Ext.util.PositionMap', {
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config: {
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minimumHeight: 50
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},
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constructor: function(config) {
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this.map = [];
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this.adjustments = {};
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this.offset = 0;
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this.initConfig(config);
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},
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populate: function(count, offset) {
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var map = this.map = this.map || [],
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minimumHeight = this.getMinimumHeight(),
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i, previousIndex, ln;
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// We add 1 item to the count so that we can get the height of the bottom item
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count++;
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map.length = count;
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map[0] = 0;
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for (i = offset + 1, ln = count - 1; i <= ln; i++) {
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previousIndex = i - 1;
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map[i] = map[previousIndex] + minimumHeight;
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}
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this.adjustments = {
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indices: [],
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heights: {}
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};
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this.offset = 0;
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for (i = 1, ln = count - 1; i <= ln; i++) {
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previousIndex = i - 1;
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this.offset += map[i] - map[previousIndex] - minimumHeight;
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}
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},
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setItemHeight: function(index, height) {
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height = Math.max(height, this.getMinimumHeight());
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if (height !== this.getItemHeight(index)) {
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var adjustments = this.adjustments;
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adjustments.indices.push(parseInt(index, 10));
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adjustments.heights[index] = height;
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}
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},
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update: function() {
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var adjustments = this.adjustments,
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indices = adjustments.indices,
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heights = adjustments.heights,
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map = this.map,
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ln = indices.length,
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minimumHeight = this.getMinimumHeight(),
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difference = 0,
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i, j, height, index, nextIndex, currentHeight;
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if (!adjustments.indices.length) {
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return false;
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}
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Ext.Array.sort(indices, function(a, b) {
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return a - b;
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});
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for (i = 0; i < ln; i++) {
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index = indices[i];
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nextIndex = indices[i + 1] || map.length - 1;
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currentHeight = (map[index + 1] !== undefined) ? (map[index + 1] - map[index] + difference) : minimumHeight;
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height = heights[index];
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difference += height - currentHeight;
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for (j = index + 1; j <= nextIndex; j++) {
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map[j] += difference;
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}
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}
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this.offset += difference;
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this.adjustments = {
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indices: [],
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heights: {}
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};
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return true;
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},
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getItemHeight: function(index) {
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return this.map[index + 1] - this.map[index];
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},
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getTotalHeight: function() {
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return ((this.map.length - 1) * this.getMinimumHeight()) + this.offset;
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},
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findIndex: function(pos) {
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return this.map.length ? this.binarySearch(this.map, pos) : 0;
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},
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binarySearch: function(sorted, value) {
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var start = 0,
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end = sorted.length;
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if (value < sorted[0]) {
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return 0;
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}
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if (value > sorted[end - 1]) {
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return end - 1;
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}
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while (start + 1 < end) {
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var mid = (start + end) >> 1,
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val = sorted[mid];
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if (val == value) {
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return mid;
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} else if (val < value) {
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start = mid;
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} else {
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end = mid;
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}
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}
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return start;
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}
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});
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