Snap grid, drag and drop with react-konva

Question

I'm creating a RPG table game, using React-Konva. I did a infinite grid and some images tokens with drag and drop.

So, its working fine. But, looking for another feature I found this using Canvas, its almost same I did, but with spap, the shapes are attracted to the Rect as a magnetic!

Here a example: Snap with Canvas
Snap with Konva.js

for (var i = 0; i < (600 / grid); i++) {
  canvas.add(new fabric.Line([ i * grid, 0, i * grid, 600], { stroke: '#ccc', selectable: false }));
  canvas.add(new fabric.Line([ 0, i * grid, 600, i * grid], { stroke: '#ccc', selectable: false }))
}

There is a way to do same with React-Konva? I Found something similar with Konva.js

EDITED:

I'm almost there!!!

const [x, setX] = useState(50)
const [y, setY] = useState(50)

const grid = 70
const gridWidth = 1100

const linesA = []
const linesB = []

  for (let i = 0; i < gridWidth / grid; i++) {
    linesA.push(
      <Line
        strokeWidth={2}
        stroke={'black'}
        points={[i * grid, 0, i * grid, gridWidth]}
      />
    )

    linesB.push(
      <Line
        strokeWidth={2}
        stroke={'black'}
        points={[0, i * grid, gridWidth, i * grid]}
      />
    )
  }

  <Layer>
    {linesA}
    {linesB}        
  </Layer>

I made the grid with lines, now I'm a little confuse about the dragEnd event X, Y.

MY RECT

  <Rect
        onDragEnd={e => {
          e.target.to({
            x: Math.round(x / grid) * grid,
            y: Math.round(y / grid) * grid,
          })
        }}
        x={x}
        y={y}
        draggable
        width={60}
        height={60}
        fill="rgba(0, 0, 0, 1)"
      />

Its really almost there.

score 9 · Accepted Answer · answered Sep 01 '20 at 15:03

Its Done! I will post my own answer to help out someone.

const grid = 70
const gridWidth = 1000

const linesA = []
const linesB = []

  for (let i = 0; i < gridWidth / grid; i++) {
    linesA.push(
      <Line
        strokeWidth={2}
        stroke={'black'}
        points={[i * grid, 0, i * grid, gridWidth]}
      />
    )

    linesB.push(
      <Line
        strokeWidth={2}
        stroke={'black'}
        points={[0, i * grid, gridWidth, i * grid]}
      />
    )
  }

  <Stage
        x={stagePos.x}
        y={stagePos.y}
        width={window.innerWidth}
        height={window.innerHeight}
        draggable
        onDragEnd={e => {
          setStagePos(e.currentTarget.position())
        }}
        onMouseDown={handleMouseDown}
        onMouseUp={handleMouseUp}
        onMouseMove={handleMouseMove}
        onContextMenu={e => {
          e.evt.preventDefault()
        }}
      >
        {/* <Layer>
          <Image image={map} opacity={1} />
        </Layer> */}

        <Layer>
          {linesA}
          {linesB}
        </Layer>

       <Rect
            onDragEnd={e => {
              e.target.to({
                x: Math.round(e.target.x() / grid) * grid,
                y: Math.round(e.target.y() / grid) * grid,
              })
            }}
            x={x}
            y={y}
            draggable
            width={65}
            height={65}
            fill="rgba(0, 0, 0, 1)"
          />

 </Stage>

Here I did a live example! Snap Grid React-Konva

Hey! This is great! I have a different question: what did you do for infinite scroll? — , Dec 20 '20 at 02:47
On my application, I dont use an infinit grid. But I think it could be achiev whith this example using rect instead line: https://stackoverflow.com/questions/58445131/konva-infinite-grid-in-react — Rogerio Azevedo, Dec 21 '20 at 13:38

Snap grid, drag and drop with react-konva

1 Answers1