Improve plot color selection

demos/xychart.html

@@ -40,7 +40,11 @@
     <h1>XY Charts demos</h1>
     <pre class="mermaid">
     xychart-beta
-    line [23, 46, 75, 43]
+    line [23, 46, 77, 34]
+    line [45, 32, 33, 12]
+    line [87, 54, 99, 85]
+    line [78, 88, 22, 4]
+    line [22, 29, 75, 33]
     bar "sample bat" [52, 96, 35, 10]
     </pre>
 

packages/mermaid/src/diagrams/xychart/chartBuilder/Interfaces.ts

@@ -13,8 +13,7 @@ export interface XYChartThemeConfig {
   xychartYAxisLableColor: string;
   xychartYAxisTitleColor: string;
   xychartYAxisTickColor: string;
-  xychartBarPlotPalette: string[];
-  xychartLinePlotPalette: string[];
+  xychartPlotBaseColor: string;
 }
 
 export interface ChartComponent {

packages/mermaid/src/diagrams/xychart/chartBuilder/components/plot/BarPlot.ts

@@ -1,5 +1,5 @@
 import { XYChartConfig } from '../../../../../config.type.js';
-import { BarPlotData, BoundingRect, DrawableElem, XYChartThemeConfig } from '../../Interfaces.js';
+import { BarPlotData, BoundingRect, DrawableElem } from '../../Interfaces.js';
 import { IAxis } from '../axis/index.js';
 
 export class BarPlot {
@@ -9,7 +9,7 @@ export class BarPlot {
     private xAxis: IAxis,
     private yAxis: IAxis,
     private orientation: XYChartConfig['chartOrientation'],
-    private chartThemeConfig: XYChartThemeConfig
+    private plotIndex: number
   ) {}
 
   getDrawableElement(): DrawableElem[] {
@@ -28,7 +28,7 @@ export class BarPlot {
     if (this.orientation === 'horizontal') {
       return [
         {
-          groupTexts: ['plot', 'bar-plot'],
+          groupTexts: ['plot', `bar-plot-${this.plotIndex}`],
           type: 'rect',
           data: finalData.map((data) => ({
             x: this.boundingRect.x,
@@ -44,7 +44,7 @@ export class BarPlot {
     } else {
       return [
         {
-          groupTexts: ['plot', 'bar-plot'],
+          groupTexts: ['plot', `bar-plot-${this.plotIndex}`],
           type: 'rect',
           data: finalData.map((data) => ({
             x: data[0] - barWidthHalf,

packages/mermaid/src/diagrams/xychart/chartBuilder/components/plot/LinePlot.ts

@@ -1,7 +1,7 @@
 import { line } from 'd3';
-import { DrawableElem, LinePlotData, XYChartThemeConfig } from '../../Interfaces.js';
-import { IAxis } from '../axis/index.js';
 import { XYChartConfig } from '../../../../../config.type.js';
+import { DrawableElem, LinePlotData } from '../../Interfaces.js';
+import { IAxis } from '../axis/index.js';
 
 export class LinePlot {
   constructor(
@@ -9,7 +9,7 @@ export class LinePlot {
     private xAxis: IAxis,
     private yAxis: IAxis,
     private orientation: XYChartConfig['chartOrientation'],
-    private chartThemeConfig: XYChartThemeConfig
+    private plotIndex: number
   ) {}
 
   getDrawableElement(): DrawableElem[] {
@@ -33,7 +33,7 @@ export class LinePlot {
     }
     return [
       {
-        groupTexts: ['plot', 'line-plot'],
+        groupTexts: ['plot', `line-plot-${this.plotIndex}`],
         type: 'path',
         data: [
           {

packages/mermaid/src/diagrams/xychart/chartBuilder/components/plot/index.ts

@@ -62,7 +62,7 @@ export class Plot implements IPlot {
         this.chartThemeConfig
       ).getDrawableElement(),
     ];
-    for (const plot of this.chartData.plots) {
+    for (const [i, plot] of this.chartData.plots.entries()) {
       switch (plot.type) {
         case 'line':
           {
@@ -71,7 +71,7 @@ export class Plot implements IPlot {
               this.xAxis,
               this.yAxis,
               this.chartConfig.chartOrientation,
-              this.chartThemeConfig
+              i
             );
             drawableElem.push(...linePlot.getDrawableElement());
           }
@@ -84,7 +84,7 @@ export class Plot implements IPlot {
               this.xAxis,
               this.yAxis,
               this.chartConfig.chartOrientation,
-              this.chartThemeConfig
+              i
             );
             drawableElem.push(...barPlot.getDrawableElement());
           }

packages/mermaid/src/diagrams/xychart/xychartDb.ts

@@ -1,4 +1,5 @@
-import { log } from '../../logger.js';
+// @ts-ignore: TODO Fix ts errors
+import { adjust, channel, toHsla, isDark, lighten, darken } from 'khroma';
 import mermaidAPI from '../../mermaidAPI.js';
 import * as configApi from '../../config.js';
 import { sanitizeText } from '../common/common.js';
@@ -27,6 +28,24 @@ const defaultThemeVariables = getThemeVariables();
 
 const config = configApi.getConfig();
 
