tests/underlay-callback.html

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