Question

我在d3中看过这个动画，

http://bl.ocks.org/mbostock/5100636

我想知道有没有办法让这个响应，所以尺寸会随着浏览器窗口的大小调整而改变？或者如果使用raphael.js会更容易吗？

以下是代码：

<!DOCTYPE html>
<meta charset="utf-8">
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>

var width = 960,
height = 500,
τ = 2 * Math.PI; // http://tauday.com/tau-manifesto

// An arc function with all values bound except the endAngle. So, to compute an
// SVG path string for a given angle, we pass an object with an endAngle
// property to the `arc` function, and it will return the corresponding string.
var arc = d3.svg.arc()
.innerRadius(180)
.outerRadius(240)
.startAngle(0);

// Create the SVG container, and apply a transform such that the origin is the
// center of the canvas. This way, we don't need to position arcs individually.
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height)
.append("g")
.attr("transform", "translate(" + width / 2 + "," + height / 2 + ")")

// Add the background arc, from 0 to 100% (τ).
var background = svg.append("path")
.datum({endAngle: τ})
.style("fill", "#ddd")
.attr("d", arc);

// Add the foreground arc in orange, currently showing 12.7%.
var foreground = svg.append("path")
.datum({endAngle: .127 * τ})
.style("fill", "orange")
.attr("d", arc);

// Every so often, start a transition to a new random angle. Use transition.call
// (identical to selection.call) so that we can encapsulate the logic for
// tweening the arc in a separate function below.
setInterval(function() {
foreground.transition()
.duration(750)
.call(arcTween, Math.random() * τ);
}, 1500);

// Creates a tween on the specified transition's "d" attribute, transitioning
// any selected arcs from their current angle to the specified new angle.
function arcTween(transition, newAngle) {

// The function passed to attrTween is invoked for each selected element when
// the transition starts, and for each element returns the interpolator to use
// over the course of transition. This function is thus responsible for
// determining the starting angle of the transition (which is pulled from the
// element's bound datum, d.endAngle), and the ending angle (simply the
// newAngle argument to the enclosing function).
transition.attrTween("d", function(d) {

// To interpolate between the two angles, we use the default d3.interpolate.
// (Internally, this maps to d3.interpolateNumber, since both of the
// arguments to d3.interpolate are numbers.) The returned function takes a
// single argument t and returns a number between the starting angle and the
// ending angle. When t = 0, it returns d.endAngle; when t = 1, it returns
// newAngle; and for 0 < t < 1 it returns an angle in-between.
var interpolate = d3.interpolate(d.endAngle, newAngle);

// The return value of the attrTween is also a function: the function that
// we want to run for each tick of the transition. Because we used
// attrTween("d"), the return value of this last function will be set to the
// "d" attribute at every tick. (It's also possible to use transition.tween
// to run arbitrary code for every tick, say if you want to set multiple
// attributes from a single function.) The argument t ranges from 0, at the
// start of the transition, to 1, at the end.
return function(t) {

// Calculate the current arc angle based on the transition time, t. Since
// the t for the transition and the t for the interpolate both range from
// 0 to 1, we can pass t directly to the interpolator.
//
// Note that the interpolated angle is written into the element's bound
// data object! This is important: it means that if the transition were
// interrupted, the data bound to the element would still be consistent
// with its appearance. Whenever we start a new arc transition, the
// correct starting angle can be inferred from the data.
d.endAngle = interpolate(t);

// Lastly, compute the arc path given the updated data! In effect, this
// transition uses data-space interpolation: the data is interpolated
// (that is, the end angle) rather than the path string itself.
// Interpolating the angles in polar coordinates, rather than the raw path
// string, produces valid intermediate arcs during the transition.
return arc(d);
};
});
}

</script>

Answer 1

有两种方法可以让SVG适应窗口大小。

第一个选项是让“可缩放矢量图形”的“可扩展”方面为您完成工作。使用相对单位（百分比或视口单位）或使用CSS媒体查询设置SVG大小以适应屏幕大小。然后在SVG中添加viewBox属性，使图像缩放以适合您放入的任何大小的框。限制是所有平均缩放，这可能会导致非常大或非常大如果图形的大小发生很大变化，则为小文本标签。好处是重新大小完全独立于您的代码和图形中的任何动画。

应用于弧补间演示的概念示例：
http://fiddle.jshell.net/h8Mg9/

密码：

var svg = d3.select("body").append("svg")
    .attr("height", "100%") //or use CSS
    .attr("width", "100%")
    .attr("viewBox", 
          "0 0 " + (margin.left + diameter + margin.right) +
          " " + (margin.top + diameter + margin.bottom) )
        //"0 0 160 120" -- defines relative units for drawing
        //(0,0) for top left corner coordinates, 
        //then width and height.
    .attr("preserveAspectRatio", "xMidYMid meet");
       //maintain aspect ratio from viewBox dimensions;
       //If they don't match svg dimensions, scale down to
       //fit the entire viewbox within the svg (meet);
       //center it vertically and horizontally (xMidYMid)

请注意，文本的大小始终与环成比例，就像环的直径为100px一样。此外，文本转换只是旧位置和新位置之间的直线转换。

第二个选项是监听窗口大小调整事件，查询svg大小然后触发重新绘制。绘图函数中的所有大小变量都必须适当地缩放到尺寸。此外，您必须考虑在转换期间发生调整大小事件的可能性。自定义弧补间实际上使这更容易，因为它在转换的每个刻度处调用弧函数;通过更改arc函数的参数，补间结果也会自动更改。

此弧形补间演示的方法示例：
http://fiddle.jshell.net/h8Mg9/2/

密码：

function setSize() {
    var svgStyles = window.getComputedStyle(svg.node());
    diameter = Math.min(
                (parseInt(svgStyles["width"]) 
                    - margin.left - margin.right), 
                (parseInt(svgStyles["height"])
                    - margin.top - margin.bottom) );

    arc.outerRadius(diameter/2)
       .innerRadius(diameter/2 - ringThickness);


    vis.attr("transform",
          "translate(" + (margin.left + diameter/2) + ","
          + (margin.top + diameter/2) + ")"); 
    background.attr("d", arc);

    if(!transitioning) {
        //don't interrupt an ongoing transition --
        //it will automatically adjust
        //because we've modified the arc function;
        //note that we've created a custom tween
        //for the label, so it will adjust too.

        //Otherwise:
        foreground.attr("d", arc);
        label.attr("transform", function(d) {
            return "translate("+arc.centroid(d)+")" 
        });        
    }
    //Note that we're not transitioning the change
    //in diameter; it isn't necessary since there
    //will be multiple resize events creating a smooth
    //shift in size.
}
setSize(); //initialize

//adapt size to window changes:
window.addEventListener("resize", setSize, false)

饼图的另一个好处是，在弧函数的outerRadius中，大小实际上只设置了一次。对于更复杂的布局重绘，您需要使用比例来确定位置和大小。 this answer on zooming的最后一个示例显示了使用比例调整大小。

对于在缩放布局中组合过渡和调整大小，可以使用与饼图中相同的方法（更改弧函数会更改补间函数的结果），并具有自定义补间查询每个刻度的比例当前状态的函数。但是，在大多数情况下，简单地中断正在进行的过渡可能会更有效 - 即创建一个新的过渡，最终将尺寸的变化与尺寸的变化结合起来。

在d3中制作动画弧响应？

1 个答案: