1 files changed, 70 insertions, 0 deletions
diff --git a/jquery.flot.symbol.js b/jquery.flot.symbol.js
new file mode 100644
index 0000000..a32fe31
--- /dev/null
+++ b/jquery.flot.symbol.js
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+/*
+Flot plugin that adds some extra symbols for plotting points.
+
+The symbols are accessed as strings through the standard symbol
+choice:
+
+  series: {
+      points: {
+          symbol: "square" // or "diamond", "triangle", "cross"
+      }
+  }
+
+*/
+
+(function ($) {
+    function processRawData(plot, series, datapoints) {
+        // we normalize the area of each symbol so it is approximately the
+        // same as a circle of the given radius
+
+        var handlers = {
+            square: function (ctx, x, y, radius, shadow) {
+                // pi * r^2 = (2s)^2  =>  s = r * sqrt(pi)/2
+                var size = radius * Math.sqrt(Math.PI) / 2;
+                ctx.rect(x - size, y - size, size + size, size + size);
+            },
+            diamond: function (ctx, x, y, radius, shadow) {
+                // pi * r^2 = 2s^2  =>  s = r * sqrt(pi/2)
+                var size = radius * Math.sqrt(Math.PI / 2);
+                ctx.moveTo(x - size, y);
+                ctx.lineTo(x, y - size);
+                ctx.lineTo(x + size, y);
+                ctx.lineTo(x, y + size);
+                ctx.lineTo(x - size, y);
+            },
+            triangle: function (ctx, x, y, radius, shadow) {
+                // pi * r^2 = 1/2 * s^2 * sin (pi / 3)  =>  s = r * sqrt(2 * pi / sin(pi / 3))
+                var size = radius * Math.sqrt(2 * Math.PI / Math.sin(Math.PI / 3));
+                var height = size * Math.sin(Math.PI / 3);
+                ctx.moveTo(x - size/2, y + height/2);
+                ctx.lineTo(x + size/2, y + height/2);
+                if (!shadow) {
+                    ctx.lineTo(x, y - height/2);
+                    ctx.lineTo(x - size/2, y + height/2);
+                }
+            },
+            cross: function (ctx, x, y, radius, shadow) {
+                // pi * r^2 = (2s)^2  =>  s = r * sqrt(pi)/2
+                var size = radius * Math.sqrt(Math.PI) / 2;
+                ctx.moveTo(x - size, y - size);
+                ctx.lineTo(x + size, y + size);
+                ctx.moveTo(x - size, y + size);
+                ctx.lineTo(x + size, y - size);
+            }
+        }
+
+        var s = series.points.symbol;
+        if (handlers[s])
+            series.points.symbol = handlers[s];
+    }
+    
+    function init(plot) {
+        plot.hooks.processDatapoints.push(processRawData);
+    }
+    
+    $.plot.plugins.push({
+        init: init,
+        name: 'symbols',
+        version: '1.0'
+    });
+})(jQuery);