jquery.flot.pie.js

/* Flot plugin for rendering pie charts.

Copyright (c) 2007-2014 IOLA and Ole Laursen.
Licensed under the MIT license.

The plugin assumes that each series has a single data value, and that each
value is a positive integer or zero.  Negative numbers don't make sense for a
pie chart, and have unpredictable results.  The values do NOT need to be
passed in as percentages; the plugin will calculate the total and per-slice
percentages internally.

* Created by Brian Medendorp

* Updated with contributions from btburnett3, Anthony Aragues and Xavi Ivars

The plugin supports these options:

  series: {
    pie: {
      show: true/false
      radius: 0-1 for percentage of fullsize, or a specified pixel length, or 'auto'
      innerRadius: 0-1 for percentage of fullsize or a specified pixel length, for creating a donut effect
      startAngle: 0-2 factor of PI used for starting angle (in radians) i.e 3/2 starts at the top, 0 and 2 have the same result
      tilt: 0-1 for percentage to tilt the pie, where 1 is no tilt, and 0 is completely flat (nothing will show)
      offset: {
        top: integer value to move the pie up or down
        left: integer value to move the pie left or right, or 'auto'
      },
      stroke: {
        color: any hexidecimal color value (other formats may or may not work, so best to stick with something like '#FFF')
        width: integer pixel width of the stroke
      },
      label: {
        show: true/false, or 'auto'
        formatter:  a user-defined function that modifies the text/style of the label text
        radius: 0-1 for percentage of fullsize, or a specified pixel length
        background: {
          color: any hexidecimal color value (other formats may or may not work, so best to stick with something like '#000')
          opacity: 0-1
        },
        threshold: 0-1 for the percentage value at which to hide labels (if they're too small)
      },
      combine: {
        threshold: 0-1 for the percentage value at which to combine slices (if they're too small)
        color: any hexidecimal color value (other formats may or may not work, so best to stick with something like '#CCC'), if null, the plugin will automatically use the color of the first slice to be combined
        label: any text value of what the combined slice should be labeled
      }
      highlight: {
        opacity: 0-1
      }
    }
  }

More detail and specific examples can be found in the included HTML file.

*/

(function($) {

  // Maximum redraw attempts when fitting labels within the plot

  var REDRAW_ATTEMPTS = 10;

  // Factor by which to shrink the pie when fitting labels within the plot

  var REDRAW_SHRINK = 0.95;

  function init(plot) {

    var canvas = null,
      target = null,
      options = null,
      maxRadius = null,
      centerLeft = null,
      centerTop = null,
      processed = false,
      ctx = null;

    // interactive variables

    var highlights = [];

    // add hook to determine if pie plugin in enabled, and then perform necessary operations

    plot.hooks.processOptions.push(function(plot, options) {
      if (options.series.pie.show) {

        options.grid.show = false;

        // set labels.show

        if (options.series.pie.label.show == "auto") {
          if (options.legend.show) {
            options.series.pie.label.show = false;
          } else {
            options.series.pie.label.show = true;
          }
        }

        // set radius

        if (options.series.pie.radius == "auto") {
          if (options.series.pie.label.show) {
            options.series.pie.radius = 3/4;
          } else {
            options.series.pie.radius = 1;
          }
        }

        // ensure sane tilt

        if (options.series.pie.tilt > 1) {
          options.series.pie.tilt = 1;
        } else if (options.series.pie.tilt < 0) {
          options.series.pie.tilt = 0;
        }
      }
    });

    plot.hooks.bindEvents.push(function(plot, eventHolder) {
      var options = plot.getOptions();
      if (options.series.pie.show) {
        if (options.grid.hoverable) {
          eventHolder.unbind("mousemove").mousemove(onMouseMove);
        }
        if (options.grid.clickable) {
          eventHolder.unbind("click").click(onClick);
        }
      }
    });

    plot.hooks.processDatapoints.push(function(plot, series, data, datapoints) {
      var options = plot.getOptions();
      if (options.series.pie.show) {
        processDatapoints(plot, series, data, datapoints);
      }
    });

