让我们从一个定义了轴范围的图开始。
p <- plot_ly() %>% layout(xaxis = list(range = c(1, 5)))
现在添加一个 JavaScript 事件监听器,它可以捕获绘图布局中的任何变化
javascript <- "
var myPlot = document.getElementsByClassName('plotly')[0];
function resize(eventdata) {
// magic happens here
}
myPlot.on('plotly_relayout', function(eventdata) {
resize(eventdata);
});
"
p <- htmlwidgets::prependContent(p,
onStaticRenderComplete(javascript))
p
事件eventdata
从我们可以获得新轴范围的地方传递。
eventdata['xaxis.range[1]']
由于我们事先不知道绘图的大小,所以我们通过轴线的大小来确定
var plot_width = Plotly.d3.select('.xlines-above').node().getBBox()['width'];
我们需要手动调用一次事件以确保绘图正确初始化
初始图

放大
完整的 R 代码
library("plotly")
library("htmlwidgets")
p <- plot_ly() %>%
add_trace(x = c(1.5, 3, 4.2),
y = c(-2, 1, 2),
type = 'scatter',
mode = 'lines+markers',
showlegend = F) %>%
add_trace(x = c(2, 3, 4.2),
y = c(2, 0, -1),
type = 'scatter',
mode = 'lines+markers',
showlegend = F) %>%
add_trace(x = c(1.5, 3, 4.2),
y = c(1, 0.5, 1),
type = 'scatter',
mode = 'markers',
showlegend = F) %>%
layout(xaxis = list(range = c(1, 5)))
javascript <- "
marker_size = 0.5; // x-axis units
var myPlot = document.getElementsByClassName('plotly')[0];
function resize(eventdata) {
var xaxis_stop = 5;
var xaxis_start = 1;
var plot_width = Plotly.d3.select('.xlines-above').node().getBBox()['width'];
if (eventdata['xaxis.range[1]'] !== undefined) {
var update = {'marker.size': marker_size * plot_width / (eventdata['xaxis.range[1]'] - eventdata['xaxis.range[0]'])};
} else {
var update = {'marker.size': marker_size * plot_width / (xaxis_stop - xaxis_start)};
}
Plotly.restyle(myPlot, update, 2);
}
resize({eventdata: {}});
myPlot.on('plotly_relayout', function(eventdata) {
resize(eventdata);
});
"
p <- htmlwidgets::prependContent(p,
onStaticRenderComplete(javascript))
p
交互式 JavaScript 示例
- 您可以从定义图形的高度/宽度和定义的轴范围开始,这样您就可以知道一个轴单位有多少像素。
- 标记的大小最初将是您想要的大小。
- 每当用户更改轴范围时,
plotly_relayout
都会触发一个事件,您可以从eventdata
in xaxis.range[1]
(start) 和xaxis.range[1]
(end)检索新范围
- 根据新范围,您可以设置
relayout
标记大小。
var plot_width = 500;
var plot_height = 500;
var margin_l = 100;
var margin_r = 100;
marker_size = 0.5; // x-axis units
xaxis_start = 1;
xaxis_stop = 5;
var trace1 = {
x: [1.5, 2, 3, 4],
y: [10, 15, 13, 17],
mode: "markers",
marker: {
size: marker_size *
(plot_width - margin_l - margin_r) /
(xaxis_stop - xaxis_start)
},
showlegend: false
};
var trace2 = {
x: [2, 3, 4, 4.5],
y: [16, 5, 11, 10],
mode: "lines"
};
var trace3 = {
x: [1.5, 2, 3, 4],
y: [12, 9, 15, 12],
mode: "lines+markers",
showlegend: false
};
var data = [trace1, trace2, trace3];
var layout = {
width: plot_width,
height: plot_height,
margin: {
l: margin_l,
r: margin_r
},
xaxis: {
range: [1, 5]
},
showlegend: false
};
Plotly.newPlot("myDiv", data, layout);
var refplot = document.getElementById("myDiv");
refplot.on("plotly_relayout", function(eventdata) {
if (eventdata["xaxis.range[1]"] !== undefined) {
var update = {
"marker.size": marker_size *
(plot_width - margin_l - margin_r) /
(eventdata["xaxis.range[1]"] - eventdata["xaxis.range[0]"])
};
} else {
var update = {
"marker.size": marker_size *
(plot_width - margin_l - margin_r) /
(xaxis_stop - xaxis_start)
};
}
Plotly.restyle("myDiv", update, 0);
});
<head>
<script src="https://cdn.plot.ly/plotly-latest.min.js"></script>
</head>
<body>
<div id="myDiv"></div>
</body>