扩展@robert-longson的答案，您可以使用SVG的椭圆弧命令来生成角，并结合使用lineto命令来生成直边。这些命令与path elements一起使用。下面是一个可能的实现：

// Returns path data for a rectangle with rounded right corners.
// The top-left corner is ⟨x,y⟩.
function rightRoundedRect(x, y, width, height, radius) {
  return "M" + x + "," + y
       + "h" + (width - radius)
       + "a" + radius + "," + radius + " 0 0 1 " + radius + "," + radius
       + "v" + (height - 2 * radius)
       + "a" + radius + "," + radius + " 0 0 1 " + -radius + "," + radius
       + "h" + (radius - width)
       + "z";
}

然后，您可以调用此函数来计算“d”属性。例如：

rects.enter().append("path")
    .attr("d", function(d) {
      return rightRoundedRect(x(0), y(d.name), x(d.value) - x(0), y.rangeBand(), 10);
    });

示例：

• http://bl.ocks.org/3468167
  **可选：**如果您愿意，可以重构rightRoundedRect函数，使其 * 可配置 *，而不是使用大量参数。这种方法类似于D3的内置shape generators。例如，您可以使用如下所示的矩形生成器：

rects.enter().append("path")
    .attr("d", rightRoundedRect()
      .x(x(0))
      .y(function(d) { return y(d.name); })
      .width(function(d) { return x(d.value) - x(0); })
      .height(y.rangeBand())
      .radius(10));

有关该方法的更多详细信息，请参见configurable function tutorial。

只是为了扩展给出的答案，这里有一个更全面的函数来返回rect的路径。

x: x-coordinate
y: y-coordinate
w: width
h: height
r: corner radius
tl: top_left rounded?
tr: top_right rounded?
bl: bottom_left rounded?
br: bottom_right rounded?

function rounded_rect(x, y, w, h, r, tl, tr, bl, br) {
    var retval;
    retval  = "M" + (x + r) + "," + y;
    retval += "h" + (w - 2*r);
    if (tr) { retval += "a" + r + "," + r + " 0 0 1 " + r + "," + r; }
    else { retval += "h" + r; retval += "v" + r; }
    retval += "v" + (h - 2*r);
    if (br) { retval += "a" + r + "," + r + " 0 0 1 " + -r + "," + r; }
    else { retval += "v" + r; retval += "h" + -r; }
    retval += "h" + (2*r - w);
    if (bl) { retval += "a" + r + "," + r + " 0 0 1 " + -r + "," + -r; }
    else { retval += "h" + -r; retval += "v" + -r; }
    retval += "v" + (2*r - h);
    if (tl) { retval += "a" + r + "," + r + " 0 0 1 " + r + "," + -r; }
    else { retval += "v" + -r; retval += "h" + r; }
    retval += "z";
    return retval;
}

如果其他人在这里想要圆化rect元素的 * 所有 * 角，您可以向rect元素添加一个rx属性（正如@mbostock在上面提到的）：

var rectangle = group.append("rect")
    .attr("width", 60)
    .attr("height", 75)
    .attr("rx", 4)
    .style("fill", function(d) { return "#e6653e"; })
    .style("stroke", function(d) { return d3.rgb("#e6653e").darker(); })

任何人谁寻找一个Eslint版本的stackmate -的答案：

function roundedRect(x, y, w, h, r, tl, tr, bl, br) {
  let retval;
  retval = `M${x + r},${y}`;
  retval += `h${w - (2 * r)}`;
  if (tr) {
    retval += `a${r},${r} 0 0 1 ${r},${r}`;
  } else {
    retval += `h${r}`; retval += `v${r}`;
  }
  retval += `v${h - (2 * r)}`;
  if (br) {
    retval += `a${r},${r} 0 0 1 ${-r},${r}`;
  } else {
    retval += `v${r}`; retval += `h${-r}`;
  }
  retval += `h${(2 * r) - w}`;
  if (bl) {
    retval += `a${r},${r} 0 0 1 ${-r},${-r}`;
  } else {
    retval += `h${-r}`; retval += `v${-r}`;
  }
  retval += `v${((2 * r) - h)}`;
  if (tl) {
    retval += `a${r},${r} 0 0 1 ${r},${-r}`;
  } else {
    retval += `v${-r}`; retval += `h${r}`;
  }
  retval += 'z';
  return retval;
}

上述@stackmate解决方案的d3.js代码示例

svg
.select(".roundedRectBox")
.attr("d", roundedRect(0, 0, 50, 50, 15, 0, 0, 15, 15))
.attr("fill", "#ff0000");

和SVG代码

<svg>
  <path className="roundedRectBox" />
</svg>