Add download feature on mining charts

frontend/src/app/components/block-fee-rates-graph/block-fee-rates-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 { formatterXAxis, formatterXAxisLabel, formatterXAxisTimeCategory } from 'src/app/shared/graphs.utils';
+import { download, formatterXAxis, formatterXAxisLabel, formatterXAxisTimeCategory } from 'src/app/shared/graphs.utils';
 import { StorageService } from 'src/app/services/storage.service';
 import { MiningService } from 'src/app/services/mining.service';
 import { selectPowerOfTen } from 'src/app/bitcoin.utils';
@@ -147,6 +147,7 @@ export class BlockFeeRatesGraphComponent implements OnInit {
 
   prepareChartOptions(data) {
     this.chartOptions = {
+      backgroundColor: '#11131f',
       color: ['#D81B60', '#8E24AA', '#1E88E5', '#7CB342', '#FDD835', '#6D4C41', '#546E7A'],
       animation: false,
       grid: {
@@ -297,4 +298,20 @@ export class BlockFeeRatesGraphComponent implements OnInit {
   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-fee-rates-${this.timespan}-${now.getTime() / 1000}`);
+    // @ts-ignore
+    this.chartOptions.grid.bottom = prevBottom;
+    this.chartInstance.setOption(this.chartOptions);
+  }
 }