Tooltip-style tx previews in block overview

frontend/src/app/components/block-overview-tooltip/block-overview-tooltip.component.ts

@@ -0,0 +1,53 @@
+import { Component, ElementRef, ViewChild, Input, OnChanges, ChangeDetectionStrategy } from '@angular/core';
+import { TransactionStripped } from 'src/app/interfaces/websocket.interface';
+import { Position } from 'src/app/components/block-overview-graph/sprite-types.js';
+
+@Component({
+  selector: 'app-block-overview-tooltip',
+  templateUrl: './block-overview-tooltip.component.html',
+  styleUrls: ['./block-overview-tooltip.component.scss'],
+})
+export class BlockOverviewTooltipComponent implements OnChanges {
+  @Input() tx: TransactionStripped | void;
+  @Input() cursorPosition: Position;
+  @Input() clickable: boolean;
+
+  txid = '';
+  fee = 0;
+  value = 0;
+  vsize = 1;
+  feeRate = 0;
+
+  tooltipPosition: Position = { x: 0, y: 0 };
+
+  @ViewChild('tooltip') tooltipElement: ElementRef<HTMLCanvasElement>;
+
+  constructor() {}
+
+  ngOnChanges(changes): void {
+    if (changes.cursorPosition && changes.cursorPosition.currentValue) {
+      let x = changes.cursorPosition.currentValue.x + 10;
+      let y = changes.cursorPosition.currentValue.y + 10;
+      if (this.tooltipElement) {
+        const elementBounds = this.tooltipElement.nativeElement.getBoundingClientRect();
+        const parentBounds = this.tooltipElement.nativeElement.offsetParent.getBoundingClientRect();
+        if ((parentBounds.left + x + elementBounds.width) > parentBounds.right) {
+          x = Math.max(0, parentBounds.width - elementBounds.width - 10);
+        }
+        if (y + elementBounds.height > parentBounds.height) {
+          y = y - elementBounds.height - 20;
+        }
+      }
+      this.tooltipPosition = { x, y };
+    }
+
+    if (changes.tx) {
+      const tx = changes.tx.currentValue || {};
+      this.txid = tx.txid || '';
+      this.fee = tx.fee || 0;
+      this.value = tx.value || 0;
+      this.vsize = tx.vsize || 1;
+      this.feeRate = this.fee / this.vsize;
+    }
+  }
+}