How can i change the rotation icon in fabricjs

Question

Please guide me to modify Fabricjs to add custom icon for Rotation.

I get some of the answers but it is not working fine.

Please let me know the code to change a particular rotation icon only.

Answer 1

Change fabric object prototype "drawControls" like this.

Here is an example and JSFiddle:

fabric.Object.prototype.drawControls = function (ctx) {
    if (!this.hasControls) return this;


    var size = this.cornerSize,
        size2 = size / 2,
        strokeWidth2 = ~~(this.strokeWidth / 2), // half strokeWidth rounded down
        left = -(this.width / 2),
        top = -(this.height / 2),
        paddingX = this.padding / this.scaleX,
        paddingY = this.padding / this.scaleY,
        scaleOffsetY = size2 / this.scaleY,
        scaleOffsetX = size2 / this.scaleX,
        scaleOffsetSizeX = (size2 - size) / this.scaleX,
        scaleOffsetSizeY = (size2 - size) / this.scaleY,
        height = this.height,
        width = this.width,
        methodName = this.transparentCorners ? 'strokeRect' : 'fillRect';

    ctx.save();

    ctx.lineWidth = 1 / Math.max(this.scaleX, this.scaleY);

    ctx.globalAlpha = this.isMoving ? this.borderOpacityWhenMoving : 1;
    ctx.strokeStyle = ctx.fillStyle = this.cornerColor;

    // top-left
    this._drawControl('tl', ctx, methodName,
        left - scaleOffsetX - strokeWidth2 - paddingX,
        top - scaleOffsetY - strokeWidth2 - paddingY);

    // top-right
    this._drawControl('tr', ctx, methodName,
        left + width - scaleOffsetX + strokeWidth2 + paddingX,
        top - scaleOffsetY - strokeWidth2 - paddingY);

    // bottom-left
    this._drawControl('bl', ctx, methodName,
        left - scaleOffsetX - strokeWidth2 - paddingX,
        top + height + scaleOffsetSizeY + strokeWidth2 + paddingY);

    // bottom-right
    this._drawControl('br', ctx, methodName,
        left + width + scaleOffsetSizeX + strokeWidth2 + paddingX,
        top + height + scaleOffsetSizeY + strokeWidth2 + paddingY);

    if (!this.get('lockUniScaling')) {

        // middle-top
        this._drawControl('mt', ctx, methodName,
            left + width / 2 - scaleOffsetX,
            top - scaleOffsetY - strokeWidth2 - paddingY);

        // middle-bottom
        this._drawControl('mb', ctx, methodName,
            left + width / 2 - scaleOffsetX,
            top + height + scaleOffsetSizeY + strokeWidth2 + paddingY);

        // middle-right
        this._drawControl('mr', ctx, methodName,
            left + width + scaleOffsetSizeX + strokeWidth2 + paddingX,
            top + height / 2 - scaleOffsetY);

        // middle-left
        this._drawControl('ml', ctx, methodName,
            left - scaleOffsetX - strokeWidth2 - paddingX,
            top + height / 2 - scaleOffsetY);
    }

    // middle-top-rotate
    if (this.hasRotatingPoint) {
        /*
         We dont need old corner for rotate :)

         this._drawControl('mtr', ctx, methodName,
         left + width/2 - scaleOffsetX,
         this.flipY
         ? (top + height + (this.rotatingPointOffset / this.scaleY) - this.cornerSize/this.scaleX/2 + strokeWidth2 + paddingY)
         : (top - (this.rotatingPointOffset / this.scaleY) - this.cornerSize/this.scaleY/2 - strokeWidth2 - paddingY));

         Draw rotate custom icon
         */
        var rotate = new Image(), rotateLeft, rotateTop;
        rotate.src = 'http://www.navifun.net/files/pins/tiny/Arrow-Rotate-Clockwise.png';

        rotateLeft = left + width / 2 - scaleOffsetX;
        rotateTop = this.flipY
            ? (top + height + (this.rotatingPointOffset / this.scaleY) - this.cornerSize / this.scaleX / 2 + strokeWidth2 + paddingY)
            : (top - (this.rotatingPointOffset / this.scaleY) - this.cornerSize / this.scaleY / 2 - strokeWidth2 - paddingY);

        ctx.drawImage(rotate, rotateLeft, rotateTop, size / this.scaleX, size / this.scaleY);


    }

    ctx.restore();

    return this;
};

Answer 2

@hlozancic's answer overrides a big important part of the prototype. Monkey patching libraries maintained by a community doesn't sit well with me, since the code in those methods could change (and, in fact drawControls has changed since July 2nd), without my knowing. Here is an alternative that I prefer:

var _original = fabric.Object.prototype._drawControl;
fabric.Object.prototype._drawControl = function(control, ctx, methodName, left, top) {
  var size = this.cornerSize;

  if (this.canvas.hasControlCallback && this.canvas.hasControlCallback[control]) {
    this.canvas.controlCallback[control](ctx, left, top, size);
  } else {
    _original.call(this, control, ctx, methodName, left, top);
  }
};

/* then, when instantiating your fabric canvas  */

var canvas = new fabric.Canvas();

/* callbacks for drawing the controls */
canvas.hasControlCallback = {
    mtr: true
};

canvas.controlCallback = {
    mtr: function mtrControlCallback (ctx, left, top, size) {
        var image = new Image(), x, y;

        image.src = 'http://www.navifun.net/files/pins/tiny/Arrow-Rotate-Clockwise.png';
        x = left - image.width/2 + size/2;
        y = top - image.height/2 + size/2;

        ctx.drawImage(image, x, y);
    }
};

Apologies for not providing a fiddle, and please be aware of the date of this writing.

