缩放限制

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怎样限制图形的缩放尺寸?

你可以通过设置 boundBoxFunc 属性来限制图形缩放尺寸。
它有点类似 dragBoundFunc。

说明：试试缩放图形。你会发现它的宽度被限制在200像素以内。

Konva Shape transform and selection Demoview raw
<!DOCTYPE html>
<html>
  <head>
    <!-- USE DEVELOPMENT VERSION -->
    <script src="https://unpkg.com/konva@4.0.18/konva.min.js"></script>
    <meta charset="utf-8" />
    <title>Konva Transform Limits Demo</title>
    <style>
      body {
        margin: 0;
        padding: 0;
        overflow: hidden;
        background-color: #f0f0f0;
      }
    </style>
  </head>

  <body>
    <div id="container"></div>
    <script>
      var width = window.innerWidth;
      var height = window.innerHeight;

      var stage = new Konva.Stage({
        container: 'container',
        width: width,
        height: height
      });

      var layer = new Konva.Layer();
      stage.add(layer);

      var rect = new Konva.Rect({
        x: 160,
        y: 60,
        width: 100,
        height: 90,
        fill: 'red',
        name: 'rect',
        stroke: 'black',
        draggable: true
      });
      layer.add(rect);

      var MAX_WIDTH = 200;
      // create new transformer
      var tr = new Konva.Transformer({
        boundBoxFunc: function(oldBoundBox, newBoundBox) {
          // "boundBox" is an object with
          // x, y, width, height and rotation properties
          // transformer tool will try to fit node into that box
          // "width" property here is a visible width of the object
          // so it equals to rect.width() * rect.scaleX()

          // the logic is simple, if new width is too big
          // we will return previous state
          if (Math.abs(newBoundBox.width) > MAX_WIDTH) {
            return oldBoundBox;
          }

          return newBoundBox;
        }
      });
      layer.add(tr);
      tr.attachTo(rect);
      layer.draw();
    </script>
  </body>
</html>