Fabric JS中的对象对齐 [英] object alignment in fabric js

问题描述

我正在尝试在画布中实现对象对齐(即，右，中，左，上，下).假设用户选择了一个对象(即文本"或图像")，那么如果用户单击向右对齐"选项，则该所选对象应与右侧对齐.

I am trying to implement object alignment (i.e Right, Center, Left, Top, Bottom) in canvas. Lets say user selected one object (i.e Text or Image) then if user hit the Align right option then that selected object should align to right side.

我尝试了以下2种方法，但没有成功.

I have tried below 2 methods but no success.

var canvas = new fabric.Canvas('a');
canvas.add(new fabric.Rect({
  left: 50,
  top: 50,
  height: 50,
  width: 50,
  fill: 'red'
}));
canvas.add(new fabric.Rect({
  left: 130,
  top: 50,
  height: 50,
  width: 50,
  fill: 'green'
}));
canvas.add(new fabric.Rect({
  left: 90,
  top: 130,
  height: 50,
  width: 50,
  fill: 'blue'
}));

canvas.renderAll();

$('.alignment').click(function() {
  var cur_value = $(this).attr('data-action');
  if (cur_value != '') {
    process_align(cur_value);
  } else {
    alert('Please select a item');
    return false;
  }
});

/* Align the selected object */
function process_align(val) {
  switch (val) {
    case 'right':
      //Tried below one with
      //activeObj.setPositionByOrigin(new fabric.Point(activeObj.top, canvas.getWidth()), activeObj.originY,'center');

      //Tried below one but its not working
      var activeObj = canvas.getActiveObject();
      activeObj.set({
        originX: 'right',
        //originY: 'center'
      });
      activeObj.setCoords();
      canvas.renderAll();
      break;
  }
}

canvas {
  border: 2px solid black;
}

<script src="https://code.jquery.com/jquery-2.2.4.min.js" integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44=" crossorigin="anonymous"></script>
<script type='text/javascript' src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/1.7.19/fabric.js"></script>
<button class="alignment" data-action="left">Align Left</button>
<button class="alignment" data-action="center">Align Center</button>
<button class="alignment" data-action="right">Align Right</button>
<button class="alignment" data-action="top">Align Top</button>
<button class="alignment" data-action="bottom">Align Bottom</button>
<canvas id="a" width="400" height="200"></canvas>

我只实现了向右对齐"，因为我不确定如何对其他对齐方式(顶部，底部，左侧，中心)进行对齐.

I have only implemented Align Right, as i am not sure how to do alignment for other Alignment (Top,Bottom, Left, Center).

推荐答案

var canvas = new fabric.Canvas('a');
canvas.add(new fabric.Rect({
  left: 50,
  top: 50,
  height: 50,
  width: 50,
  fill: 'red'
}));
canvas.add(new fabric.Rect({
  left: 130,
  top: 50,
  height: 50,
  width: 50,
  fill: 'green'
}));
canvas.add(new fabric.Rect({
  left: 90,
  top: 130,
  height: 50,
  width: 50,
  fill: 'blue'
}));

canvas.renderAll();

$('.alignment').click(function() {
  var cur_value = $(this).attr('data-action');
  var activeObj = canvas.getActiveObject() || canvas.getActiveGroup();
  if (cur_value != '' && activeObj) {
    process_align(cur_value, activeObj);
    activeObj.setCoords();
    canvas.renderAll();
  } else {
    alert('Please select a item');
    return false;
  }
});

/* Align the selected object */
function process_align(val, activeObj) {
  switch (val) {

    case 'left':
      activeObj.set({
        left: 0
      });
      break;
    case 'right':
      activeObj.set({
        left: canvas.width - (activeObj.width * activeObj.scaleX)
      });
      break;
    case 'top':
      activeObj.set({
        top: 0
      });
      break;
    case 'bottom':
      activeObj.set({
        top: canvas.height - (activeObj.height * activeObj.scaleY)
      });
      break;
    case 'center':
      activeObj.set({
        left: (canvas.width / 2) - ((activeObj.width * activeObj.scaleX) / 2)
      });
      break;
  }
}

canvas {
  border: 2px solid black;
}

<script
  src="https://code.jquery.com/jquery-2.2.4.min.js"
  integrity="sha256-BbhdlvQf/xTY9gja0Dq3HiwQF8LaCRTXxZKRutelT44="
  crossorigin="anonymous"></script>
<script type='text/javascript' src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/1.7.19/fabric.js"></script>
<button class="alignment" data-action="left">Align Left</button>
<button class="alignment" data-action="center">Align Center</button>
<button class="alignment" data-action="right">Align Right</button>
<button class="alignment" data-action="top">Align Top</button>
<button class="alignment" data-action="bottom">Align Bottom</button>
<canvas id="a" width="400" height="200"></canvas>

您可以根据需要设置左/上，然后按setCoords().检查代码段.

You can set left/top according as your need, then setCoords(). Check snippet.

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