refactor: less copy-paste code

Author: biggates

src/component/dataZoom/SliderZoomView.ts

@@ -19,6 +19,7 @@
 
 import {bind, each, isFunction, isString, indexOf} from 'zrender/src/core/util';
 import * as eventTool from 'zrender/src/core/event';
+import { Dictionary } from 'zrender/src/core/types';
 import * as graphic from '../../util/graphic';
 import * as throttle from '../../util/throttle';
 import DataZoomView from './DataZoomView';
@@ -43,6 +44,7 @@ import { PointLike } from 'zrender/src/core/Point';
 import Displayable from 'zrender/src/graphic/Displayable';
 import {createTextStyle} from '../../label/labelStyle';
 import SeriesData from '../../data/SeriesData';
+import { doDataSampling } from '../../processor/dataSample';
 
 const Rect = graphic.Rect;
 
@@ -384,91 +386,75 @@ class SliderZoomView extends DataZoomView {
             ];
             const otherShadowExtent = [0, size[1]];
             const thisShadowExtent = [0, size[0]];
+
+            const areaPoints = [[size[0], 0], [0, 0]];
+            const linePoints: number[][] = [];
+
             let lastIsEmpty: boolean;
 
             // Optimize for large data shadow
             const stride = Math.round(data.count() / size[0]);
             const coordSys = seriesModel.coordinateSystem;
             const sampling = this.dataZoomModel.get('sampling');
-            if (data.count() > 10 && coordSys.type === 'cartesian2d' && (sampling && sampling !== 'none')) {
-                const baseAxis = coordSys.getBaseAxis();
-                const valueAxis = coordSys.getOtherAxis(baseAxis);
+            let sampledData = data;
 
-                let downsampled = data;
-                if (sampling === 'lttb') {
-                    downsampled = data.lttbDownSample(data.mapDimension(valueAxis.dim), 1 / stride);
+            let useOldSampling = true;
+            if (data.count() > 10 && coordSys.type === 'cartesian2d' && (sampling && sampling !== 'none')) {
+                const downsampled = doDataSampling(
+                    data,
+                    sampling,
+                    seriesModel.coordinateSystem,
+                    this.api.getDevicePixelRatio()
+                );
+                if (downsampled) {
+                    useOldSampling = false;
+                    sampledData = downsampled;
                 }
-                // TODO: 支持其他类型的 sampling
-
-                const lp = [[size[0], 0], [0, 0]];
-                const ap: number[][] = [];
-                downsampled.each([otherDim], function (value: ParsedValue, index) {
-                    const isEmpty = value == null || isNaN(value as number) || value === '';
-                    // See #4235.
-                    const otherCoord = isEmpty
-                        ? 0 : linearMap(value as number, otherDataExtent, otherShadowExtent, true);
-
-                    // Attempt to draw data shadow precisely when there are empty value.
-                    if (isEmpty && !lastIsEmpty && index) {
-                        ap.push([ap[ap.length - 1][0], 0]);
-                        lp.push([lp[lp.length - 1][0], 0]);
-                    }
-                    else if (!isEmpty && lastIsEmpty) {
-                        ap.push([index, 0]);
-                        lp.push([index, 0]);
-                    }
-
-                    ap.push([index, otherCoord]);
-                    lp.push([index, otherCoord]);
-
-                    lastIsEmpty = isEmpty;
-                });
-
-                polygonPts = this._shadowPolygonPts = ap;
-                polylinePts = this._shadowPolylinePts = lp;
             }
-            else {
-                const areaPoints = [[size[0], 0], [0, 0]];
-                const linePoints: number[][] = [];
-                const step = thisShadowExtent[1] / (data.count() - 1);
-                let thisCoord = 0;
 
-                data.each([otherDim], function (value: ParsedValue, index) {
+            const step = thisShadowExtent[1] / (data.count() - 1);
+            let thisCoord = 0;
+
+            sampledData.each([otherDim], function (value: ParsedValue, index) {
+                if (useOldSampling) {
                     if (stride > 0 && (index % stride)) {
                         thisCoord += step;
                         return;
                     }
+                }
+                else {
+                    thisCoord = index;
+                }
 
-                    // FIXME
-                    // Should consider axis.min/axis.max when drawing dataShadow.
+                // FIXME
+                // Should consider axis.min/axis.max when drawing dataShadow.
 
-                    // FIXME
-                    // 应该使用统一的空判断？还是在list里进行空判断？
-                    const isEmpty = value == null || isNaN(value as number) || value === '';
-                    // See #4235.
-                    const otherCoord = isEmpty
-                        ? 0 : linearMap(value as number, otherDataExtent, otherShadowExtent, true);
+                // FIXME
+                // 应该使用统一的空判断？还是在list里进行空判断？
+                const isEmpty = value == null || isNaN(value as number) || value === '';
+                // See #4235.
+                const otherCoord = isEmpty
+                    ? 0 : linearMap(value as number, otherDataExtent, otherShadowExtent, true);
 
-                    // Attempt to draw data shadow precisely when there are empty value.
-                    if (isEmpty && !lastIsEmpty && index) {
-                        areaPoints.push([areaPoints[areaPoints.length - 1][0], 0]);
-                        linePoints.push([linePoints[linePoints.length - 1][0], 0]);
-                    }
-                    else if (!isEmpty && lastIsEmpty) {
-                        areaPoints.push([thisCoord, 0]);
-                        linePoints.push([thisCoord, 0]);
-                    }
+                // Attempt to draw data shadow precisely when there are empty value.
+                if (isEmpty && !lastIsEmpty && index) {
+                    areaPoints.push([areaPoints[areaPoints.length - 1][0], 0]);
+                    linePoints.push([linePoints[linePoints.length - 1][0], 0]);
+                }
+                else if (!isEmpty && lastIsEmpty) {
+                    areaPoints.push([thisCoord, 0]);
+                    linePoints.push([thisCoord, 0]);
+                }
 
