feat：normal line use min display count

components/NormalLine/NormalLine.vue

@@ -190,23 +190,58 @@
 			*/
 			switchData(event,count) {
 				const categories = this.elementData.dataList.datas[this.index].categories
-				// 容错在一个百分点内，认为是滑块滚动
-				const flag = Math.abs(lastCount - count) <= categories.length / 100 ? true : false
+				// 容错在拖拽0.5内，认为是滑块滚动
+				const flag = Math.abs(lastCount - count) <= categories.length * 0.5 / 100 ? true : false
 				if(flag && event.end === 100 && this.index != this.elementData.dataList.datas.length - 1) {
 					this.index += 1
-					this.setChartDatas()
+					this.setChartDatas("next", event)
 				}
 				if(flag && event.start === 0 && this.index != 0) {
 					this.index -= 1
-					this.setChartDatas()
+					this.setChartDatas("prev", event)
 				}
 			},
-			setChartDatas() {
+			setChartDatas(op, event) {
 				const categories = this.elementData.dataList.datas[this.index].categories
 			    const series = this.elementData.dataList.datas[this.index].series
 				const dealSeries = this.dealSeriesData(series)
+				const count = categories.length * (event.end - event.start) / 100
+				var flag = false
+				var start = event.start
+				var end = event.end
+				const minCount = 5
+				// 当整体的数量小于minCount时，全部显示
+				if(categories <= minCount) {
+					flag = true
+					start = 0
+					end = 100
+				} else {
+					// 当切换过来显示的数量小于minCount时,需要更改start和end的值，使显示的数量为最小数量
+					if(count < minCount) {
+						// 向后切换
+						if(op === 'next') {
+							start = 1
+							end = parseInt(100 * minCount / categories.length) + start
+							end = end > 100 ? 100 : end
+						}
+						// 向前切换
+						if(op === 'prev') {
+							end = 99
+							start = end - parseInt(100 * minCount / categories.length)
+							start = start >= 0 ? start : 0
+						}
+						flag = true
+					}	
+				}
+				if(flag) {
+					this.$set(this.ec.option, 'dataZoom.start', start)
+					this.$set(this.ec.option, 'dataZoom.end', end)
+					
+				}
 				this.$set(this.ec.option, 'xAxis.data', categories)
 				this.$set(this.ec.option, 'series', dealSeries)
+				this.$set(this.ec.option, 'dataZoom.start', start)
+				this.$set(this.ec.option, 'dataZoom.end', end)
 			}
 		}
 	}