Answer 3

For fabricjs above 1.6.6 changing function object prototype drawControls, small changes on hasRotation condition, result can be seen this JSFidle

fabric.Object.prototype.drawControls = function (ctx) {

  if (!this.hasControls) {
    return this;
  }

  var wh = this._calculateCurrentDimensions(),
  width = wh.x,
  height = wh.y,
  scaleOffset = this.cornerSize,
  left = -(width + scaleOffset) / 2,
  top = -(height + scaleOffset) / 2,
  methodName = this.transparentCorners ? 'stroke' : 'fill';

  ctx.save();
  ctx.strokeStyle = ctx.fillStyle = this.cornerColor;
  if (!this.transparentCorners) {
    ctx.strokeStyle = this.cornerStrokeColor;
  }
 this._setLineDash(ctx, this.cornerDashArray, null);

  // top-left
 this._drawControl('tl', ctx, methodName,left,top);

 // top-right
this._drawControl('tr', ctx, methodName, left + width,top);

// bottom-left
this._drawControl('bl', ctx, methodName,left, top + height);

// bottom-right
this._drawControl('br', ctx, methodName,left + width,top + height);

if (!this.get('lockUniScaling')) {

// middle-top
this._drawControl('mt', ctx, methodName,
  left + width / 2,
  top);

// middle-bottom
this._drawControl('mb', ctx, methodName,
  left + width / 2,
  top + height);

// middle-right
this._drawControl('mr', ctx, methodName,
  left + width,
  top + height / 2);

// middle-left
this._drawControl('ml', ctx, methodName,
  left,
  top + height / 2);
}

// middle-top-rotate
if (this.hasRotatingPoint) {
  var rotate = new Image(), rotateLeft, rotateTop;
  rotate.src = 'http://localhost:8000/images/toolbar/close.svg';
  rotateLeft = left + width / 2;
  rotateTop = top - this.rotatingPointOffset;
  ctx.drawImage(rotate, rotateLeft, rotateTop, 10, 15);
}

ctx.restore();

return this;

}

Answer 4

With the release of v4.0 in August of 2020, Fabric.js now includes a complete control customization system which makes styling the rotate control quite easy.

var canvas = new fabric.Canvas('c');
// set your icon here as a base64 string
var rotateIcon = "data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIGhlaWdodD0iMjQiIHZpZXdCb3g9IjAgMCAyNCAyNCIgd2lkdGg9IjI0Ij48cGF0aCBkPSJNMCAwaDI0djI0SDB6IiBmaWxsPSJub25lIi8+PHBhdGggZD0iTTEyIDZ2M2w0LTQtNC00djNjLTQuNDIgMC04IDMuNTgtOCA4IDAgMS41Ny40NiAzLjAzIDEuMjQgNC4yNkw2LjcgMTQuOGMtLjQ1LS44My0uNy0xLjc5LS43LTIuOCAwLTMuMzEgMi42OS02IDYtNnptNi43NiAxLjc0TDE3LjMgOS4yYy40NC44NC43IDEuNzkuNyAyLjggMCAzLjMxLTIuNjkgNi02IDZ2LTNsLTQgNCA0IDR2LTNjNC40MiAwIDgtMy41OCA4LTggMC0xLjU3LS40Ni0zLjAzLTEuMjQtNC4yNnoiLz48L3N2Zz4=";
var img = document.createElement('img');
img.src = rotateIcon;

// here's where your custom rotation control is defined
// by changing the values you can customize the location, size, look, and behavior of the control
fabric.Object.prototype.controls.mtr = new fabric.Control({
  x: 0,
  y: -0.5,
  offsetY: -40,
  cursorStyle: 'crosshair',
  actionHandler: fabric.controlsUtils.rotationWithSnapping,
  actionName: 'rotate',
  render: renderIcon,
  cornerSize: 28,
  withConnection: true
});

// here's where the render action for the control is defined
function renderIcon(ctx, left, top, styleOverride, fabricObject) {
  var size = this.cornerSize;
  ctx.save();
  ctx.translate(left, top);
  ctx.rotate(fabric.util.degreesToRadians(fabricObject.angle));
  ctx.drawImage(img, -size / 2, -size / 2, size, size);
  ctx.restore();
}

var rect = new fabric.Rect({
  left: 50,
  top: 70,
  fill: 'red',
  width: 200,
  height: 100,
  objectCaching: false,
  stroke: 'blue',
  strokeWidth: 4,
});

canvas.add(rect);
canvas.setActiveObject(rect);

<script src="https://unpkg.com/[email protected]/dist/fabric.js"></script>
<canvas id="c" width="400" height="250" style="border:1px solid #ccc"></canvas>