--- /dev/null
+// Copyright 2011 Google Inc. All Rights Reserved.
+
+/**
+ * @fileoverview Description of this file.
+ * @author danvk@google.com (Dan Vanderkam)
+ *
+ * A ticker is a function with the following interface:
+ *
+ * function(a, b, pixels, pixels_per_tick, options_view, forced_values);
+ * -> [ { v: tick1_v, label: tick1_label[, label_v: label_v1] },
+ * { v: tick2_v, label: tick2_label[, label_v: label_v2] },
+ * ...
+ * ]
+ *
+ * The returned value is called a "tick list".
+ *
+ * Arguments
+ * ---------
+ *
+ * [a, b] is the range of the axis for which ticks are being generated. For a
+ * numeric axis, these will simply be numbers. For a date axis, these will be
+ * millis since epoch (convertable to Date objects using "new Date(a)" and "new
+ * Date(b)").
+ *
+ * pixels is the length of the axis in pixels and pixels_per_tick is the
+ * minimum amount of space to be allotted to each label. For instance, if
+ * pixels=400 and pixels_per_tick=40 then the ticker should return between
+ * zero and ten (400/40) ticks.
+ *
+ * opts provides access to chart- and axis-specific options. It can be used to
+ * access number/date formatting code/options, check for a log scale, etc.
+ *
+ * dygraph is the Dygraph object for which an axis is being constructed.
+ *
+ * forced_values is used for secondary y-axes. The tick positions are typically
+ * set by the primary y-axis, so the secondary y-axis has no choice in where to
+ * put these. It simply has to generate labels for these data values.
+ *
+ * Tick lists
+ * ----------
+ * Typically a tick will have both a grid/tick line and a label at one end of
+ * that line (at the bottom for an x-axis, at left or right for the y-axis).
+ *
+ * A tick may be missing one of these two components:
+ * - If "label_v" is specified instead of "v", then there will be no tick or
+ * gridline, just a label.
+ * - Similarly, if "label" is not specified, then there will be a gridline
+ * without a label.
+ *
+ * This flexibility is useful in a few situations:
+ * - For log scales, some of the tick lines may be too close to all have labels.
+ * - For date scales where years are being displayed, it is desirable to display
+ * tick marks at the beginnings of years but labels (e.g. "2006") in the
+ * middle of the years.
+ */
+
+Dygraph.newNumericTicks = function(a, b, pixels, pixels_per_tick,
+ opts, dygraph, vals) {
+ var ticks = [];
+ if (vals) {
+ for (var i = 0; i < vals.length; i++) {
+ ticks.push({v: vals[i]});
+ }
+ } else {
+ // TODO(danvk): factor this log-scale block out into a separate function.
+ if (opts("logscale")) {
+ // NOTE(konigsberg): Dan, should self.height_ be self.plotter_.area.h?
+ var nTicks = Math.floor(pixels / pixels_per_tick);
+ var minIdx = Dygraph.binarySearch(minV, Dygraph.PREFERRED_LOG_TICK_VALUES, 1);
+ var maxIdx = Dygraph.binarySearch(maxV, Dygraph.PREFERRED_LOG_TICK_VALUES, -1);
+ if (minIdx == -1) {
+ minIdx = 0;
+ }
+ if (maxIdx == -1) {
+ maxIdx = Dygraph.PREFERRED_LOG_TICK_VALUES.length - 1;
+ }
+ // Count the number of tick values would appear, if we can get at least
+ // nTicks / 4 accept them.
+ var lastDisplayed = null;
+ if (maxIdx - minIdx >= nTicks / 4) {
+ var axisId = axis_props.yAxisId;
+ for (var idx = maxIdx; idx >= minIdx; idx--) {
+ var tickValue = Dygraph.PREFERRED_LOG_TICK_VALUES[idx];
+ var pixel_coord = Math.log(tickValue / a) / Math.log(b / a) * pixels;
+ var tick = { v: tickValue };
+ if (lastDisplayed == null) {
+ lastDisplayed = {
+ tickValue : tickValue,
+ pixel_coord : pixel_coord
+ };
+ } else {
+ if (pixel_coord - lastDisplayed.pixel_coord >= pixels_per_tick) {
+ lastDisplayed = {
+ tickValue : tickValue,
+ pixel_coord : pixel_coord
+ };
+ } else {
+ tick.label = "";
+ }
+ }
+ ticks.push(tick);
+ }
+ // Since we went in backwards order.
