From: Dan Vanderkam Date: Fri, 10 Jun 2011 21:36:47 +0000 (-0400) Subject: factor out tickers X-Git-Url: https://adrianiainlam.tk/git/?a=commitdiff_plain;h=1363cf3748f57ef6048e6181487408f04bf3ca15;p=dygraphs.git factor out tickers --- diff --git a/dygraph-dev.js b/dygraph-dev.js index 1e7bada..e572dba 100644 --- a/dygraph-dev.js +++ b/dygraph-dev.js @@ -24,6 +24,7 @@ "dygraph-gviz.js", "dygraph-interaction-model.js", "dygraph-options-reference.js" // Shouldn't be included in generate-combined.sh + , "dygraph-tickers.js" ]; for (var i = 0; i < source_files.length; i++) { diff --git a/dygraph-tickers.js b/dygraph-tickers.js new file mode 100644 index 0000000..2f11a14 --- /dev/null +++ b/dygraph-tickers.js @@ -0,0 +1,309 @@ +// 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; +}; +