GraphOperation

src/main/angular/src/app/COMMON.ts

@@ -53,6 +53,14 @@ export function validateBoolean(json: any): boolean {
   return json;
 }
 
+export function validateEnum<T extends Record<string, string>>(value: any, enumType: T): T[keyof T] {
+  const str = validateString(value);
+  if (Object.values(enumType).includes(str)) {
+    return str as T[keyof T];
+  }
+  throw new Error(`Invalid enum value: ${str}`);
+}
+
 export function validateList<T>(json: any, fromJson: FromJson<T>): T[] {
   return json.map(fromJson);
 }

src/main/angular/src/app/plot/axis/graph/Graph.ts

@@ -1,10 +1,20 @@
 import {Series} from "../../../series/Series";
 import {Group} from "../../Group";
-import {validateBoolean, validateNumber, validateString} from "../../../COMMON";
+import {mapNotNull, validateBoolean, validateEnum, validateNumber, validateString} from "../../../COMMON";
 import {Axis} from '../Axis';
 import {SeriesType} from '../../../series/SeriesType';
 import {GraphType} from './GraphType';
 
+export enum GraphOperation {
+  MINUS = 'MINUS',
+  PLUS = 'PLUS',
+  DIVIDE = 'DIVIDE',
+}
+
+export function listGraphOperation() {
+  return Object.keys(GraphOperation);
+}
+
 export class Graph {
 
   readonly showMin: boolean;
@@ -18,12 +28,15 @@ export class Graph {
     readonly id: number,
     readonly version: number,
     readonly series: Series,
+    readonly factor: number,
+    readonly operation: GraphOperation,
+    readonly series2: Series | null,
+    readonly factor2: number,
     readonly name: string,
     readonly visible: boolean,
     readonly type: GraphType,
     readonly fill: string,
     readonly color: string,
-    readonly factor: number,
     readonly group: Group,
     readonly stack: string,
     readonly min: boolean,
@@ -41,12 +54,15 @@ export class Graph {
       validateNumber(json.id),
       validateNumber(json.version),
       Series.fromJson(json.series),
+      validateNumber(json.factor),
+      validateEnum(json.operation, GraphOperation),
+      mapNotNull(json.series2, Series.fromJson),
+      validateNumber(json.factor2),
       validateString(json.name),
       validateBoolean(json.visible),
       GraphType.fromJson(json.type),
       validateString(json.fill),
       validateString(json.color),
-      validateNumber(json.factor),
       validateString(json.group) as Group,
       validateString(json.stack),
       validateBoolean(json.min),

src/main/angular/src/app/plot/editor/plot-editor.component.html

@@ -136,9 +136,9 @@
           </th>
           <th>Name</th>
           <th>Serie</th>
+          <th>Faktor</th>
           <th>Typ</th>
           <th>Farbe</th>
-          <th>Faktor</th>
           <th>Aggregat</th>
           <th>Stack</th>
           <th class="vertical">min</th>
@@ -163,6 +163,27 @@
                   }
                 </select>
               </td>
+              <td>
+                <app-number-nn [initial]="graph.factor" (onChange)="plotService.graphFactor(graph, $event)"></app-number-nn>
+              </td>
+              <td>
+                <select [ngModel]="graph.operation" (ngModelChange)="plotService.graphOperation(graph, $event)">
+                  @for (operation of listGraphOperation(); track operation) {
+                    <option [ngValue]="operation">{{ operation }}</option>
+                  }
+                </select>
+              </td>
+              <td>
+                <select [ngModel]="graph.series2?.id" (ngModelChange)="plotService.graphSeries2(graph, $event)">
+                  <option [ngValue]="null">-</option>
+                  @for (s of seriesService.list; track s.name) {
+                    <option [ngValue]="s.id">{{ s.name }} [{{ s.valueString }}]</option>
+                  }
+                </select>
+              </td>
+              <td>
+                <app-number-nn [initial]="graph.factor2" (onChange)="plotService.graphFactor2(graph, $event)"></app-number-nn>
+              </td>
               <td>
                 <select [ngModel]="graph.type" (ngModelChange)="plotService.graphType(graph, $event)">
                   @for (type of GraphType.values; track type.jsonName) {
@@ -173,9 +194,6 @@
               <td>
                 <app-text [initial]="graph.color" (onChange)="plotService.graphColor(graph, $event)"></app-text>
               </td>
-              <td>
-                <app-number-nn [initial]="graph.factor" (onChange)="plotService.graphFactor(graph, $event)"></app-number-nn>
-              </td>
               <td>
                 <select [ngModel]="graph.group" (ngModelChange)="plotService.graphGroup(graph, $event)">
                   @for (group of groups(); track group) {

src/main/angular/src/app/plot/editor/plot-editor.component.ts

@@ -19,6 +19,7 @@ import {Location} from '@angular/common';
 import {PlotComponent} from '../plot/plot.component';
 import {ActivatedRoute} from '@angular/router';
 import {GraphType} from '../axis/graph/GraphType';
+import {GraphOperation, listGraphOperation} from '../axis/graph/Graph';
 
 Chart.register(
   CategoryScale,
@@ -35,13 +36,6 @@ Chart.register(
   Filler,
 );
 
-export function unitInBrackets(unit: string): string {
-  if (!unit) {
-    return '';
-  }
-  return ` [${unit}]`;
-}
-
 @Component({
   selector: 'app-plot-editor',
   imports: [
@@ -58,6 +52,12 @@ export function unitInBrackets(unit: string): string {
 })
 export class PlotEditor implements OnInit, OnDestroy {
 
