d3.js将缩放行为更改为语义缩放 [英] d3.js change zoom behavior to semantic zoom

问题描述

我正在用d3.js做一些关于缩放的测试。目前，我已在测试中成功实现了几何缩放，但它有一个缺点：缩放 g 下的元素正在缩放。据我了解，这可以通过使用语义缩放来解决。

I'm doing some tests with d3.js regarding zooming. At the moment, I have successfully implemented geometric zoom in my test, but it has a drawback: the elements under the zoomed g are being scaled. As I understood it, this could be solved by using semantic zooming.

问题是我在测试中需要 scale ，因为我正在将它与jQuery.UI同步滑块值。

The problem is that I need scale in my test, as I'm syncing it with a jQuery.UI slider value.

另一方面，我想要文本调整元素大小以在缩放操作后保持其大小。

On the other hand, I would like the text elements being resized to maintain their size after a zoom operation.

我有一个当前尝试的示例这里。

I have an example of my current attempt here.

我无法更改代码以适应此目的。任何人都可以分享一些见解/想法吗？

I'm having trouble changing my code to fit this purpose. Can any one share some insight/ideas?

推荐答案

对于你的解决方案，我合并了两个例子：

For your solution I have merged 2 examples:

• 语义缩放


• 程序化缩放

• Semantic Zooming
• Programmatic Zooming

代码段：

function zoom() {
  text.attr("transform", transform);
  var scale = zoombehavior.scale();
  //to make the scale rounded to 2 decimal digits
  scale = Math.round(scale * 100) / 100;
  //setting the slider to the new value
  $("#slider").slider( "option", "value", scale );
  //setting the slider text to the new value
  $("#scale").val(scale);
}
//note here we are not handling the scale as its Semantic Zoom
function transform(d) {
  //translate string
  return "translate(" + x(d[0]) + "," + y(d[1]) + ")";
}

function interpolateZoom(translate, scale) {
  zoombehavior
        .scale(scale)//we are setting this zoom only for detecting the scale for slider..we are not zoooming using scale.
        .translate(translate);
      zoom();
}
var slider = $(function() {
  $("#slider").slider({
    value: zoombehavior.scaleExtent()[0],//setting the value
    min: zoombehavior.scaleExtent()[0],//setting the min value
    max: zoombehavior.scaleExtent()[1],//settinng the ax value
    step: 0.01,
    slide: function(event, ui) {
      var newValue = ui.value;
      var  center = [centerX, centerY],
        extent = zoombehavior.scaleExtent(),
        translate = zoombehavior.translate(),
        l = [],
        view = {
          x: translate[0],
          y: translate[1],
          k: zoombehavior.scale()
        };
      //translate w.r.t the center
      translate0 = [(center[0] - view.x) / view.k, (center[1] - view.y) / view.k];
      view.k = newValue;//the scale as per the slider
      //the translate after the scale(so we are multiplying the translate)
      l = [translate0[0] * view.k + view.x, translate0[1] * view.k + view.y];

      view.x += center[0] - l[0];
      view.y += center[1] - l[1];

      interpolateZoom([view.x, view.y], view.k);

    }
  });
});

我正在缩放w.r.t. 250,250这是剪辑圈的中心。

I am zooming w.r.t. 250,250 which is the center of the clip circle.

工作代码这里（已添加必要的评论）

Working code here (have added necessary comments)

希望这有帮助！

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