fabric 自定义图形

摘自:
https://www.cnblogs.com/k21vin/articles/17791973.html

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
        <script src="js/fabric.min-5.0.0.js"></script>
    </head>
    <body>
        <div class="controls">
          <p>
            <button id="add" onclick="Add()">Add a rectangle</button>
          </p>
        </div>
        <canvas id="c" width="500" height="400" style="border:1px solid #ccc"></canvas>

        <script>
          var canvas = this.__canvas = new fabric.Canvas('c');

          var deleteIcon = "data:image/svg+xml,%3C%3Fxml version='1.0' encoding='utf-8'%3F%3E%3C!DOCTYPE svg PUBLIC '-//W3C//DTD SVG 1.1//EN' 'http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd'%3E%3Csvg version='1.1' id='Ebene_1' xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' x='0px' y='0px' width='595.275px' height='595.275px' viewBox='200 215 230 470' xml:space='preserve'%3E%3Ccircle style='fill:%23F44336;' cx='299.76' cy='439.067' r='218.516'/%3E%3Cg%3E%3Crect x='267.162' y='307.978' transform='matrix(0.7071 -0.7071 0.7071 0.7071 -222.6202 340.6915)' style='fill:white;' width='65.545' height='262.18'/%3E%3Crect x='266.988' y='308.153' transform='matrix(0.7071 0.7071 -0.7071 0.7071 398.3889 -83.3116)' style='fill:white;' width='65.544' height='262.179'/%3E%3C/g%3E%3C/svg%3E";

          var cloneIcon = "data:image/svg+xml,%3C%3Fxml version='1.0' encoding='iso-8859-1'%3F%3E%3Csvg version='1.1' xmlns='http://www.w3.org/2000/svg' xmlns:xlink='http://www.w3.org/1999/xlink' viewBox='0 0 55.699 55.699' width='100px' height='100px' xml:space='preserve'%3E%3Cpath style='fill:%23010002;' d='M51.51,18.001c-0.006-0.085-0.022-0.167-0.05-0.248c-0.012-0.034-0.02-0.067-0.035-0.1 c-0.049-0.106-0.109-0.206-0.194-0.291v-0.001l0,0c0,0-0.001-0.001-0.001-0.002L34.161,0.293c-0.086-0.087-0.188-0.148-0.295-0.197 c-0.027-0.013-0.057-0.02-0.086-0.03c-0.086-0.029-0.174-0.048-0.265-0.053C33.494,0.011,33.475,0,33.453,0H22.177 c-3.678,0-6.669,2.992-6.669,6.67v1.674h-4.663c-3.678,0-6.67,2.992-6.67,6.67V49.03c0,3.678,2.992,6.669,6.67,6.669h22.677 c3.677,0,6.669-2.991,6.669-6.669v-1.675h4.664c3.678,0,6.669-2.991,6.669-6.669V18.069C51.524,18.045,51.512,18.025,51.51,18.001z M34.454,3.414l13.655,13.655h-8.985c-2.575,0-4.67-2.095-4.67-4.67V3.414z M38.191,49.029c0,2.574-2.095,4.669-4.669,4.669H10.845 c-2.575,0-4.67-2.095-4.67-4.669V15.014c0-2.575,2.095-4.67,4.67-4.67h5.663h4.614v10.399c0,3.678,2.991,6.669,6.668,6.669h10.4 v18.942L38.191,49.029L38.191,49.029z M36.777,25.412h-8.986c-2.574,0-4.668-2.094-4.668-4.669v-8.985L36.777,25.412z M44.855,45.355h-4.664V26.412c0-0.023-0.012-0.044-0.014-0.067c-0.006-0.085-0.021-0.167-0.049-0.249 c-0.012-0.033-0.021-0.066-0.036-0.1c-0.048-0.105-0.109-0.205-0.194-0.29l0,0l0,0c0-0.001-0.001-0.002-0.001-0.002L22.829,8.637 c-0.087-0.086-0.188-0.147-0.295-0.196c-0.029-0.013-0.058-0.021-0.088-0.031c-0.086-0.03-0.172-0.048-0.263-0.053 c-0.021-0.002-0.04-0.013-0.062-0.013h-4.614V6.67c0-2.575,2.095-4.67,4.669-4.67h10.277v10.4c0,3.678,2.992,6.67,6.67,6.67h10.399 v21.616C49.524,43.26,47.429,45.355,44.855,45.355z'/%3E%3C/svg%3E%0A"

          var deleteImg = document.createElement('img');
          deleteImg.src = deleteIcon;

          var cloneImg = document.createElement('img');
          cloneImg.src = cloneIcon;

          fabric.Object.prototype.transparentCorners = false;
          fabric.Object.prototype.cornerColor = 'blue';
          fabric.Object.prototype.cornerStyle = 'circle';

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

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

          function renderIcon(icon) {
            return 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(icon, -size/2, -size/2, size, size);
              ctx.restore();
            }
          }

          fabric.Object.prototype.controls.deleteControl = new fabric.Control({
            x: 0.5,
            y: -0.5,
            offsetY: -16,
            offsetX: 16,
            cursorStyle: 'pointer',
            mouseUpHandler: deleteObject,
            render: renderIcon(deleteImg),
            cornerSize: 24
          });

          fabric.Object.prototype.controls.clone = new fabric.Control({
            x: -0.5,
            y: -0.5,
            offsetY: -16,
            offsetX: -16,
            cursorStyle: 'pointer',
            mouseUpHandler: cloneObject,
            render: renderIcon(cloneImg),
            cornerSize: 24
          });

          Add();

          function deleteObject(eventData, transform) {
            var target = transform.target;
                var canvas = target.canvas;
              canvas.remove(target);
              canvas.requestRenderAll();
            }

          function cloneObject(eventData, transform) {
            var target = transform.target;
            var canvas = target.canvas;
            target.clone(function(cloned) {
              cloned.left += 10;
              cloned.top += 10;
              canvas.add(cloned);
            });
          }
        </script>
    </body>
</html>