+  protected readonly GraphType = GraphType;
+
+  protected readonly GraphOperation = GraphOperation;
+
+  protected readonly listGraphOperation = listGraphOperation;
+
   protected readonly SeriesType = SeriesType;
 
   protected readonly Interval = Interval;
@@ -142,5 +142,4 @@ export class PlotEditor implements OnInit, OnDestroy {
     return Object.keys(Group);
   }
 
-  protected readonly GraphType = GraphType;
 }

src/main/angular/src/app/plot/plot.service.ts

@@ -2,7 +2,7 @@ import {Injectable} from '@angular/core';
 import {ApiService, EntityListService, Next} from '../COMMON';
 import {Plot} from './Plot';
 import {Axis} from './axis/Axis';
-import {Graph} from './axis/graph/Graph';
+import {Graph, GraphOperation} from './axis/graph/Graph';
 import {Group} from './Group';
 import {Interval} from '../series/Interval';
 import {GraphType} from './axis/graph/GraphType';
@@ -118,14 +118,26 @@ export class PlotService extends EntityListService<Plot> {
     this.postSingle(['Graph', graph.id, 'series'], value, next);
   }
 
-  graphColor(graph: Graph, value: string, next?: Next<Plot>): void {
-    this.postSingle(['Graph', graph.id, 'color'], value, next);
-  }
-
   graphFactor(graph: Graph, value: number, next?: Next<Plot>): void {
     this.postSingle(['Graph', graph.id, 'factor'], value, next);
   }
 
+  graphOperation(graph: Graph, value: GraphOperation, next?: Next<Plot>): void {
+    this.postSingle(['Graph', graph.id, 'operation'], value, next);
+  }
+
+  graphSeries2(graph: Graph, value: number, next?: Next<Plot>): void {
+    this.postSingle(['Graph', graph.id, 'series2'], value, next);
+  }
+
+  graphFactor2(graph: Graph, value: number, next?: Next<Plot>): void {
+    this.postSingle(['Graph', graph.id, 'factor2'], value, next);
+  }
+
+  graphColor(graph: Graph, value: string, next?: Next<Plot>): void {
+    this.postSingle(['Graph', graph.id, 'color'], value, next);
+  }
+
   graphGroup(graph: Graph, value: Group, next?: Next<Plot>): void {
     this.postSingle(['Graph', graph.id, 'group'], value, next);
   }

src/main/angular/src/app/plot/plot/plot.component.ts

@@ -216,24 +216,21 @@ export class PlotComponent implements AfterViewInit, OnDestroy {
 
   private points(graph: Graph, min: Dataset, mid: Dataset, max: Dataset): void {
     this.seriesService.oneSeriesPoints(
-      graph.series,
-      graph.axis.plot.interval,
-      graph.axis.plot.offset,
-      graph.axis.plot.duration,
+      graph,
       points => {
         if (graph.series.type === SeriesType.BOOL) {
-          mid.data = toBool(points, graph.factor);
+          mid.data = toBool(points);
         } else if (graph.series.type === SeriesType.DELTA) {
-          mid.data = toDelta(points, graph.factor);
+          mid.data = toDelta(points);
         } else if (graph.series.type === SeriesType.VARYING) {
           if (min) {
-            min.data = toMin(points, graph.factor);
+            min.data = toMin(points);
           }
           if (max) {
-            max.data = toMax(points, graph.factor);
+            max.data = toMax(points);
           }
           if (mid) {
-            mid.data = toAvg(points, graph.factor);
+            mid.data = toAvg(points);
           }
         }
         this.chart.update();
@@ -264,14 +261,13 @@ export class PlotComponent implements AfterViewInit, OnDestroy {
   private updatePoint(graph: Graph, dataset: Dataset, date: Date, y: number): void {
     const x = date.getTime();
     const point = dataset.data.filter((p: PointElement) => p.x === x)[0];
-    const yMultiplied = y * graph.factor;
     if (point) {
-      if (point.y !== yMultiplied) {
-        point.y = yMultiplied;
+      if (point.y !== y) {
+        point.y = y * graph.factor; // TODO this is wrong. we need to take GraphOperation into account
         this.chart.update();
       }
     } else {
-      dataset.data.push({x: x, y: yMultiplied}); // TODO check if this is a LIVE/SCROLLING plot (right end of plot is 'now')
+      dataset.data.push({x: x, y: y}); // TODO check if this is a LIVE/SCROLLING plot (right end of plot is 'now')
       this.chart.update();
     }
   }

src/main/angular/src/app/series/MinMaxAvg.ts

@@ -9,10 +9,7 @@ export class Point {
 
 }
 
-export  type PointMapper = (p: number[][], factor: number) => Point[];
-
-// noinspection JSUnusedLocalSymbols
-export function toBool(points: number[][], factor: number): Point[] {
+export function toBool(points: number[][]): Point[] {
   const result = [];
   let postPone: Point | null = null;
   for (const p of points) {
@@ -44,45 +41,45 @@ export function toBool(points: number[][], factor: number): Point[] {
   return result;
 }
 
-export function toDelta(points: number[][], factor: number): Point[] {
+export function toDelta(points: number[][]): Point[] {
   const result = [];
   for (const p of points) {
     result.push({
       x: p[0] * 1000,
-      y: (p[1]) * factor,
+      y: (p[1]),
     });
   }
   return result;
 }
 
