fabricjs-history's Introduction

fabricjs-history

fabric.js添加历史记录维护，支持撤销重做等操作； Maintain fabric history, support undo redo, etc.

Install

npm install fabricjs-history -S

Usage

Initialization

createHistory() 将初始化历史记录状态

import { fabric } from "fabric";
import { createHistory } from "fabricjs-history";

const canvas = new fabric.Canvas($canvas, {
  width,
  height,
  selection: false,
  hoverCursor: "default",
  freeDrawingCursor: "none",
});
// ...
createHistory({ canvas });

Operation

record：记录当前画布状态

canvas.setBackgroundColor(color, canvas.renderAll.bind(canvas));
canvas.record();

fabric.Image.fromURL(
  url,
  function (img) {
    canvas.setBackgroundImage(img);
    canvas.renderAll();
    canvas.record(); // 记录当前画布状态
  },
  { crossOrigin: "Anonymous" }
);

除了手动 record 历史记录，还可以监听画布事件，自动记录历史记录

import { fabric } from "fabric";
import { createHistory } from "fabricjs-history";

const canvas = new fabric.Canvas($canvas, {
  width,
  height,
});

// ...

createHistory({
  canvas,
  maxHistoryLength: 20, //可选，最大历史记录长度，默认20
  historyEvent: ["path:created", "erasing:end", ...], // 可选，监听的画布事件自动记录，默认为[]
});

注：fabricjs 相关基础事件可见 http://fabricjs.com/events

undo：撤销操作

redo：重做操作

reset：重置历史记录

Properties

canvas._stack：历史记录栈，查看历史记录条数 canvas._stack.length

canvas._historyIndex：当前历史记录索引

Event

canvas.on("history:change", function (action) {
  console.log(action); // undo | redo | reset | record
  console.log(canvas._historyIndex, canvas.canvas._stack);
});

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