-                    areaPoints.push([thisCoord, otherCoord]);
-                    linePoints.push([thisCoord, otherCoord]);
+                areaPoints.push([thisCoord, otherCoord]);
+                linePoints.push([thisCoord, otherCoord]);
 
-                    thisCoord += step;
-                    lastIsEmpty = isEmpty;
-                });
+                thisCoord += step;
+                lastIsEmpty = isEmpty;
+            });
 
-                polygonPts = this._shadowPolygonPts = areaPoints;
-                polylinePts = this._shadowPolylinePts = linePoints;
-            }
+            polygonPts = this._shadowPolygonPts = areaPoints;
+            polylinePts = this._shadowPolylinePts = linePoints;
 
         }
         this._shadowData = data;

src/processor/dataSample.ts

@@ -17,10 +17,12 @@
 * under the License.
 */
 
-import { StageHandler, SeriesOption, SeriesSamplingOptionMixin } from '../util/types';
+import { StageHandler, SeriesOption, SeriesSamplingOptionMixin, SamplingValues } from '../util/types';
 import { Dictionary } from 'zrender/src/core/types';
 import SeriesModel from '../model/Series';
 import { isFunction, isString } from 'zrender/src/core/util';
+import SeriesData from '../data/SeriesData';
+import { CoordinateSystem } from '../coord/CoordinateSystem';
 
 
 type Sampler = (frame: ArrayLike<number>) => number;
@@ -72,6 +74,44 @@ const indexSampler = function (frame: ArrayLike<number>) {
     return Math.round(frame.length / 2);
 };
 
+export function doDataSampling(
+    data: SeriesData,
+    sampling: SamplingValues,
+    coordSys: CoordinateSystem,
+    dpr: number
+) {
+    const count = data.count();
+    // Only cartesian2d support down sampling. Disable it when there is few data.
+    if (count > 10 && coordSys.type === 'cartesian2d' && sampling) {
+        const baseAxis = coordSys.getBaseAxis();
+        const valueAxis = coordSys.getOtherAxis(baseAxis);
+        const extent = baseAxis.getExtent();
+        // Coordinste system has been resized
+        const size = Math.abs(extent[1] - extent[0]) * (dpr || 1);
+        const rate = Math.round(count / size);
+
+        if (isFinite(rate) && rate > 1) {
+            if (sampling === 'lttb') {
+                return data.lttbDownSample(data.mapDimension(valueAxis.dim), 1 / rate);
+            }
+            let sampler;
+            if (isString(sampling)) {
+                sampler = samplers[sampling];
+            }
+            else if (isFunction(sampling)) {
+                sampler = sampling;
+            }
+            if (sampler) {
+                // Only support sample the first dim mapped from value axis.
+                return data.downSample(
+                    data.mapDimension(valueAxis.dim), 1 / rate, sampler, indexSampler
+                );
+            }
+        }
+    }
+    return null;
+}
+
 export default function dataSample(seriesType: string): StageHandler {
     return {
 
@@ -84,36 +124,11 @@ export default function dataSample(seriesType: string): StageHandler {
             const data = seriesModel.getData();
             const sampling = seriesModel.get('sampling');
             const coordSys = seriesModel.coordinateSystem;
-            const count = data.count();
-            // Only cartesian2d support down sampling. Disable it when there is few data.
-            if (count > 10 && coordSys.type === 'cartesian2d' && sampling) {
-                const baseAxis = coordSys.getBaseAxis();
-                const valueAxis = coordSys.getOtherAxis(baseAxis);
-                const extent = baseAxis.getExtent();
-                const dpr = api.getDevicePixelRatio();
-                // Coordinste system has been resized
-                const size = Math.abs(extent[1] - extent[0]) * (dpr || 1);
-                const rate = Math.round(count / size);
-
-                if (isFinite(rate) && rate > 1) {
-                    if (sampling === 'lttb') {
-                        seriesModel.setData(data.lttbDownSample(data.mapDimension(valueAxis.dim), 1 / rate));
-                    }
-                    let sampler;
-                    if (isString(sampling)) {
-                        sampler = samplers[sampling];
-                    }
-                    else if (isFunction(sampling)) {
-                        sampler = sampling;
-                    }
-                    if (sampler) {
-                        // Only support sample the first dim mapped from value axis.
-                        seriesModel.setData(data.downSample(
-                            data.mapDimension(valueAxis.dim), 1 / rate, sampler, indexSampler
-                        ));
-                    }
-                }
+            const dpr = api.getDevicePixelRatio();
+            const resampled = doDataSampling(data, sampling, coordSys, dpr);
+            if (resampled) {
+                seriesModel.setData(resampled);
             }
         }
     };
-}
+}

src/util/types.ts

@@ -1673,8 +1673,9 @@ export interface SeriesStackOptionMixin {
 
 type SamplingFunc = (frame: ArrayLike<number>) => number;
 
+export type SamplingValues = 'none' | 'average' | 'min' | 'max' | 'sum' | 'lttb' | SamplingFunc;
 export interface SeriesSamplingOptionMixin {
-    sampling?: 'none' | 'average' | 'min' | 'max' | 'sum' | 'lttb' | SamplingFunc
+    sampling?: SamplingValues
 }
 
 export interface SeriesEncodeOptionMixin {