Layouts

components.layout\.js

import Component from '@ember/component';

export default class extends Component {
  classNames = ['layout'];
  
  clickX = -1;
  clickY = -1;
  minX = 0;
  minY = 0;
  maxX = 0;
  maxY = 0;
  dragging = false;
  rectId = -1;

  didRender() {
    this._super(...arguments);
    
    this.minX = this.element.offsetLeft;
  	this.minY = this.element.offsetTop;
    this.maxX = this.minX + this.element.width;
    this.maxY = this.minY + this.element.height;
  }


	mouseDown(event) {
    this.clickX = event.pageX - this.minX;
    this.clickY = event.pageY - this.minY;
    
    let selectedRectangle = event.target.classList.contains('rectangle');
    let rightClick = event.which == 3;
    
    if (selectedRectangle) {
      if (rightClick) {
        this.deleteRectangle(event.target.id);
      } else {
        this.dragging = true;
        this.rectId = event.target.id;
      }
    }
  }

	mouseUp(event) {
    let x = event.pageX - this.minX;
    let y = event.pageY - this.minY;
    
    if (this.dragging) {
      let distX = x - this.clickX;
      let distY = y - this.clickY;
      
      this.updateRectangle(this.rectId, distX, distY);
    } else {
      let rect = {
        startX: Math.max(0, Math.min(this.clickX, x)),
        startY: Math.max(0, Math.min(this.clickY, y)),
        endX: Math.max(this.clickX, x),
        endY: Math.max(this.clickY, y),
        color: 'blue'
      }
      
      this.addRectangle(rect);
    }
    
		this.dragging = false;
    this.clickX = -1;
    this.clickY = -1;
  }
}

components.rectangle\.js

import Component from '@glimmer/component';
import { tracked } from '@glimmer/tracking';

export default class extends Component {
  get width() {
    return this.args.endX - this.args.startX;
  }
  
  get height() {
    return this.args.endY - this.args.startY;
  }
}

controllers.application\.js

import Controller from '@ember/controller';
import { action } from "@ember/object";
import { tracked } from '@glimmer/tracking';
import { set } from '@ember/object';

export default class ApplicationController extends Controller {
  appName = 'Meep';
  @tracked
	autoId = 3;

	@tracked
  rectangles = [
    {id: 1, startX: 0, startY: 0, endX: 100, endY: 100, color: 'red'},
    {id: 2, startX: 300, startY: 300, endX: 500, endY: 500, color: 'green'}
  ];

	@action
  addRectangle(rect) {
    rect.id = this.autoId;
    this.autoId++;
    
    this.rectangles.push(rect);
    
    this.rectangles = this.rectangles;
  }

  @action
  updateRectangle(id, distX, distY) {
    let rectId = -1;
    
    for (rectId = 0; rectId < this.rectangles.length; rectId++) {
      if (id == this.rectangles[rectId].id) {
        break; 
      }
    };
    let ogRect = this.rectangles[rectId];
    
    set(ogRect, 'startX', ogRect.startX + distX);
    set(ogRect, 'startY', ogRect.startY + distY);
    set(ogRect, 'endX', ogRect.endX + distX);
    set(ogRect, 'endY', ogRect.endY + distY);
  }

  @action
  deleteRectangle(id) {
    let rectId = -1;
    
    for (rectId = 0; rectId < this.rectangles.length; rectId++) {
      if (id == this.rectangles[rectId].id) {
        break; 
      }
    };
    
    this.rectangles.splice(rectId, 1);
		// this.rectangles = this.rectangles;
  }
}

styles.app\.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
  display: flex;
  min-height: 100vh;
  flex-direction: column;
}

#main {
  display: flex;
  flex: 1;
}

.ember-view {
  display: flex;
  flex: 1;
  flex-direction: column;
}

.layout {
  border: 1px solid black;
  position: relative;
  width: 100%;
  height: 100%;
}

templates.application\.hbs

<h1>Layout</h1>

<Layout @rectangles={{rectangles}} 
				@addRectangle={{addRectangle}}
        @updateRectangle={{updateRectangle}}
        @deleteRectangle={{deleteRectangle}}/>

templates.components.layout\.hbs

{{#each @rectangles as |rect|}}
  <Rectangle @id={{rect.id}}
             @startX={{rect.startX}} 
  					 @startY={{rect.startY}} 
             @endX={{rect.endX}}
             @endY={{rect.endY}} 
             @color={{rect.color}}/>
{{/each}}

templates.components.rectangle\.hbs

<div class="rectangle"
  id={{@id}}
  style="position: absolute;
         left:{{@startX}}px;
         top:{{@startY}}px;
         width:{{this.width}}px;
         height:{{this.height}}px;
         background-color:{{@color}};">
</div>

twiddle\.json

{
  "version": "0.17.0",
  "EmberENV": {
    "FEATURES": {},
    "_TEMPLATE_ONLY_GLIMMER_COMPONENTS": false,
    "_APPLICATION_TEMPLATE_WRAPPER": true,
    "_JQUERY_INTEGRATION": true
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.17.0",
    "ember-template-compiler": "3.17.0",
    "ember-testing": "3.17.0"
  },
  "addons": {
    "@glimmer/component": "1.0.0"
  }
}