-export function toMin(points: number[][], factor: number): Point[] {
+export function toMin(points: number[][]): Point[] {
   const result = [];
   for (const p of points) {
     result.push({
       x: p[0] * 1000,
-      y: p[1] * factor,
+      y: p[1],
     });
   }
   return result;
 }
 
-export function toMax(points: number[][], factor: number): Point[] {
+export function toMax(points: number[][]): Point[] {
   const result = [];
   for (const p of points) {
     result.push({
       x: p[0] * 1000,
-      y: p[2] * factor,
+      y: p[2],
     });
   }
   return result;
 }
 
-export function toAvg(points: number[][], factor: number): Point[] {
+export function toAvg(points: number[][]): Point[] {
   const result = [];
   for (const p of points) {
     result.push({
       x: p[0] * 1000,
-      y: p[3] * factor,
+      y: p[3],
     });
   }
   return result;

src/main/angular/src/app/series/series.service.ts

@@ -4,6 +4,7 @@ import {Series} from './Series';
 import {Interval} from './Interval';
 import {AllSeriesPointResponse} from './AllSeriesPointResponse';
 import {AllSeriesPointRequest} from './AllSeriesPointRequest';
+import {Graph} from "../plot/axis/graph/Graph";
 
 @Injectable({
   providedIn: 'root',
@@ -16,12 +17,16 @@ export class SeriesService extends EntityListService<Series> {
     super(api, ['Series'], Series.fromJson, Series.equals, Series.compareName);
   }
 
-  oneSeriesPoints(series: Series, interval: Interval, offset: number, duration: number, next: Next<number[][]>): void {
+  oneSeriesPoints(graph: Graph, next: Next<number[][]>): void {
     const request = {
-      id: series.id,
-      interval: interval.name,
-      offset: offset,
-      duration: duration,
+      id: graph.series.id,
+      factor: graph.factor,
+      operation: graph.operation,
+      id2: graph.series2?.id,
+      factor2: graph.factor2,
+      interval: graph.axis.plot.interval.name,
+      offset: graph.axis.plot.offset,
+      duration: graph.axis.plot.duration,
     };
     this.api.postList([...this.path, 'oneSeriesPoints'], request, (outer: any[]) => outer.map(validateNumber), next);
   }

src/main/java/de/ph87/data/DemoService.java

@@ -43,7 +43,6 @@ public class DemoService {
   @EventListener(ApplicationReadyEvent.class)
   public void init() {
     topics();
-//    plots();
   }
 
   private void topics() {
@@ -168,6 +167,7 @@ public class DemoService {
     zuhauseEnergie();
     zuhauseTemperatur();
     eltern();
+    leistungVergleich();
   }
 
   private void zuhauseEnergie() {
@@ -181,30 +181,33 @@ public class DemoService {
     energy.setName("Energie");
     energy.setUnit("kWh");
 
-    final Series electricityEnergyPurchase = seriesRepository.findByName("electricity/energy/purchase").orElseThrow();
-    final Graph electricityEnergyPurchaseGraph = graphRepository.save(new Graph(energy, electricityEnergyPurchase));
-    electricityEnergyPurchaseGraph.setType(GraphType.BAR);
-    electricityEnergyPurchaseGraph.setStack("a");
-    electricityEnergyPurchaseGraph.setName("Bezug");
-    electricityEnergyPurchaseGraph.setColor("#FF8800");
-    energy.addGraph(electricityEnergyPurchaseGraph);
+    final String stack = "a";
 
     final Series electricityEnergyDelivery = seriesRepository.findByName("electricity/energy/delivery").orElseThrow();
     final Graph electricityEnergyDeliveryGraph = graphRepository.save(new Graph(energy, electricityEnergyDelivery));
     electricityEnergyDeliveryGraph.setType(GraphType.BAR);
-    electricityEnergyDeliveryGraph.setStack("a");
-    electricityEnergyDeliveryGraph.setName("Überschuss");
+    electricityEnergyDeliveryGraph.setStack(stack);
+    electricityEnergyDeliveryGraph.setName("Zuhause Überschuss");
     electricityEnergyDeliveryGraph.setColor("#FF00FF");
     electricityEnergyDeliveryGraph.setFactor(-1);
     energy.addGraph(electricityEnergyDeliveryGraph);
 
     final Series electricityEnergyProduce = seriesRepository.findByName("electricity/energy/produce").orElseThrow();
     final Graph electricityEnergyProduceGraph = graphRepository.save(new Graph(energy, electricityEnergyProduce));
+    electricityEnergyProduceGraph.setSeries2(electricityEnergyDelivery);
+    electricityEnergyProduceGraph.setName("Zuhause Eigenverbrauch");
     electricityEnergyProduceGraph.setType(GraphType.BAR);
-    electricityEnergyProduceGraph.setStack("a");
-    electricityEnergyProduceGraph.setName("Produktion");
-    electricityEnergyProduceGraph.setColor("#0000FF");
+    electricityEnergyProduceGraph.setStack(stack);
+    electricityEnergyProduceGraph.setColor("#008800");
     energy.addGraph(electricityEnergyProduceGraph);
+
+    final Series electricityEnergyPurchase = seriesRepository.findByName("electricity/energy/purchase").orElseThrow();
+    final Graph electricityEnergyPurchaseGraph = graphRepository.save(new Graph(energy, electricityEnergyPurchase));
+    electricityEnergyPurchaseGraph.setType(GraphType.BAR);
+    electricityEnergyPurchaseGraph.setStack(stack);
+    electricityEnergyPurchaseGraph.setName("Zuhause Bezug");
+    electricityEnergyPurchaseGraph.setColor("#FF8800");
+    energy.addGraph(electricityEnergyPurchaseGraph);
   }
 
