tests/underlay-callback.html

   1 <!DOCTYPE html>
   2 <html>
   3   <head>
   4     <title>Custom underlay callback</title>
   5     <!--
   6     For production (minified) code, use:
   7     <script type="text/javascript" src="dygraph-combined.js"></script>
   8     -->
   9     <script type="text/javascript" src="../dygraph-dev.js"></script>
  10
  11     <script type="text/javascript" src="data.js"></script>
  12   </head>
  13   <body>
  14     <p>Should draw a three-colored background, split horizontally at y:2.25, and
  15     again on the top at x:19Nov:</p>
  16     <div id="div_g" style="width:600px; height:300px;"></div>
  17
  18     <div id="status" style="width:100%; height:200px;"></div>
  19
  20     <script type="text/javascript">
  21       s = document.getElementById("status");
  22
  23       g = new Dygraph(
  24             document.getElementById("div_g"),
  25             NoisyData, {
  26               rollPeriod: 7,
  27               showRoller: true,
  28               errorBars: true,
  29
  30               underlayCallback: function(canvas, area, g) {
  31                 // Selecting a date in the middle of the graph.
  32                 var splitDate = new Date("2006-11-19").getTime();
  33                 var coords = g.toDomCoords(splitDate, 2.25);
  34
  35                 // splitX and splitY are the coordinates on the canvas for (2006-11-19, 2.25).
  36                 var splitX = coords[0];
  37                 var splitY = coords[1];
  38
  39                 // The drawing area doesn't start at (0, 0), it starts at (area.x, area.y).
  40                 // That's why we subtract them from splitX and splitY. This gives us the
  41                 // actual distance from the upper-left hand corder of the graph itself.
  42                 var leftSideWidth = splitX - area.x;
  43                 var rightSideWidth = area.w - leftSideWidth;
  44                 var topHeight = splitY - area.y;
  45                 var bottomHeight = area.h - topHeight;
  46
  47                 // fillRect(x, y, width, height)
  48                 // Top section: y = (2.25, +Infinity)
  49                 // left: (x < 2006-11-19)
  50                 canvas.fillStyle = 'lightblue';
  51                 canvas.fillRect(area.x, area.y, leftSideWidth, topHeight);
  52
  53                 // right: (x > 2006-11-19)
  54                 canvas.fillStyle = 'orange';
  55                 canvas.fillRect(splitX, area.y, rightSideWidth, topHeight);
  56
  57                 // Bottom section: y = (-Infinity, 2.25)
  58                 canvas.fillStyle = 'pink';
  59                 canvas.fillRect(area.x, splitY, area.w, bottomHeight);
  60               }
  61             }
  62           );
  63     </script>
  64   </body>
  65 </html>