+function plotColorPaletteGenerator(baseColor: string, noOfColorNeeded = 15): string[] {
+  const colors = [];
+  const MAX_HUE_VALUE = 360;
+  const baseHue = channel(baseColor, 'h');
+  if (baseHue > MAX_HUE_VALUE / 2) {
+    const decr = Math.floor(baseHue / noOfColorNeeded);
+    for (let i = 0; i <= baseHue; i += decr) {
+      colors.push(adjust(baseColor, { h: -i }));
+    }
+  } else {
+    const incr = Math.floor((MAX_HUE_VALUE - baseHue) / noOfColorNeeded);
+    for (let i = 0; i <= baseHue; i += incr) {
+      colors.push(adjust(baseColor, { h: i }));
+    }
+  }
+  return colors;
+}
+
 function getChartDefaultThemeConfig(): XYChartThemeConfig {
   return {
     xychartTitleColor:
@@ -45,10 +64,8 @@ function getChartDefaultThemeConfig(): XYChartThemeConfig {
       config.themeVariables?.xychartYAxisTitleColor || defaultThemeVariables.xychartYAxisTitleColor,
     xychartYAxisTickColor:
       config.themeVariables?.xychartYAxisTickColor || defaultThemeVariables.xychartYAxisTickColor,
-    xychartBarPlotPalette:
-      config.themeVariables?.xychartBarPlotPalette || defaultThemeVariables.xychartBarPlotPalette,
-    xychartLinePlotPalette:
-      config.themeVariables?.xychartLinePlotPalette || defaultThemeVariables.xychartLinePlotPalette,
+    xychartPlotBaseColor:
+      config.themeVariables?.xychartPlotBaseColor || defaultThemeVariables.xychartPlotBaseColor,
   };
 }
 function getChartDefaultConfig(): XYChartConfig {
@@ -110,6 +127,9 @@ function getChartDefalutData(): XYChartData {
 let xyChartConfig: XYChartConfig = getChartDefaultConfig();
 let xyChartThemeConfig: XYChartThemeConfig = getChartDefaultThemeConfig();
 let xyChartData: XYChartData = getChartDefalutData();
+let plotColorPalette = Array.isArray(xyChartThemeConfig.xychartPlotBaseColor)
+  ? xyChartThemeConfig.xychartPlotBaseColor
+  : plotColorPaletteGenerator(xyChartThemeConfig.xychartPlotBaseColor);
 let hasSetXAxis = false;
 let hasSetYAxis = false;
 
@@ -197,27 +217,32 @@ function transformDataWithOutCategory(data: number[]): SimplePlotDataType {
 
   return retData;
 }
+
+let plotIndex = 0;
+
+function getPlotColorFromPalette(plotIndex: number): string {
+  return plotColorPalette[plotIndex === 0 ? 0 : plotIndex % (plotColorPalette.length - 1)];
+}
+
 function setLineData(title: string, data: number[]) {
   const plotData = transformDataWithOutCategory(data);
   xyChartData.plots.push({
     type: 'line',
-    strokeFill:
-      xyChartThemeConfig.xychartLinePlotPalette[
-        Math.floor(Math.random() * (xyChartThemeConfig.xychartLinePlotPalette.length - 1))
-      ],
+    strokeFill: getPlotColorFromPalette(plotIndex),
     strokeWidth: 2,
     data: plotData,
   });
+  plotIndex++;
 }
+
 function setBarData(title: string, data: number[]) {
   const plotData = transformDataWithOutCategory(data);
   xyChartData.plots.push({
     type: 'bar',
-    fill: xyChartThemeConfig.xychartBarPlotPalette[
-      Math.floor(Math.random() * (xyChartThemeConfig.xychartBarPlotPalette.length - 1))
-    ],
+    fill: getPlotColorFromPalette(plotIndex),
     data: plotData,
   });
+  plotIndex++;
 }
 
 function getDrawableElem(): DrawableElem[] {
@@ -238,9 +263,13 @@ function setWidth(width: number) {
 
 const clear = function () {
   commonClear();
+  plotIndex = 0;
   xyChartConfig = getChartDefaultConfig();
   xyChartData = getChartDefalutData();
   xyChartThemeConfig = getChartDefaultThemeConfig();
+  plotColorPalette = Array.isArray(xyChartThemeConfig.xychartPlotBaseColor)
+    ? xyChartThemeConfig.xychartPlotBaseColor
+    : plotColorPaletteGenerator(xyChartThemeConfig.xychartPlotBaseColor);
   hasSetXAxis = false;
   hasSetYAxis = false;
 };

packages/mermaid/src/themes/theme-default.js

@@ -282,10 +282,7 @@ class Theme {
     this.xychartYAxisTitleColor = this.xychartYAxisTitleColor || this.primaryTextColor;
     this.xychartYAxisLableColor = this.xychartYAxisLableColor || this.primaryTextColor;
     this.xychartYAxisTickColor = this.xychartYAxisTickColor || this.primaryTextColor;
-    this.xychartBarPlotPalette = this.xychartBarPlotPalette || [this.primaryColor];
-    this.xychartLinePlotPalette = this.xychartLinePlotPalette || [
-      adjust(this.primaryColor, { r: -100, g: -100, b: -100 }),
-    ];
+    this.xychartPlotBaseColor = this.xychartPlotBaseColor || darken(this.primaryColor, 25);
 
     /* requirement-diagram */
     this.requirementBackground = this.requirementBackground || this.primaryColor;