   private void zuhauseTemperatur() {
@@ -236,6 +239,24 @@ public class DemoService {
     gardenTemperatureGraph.setAvg(false);
     gardenTemperatureGraph.setMax(true);
     temperature.addGraph(gardenTemperatureGraph);
+
+    final Series bufferTemperature = seriesRepository.findByName("heating/buffer/inside/temperature").orElseThrow();
+    final Graph bufferTemperatureGraph = graphRepository.save(new Graph(temperature, bufferTemperature));
+    bufferTemperatureGraph.setName("Puffer");
+    bufferTemperatureGraph.setColor("#FF00FF");
+    bufferTemperatureGraph.setMin(true);
+    bufferTemperatureGraph.setAvg(false);
+    bufferTemperatureGraph.setMax(true);
+    temperature.addGraph(bufferTemperatureGraph);
+
+    final Series circuitTemperature = seriesRepository.findByName("heating/circuit/supply/temperature").orElseThrow();
+    final Graph circuitTemperatureGraph = graphRepository.save(new Graph(temperature, circuitTemperature));
+    circuitTemperatureGraph.setName("Heizkreis");
+    circuitTemperatureGraph.setColor("#FF0000");
+    circuitTemperatureGraph.setMin(true);
+    circuitTemperatureGraph.setAvg(false);
+    circuitTemperatureGraph.setMax(true);
+    temperature.addGraph(circuitTemperatureGraph);
   }
 
   private void eltern() {
@@ -249,14 +270,6 @@ public class DemoService {
     energy.setName("Energie");
     energy.setUnit("kWh");
 
-    final Series electricityEnergyPurchase = seriesRepository.findByName("eltern/electricity/energy/purchase").orElseThrow();
-    final Graph electricityEnergyPurchaseGraph = graphRepository.save(new Graph(energy, electricityEnergyPurchase));
-    electricityEnergyPurchaseGraph.setName("Bezug");
-    electricityEnergyPurchaseGraph.setType(GraphType.BAR);
-    electricityEnergyPurchaseGraph.setStack("a");
-    electricityEnergyPurchaseGraph.setColor("#FF8800");
-    energy.addGraph(electricityEnergyPurchaseGraph);
-
     final Series electricityEnergyDelivery = seriesRepository.findByName("eltern/electricity/energy/delivery").orElseThrow();
     final Graph electricityEnergyDeliveryGraph = graphRepository.save(new Graph(energy, electricityEnergyDelivery));
     electricityEnergyDeliveryGraph.setName("Überschuss");
@@ -268,11 +281,46 @@ public class DemoService {
 
     final Series electricityEnergyProduce = seriesRepository.findByName("eltern/electricity/energy/produce").orElseThrow();
     final Graph electricityEnergyProduceGraph = graphRepository.save(new Graph(energy, electricityEnergyProduce));
-    electricityEnergyProduceGraph.setName("Produktion");
+    electricityEnergyProduceGraph.setSeries2(electricityEnergyDelivery);
+    electricityEnergyProduceGraph.setName("Eigenverbrauch");
     electricityEnergyProduceGraph.setType(GraphType.BAR);
     electricityEnergyProduceGraph.setStack("a");
-    electricityEnergyProduceGraph.setColor("#0000FF");
+    electricityEnergyProduceGraph.setColor("#008800");
     energy.addGraph(electricityEnergyProduceGraph);
+
+    final Series electricityEnergyPurchase = seriesRepository.findByName("eltern/electricity/energy/purchase").orElseThrow();
+    final Graph electricityEnergyPurchaseGraph = graphRepository.save(new Graph(energy, electricityEnergyPurchase));
+    electricityEnergyPurchaseGraph.setName("Bezug");
+    electricityEnergyPurchaseGraph.setType(GraphType.BAR);
+    electricityEnergyPurchaseGraph.setStack("a");
+    electricityEnergyPurchaseGraph.setColor("#FF8800");
+    energy.addGraph(electricityEnergyPurchaseGraph);
+  }
+
+  private void leistungVergleich() {
+    final Plot plot = plotRepository.save(new Plot(plotRepository.count()));
+    plot.setName("Leistung Vergleich");
+
+    final Axis power = axisRepository.save(new Axis(plot));
+    plot.addAxis(power);
+    plot.setDashboard(true);
+    power.setRight(true);
+    power.setName("Leistung");
+    power.setUnit("W");
+
+    final Series electricityPowerProduce = seriesRepository.findByName("electricity/power/produce").orElseThrow();
+    final Graph electricityPowerProduceGraph = graphRepository.save(new Graph(power, electricityPowerProduce));
+    electricityPowerProduceGraph.setName("Zuhause");
+    electricityPowerProduceGraph.setType(GraphType.BAR);
+    electricityPowerProduceGraph.setColor("#008800");
+    power.addGraph(electricityPowerProduceGraph);
+
+    final Series elternElectricityPowerProduce = seriesRepository.findByName("eltern/electricity/power/produce").orElseThrow();
+    final Graph elternElectricityPowerProduceGraph = graphRepository.save(new Graph(power, elternElectricityPowerProduce));
+    elternElectricityPowerProduceGraph.setName("Eltern");
+    elternElectricityPowerProduceGraph.setType(GraphType.BAR);
+    elternElectricityPowerProduceGraph.setColor("#0088FF");
+    power.addGraph(elternElectricityPowerProduceGraph);
   }
 