+ ticks.reverse();
+ }
+ }
+
+ // ticks.length won't be 0 if the log scale function finds values to insert.
+ if (ticks.length == 0) {
+ // Basic idea:
+ // Try labels every 1, 2, 5, 10, 20, 50, 100, etc.
+ // Calculate the resulting tick spacing (i.e. this.height_ / nTicks).
+ // The first spacing greater than pixelsPerYLabel is what we use.
+ // TODO(danvk): version that works on a log scale.
+ var kmg2 = opts("labelsKMG2");
+ if (kmg2) {
+ var mults = [1, 2, 4, 8];
+ } else {
+ var mults = [1, 2, 5];
+ }
+ var scale, low_val, high_val, nTicks;
+ for (var i = -10; i < 50; i++) {
+ if (kmg2) {
+ var base_scale = Math.pow(16, i);
+ } else {
+ var base_scale = Math.pow(10, i);
+ }
+ for (var j = 0; j < mults.length; j++) {
+ scale = base_scale * mults[j];
+ low_val = Math.floor(a / scale) * scale;
+ high_val = Math.ceil(b / scale) * scale;
+ nTicks = Math.abs(high_val - low_val) / scale;
+ var spacing = pixels / nTicks;
+ // wish I could break out of both loops at once...
+ if (spacing > pixels_per_tick) break;
+ }
+ if (spacing > pixels_per_tick) break;
+ }
+
+ // Construct the set of ticks.
+ // Allow reverse y-axis if it's explicitly requested.
+ if (low_val > high_val) scale *= -1;
+ for (var i = 0; i < nTicks; i++) {
+ var tickV = low_val + i * scale;
+ ticks.push( {v: tickV} );
+ }
+ }
+ }
+
+ // Add formatted labels to the ticks.
+ var k;
+ var k_labels = [];
+ if (opts("labelsKMB")) {
+ k = 1000;
+ k_labels = [ "K", "M", "B", "T" ];
+ }
+ if (opts("labelsKMG2")) {
+ if (k) self.warn("Setting both labelsKMB and labelsKMG2. Pick one!");
+ k = 1024;
+ k_labels = [ "k", "M", "G", "T" ];
+ }
+
+ var formatter = opts('yAxisLabelFormatter') || opts('yValueFormatter');
+
+ // Add labels to the ticks.
+ for (var i = 0; i < ticks.length; i++) {
+ if (ticks[i].label !== undefined) continue; // Use current label.
+ var tickV = ticks[i].v;
+ var absTickV = Math.abs(tickV);
+ var label = formatter(tickV, g);
+ if (k_labels.length > 0) {
+ // TODO(danvk): should this be integrated into the axisLabelFormatter?
+ // Round up to an appropriate unit.
+ var n = k*k*k*k;
+ for (var j = 3; j >= 0; j--, n /= k) {
+ if (absTickV >= n) {
+ label = Dygraph.round_(tickV / n, opts('digitsAfterDecimal')) +
+ k_labels[j];
+ break;
+ }
+ }
+ }
+ ticks[i].label = label;
+ }
+
+ return ticks;
+};
+
+
+Dygraph.newDateTicker = function(a, b, pixels, pixels_per_tick,
+ opts, dygraph, vals) {
+ var chosen = -1;
+ for (var i = 0; i < Dygraph.NUM_GRANULARITIES; i++) {
+ var num_ticks = Dygraph.newNumDateTicks(a, b, i);
+ if (pixels / num_ticks >= pixels_per_tick) {
+ chosen = i;
+ break;
+ }
+ }
+
+ if (chosen >= 0) {
+ return Dygraph.newGetDateAxis(a, b, chosen, opts);
+ } else {
+ // TODO(danvk): signal error.
+ }
+};
+
+Dygraph.newNumDateTicks = function(start_time, end_time, granularity) {
+ if (granularity < Dygraph.MONTHLY) {
+ // Generate one tick mark for every fixed interval of time.
