Add download feature on mining charts

frontend/src/app/components/block-rewards-graph/block-rewards-graph.component.html

@@ -2,6 +2,10 @@
 
   <div class="card-header mb-0 mb-md-4">
     <span i18n="mining.block-rewards">Block rewards</span>
+    <button #saveChart class="btn" style="position: absolute; right: 30px" (click)="onSaveChart()">
+      <fa-icon [icon]="['fas', 'download']" [fixedWidth]="true"></fa-icon>
+    </button>
+
     <form [formGroup]="radioGroupForm" class="formRadioGroup" *ngIf="(statsObservable$ | async) as stats">
       <div class="btn-group btn-group-toggle" ngbRadioGroup name="radioBasic" formControlName="dateSpan">
         <label ngbButtonLabel class="btn-primary btn-sm" *ngIf="stats.blockCount >= 144">
@@ -38,7 +42,8 @@
     </form>
   </div>
 
-  <div class="chart" echarts [initOpts]="chartInitOptions" [options]="chartOptions">
+  <div class="chart" echarts [initOpts]="chartInitOptions" [options]="chartOptions"
+    (chartInit)="onChartInit($event)">
   </div>
   <div class="text-center loadingGraphs" *ngIf="isLoading">
     <div class="spinner-border text-light"></div>

frontend/src/app/components/block-rewards-graph/block-rewards-graph.component.ts

@@ -6,7 +6,7 @@ import { ApiService } from 'src/app/services/api.service';
 import { SeoService } from 'src/app/services/seo.service';
 import { formatNumber } from '@angular/common';
 import { FormBuilder, FormGroup } from '@angular/forms';
-import { formatterXAxisLabel } from 'src/app/shared/graphs.utils';
+import { download, formatterXAxisLabel } from 'src/app/shared/graphs.utils';
 import { MiningService } from 'src/app/services/mining.service';
 import { StorageService } from 'src/app/services/storage.service';
 
@@ -40,6 +40,7 @@ export class BlockRewardsGraphComponent implements OnInit {
   isLoading = true;
   formatNumber = formatNumber;
   timespan = '';
+  chartInstance: any = undefined;
 
   constructor(
     @Inject(LOCALE_ID) public locale: string,
@@ -85,6 +86,7 @@ export class BlockRewardsGraphComponent implements OnInit {
 
   prepareChartOptions(data) {
     this.chartOptions = {
+      backgroundColor: '#11131f',
       animation: false,
       color: [
         new graphic.LinearGradient(0, 0, 0, 0.65, [
@@ -194,7 +196,27 @@ export class BlockRewardsGraphComponent implements OnInit {
     };
   }
 
+  onChartInit(ec) {
+    this.chartInstance = ec;
+  }
+
   isMobile() {
     return (window.innerWidth <= 767.98);
   }
+
+  onSaveChart() {
+    // @ts-ignore
+    const prevBottom = this.chartOptions.grid.bottom;
+    const now = new Date();
+    // @ts-ignore
+    this.chartOptions.grid.bottom = 40;
+    this.chartInstance.setOption(this.chartOptions);
+    download(this.chartInstance.getDataURL({
+      pixelRatio: 2,
+      excludeComponents: ['dataZoom'],
+    }), `block-rewards-${this.timespan}-${now.getTime() / 1000}`);
+    // @ts-ignore
+    this.chartOptions.grid.bottom = prevBottom;
+    this.chartInstance.setOption(this.chartOptions);
+  }
 }