   @NonNull

src/main/java/de/ph87/data/Helpers.java

@@ -3,6 +3,7 @@ package de.ph87.data;
 import jakarta.annotation.Nullable;
 import lombok.NonNull;
 
+import java.util.function.BiFunction;
 import java.util.function.Function;
 
 public class Helpers {
@@ -15,6 +16,14 @@ public class Helpers {
     return mapper.apply(t);
   }
 
+  @Nullable
+  public static <T, U, R> R map(@Nullable final T t, @NonNull final U u, @NonNull final BiFunction<T, U, R> mapper) {
+    if (t == null) {
+      return null;
+    }
+    return mapper.apply(t, u);
+  }
+
   @NonNull
   public static <T> T or(@Nullable final T t, @NonNull final T r) {
     if (t == null) {

src/main/java/de/ph87/data/plot/axis/graph/Graph.java

@@ -2,6 +2,7 @@ package de.ph87.data.plot.axis.graph;
 
 import de.ph87.data.plot.axis.Axis;
 import de.ph87.data.series.Series;
+import jakarta.annotation.Nullable;
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;
 import jakarta.persistence.EnumType;
@@ -41,6 +42,24 @@ public class Graph {
   @ManyToOne(optional = false)
   private Series series;
 
+  @Setter
+  @Column(nullable = false)
+  private double factor = 1;
+
+  @Setter
+  @Column(nullable = false)
+  @Enumerated(EnumType.STRING)
+  private GraphOperation operation = GraphOperation.MINUS;
+
+  @Setter
+  @Nullable
+  @ManyToOne
+  private Series series2;
+
+  @Setter
+  @Column(nullable = false)
+  private double factor2 = 1;
+
   @Setter
   @NonNull
   @Column(nullable = false)
@@ -66,10 +85,6 @@ public class Graph {
   @Column(nullable = false)
   private String color = "#FF0000";
 
-  @Setter
-  @Column(nullable = false)
-  private double factor = 1;
-
   @Setter
   @NonNull
   @Enumerated(EnumType.STRING)

src/main/java/de/ph87/data/plot/axis/graph/GraphController.java

@@ -56,16 +56,31 @@ public class GraphController {
     return graphService.set(id, graph -> graph.setSeries(seriesRepository.findById(value).orElseThrow()));
   }
 
-  @PostMapping("{id}/color")
-  public PlotDto color(@PathVariable final long id, @RequestBody @NonNull final String value) {
-    return graphService.set(id, graph -> graph.setColor(value));
-  }
-
   @PostMapping("{id}/factor")
   public PlotDto factor(@PathVariable final long id, @RequestBody final double value) {
     return graphService.set(id, graph -> graph.setFactor(value));
   }
 
+  @PostMapping("{id}/operation")
+  public PlotDto operation(@PathVariable final long id, @RequestBody @NonNull final String value) {
+    return graphService.set(id, graph -> graph.setOperation(GraphOperation.valueOf(value)));
+  }
+
+  @PostMapping("{id}/series2")
+  public PlotDto series2(@PathVariable final long id, @RequestBody(required = false) @Nullable final Long value) {
+    return graphService.set(id, graph -> graph.setSeries2(value == null ? null : seriesRepository.findById(value).orElseThrow()));
+  }
+
+  @PostMapping("{id}/factor2")
+  public PlotDto factor2(@PathVariable final long id, @RequestBody final double value) {
+    return graphService.set(id, graph -> graph.setFactor2(value));
+  }
+
+  @PostMapping("{id}/color")
+  public PlotDto color(@PathVariable final long id, @RequestBody @NonNull final String value) {
+    return graphService.set(id, graph -> graph.setColor(value));
+  }
+
   @PostMapping("{id}/group")
   public PlotDto group(@PathVariable final long id, @RequestBody @NonNull final String value) {
     return graphService.set(id, graph -> graph.setGroup(Group.valueOf(value)));

src/main/java/de/ph87/data/plot/axis/graph/GraphDivisionByZero.java

@@ -0,0 +1,5 @@
+package de.ph87.data.plot.axis.graph;
+
+public class GraphDivisionByZero extends Exception {
+
+}

src/main/java/de/ph87/data/plot/axis/graph/GraphDto.java

@@ -1,9 +1,12 @@
 package de.ph87.data.plot.axis.graph;
 
 import de.ph87.data.series.SeriesDto;
+import jakarta.annotation.Nullable;
 import lombok.Data;
 import lombok.NonNull;
 
+import static de.ph87.data.Helpers.map;
+
 @Data
 public class GraphDto {
 
@@ -14,6 +17,15 @@ public class GraphDto {
   @NonNull
   public final SeriesDto series;
 
+  public final double factor;
+
+  public final GraphOperation operation;
+
+  @Nullable
+  public final SeriesDto series2;
+
+  public final double factor2;
+
   @NonNull
   public final String name;
 
@@ -26,8 +38,6 @@ public class GraphDto {
   @NonNull
   public final String color;
 
