JSFiddle - React, Tailwind, and code Playground
HTML
<script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/2.1.0/fabric.min.js"></script>
<canvas id="canvas" style="border:1px solid #d3d3d3;"></canvas>
CSS
canvas {
border: 1px solid red;
}
JavaScript
var canvas = new fabric.Canvas('canvas', {backgroundColor: 'blue'});
canvas.setHeight(300);
canvas.setWidth(300);
canvas.on('mouse:down', function(opt) {
var evt = opt.e;
if (evt.altKey === true) {
this.isDragging = true;
this.selection = false;
this.lastPosX = evt.clientX;
this.lastPosY = evt.clientY;
}
});
canvas.on('mouse:move', function(opt) {
if (this.isDragging) {
var e = opt.e;
this.viewportTransform[4] += e.clientX - this.lastPosX;
this.viewportTransform[5] += e.clientY - this.lastPosY;
this.requestRenderAll();
this.lastPosX = e.clientX;
this.lastPosY = e.clientY;
}
});
canvas.on('mouse:up', function(opt) {
this.isDragging = false;
this.selection = true;
});
canvas.on('mouse:wheel', function(opt) {
var delta = opt.e.deltaY;
var pointer = canvas.getPointer(opt.e);
var zoom = canvas.getZoom();
zoom = zoom + delta/200;
if (zoom > 20) zoom = 20;
if (zoom < 0.01) zoom = 0.01;
canvas.zoomToPoint({ x: opt.e.offsetX, y: opt.e.offsetY }, zoom);
opt.e.preventDefault();
opt.e.stopPropagation();
});
console.log(canvas.viewportTransform)
var backgroundRect = new fabric.Rect({
left: 0,
top: 0,
fill: 'red',
width: canvas.width-100,
height: canvas.height-100
});
var rect = new fabric.Rect({
left: 100,
top: 100,
fill: 'rgba(0,0,0,0.5)',
width: 100,
height: 100,
strokeWidth: 0,
});
canvas.add(backgroundRect);
canvas.add(rect);
canvas.renderAll();