+ var spacing = Dygraph.SHORT_SPACINGS[granularity];
+ return Math.floor(0.5 + 1.0 * (end_time - start_time) / spacing);
+ } else {
+ var year_mod = 1; // e.g. to only print one point every 10 years.
+ var num_months = 12;
+ if (granularity == Dygraph.QUARTERLY) num_months = 3;
+ if (granularity == Dygraph.BIANNUAL) num_months = 2;
+ if (granularity == Dygraph.ANNUAL) num_months = 1;
+ if (granularity == Dygraph.DECADAL) { num_months = 1; year_mod = 10; }
+ if (granularity == Dygraph.CENTENNIAL) { num_months = 1; year_mod = 100; }
+
+ var msInYear = 365.2524 * 24 * 3600 * 1000;
+ var num_years = 1.0 * (end_time - start_time) / msInYear;
+ return Math.floor(0.5 + 1.0 * num_years * num_months / year_mod);
+ }
+};
+
+Dygraph.newGetDateAxis = function(start_time, end_time, granularity, opts) {
+ var formatter = opts("xAxisLabelFormatter"); // TODO(danvk): fix
+ var ticks = [];
+ if (granularity < Dygraph.MONTHLY) {
+ // Generate one tick mark for every fixed interval of time.
+ var spacing = Dygraph.SHORT_SPACINGS[granularity];
+ var format = '%d%b'; // e.g. "1Jan"
+
+ // Find a time less than start_time which occurs on a "nice" time boundary
+ // for this granularity.
+ var g = spacing / 1000;
+ var d = new Date(start_time);
+ if (g <= 60) { // seconds
+ var x = d.getSeconds(); d.setSeconds(x - x % g);
+ } else {
+ d.setSeconds(0);
+ g /= 60;
+ if (g <= 60) { // minutes
+ var x = d.getMinutes(); d.setMinutes(x - x % g);
+ } else {
+ d.setMinutes(0);
+ g /= 60;
+
+ if (g <= 24) { // days
+ var x = d.getHours(); d.setHours(x - x % g);
+ } else {
+ d.setHours(0);
+ g /= 24;
+
+ if (g == 7) { // one week
+ d.setDate(d.getDate() - d.getDay());
+ }
+ }
+ }
+ }
+ start_time = d.getTime();
+
+ for (var t = start_time; t <= end_time; t += spacing) {
+ ticks.push({ v:t, label: formatter(new Date(t), granularity) });
+ }
+ } else {
+ // Display a tick mark on the first of a set of months of each year.
+ // Years get a tick mark iff y % year_mod == 0. This is useful for
+ // displaying a tick mark once every 10 years, say, on long time scales.
+ var months;
+ var year_mod = 1; // e.g. to only print one point every 10 years.
+
+ if (granularity == Dygraph.MONTHLY) {
+ months = [ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 ];
+ } else if (granularity == Dygraph.QUARTERLY) {
+ months = [ 0, 3, 6, 9 ];
+ } else if (granularity == Dygraph.BIANNUAL) {
+ months = [ 0, 6 ];
+ } else if (granularity == Dygraph.ANNUAL) {
+ months = [ 0 ];
+ } else if (granularity == Dygraph.DECADAL) {
+ months = [ 0 ];
+ year_mod = 10;
+ } else if (granularity == Dygraph.CENTENNIAL) {
+ months = [ 0 ];
+ year_mod = 100;
+ } else {
+ Dygraph.warn("Span of dates is too long");
+ }
+
+ var start_year = new Date(start_time).getFullYear();
+ var end_year = new Date(end_time).getFullYear();
+ var zeropad = Dygraph.zeropad;
+ for (var i = start_year; i <= end_year; i++) {
+ if (i % year_mod != 0) continue;
+ for (var j = 0; j < months.length; j++) {
+ var date_str = i + "/" + zeropad(1 + months[j]) + "/01";
+ var t = Dygraph.dateStrToMillis(date_str);
+ if (t < start_time || t > end_time) continue;
+ ticks.push({ v:t, label: formatter(new Date(t), granularity) });
+ }
+ }
+ }
+
+ return ticks;
+};
+
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