    plot.hooks.drawOverlay.push(function(plot, octx) {
      var options = plot.getOptions();
      if (options.series.pie.show) {
        drawOverlay(plot, octx);
      }
    });

    plot.hooks.draw.push(function(plot, newCtx) {
      var options = plot.getOptions();
      if (options.series.pie.show) {
        draw(plot, newCtx);
      }
    });

    function processDatapoints(plot, series, datapoints) {
      if (!processed)	{
        processed = true;
        canvas = plot.getCanvas();
        target = $(canvas).parent();
        options = plot.getOptions();
        plot.setData(combine(plot.getData()));
      }
    }

    function combine(data) {

      var total = 0,
        combined = 0,
        numCombined = 0,
        color = options.series.pie.combine.color,
        newdata = [];

      // Fix up the raw data from Flot, ensuring the data is numeric

      for (var i = 0; i < data.length; ++i) {

        var value = data[i].data;

        // If the data is an array, we'll assume that it's a standard
        // Flot x-y pair, and are concerned only with the second value.

        // Note how we use the original array, rather than creating a
        // new one; this is more efficient and preserves any extra data
        // that the user may have stored in higher indexes.

        if ($.isArray(value) && value.length == 1) {
            value = value[0];
        }

        if ($.isArray(value)) {
          // Equivalent to $.isNumeric() but compatible with jQuery < 1.7
          if (!isNaN(parseFloat(value[1])) && isFinite(value[1])) {
            value[1] = +value[1];
          } else {
            value[1] = 0;
          }
        } else if (!isNaN(parseFloat(value)) && isFinite(value)) {
          value = [1, +value];
        } else {
          value = [1, 0];
        }

        data[i].data = [value];
      }

      // Sum up all the slices, so we can calculate percentages for each

      for (var i = 0; i < data.length; ++i) {
        total += data[i].data[0][1];
      }

      // Count the number of slices with percentages below the combine
      // threshold; if it turns out to be just one, we won't combine.

      for (var i = 0; i < data.length; ++i) {
        var value = data[i].data[0][1];
        if (value / total <= options.series.pie.combine.threshold) {
          combined += value;
          numCombined++;
          if (!color) {
            color = data[i].color;
          }
        }
      }

      for (var i = 0; i < data.length; ++i) {
        var value = data[i].data[0][1];
        if (numCombined < 2 || value / total > options.series.pie.combine.threshold) {
          newdata.push(
            $.extend(data[i], {     /* extend to allow keeping all other original data values
                                       and using them e.g. in labelFormatter. */
              data: [[1, value]],
              color: data[i].color,
              label: data[i].label,
              angle: value * Math.PI * 2 / total,
              percent: value / (total / 100)
            })
          );
        }
      }

      if (numCombined > 1) {
        newdata.push({
          data: [[1, combined]],
          color: color,
          label: options.series.pie.combine.label,
          angle: combined * Math.PI * 2 / total,
          percent: combined / (total / 100)
        });
      }

      return newdata;
    }

    function draw(plot, newCtx) {

      if (!target) {
        return; // if no series were passed
      }

      var canvasWidth = plot.getPlaceholder().width(),
        canvasHeight = plot.getPlaceholder().height(),
        legendWidth = target.children().filter(".legend").children().width() || 0;

      ctx = newCtx;

      // WARNING: HACK! REWRITE THIS CODE AS SOON AS POSSIBLE!

      // When combining smaller slices into an 'other' slice, we need to
      // add a new series.  Since Flot gives plugins no way to modify the
      // list of series, the pie plugin uses a hack where the first call
      // to processDatapoints results in a call to setData with the new
      // list of series, then subsequent processDatapoints do nothing.

      // The plugin-global 'processed' flag is used to control this hack;
      // it starts out false, and is set to true after the first call to
      // processDatapoints.

      // Unfortunately this turns future setData calls into no-ops; they
      // call processDatapoints, the flag is true, and nothing happens.

