如何在 fabric.js 中选择和拖动对象答案

【问题标题】：how to select and drag objects in fabric.js如何在 fabric.js 中选择和拖动对象
【发布时间】：2016-02-14 12:53:26
【问题描述】：

我以jsfiddle 为例，在这里我使用了fabric.js，当我们单击按钮时会创建线条。我的问题是如何在fabric.js 中选择或移动画布中的对象？

var canvas = new fabric.Canvas('c', { selection: false });

var line, isDown;

canvas.on('mouse:down', function(o){
  isDown = true;
  var pointer = canvas.getPointer(o.e);
  var points = [ pointer.x, pointer.y, pointer.x, pointer.y ];
  line = new fabric.Line(points, {
    strokeWidth: 5,
    fill: 'red',
    stroke: 'red',
    originX: 'center',
    originY: 'center'
  });
  canvas.add(line);
});

canvas.on('mouse:move', function(o){
  if (!isDown) return;
  var pointer = canvas.getPointer(o.e);
  line.set({ x2: pointer.x, y2: pointer.y });
  canvas.renderAll();
});

canvas.on('mouse:up', function(o){
  isDown = false;
});

如果我将第一行设为var canvas = new fabric.Canvas('c', { selection: true });，我可以获得边界框，但我无法拖动

【问题讨论】：

标签： javascript canvas fabricjs

【解决方案1】：

我解决了这个问题。

var canvas = new fabric.Canvas('c', { selection: false });

var line, isDown;

canvas.on('mouse:down', function(o){
    if(canvas.findTarget(o.e))return;
  isDown = true;
  var pointer = canvas.getPointer(o.e);
  var points = [ pointer.x, pointer.y, pointer.x, pointer.y ];
  line = new fabric.Line(points, {
    strokeWidth: 5,
    fill: 'red',
    stroke: 'red',
    originX: 'center',
    originY: 'center'
  });
  canvas.add(line);
});

canvas.on('mouse:move', function(o){
  if (!isDown) return;
  var pointer = canvas.getPointer(o.e);
  line.set({ x2: pointer.x, y2: pointer.y });
  line.setCoords();
  canvas.renderAll();
});

canvas.on('mouse:up', function(o){
  isDown = false;
});

【讨论】：