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Say I have a HTML5 canvas (In this case using fabric.js), and I want to change the cursor over the canvas to represent whatever brush size and colour has been selected. I'm thinking there should be a way to do this by changing an SVG's properties (size & colour) dynamically with JS so we don't have to use multiple images. Any ideas on if this is possible?

var canvas = new fabric.Canvas(c, {
            isDrawingMode: true,
            freeDrawingCursor: 'url("img/cursor.svg"), auto'
});

Say I have a HTML5 canvas (In this case using fabric.js), and I want to change the cursor over the canvas to represent whatever brush size and colour has been selected. I'm thinking there should be a way to do this by changing an SVG's properties (size & colour) dynamically with JS so we don't have to use multiple images. Any ideas on if this is possible?

var canvas = new fabric.Canvas(c, {
            isDrawingMode: true,
            freeDrawingCursor: 'url("img/cursor.svg"), auto'
});

• javascript
• fabricjs

Share Improve this question Follow asked Aug 18, 2016 at 15:47 Paul RedmondPaul Redmond 3,29644 gold badges3535 silver badges5353 bronze badges

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3 Answers 3

Sorted by: Reset to default 5

I think freeDrawingCursor is just looking for normal css property names. Here is an example of how to have a fabric object represent the cursor size and color:

var canvas = new fabric.Canvas('c', {
  isDrawingMode: true,
  freeDrawingCursor: 'none'
});

canvas.freeDrawingBrush.width = 10;
canvas.freeDrawingBrush.color = '#9f9';

var mousecursor = new fabric.Circle({ 
  left: 0, 
  top: 0, 
  radius: canvas.freeDrawingBrush.width / 2, 
  fill: canvas.freeDrawingBrush.color, 
  originX: 'right', 
  originY: 'bottom',
})

canvas.add(mousecursor);

canvas.on('mouse:move', function(obj) {
  mousecursor.top = obj.e.y - mousecursor.radius;
  mousecursor.left = obj.e.x - mousecursor.radius;
  canvas.renderAll()
})

canvas.on('mouse:out', function(obj) {
  // put circle off screen
  mousecursor.top = -100;
  mousecursor.left = -100;
  canvas.renderAll()
})

canvas {
    border: 1px solid #ccc;
}

<script src="https://cdnjs.cloudflare./ajax/libs/fabric.js/1.6.3/fabric.js"></script>

<canvas id="c" width="600" height="600"></canvas>

Existing answers didn't work for me in 2020. Try the following:

    this.canvas.isDrawingMode = true;
    this.canvas.freeDrawingCursor = 'none';

    const mousecursor = new fabric.Circle({
        left: 0,
        top: 0,
        radius: this.canvas.freeDrawingBrush.width / 2,
        fill: this.canvas.freeDrawingBrush.color,
        originX: 'right',
        originY: 'bottom',
    });

    this.canvas.add(mousecursor);

    // Cursor in canvas
    this.canvas.on('mouse:move', event => {
        mousecursor.top = event.e.layerY + mousecursor.radius;
        mousecursor.left = event.e.layerX + mousecursor.radius;
        this.canvas.renderAll();
    });

    // Cursor out of canvas
    this.canvas.on('mouse:out', event => {
        mousecursor.top = -100;
        mousecursor.left = -100;
        this.canvas.renderAll();
    });

Worked fine with Angular 7.

I was looking for the same and found my way to this question. Unfortunately the solution by STHayden is not working for me. So I've modified it a bit and came up with the code below. It uses two canvas layers, the bottom for drawing, the top for the "cursor". Works pretty well for me now, maybe someone will find it helpful :)

//drawing layer
var canvas = new fabric.Canvas("draw", {
  isDrawingMode: true,
  freeDrawingCursor: 'none'
});
//mouse cursor layer
var cursor = new fabric.StaticCanvas("cursor");

canvas.freeDrawingBrush.width = 20;
canvas.freeDrawingBrush.color = '#ff0000';

var cursorOpacity = .5;
//create cursor and place it off screen
var mousecursor = new fabric.Circle({ 
  left: -100, 
  top: -100, 
  radius: canvas.freeDrawingBrush.width / 2, 
  fill: "rgba(255,0,0," + cursorOpacity + ")",
  stroke: "black",
  originX: 'center', 
  originY: 'center'
});

cursor.add(mousecursor);

//redraw cursor on new mouse position when moved
canvas.on('mouse:move', function (evt) {
  var mouse = this.getPointer(evt.e);  
  mousecursor
    .set({
      top: mouse.y,
      left: mouse.x
    })
    .setCoords()
    .canvas.renderAll();
});

//put cursor off screen again when mouse is leaving
canvas.on('mouse:out', function () {
  mousecursor
    .set({
      top: mousecursor.originalState.top,
      left: mousecursor.originalState.left
    })
    .setCoords()
    .canvas.renderAll();
});

//while brush size is changed show cursor in center of canvas
document.getElementById("size").oninput = function () {
  var size = parseInt(this.value, 10);
  mousecursor
    .center()
    .set({
      radius: size/2
    })
    .setCoords()
    .canvas.renderAll();
};

//after brush size has been changed move offscreen, update brush size
document.getElementById("size").onchange = function () {
  var size = parseInt(this.value, 10);
  canvas.freeDrawingBrush.width = size;
  mousecursor
    .set({
      left: mousecursor.originalState.left,
      top: mousecursor.originalState.top,
      radius: size/2
    })
    .setCoords()
    .canvas.renderAll();
};

//change mousecursor opacity
document.getElementById("opacity").onchange = function () {
  cursorOpacity = this.value;
  var fill = mousecursor.fill.split(",");
  fill[fill.length-1] = cursorOpacity + ")";
  mousecursor.fill = fill.join(",");
};

//change drawing color
document.getElementById("color").onchange = function () {
  canvas.freeDrawingBrush.color = this.value;  
  var bigint = parseInt(this.value.replace("#", ""), 16);
  var r = (bigint >> 16) & 255;
  var g = (bigint >> 8) & 255;
  var b = bigint & 255;  
  mousecursor.fill = "rgba(" + [r,g,b,cursorOpacity].join(",") + ")";
};

#cont {
  position: relative;
  width: 500px;
  height: 500px;
}

canvas {
  border: 1px solid;
}

#cont canvas, .canvas-container {
  position: absolute!important;
  left: 0!important;
  top: 0!important;
  width: 100%!important;
  height: 100%!important;
}

#cursor {
  pointer-events: none!important;
}

<script src="https://cdnjs.cloudflare./ajax/libs/fabric.js/1.6.4/fabric.min.js"></script>
Color: <input id="color" type="color" value="#ff0000"><br/>
Brush size: <input id="size" type="range" min="1" max="100" step="1" value="20"><br/>
Brush opacity: <input id="opacity" type="number" min="0" max="1" step="0.1" value="0.5"><br/>
<div id="cont">
  <canvas id="draw" width="500" height="500"></canvas>
  <canvas id="cursor" width="500" height="500"></canvas>
</div>

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