      // To fix this we'll set the flag back to false here in draw, when
      // all series have been processed, so the next sequence of calls to
      // processDatapoints once again starts out with a slice-combine.
      // This is really a hack; in 0.9 we need to give plugins a proper
      // way to modify series before any processing begins.

      processed = false;

      // calculate maximum radius and center point

      maxRadius =  Math.min(canvasWidth, canvasHeight / options.series.pie.tilt) / 2;
      centerTop = canvasHeight / 2 + options.series.pie.offset.top;
      centerLeft = canvasWidth / 2;

      if (options.series.pie.offset.left == "auto") {
        if (options.legend.position.match("w")) {
          centerLeft += legendWidth / 2;
        } else {
          centerLeft -= legendWidth / 2;
        }
        if (centerLeft < maxRadius) {
          centerLeft = maxRadius;
        } else if (centerLeft > canvasWidth - maxRadius) {
          centerLeft = canvasWidth - maxRadius;
        }
      } else {
        centerLeft += options.series.pie.offset.left;
      }

      var slices = plot.getData(),
        attempts = 0;

      // Keep shrinking the pie's radius until drawPie returns true,
      // indicating that all the labels fit, or we try too many times.

      do {
        if (attempts > 0) {
          maxRadius *= REDRAW_SHRINK;
        }
        attempts += 1;
        clear();
        if (options.series.pie.tilt <= 0.8) {
          drawShadow();
        }
      } while (!drawPie() && attempts < REDRAW_ATTEMPTS)

      if (attempts >= REDRAW_ATTEMPTS) {
        clear();
        target.prepend("<div class='error'>Could not draw pie with labels contained inside canvas</div>");
      }

      if (plot.setSeries && plot.insertLegend) {
        plot.setSeries(slices);
        plot.insertLegend();
      }

      // we're actually done at this point, just defining internal functions at this point

      function clear() {
        ctx.clearRect(0, 0, canvasWidth, canvasHeight);
        target.children().filter(".pieLabel, .pieLabelBackground").remove();
      }

      function drawShadow() {

        var shadowLeft = options.series.pie.shadow.left;
        var shadowTop = options.series.pie.shadow.top;
        var edge = 10;
        var alpha = options.series.pie.shadow.alpha;
        var radius = options.series.pie.radius > 1 ? options.series.pie.radius : maxRadius * options.series.pie.radius;

        if (radius >= canvasWidth / 2 - shadowLeft || radius * options.series.pie.tilt >= canvasHeight / 2 - shadowTop || radius <= edge) {
          return;	// shadow would be outside canvas, so don't draw it
        }

        ctx.save();
        ctx.translate(shadowLeft,shadowTop);
        ctx.globalAlpha = alpha;
        ctx.fillStyle = "#000";

        // center and rotate to starting position

        ctx.translate(centerLeft,centerTop);
        ctx.scale(1, options.series.pie.tilt);

        //radius -= edge;

        for (var i = 1; i <= edge; i++) {
          ctx.beginPath();
          ctx.arc(0, 0, radius, 0, Math.PI * 2, false);
          ctx.fill();
          radius -= i;
        }

        ctx.restore();
      }

      function drawPie() {

        var startAngle = Math.PI * options.series.pie.startAngle;
        var radius = options.series.pie.radius > 1 ? options.series.pie.radius : maxRadius * options.series.pie.radius;

        // center and rotate to starting position

        ctx.save();
        ctx.translate(centerLeft,centerTop);
        ctx.scale(1, options.series.pie.tilt);
        //ctx.rotate(startAngle); // start at top; -- This doesn't work properly in Opera

        // draw slices

        ctx.save();
        var currentAngle = startAngle;
        for (var i = 0; i < slices.length; ++i) {
          slices[i].startAngle = currentAngle;
          drawSlice(slices[i].angle, slices[i].color, true);
        }
        ctx.restore();

        // draw slice outlines

        if (options.series.pie.stroke.width > 0) {
          ctx.save();
          ctx.lineWidth = options.series.pie.stroke.width;
          currentAngle = startAngle;
          for (var i = 0; i < slices.length; ++i) {
            drawSlice(slices[i].angle, options.series.pie.stroke.color, false);
          }
          ctx.restore();
        }

        // draw donut hole

        drawDonutHole(ctx);

        ctx.restore();

