(function() { "use strict"; var root = this, Chart = root.Chart, helpers = Chart.helpers; var defaultConfig = { position: "left", // label settings ticks: { template: "<%var remain = value / (Math.pow(10, Math.floor(Chart.helpers.log10(value))));if (remain === 1 || remain === 2 || remain === 5) {%><%=value.toExponential()%><%} else {%><%= null %><%}%>", } }; var LogarithmicScale = Chart.Scale.extend({ buildTicks: function() { // Calculate Range (we may break this out into it's own lifecycle function) this.min = null; this.max = null; var values = []; if (this.options.stacked) { helpers.each(this.data.datasets, function(dataset) { if (this.isHorizontal() ? dataset.xAxisID === this.id : dataset.yAxisID === this.id) { helpers.each(dataset.data, function(rawValue, index) { var value = this.getRightValue(rawValue); values[index] = values[index] || 0; if (this.options.relativePoints) { values[index] = 100; } else { // Don't need to split positive and negative since the log scale can't handle a 0 crossing values[index] += value; } }, this); } }, this); this.min = helpers.min(values); this.max = helpers.max(values); } else { helpers.each(this.data.datasets, function(dataset) { if (this.isHorizontal() ? dataset.xAxisID === this.id : dataset.yAxisID === this.id) { helpers.each(dataset.data, function(rawValue, index) { var value = this.getRightValue(rawValue); if (this.min === null) { this.min = value; } else if (value < this.min) { this.min = value; } if (this.max === null) { this.max = value; } else if (value > this.max) { this.max = value; } }, this); } }, this); } if (this.min === this.max) { if (this.min !== 0 && this.min !== null) { this.min = Math.pow(10, Math.floor(helpers.log10(this.min)) - 1); this.max = Math.pow(10, Math.floor(helpers.log10(this.max)) + 1); } else { this.min = 1; this.max = 10; } } // Reset the ticks array. Later on, we will draw a grid line at these positions // The array simply contains the numerical value of the spots where ticks will be this.tickValues = []; // Figure out what the max number of ticks we can support it is based on the size of // the axis area. For now, we say that the minimum tick spacing in pixels must be 50 // We also limit the maximum number of ticks to 11 which gives a nice 10 squares on // the graph var minExponent = Math.floor(helpers.log10(this.min)); var maxExponent = Math.ceil(helpers.log10(this.max)); for (var exponent = minExponent; exponent < maxExponent; ++exponent) { for (var i = 1; i < 10; ++i) { this.tickValues.push(i * Math.pow(10, exponent)); } } this.tickValues.push(1.0 * Math.pow(10, maxExponent)); if (this.options.position == "left" || this.options.position == "right") { // We are in a vertical orientation. The top value is the highest. So reverse the array this.tickValues.reverse(); } // At this point, we need to update our max and min given the tick values since we have expanded the // range of the scale this.max = helpers.max(this.tickValues); this.min = helpers.min(this.tickValues); if (this.options.ticks.reverse) { this.tickValues.reverse(); this.start = this.max; this.end = this.min; } else { this.start = this.min; this.end = this.max; } this.ticks = this.tickValues.slice(); }, // Get the correct value. If the value type is object get the x or y based on whether we are horizontal or not getRightValue: function(rawValue) { return typeof rawValue === "object" ? (this.isHorizontal() ? rawValue.x : rawValue.y) : rawValue; }, getPixelForTick: function(index, includeOffset) { return this.getPixelForValue(this.tickValues[index], null, null, includeOffset); }, getPixelForValue: function(value, index, datasetIndex, includeOffset) { var pixel; var newVal = this.getRightValue(value); var range = helpers.log10(this.end) - helpers.log10(this.start); if (this.isHorizontal()) { if (newVal === 0) { pixel = this.left + this.paddingLeft; } else { var innerWidth = this.width - (this.paddingLeft + this.paddingRight); pixel = this.left + (innerWidth / range * (helpers.log10(newVal) - helpers.log10(this.start))); return pixel + this.paddingLeft; } } else { // Bottom - top since pixels increase downard on a screen if (newVal === 0) { pixel = this.top + this.paddingTop; } else { var innerHeight = this.height - (this.paddingTop + this.paddingBottom); return (this.bottom - this.paddingBottom) - (innerHeight / range * (helpers.log10(newVal) - helpers.log10(this.start))); } } }, }); Chart.scaleService.registerScaleType("logarithmic", LogarithmicScale, defaultConfig); }).call(this);