feat(bar): add startValue option to specify where the bars start

src/chart/bar/BarSeries.ts

@@ -81,6 +81,8 @@ export interface BarSeriesOption
 
     showBackground?: boolean
 
+    startValue?: number
+
     backgroundStyle?: ItemStyleOption & {
         borderRadius?: number | number[]
     }

src/coord/axisCommonTypes.ts

@@ -78,6 +78,7 @@ export interface AxisBaseOptionCommon extends ComponentOption,
      * + null/undefined: auto decide max value (consider pretty look and boundaryGap).
      */
     max?: ScaleDataValue | 'dataMax' | ((extent: {min: number, max: number}) => ScaleDataValue);
+    startValue?: number;
 
 }
 

src/coord/scaleRawExtentInfo.ts

@@ -98,7 +98,11 @@ export class ScaleRawExtentInfo {
         const isOrdinal = this._isOrdinal = scale.type === 'ordinal';
         this._needCrossZero = scale.type === 'interval' && model.getNeedCrossZero && model.getNeedCrossZero();
 
-        const modelMinRaw = this._modelMinRaw = model.get('min', true);
+        let axisMinValue = model.get('min', true);
+        if (axisMinValue == null) {
+            axisMinValue = model.get('startValue', true);
+        }
+        const modelMinRaw = this._modelMinRaw = axisMinValue;
         if (isFunction(modelMinRaw)) {
             // This callback alway provide users the full data extent (before data filtered).
             this._modelMinNum = parseAxisModelMinMax(scale, modelMinRaw({

src/layout/barGrid.ts

@@ -512,14 +512,13 @@ export function createProgressiveLayout(seriesType: string): StageHandler {
                     while ((dataIndex = params.next()) != null) {
                         const value = store.get(stacked ? stackedDimIdx : valueDimIdx, dataIndex);
                         const baseValue = store.get(baseDimIdx, dataIndex) as number;
-
                         let baseCoord = valueAxisStart;
-                        let startValue;
+                        let stackStartValue;
 
                         // Because of the barMinHeight, we can not use the value in
                         // stackResultDimension directly.
                         if (stacked) {
-                            startValue = +value - (store.get(valueDimIdx, dataIndex) as number);
+                            stackStartValue = +value - (store.get(valueDimIdx, dataIndex) as number);
                         }
 
                         let x;
@@ -530,7 +529,7 @@ export function createProgressiveLayout(seriesType: string): StageHandler {
                         if (isValueAxisH) {
                             const coord = cartesian.dataToPoint([value, baseValue]);
                             if (stacked) {
-                                const startCoord = cartesian.dataToPoint([startValue, baseValue]);
+                                const startCoord = cartesian.dataToPoint([stackStartValue, baseValue]);
                                 baseCoord = startCoord[0];
                             }
                             x = baseCoord;
@@ -545,7 +544,7 @@ export function createProgressiveLayout(seriesType: string): StageHandler {
                         else {
                             const coord = cartesian.dataToPoint([baseValue, value]);
                             if (stacked) {
-                                const startCoord = cartesian.dataToPoint([baseValue, startValue]);
+                                const startCoord = cartesian.dataToPoint([baseValue, stackStartValue]);
                                 baseCoord = startCoord[1];
                             }
                             x = coord[0] + columnOffset;
@@ -603,5 +602,13 @@ function isInLargeMode(seriesModel: BarSeriesModel) {
 
 // See cases in `test/bar-start.html` and `#7412`, `#8747`.
 function getValueAxisStart(baseAxis: Axis2D, valueAxis: Axis2D) {
-    return valueAxis.toGlobalCoord(valueAxis.dataToCoord(valueAxis.type === 'log' ? 1 : 0));
+    let startValue = valueAxis.model.get('startValue');
+    if (!startValue) {
+        startValue = 0;
+    }
+    return valueAxis.toGlobalCoord(
+        valueAxis.dataToCoord(
+            valueAxis.type === 'log'
+            ? (startValue > 0 ? startValue : 1)
+            : startValue));
 }

src/layout/barPolar.ts

@@ -27,6 +27,7 @@ import RadiusAxis from '../coord/polar/RadiusAxis';
 import GlobalModel from '../model/Global';
 import ExtensionAPI from '../core/ExtensionAPI';
 import { Dictionary } from '../util/types';
+import { PolarAxisModel } from '../coord/polar/AxisModel';
 
 type PolarAxis = AngleAxis | RadiusAxis;
 
@@ -104,7 +105,10 @@ function barLayoutPolar(seriesType: string, ecModel: GlobalModel, api: Extension
         const clampLayout = baseAxis.dim !== 'radius'
             || !seriesModel.get('roundCap', true);
 
-        const valueAxisStart = valueAxis.dataToCoord(0);
+        const valueAxisModel = valueAxis.model as PolarAxisModel;
+        const startValue = valueAxisModel.get('startValue');
+        const valueAxisStart = valueAxis.dataToCoord(startValue || 0);
+
         for (let idx = 0, len = data.count(); idx < len; idx++) {
             const value = data.get(valueDim, idx) as number;
             const baseValue = data.get(baseDim, idx) as number;