        // Draw the labels, returning true if they fit within the plot

        if (options.series.pie.label.show) {
          return drawLabels();
        } else return true;

        function drawSlice(angle, color, fill) {

          if (angle <= 0 || isNaN(angle)) {
            return;
          }

          if (fill) {
            ctx.fillStyle = color;
          } else {
            ctx.strokeStyle = color;
            ctx.lineJoin = "round";
          }

          ctx.beginPath();
          if (Math.abs(angle - Math.PI * 2) > 0.000000001) {
            ctx.moveTo(0, 0); // Center of the pie
          }

          //ctx.arc(0, 0, radius, 0, angle, false); // This doesn't work properly in Opera
          ctx.arc(0, 0, radius,currentAngle, currentAngle + angle / 2, false);
          ctx.arc(0, 0, radius,currentAngle + angle / 2, currentAngle + angle, false);
          ctx.closePath();
          //ctx.rotate(angle); // This doesn't work properly in Opera
          currentAngle += angle;

          if (fill) {
            ctx.fill();
          } else {
            ctx.stroke();
          }
        }

        function drawLabels() {

          var currentAngle = startAngle;
          var radius = options.series.pie.label.radius > 1 ? options.series.pie.label.radius : maxRadius * options.series.pie.label.radius;

          for (var i = 0; i < slices.length; ++i) {
            if (slices[i].percent >= options.series.pie.label.threshold * 100) {
              if (!drawLabel(slices[i], currentAngle, i)) {
                return false;
              }
            }
            currentAngle += slices[i].angle;
          }

          return true;

          function drawLabel(slice, startAngle, index) {

            if (slice.data[0][1] == 0) {
              return true;
            }

            // format label text

            var lf = options.legend.labelFormatter, text, plf = options.series.pie.label.formatter;

            if (lf) {
              text = lf(slice.label, slice);
            } else {
              text = slice.label;
            }

            if (plf) {
              text = plf(text, slice);
            }

            var halfAngle = ((startAngle + slice.angle) + startAngle) / 2;
            var x = centerLeft + Math.round(Math.cos(halfAngle) * radius);
            var y = centerTop + Math.round(Math.sin(halfAngle) * radius) * options.series.pie.tilt;

            var html = "<span class='pieLabel' id='pieLabel" + index + "' style='position:absolute;top:" + y + "px;left:" + x + "px;'>" + text + "</span>";
            target.append(html);

            var label = target.children("#pieLabel" + index);
            var labelTop = (y - label.height() / 2);
            var labelLeft = (x - label.width() / 2);

            label.css("top", labelTop);
            label.css("left", labelLeft);

            // check to make sure that the label is not outside the canvas

            if (0 - labelTop > 0 || 0 - labelLeft > 0 || canvasHeight - (labelTop + label.height()) < 0 || canvasWidth - (labelLeft + label.width()) < 0) {
              return false;
            }

            if (options.series.pie.label.background.opacity != 0) {

              // put in the transparent background separately to avoid blended labels and label boxes

              var c = options.series.pie.label.background.color;

              if (c == null) {
                c = slice.color;
              }

              var pos = "top:" + labelTop + "px;left:" + labelLeft + "px;";
              $("<div class='pieLabelBackground' style='position:absolute;width:" + label.width() + "px;height:" + label.height() + "px;" + pos + "background-color:" + c + ";'></div>")
                .css("opacity", options.series.pie.label.background.opacity)
                .insertBefore(label);
            }

            return true;
          } // end individual label function
        } // end drawLabels function
      } // end drawPie function
    } // end draw function

    // Placed here because it needs to be accessed from multiple locations

    function drawDonutHole(layer) {
      if (options.series.pie.innerRadius > 0) {

        // subtract the center

        layer.save();
        var innerRadius = options.series.pie.innerRadius > 1 ? options.series.pie.innerRadius : maxRadius * options.series.pie.innerRadius;
        layer.globalCompositeOperation = "destination-out"; // this does not work with excanvas, but it will fall back to using the stroke color
        layer.beginPath();
        layer.fillStyle = options.series.pie.stroke.color;
        layer.arc(0, 0, innerRadius, 0, Math.PI * 2, false);
        layer.fill();
        layer.closePath();
        layer.restore();

