// Set up the canvas and shapes
let stage = new Konva.Stage({container: 'container1', width: 300, height: 200});
let layer = new Konva.Layer({draggable: false});
stage.add(layer);
// Add a transformer.
let transFormer1 = new Konva.Transformer();
layer.add(transFormer1);
// Create a sample group
let group1 = new Konva.Group();
layer.add(group1);
group1.add(new Konva.Circle({x: 20, y: 30, radius: 15, fill: 'magenta', stroke: 'black'}))
group1.add(new Konva.Circle({x: 60, y: 40, radius: 15, fill: 'magenta', stroke: 'black'}))
group1.add(new Konva.Rect({x: 90, y: 60, width: 25, height: 25, fill: 'magenta', stroke: 'black'}));
let pos = group1.getClientRect();
let boundRect1 = new Konva.Rect({name: 'boundRect', x: pos.x, y: pos.y, width: pos.width, height: pos.height, fill: 'transparent', stroke: 'transparent'});
group1.add(boundRect1);
// When mouse enters the group show a border
group1.on('mouseenter', function(){
let boundRect = this.find('.boundRect');
boundRect[0].stroke('red');
layer.draw();
})
// and remove border when mouse leaves
group1.on('mouseleave', function(){
let boundRect = this.find('.boundRect');
boundRect[0].stroke('transparent');
layer.draw();
})
// If the group is clicked, enable the transformer on that group.
group1.on('click', function(){
transFormer1.attachTo(this)
layer.batchDraw();
})
// For a more pleasing demo let us have 2 groups.
// Make a copy of group1, offset new group, and change fill on its child shapes except the bound rect
let group2 = group1.clone();
layer.add(group2)
group2.position({x: 120, y: 30});
for (let i = 0, shapes = group2.getChildren(); i < shapes.length; i = i + 1){
shapes[i].fill(shapes[i].fill() !== 'transparent' ? 'cyan' : 'transparent');
}
stage.draw();
<script src="https://unpkg.com/konva@^3/konva.min.js"></script>
<p>Move mouse over the shapes to see the group borders, click a group to apply the transformer.
</p>
<div id='container1' style="display: inline-block; width: 300px, height: 200px; background-color: silver; overflow: hidden; position: relative;"></div>