-  public final double factor;
-
   @NonNull
   public final Group group;
 
@@ -44,12 +54,15 @@ public class GraphDto {
     this.id = graph.getId();
     this.version = graph.getVersion();
     this.series = new SeriesDto(graph.getSeries(), false);
+    this.factor = graph.getFactor();
+    this.operation = graph.getOperation();
+    this.series2 = map(graph.getSeries2(), false, SeriesDto::new);
+    this.factor2 = graph.getFactor2();
     this.name = graph.getName();
     this.visible = graph.isVisible();
     this.type = graph.getType();
     this.fill = graph.getFill();
     this.color = graph.getColor();
-    this.factor = graph.getFactor();
     this.group = graph.getGroup();
     this.stack = graph.getStack();
     this.min = graph.isMin();

src/main/java/de/ph87/data/plot/axis/graph/GraphOperation.java

@@ -0,0 +1,27 @@
+package de.ph87.data.plot.axis.graph;
+
+import lombok.NonNull;
+
+public enum GraphOperation {
+  MINUS((s0, s1) -> s0 - s1),
+  PLUS(Double::sum),
+  DIVIDE((s0, s1) -> {
+    if (s1 == 0) {
+      throw new GraphDivisionByZero();
+    }
+    return s0 / s1;
+  }),
+  ;
+
+  @NonNull
+  private final GraphOperationFunction<Double, Double, Double> function;
+
+  GraphOperation(@NonNull final GraphOperationFunction<Double, Double, Double> function) {
+    this.function = function;
+  }
+
+  public double apply(final double a, final double b) throws GraphDivisionByZero {
+    return function.apply(a, b);
+  }
+
+}

src/main/java/de/ph87/data/plot/axis/graph/GraphOperationFunction.java

@@ -0,0 +1,8 @@
+package de.ph87.data.plot.axis.graph;
+
+@FunctionalInterface
+public interface GraphOperationFunction<A, B, R> {
+
+  R apply(A a, B b) throws GraphDivisionByZero;
+
+}

src/main/java/de/ph87/data/series/AllSeriesPointResponse.java

@@ -22,7 +22,7 @@ public class AllSeriesPointResponse {
     public final SeriesDto series;
 
     @Nullable
-    public final SeriesPoint point;
+    public final SeriesPoint<?> point;
 
   }
 

src/main/java/de/ph87/data/series/OneSeriesPointsRequest.java

@@ -2,7 +2,9 @@ package de.ph87.data.series;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import com.fasterxml.jackson.annotation.JsonProperty;
+import de.ph87.data.plot.axis.graph.GraphOperation;
 import de.ph87.data.series.data.Interval;
+import jakarta.annotation.Nullable;
 import lombok.Data;
 import lombok.NonNull;
 
@@ -13,6 +15,15 @@ public class OneSeriesPointsRequest implements ISeriesPointRequest {
 
   public final long id;
 
+  public final double factor;
+
+  public final GraphOperation operation;
+
+  @Nullable
+  public final Long id2;
+
+  public final double factor2;
+
   @NonNull
   public final Interval interval;
 
@@ -30,11 +41,19 @@ public class OneSeriesPointsRequest implements ISeriesPointRequest {
 
   public OneSeriesPointsRequest(
     @JsonProperty("id") final long id,
+    @JsonProperty("factor") final double factor,
+    @JsonProperty("operation") final GraphOperation operation,
+    @JsonProperty("id2") @Nullable final Long id2,
+    @JsonProperty("factor2") final double factor2,
     @JsonProperty("interval") final Interval interval,
     @JsonProperty("offset") final long offset,
     @JsonProperty("duration") final long duration
   ) {
     this.id = id;
+    this.factor = factor;
+    this.operation = operation;
+    this.id2 = id2;
+    this.factor2 = factor2;
     this.interval = interval;
     this.offset = offset;
     this.duration = duration;

src/main/java/de/ph87/data/series/OneSeriesPointsResponse.java

@@ -9,6 +9,6 @@ import java.util.List;
 @JsonSerialize(using = OneSeriesPointsResponseSerializer.class)
 public class OneSeriesPointsResponse {
 
-  public final List<? extends SeriesPoint> points;
+  public final List<? extends SeriesPoint<?>> points;
 
 }

src/main/java/de/ph87/data/series/SeriesPoint.java

@@ -1,11 +1,67 @@
 package de.ph87.data.series;
 
 import com.fasterxml.jackson.core.JsonGenerator;
+import de.ph87.data.plot.axis.graph.GraphDivisionByZero;
+import de.ph87.data.plot.axis.graph.GraphOperation;
+import lombok.NonNull;
 
 import java.io.IOException;
+import java.time.ZonedDateTime;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
 
-public interface SeriesPoint {
+public interface SeriesPoint<T extends SeriesPoint<T>> {
+
+  ZonedDateTime getDate();
+
+  double getValue();
 
   void toJson(final JsonGenerator jsonGenerator) throws IOException;
 
