1 <?xml version="1.0" encoding="utf-8"?>
2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
3 "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
4 <html xml:lang="en" lang="en" xmlns="http://www.w3.org/1999/xhtml">
19 return xzero + ((x - tmin) * tfact);
22 return wh - yzero - (y * hfact);
26 ctx.moveTo(px(tmin), py(0));
27 ctx.lineTo(px(tmax), py(0));
28 ctx.strokeStyle = "black";
33 ctx.moveTo(px(tmin), py(0));
34 ctx.lineTo(px(tmin), py(hmax));
35 ctx.strokeStyle = "black";
38 function differentiate(times) { /* updates glbal hmax */
42 for (i = 0; i < times.length - 1; i++) {
43 dv = times[i+1][1] - times[i][1];
44 dt = times[i+1][0] - times[i][0];
45 if (dt != 0 && dv != 0) {
47 if (hmax < v) hmax = v;
48 res.push([times[i][0], v]);
51 res.push([times[i][0], v]);
55 function drawplot(data, color) {
59 ctx.moveTo(px(data[0][0]), py(data[0][1]));
60 for (i = 1; i < data.length; i++) {
61 ctx.lineTo(px(data[i][0]), py(data[i - 1][1]));
62 ctx.lineTo(px(data[i][0]), py(data[i][1]));
64 ctx.strokeStyle = color;
67 function gotdata(data) {
68 var cold_d = [], hot_d = [];
70 document.getElementById("cold").innerHTML =
71 (data.current.cold / 100).toFixed(2);
72 document.getElementById("hot").innerHTML =
73 (data.current.hot / 100).toFixed(2);
74 canvas = document.getElementById("plot");
76 ctx = canvas.getContext("2d");
82 tfact = (ww - xzero) / (tmax - tmin);
83 cold_d = differentiate(data.cold);
84 hot_d = differentiate(data.hot);
85 /* differetiate() updates hmax */
86 hfact = (wh - yzero) / hmax;
88 document.getElementById("debug").innerHTML.append("<br>" ++ cold_d + "<br>" + hot_d);
90 drawplot(cold_d, "blue");
91 drawplot(hot_d, "red");
114 border: solid 1px black;
119 background-color: #d0e0ff;
123 background-color: #ffd0e0;
133 border: solid 1px black;
136 <title>Water Meters</title>
138 <h1>Water Meters</h1>
139 <div id="currentvals">
141 <div class="current" id="cold">cold</div>
142 <div class="current" id="hot">hot</div>
145 <canvas id="plot" width="640" height = "320"></canvas>
150 var xmlhttp = new XMLHttpRequest();
151 var url = "query.cgi";
152 var qstr = "?lo=2015-12-19+00:00:00&hi=2015-12-20+00:00:00";
154 xmlhttp.onreadystatechange = function() {
155 if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
156 document.getElementById("debug").innerHTML = xmlhttp.responseText;
157 var myData = JSON.parse(xmlhttp.responseText);
161 xmlhttp.open("GET", url+qstr, true);