Angular Konva Transformer Tutorial

To use transformers with Konva in Angular, you can use the ng2-konva library with the Transformer component to enable shape selection and transformation.

For full list of properties and methods, see the Konva API Reference.

Transformer Example

import { Component, ViewChild, AfterViewInit } from '@angular/core';
import { StageConfig } from 'konva/lib/Stage';
import { RectConfig } from 'konva/lib/shapes/Rect';

import {
  CoreShapeComponent,
  StageComponent,
} from 'ng2-konva';

@Component({
  selector: 'app-root',
  template: `
    <ko-stage [config]="configStage" (click)="handleStageClick($event.event)">
      <ko-layer>
        <ko-rect
          #rect
          [config]="configRect"
          (click)="handleShapeClick()"
        ></ko-rect>
        <ko-transformer #transformer></ko-transformer>
      </ko-layer>
    </ko-stage>
  `,
  imports: [StageComponent, CoreShapeComponent],
})
export default class App implements AfterViewInit {
  @ViewChild('rect') rect!: any;
  @ViewChild('transformer') transformer!: any;

  public configStage: StageConfig = {
    width: window.innerWidth,
    height: window.innerHeight,
  };
  public configRect: RectConfig = {
    x: 100,
    y: 100,
    width: 100,
    height: 100,
    fill: 'red',
    stroke: 'black',
    strokeWidth: 4,
    draggable: true
  };

  ngAfterViewInit() {
    this.transformer.getNode().nodes([this.rect.getNode()]);
  }

  public handleStageClick(event: any): void {
    if (!event) {
      // TODO: there is currently a bug in ng2-konva where the event is not passed in the click event
      return;
    }
    if (event.target === event.target.getStage()) {
      this.transformer.getNode().nodes([]);
    }
  }

  public handleShapeClick(): void {
    this.transformer.getNode().nodes([this.rect.getNode()]);
  }
}

Open Sandbox