+  T times(final double factor);
+
+  T combine(@NonNull final SeriesPoint<?> other, @NonNull final GraphOperation operation) throws GraphDivisionByZero;
+
+  @NonNull
+  static List<SeriesPoint<?>> combine(@NonNull final List<? extends SeriesPoint<?>> points1, @NonNull final List<? extends SeriesPoint<?>> points2, @NonNull final GraphOperation operation) {
+    if (points1.isEmpty() || points2.isEmpty()) {
+      return Collections.emptyList();
+    }
+    final List<SeriesPoint<?>> as = new ArrayList<>(points1);
+    final List<SeriesPoint<?>> bs = new ArrayList<>(points2);
+    SeriesPoint<?> a = as.removeFirst();
+    SeriesPoint<?> b = bs.removeFirst();
+    final List<SeriesPoint<?>> result = new ArrayList<>(Math.min(as.size(), bs.size()));
+    while (true) {
+      final int diff = a.getDate().compareTo(b.getDate());
+      if (diff == 0) {
+        try {
+          result.add(a.combine(b, operation));
+        } catch (GraphDivisionByZero e) {
+          // just not add
+        }
+        a = null;
+        b = null;
+      } else if (diff < 0) {
+        a = null;
+      } else {
+        b = null;
+      }
+      if (a == null) {
+        if (as.isEmpty()) {
+          break;
+        }
+        a = as.removeFirst();
+      }
+      if (b == null) {
+        if (bs.isEmpty()) {
+          break;
+        }
+        b = bs.removeFirst();
+      }
+    }
+    return result;
+  }
+
 }

src/main/java/de/ph87/data/series/SeriesService.java

@@ -3,6 +3,7 @@ package de.ph87.data.series;
 import de.ph87.data.series.data.bool.BoolService;
 import de.ph87.data.series.data.delta.DeltaService;
 import de.ph87.data.series.data.varying.VaryingService;
+import jakarta.annotation.Nullable;
 import lombok.NonNull;
 import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
@@ -27,8 +28,14 @@ public class SeriesService {
 
   @NonNull
   public OneSeriesPointsResponse oneSeriesPoints(@NonNull final OneSeriesPointsRequest request) {
-    final Series series = seriesRepository.findById(request.id).orElseThrow(() -> new ResponseStatusException(HttpStatus.NOT_FOUND));
-    return new OneSeriesPointsResponse(getSeriesPoints(series, request));
+    final Series series1 = seriesRepository.findById(request.id).orElseThrow(() -> new ResponseStatusException(HttpStatus.NOT_FOUND));
+    final List<? extends SeriesPoint<?>> points1 = getSeriesPoints(series1, request, request.factor);
+    if (request.id2 != null) {
+      final Series series2 = seriesRepository.findById(request.id2).orElseThrow(() -> new ResponseStatusException(HttpStatus.NOT_FOUND));
+      final List<? extends SeriesPoint<?>> points2 = getSeriesPoints(series2, request, request.factor2);
+      return new OneSeriesPointsResponse(SeriesPoint.combine(points1, points2, request.operation));
+    }
+    return new OneSeriesPointsResponse(points1);
   }
 
   @NonNull
@@ -39,19 +46,23 @@ public class SeriesService {
 
   @NonNull
   private AllSeriesPointResponse.Entry map(@NonNull final Series series, @NonNull final ISeriesPointRequest request) {
-    final List<? extends SeriesPoint> points = getSeriesPoints(series, request);
+    final List<? extends SeriesPoint<?>> points = getSeriesPoints(series, request, null);
     final SeriesDto seriesDto = new SeriesDto(series, false);
-    final SeriesPoint point = points.isEmpty() ? null : points.getFirst();
+    final SeriesPoint<?> point = points.isEmpty() ? null : points.getFirst();
     return new AllSeriesPointResponse.Entry(seriesDto, point);
   }
 
   @NonNull
-  private List<? extends SeriesPoint> getSeriesPoints(@NonNull final Series series, @NonNull final ISeriesPointRequest request) {
-    return switch (series.getType()) {
+  private List<? extends SeriesPoint<?>> getSeriesPoints(@NonNull final Series series, @NonNull final ISeriesPointRequest request, @Nullable final Double factor) {
+    final List<? extends SeriesPoint<?>> points = switch (series.getType()) {
       case BOOL -> boolService.points(series, request);
       case DELTA -> deltaService.points(series, request);
       case VARYING -> varyingService.points(series, request);
     };
+    if (factor == null || factor == 1) {
+      return points;
+    }
+    return points.stream().map(p -> p.times(factor)).toList();
   }
 
 }

src/main/java/de/ph87/data/series/data/bool/BoolPoint.java

@@ -1,14 +1,17 @@
 package de.ph87.data.series.data.bool;
 
 import com.fasterxml.jackson.core.JsonGenerator;
+import de.ph87.data.plot.axis.graph.GraphDivisionByZero;
+import de.ph87.data.plot.axis.graph.GraphOperation;
 import de.ph87.data.series.SeriesPoint;
+import lombok.Data;
 import lombok.NonNull;
 
 import java.io.IOException;
 import java.time.ZonedDateTime;
 
-@SuppressWarnings("unused") // used by repository query
-public class BoolPoint implements SeriesPoint {
+@Data
+public class BoolPoint implements SeriesPoint<BoolPoint> {
 
   public final ZonedDateTime begin;
 
@@ -25,6 +28,13 @@ public class BoolPoint implements SeriesPoint {
     this.terminated = bool.isTerminated();
   }
 
+  public BoolPoint(final ZonedDateTime begin, final ZonedDateTime end, final boolean state, final boolean terminated) {
+    this.begin = begin;
+    this.end = end;
+    this.state = state;
+    this.terminated = terminated;
+  }
+
   @Override
   public void toJson(final JsonGenerator jsonGenerator) throws IOException {
     jsonGenerator.writeNumber(begin.toEpochSecond());
@@ -33,4 +43,24 @@ public class BoolPoint implements SeriesPoint {
     jsonGenerator.writeNumber(terminated ? 1 : 0);
   }
 