        // add inner stroke

        layer.save();
        layer.beginPath();
        layer.strokeStyle = options.series.pie.stroke.color;
        layer.arc(0, 0, innerRadius, 0, Math.PI * 2, false);
        layer.stroke();
        layer.closePath();
        layer.restore();

        // TODO: add extra shadow inside hole (with a mask) if the pie is tilted.
      }
    }

    //-- Additional Interactive related functions --

    function isPointInPoly(poly, pt) {
      for(var c = false, i = -1, l = poly.length, j = l - 1; ++i < l; j = i)
        ((poly[i][1] <= pt[1] && pt[1] < poly[j][1]) || (poly[j][1] <= pt[1] && pt[1]< poly[i][1]))
        && (pt[0] < (poly[j][0] - poly[i][0]) * (pt[1] - poly[i][1]) / (poly[j][1] - poly[i][1]) + poly[i][0])
        && (c = !c);
      return c;
    }

    function findNearbySlice(mouseX, mouseY) {

      var slices = plot.getData(),
        options = plot.getOptions(),
        radius = options.series.pie.radius > 1 ? options.series.pie.radius : maxRadius * options.series.pie.radius,
        x, y;

      for (var i = 0; i < slices.length; ++i) {

        var s = slices[i];

        if (s.pie.show) {

          ctx.save();
          ctx.beginPath();
          ctx.moveTo(0, 0); // Center of the pie
          //ctx.scale(1, options.series.pie.tilt);	// this actually seems to break everything when here.
          ctx.arc(0, 0, radius, s.startAngle, s.startAngle + s.angle / 2, false);
          ctx.arc(0, 0, radius, s.startAngle + s.angle / 2, s.startAngle + s.angle, false);
          ctx.closePath();
          x = mouseX - centerLeft;
          y = mouseY - centerTop;

          if (ctx.isPointInPath) {
            if (ctx.isPointInPath(mouseX - centerLeft, mouseY - centerTop)) {
              ctx.restore();
              return {
                datapoint: [s.percent, s.data],
                dataIndex: 0,
                series: s,
                seriesIndex: i
              };
            }
          } else {

            // excanvas for IE doesn;t support isPointInPath, this is a workaround.

            var p1X = radius * Math.cos(s.startAngle),
              p1Y = radius * Math.sin(s.startAngle),
              p2X = radius * Math.cos(s.startAngle + s.angle / 4),
              p2Y = radius * Math.sin(s.startAngle + s.angle / 4),
              p3X = radius * Math.cos(s.startAngle + s.angle / 2),
              p3Y = radius * Math.sin(s.startAngle + s.angle / 2),
              p4X = radius * Math.cos(s.startAngle + s.angle / 1.5),
              p4Y = radius * Math.sin(s.startAngle + s.angle / 1.5),
              p5X = radius * Math.cos(s.startAngle + s.angle),
              p5Y = radius * Math.sin(s.startAngle + s.angle),
              arrPoly = [[0, 0], [p1X, p1Y], [p2X, p2Y], [p3X, p3Y], [p4X, p4Y], [p5X, p5Y]],
              arrPoint = [x, y];

            // TODO: perhaps do some mathmatical trickery here with the Y-coordinate to compensate for pie tilt?

            if (isPointInPoly(arrPoly, arrPoint)) {
              ctx.restore();
              return {
                datapoint: [s.percent, s.data],
                dataIndex: 0,
                series: s,
                seriesIndex: i
              };
            }
          }

          ctx.restore();
        }
      }

      return null;
    }

    function onMouseMove(e) {
      triggerClickHoverEvent("plothover", e);
    }

    function onClick(e) {
      triggerClickHoverEvent("plotclick", e);
    }

    // trigger click or hover event (they send the same parameters so we share their code)

    function triggerClickHoverEvent(eventname, e) {

      var offset = plot.offset();
      var canvasX = parseInt(e.pageX - offset.left);
      var canvasY =  parseInt(e.pageY - offset.top);
      var item = findNearbySlice(canvasX, canvasY);

      if (options.grid.autoHighlight) {

        // clear auto-highlights

        for (var i = 0; i < highlights.length; ++i) {
          var h = highlights[i];
          if (h.auto == eventname && !(item && h.series == item.series)) {
            unhighlight(h.series);
          }
        }
      }

