tests/underlay-callback.html

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