+  @Override
+  public BoolPoint times(final double factor) {
+    return this;
+  }
+
+  @Override
+  public ZonedDateTime getDate() {
+    return begin;
+  }
+
+  @Override
+  public double getValue() {
+    return state ? 1 : 0;
+  }
+
+  @Override
+  public BoolPoint combine(@NonNull final SeriesPoint<?> other, @NonNull final GraphOperation operation) throws GraphDivisionByZero {
+    return new BoolPoint(begin, end, operation.apply(getValue(), other.getValue()) > 0, terminated);
+  }
+
 }

src/main/java/de/ph87/data/series/data/delta/DeltaPoint.java

@@ -1,14 +1,17 @@
 package de.ph87.data.series.data.delta;
 
 import com.fasterxml.jackson.core.JsonGenerator;
+import de.ph87.data.plot.axis.graph.GraphDivisionByZero;
+import de.ph87.data.plot.axis.graph.GraphOperation;
 import de.ph87.data.series.SeriesPoint;
+import lombok.Data;
 import lombok.NonNull;
 
 import java.io.IOException;
 import java.time.ZonedDateTime;
 
-@SuppressWarnings("unused") // used by repository query
-public class DeltaPoint implements SeriesPoint {
+@Data
+public class DeltaPoint implements SeriesPoint<DeltaPoint> {
 
   @NonNull
   public final ZonedDateTime date;
@@ -26,4 +29,19 @@ public class DeltaPoint implements SeriesPoint {
     jsonGenerator.writeNumber(delta);
   }
 
+  @Override
+  public DeltaPoint times(final double factor) {
+    return new DeltaPoint(date, delta * factor);
+  }
+
+  @Override
+  public double getValue() {
+    return delta;
+  }
+
+  @Override
+  public DeltaPoint combine(@NonNull final SeriesPoint<?> other, @NonNull final GraphOperation operation) throws GraphDivisionByZero {
+    return new DeltaPoint(date, operation.apply(getValue(), other.getValue()));
+  }
+
 }

src/main/java/de/ph87/data/series/data/delta/DeltaRepo.java

@@ -13,7 +13,7 @@ import java.util.List;
 public interface DeltaRepo<T extends Delta> extends CrudRepository<T, DeltaId> {
 
   @NonNull
-  @Query("select new de.ph87.data.series.data.delta.DeltaPoint(e.id.date, sum(e.last - e.first)) from #{#entityName} e where e.id.meter.series = :series and e.id.date >= :first and e.id.date < :after group by e.id.date")
+  @Query("select new de.ph87.data.series.data.delta.DeltaPoint(e.id.date, sum((e.last - e.first))) from #{#entityName} e where e.id.meter.series = :series and e.id.date >= :first and e.id.date < :after group by e.id.date")
   List<DeltaPoint> points(@NonNull Series series, @NonNull ZonedDateTime first, @NonNull ZonedDateTime after);
 
 }

src/main/java/de/ph87/data/series/data/varying/VaryingPoint.java

@@ -1,14 +1,17 @@
 package de.ph87.data.series.data.varying;
 
 import com.fasterxml.jackson.core.JsonGenerator;
+import de.ph87.data.plot.axis.graph.GraphDivisionByZero;
+import de.ph87.data.plot.axis.graph.GraphOperation;
 import de.ph87.data.series.SeriesPoint;
+import lombok.Data;
 import lombok.NonNull;
 
 import java.io.IOException;
 import java.time.ZonedDateTime;
 
-@SuppressWarnings("unused") // used by repository query
-public class VaryingPoint implements SeriesPoint {
+@Data
+public class VaryingPoint implements SeriesPoint<VaryingPoint> {
 
   public final ZonedDateTime date;
 
@@ -25,6 +28,13 @@ public class VaryingPoint implements SeriesPoint {
     this.avg = varying.getAvg();
   }
 
+  private VaryingPoint(final ZonedDateTime date, final double min, final double avg, final double max) {
+    this.date = date;
+    this.min = min;
+    this.avg = avg;
+    this.max = max;
+  }
+
   @Override
   public void toJson(final JsonGenerator jsonGenerator) throws IOException {
     jsonGenerator.writeNumber(date.toEpochSecond());
@@ -33,4 +43,22 @@ public class VaryingPoint implements SeriesPoint {
     jsonGenerator.writeNumber(avg);
   }
 
+  @Override
+  public VaryingPoint times(final double factor) {
+    return new VaryingPoint(date, min * factor, avg * factor, max * factor);
+  }
+
+  @Override
+  public double getValue() {
+    return avg;
+  }
+
+  @Override
+  public VaryingPoint combine(@NonNull final SeriesPoint<?> other, @NonNull final GraphOperation operation) throws GraphDivisionByZero {
+    if (other instanceof final VaryingPoint otherVarying) {
+      return new VaryingPoint(date, operation.apply(min, otherVarying.min), operation.apply(avg, otherVarying.avg), operation.apply(max, otherVarying.max));
+    }
+    return new VaryingPoint(date, operation.apply(min, other.getValue()), operation.apply(avg, other.getValue()), operation.apply(max, other.getValue()));
+  }
+
 }