      // highlight the slice

      if (item) {
        highlight(item.series, eventname);
      }

      // trigger any hover bind events

      var pos = { pageX: e.pageX, pageY: e.pageY };
      target.trigger(eventname, [pos, item]);
    }

    function highlight(s, auto) {
      //if (typeof s == "number") {
      //	s = series[s];
      //}

      var i = indexOfHighlight(s);

      if (i == -1) {
        highlights.push({ series: s, auto: auto });
        plot.triggerRedrawOverlay();
      } else if (!auto) {
        highlights[i].auto = false;
      }
    }

    function unhighlight(s) {
      if (s == null) {
        highlights = [];
        plot.triggerRedrawOverlay();
      }

      //if (typeof s == "number") {
      //	s = series[s];
      //}

      var i = indexOfHighlight(s);

      if (i != -1) {
        highlights.splice(i, 1);
        plot.triggerRedrawOverlay();
      }
    }

    function indexOfHighlight(s) {
      for (var i = 0; i < highlights.length; ++i) {
        var h = highlights[i];
        if (h.series == s)
          return i;
      }
      return -1;
    }

    function drawOverlay(plot, octx) {

      var options = plot.getOptions();

      var radius = options.series.pie.radius > 1 ? options.series.pie.radius : maxRadius * options.series.pie.radius;

      octx.save();
      octx.translate(centerLeft, centerTop);
      octx.scale(1, options.series.pie.tilt);

      for (var i = 0; i < highlights.length; ++i) {
        drawHighlight(highlights[i].series);
      }

      drawDonutHole(octx);

      octx.restore();

      function drawHighlight(series) {

        if (series.angle <= 0 || isNaN(series.angle)) {
          return;
        }

        //octx.fillStyle = parseColor(options.series.pie.highlight.color).scale(null, null, null, options.series.pie.highlight.opacity).toString();
        octx.fillStyle = "rgba(255, 255, 255, " + options.series.pie.highlight.opacity + ")"; // this is temporary until we have access to parseColor
        octx.beginPath();
        if (Math.abs(series.angle - Math.PI * 2) > 0.000000001) {
          octx.moveTo(0, 0); // Center of the pie
        }
        octx.arc(0, 0, radius, series.startAngle, series.startAngle + series.angle / 2, false);
        octx.arc(0, 0, radius, series.startAngle + series.angle / 2, series.startAngle + series.angle, false);
        octx.closePath();
        octx.fill();
      }
    }
  } // end init (plugin body)

  // define pie specific options and their default values

  var options = {
    series: {
      pie: {
        show: false,
        radius: "auto",	// actual radius of the visible pie (based on full calculated radius if <=1, or hard pixel value)
        innerRadius: 0, /* for donut */
        startAngle: 3/2,
        tilt: 1,
        shadow: {
          left: 5,	// shadow left offset
          top: 15,	// shadow top offset
          alpha: 0.02	// shadow alpha
        },
        offset: {
          top: 0,
          left: "auto"
        },
        stroke: {
          color: "#fff",
          width: 1
        },
        label: {
          show: "auto",
          formatter: function(label, slice) {
            return "<div style='font-size:x-small;text-align:center;padding:2px;color:" + slice.color + ";'>" + label + "<br/>" + Math.round(slice.percent) + "%</div>";
          },	// formatter function
          radius: 1,	// radius at which to place the labels (based on full calculated radius if <=1, or hard pixel value)
          background: {
            color: null,
            opacity: 0
          },
          threshold: 0	// percentage at which to hide the label (i.e. the slice is too narrow)
        },
        combine: {
          threshold: -1,	// percentage at which to combine little slices into one larger slice
          color: null,	// color to give the new slice (auto-generated if null)
          label: "Other"	// label to give the new slice
        },
        highlight: {
          //color: "#fff",		// will add this functionality once parseColor is available
          opacity: 0.5
        }
      }
    }
  };

  $.plot.plugins.push({
    init: init,
    options: options,
    name: "pie",
    version: "1.1"
  });

})(jQuery);