X-Git-Url: https://adrianiainlam.tk/git/?a=blobdiff_plain;f=dygraph-tickers.js;h=f4778b12b7a3ddc918bcafcc61800bbe914809c3;hb=1dc23fac4c126b2b3742801b2d82137044498ebf;hp=0e18394da0519253a801d0fd012ebcdc1c88f503;hpb=2fd143d3e284124506b00e4afa9e29f9de636543;p=dygraphs.git

diff --git a/dygraph-tickers.js b/dygraph-tickers.js
index 0e18394..f4778b1 100644
--- a/dygraph-tickers.js
+++ b/dygraph-tickers.js
@@ -259,6 +259,39 @@ Dygraph.SHORT_SPACINGS[Dygraph.SIX_HOURLY]      = 1000 * 3600 * 6;
 Dygraph.SHORT_SPACINGS[Dygraph.DAILY]           = 1000 * 86400;
 Dygraph.SHORT_SPACINGS[Dygraph.WEEKLY]          = 1000 * 604800;
 
+/** 
+ * A collection of objects specifying where it is acceptable to place tick
+ * marks for granularities larger than WEEKLY.  
+ * 'months' is an array of month indexes on which to place tick marks.
+ * 'year_mod' ticks are placed when year % year_mod = 0.
+ * @type {Array.<Object>} 
+ */
+Dygraph.LONG_TICK_PLACEMENTS = [];
+Dygraph.LONG_TICK_PLACEMENTS[Dygraph.MONTHLY] = {
+  months : [0,1,2,3,4,5,6,7,8,9,10,11], 
+  year_mod : 1
+};
+Dygraph.LONG_TICK_PLACEMENTS[Dygraph.QUARTERLY] = {
+  months: [0,3,6,9], 
+  year_mod: 1
+};
+Dygraph.LONG_TICK_PLACEMENTS[Dygraph.BIANNUAL] = {
+  months: [0,6], 
+  year_mod: 1
+};
+Dygraph.LONG_TICK_PLACEMENTS[Dygraph.ANNUAL] = {
+  months: [0], 
+  year_mod: 1
+};
+Dygraph.LONG_TICK_PLACEMENTS[Dygraph.DECADAL] = {
+  months: [0], 
+  year_mod: 10
+};
+Dygraph.LONG_TICK_PLACEMENTS[Dygraph.CENTENNIAL] = {
+  months: [0], 
+  year_mod: 100
+};
+
 /**
  * This is a list of human-friendly values at which to show tick marks on a log
  * scale. It is k * 10^n, where k=1..9 and n=-39..+39, so:
@@ -312,17 +345,11 @@ Dygraph.numDateTicks = function(start_time, end_time, granularity) {
     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 tickPlacement = Dygraph.LONG_TICK_PLACEMENTS[granularity];
 
     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);
+    return Math.floor(0.5 + 1.0 * num_years * tickPlacement.months.length / tickPlacement.year_mod);
   }
 };
 
@@ -348,21 +375,25 @@ Dygraph.getDateAxis = function(start_time, end_time, granularity, opts, dg) {
     // for this granularity.
     var g = spacing / 1000;
     var d = new Date(start_time);
-    d.setMilliseconds(0);
+    Dygraph.setDateSameTZ(d, {ms: 0});
+
     var x;
     if (g <= 60) {  // seconds
-      x = d.getSeconds(); d.setSeconds(x - x % g);
+      x = d.getSeconds();
+      Dygraph.setDateSameTZ(d, {s: x - x % g});
     } else {
-      d.setSeconds(0);
+      Dygraph.setDateSameTZ(d, {s: 0});
       g /= 60;
       if (g <= 60) {  // minutes
-        x = d.getMinutes(); d.setMinutes(x - x % g);
+        x = d.getMinutes();
+        Dygraph.setDateSameTZ(d, {m: x - x % g});
       } else {
-        d.setMinutes(0);
+        Dygraph.setDateSameTZ(d, {m: 0});
         g /= 60;
 
         if (g <= 24) {  // days
-          x = d.getHours(); d.setHours(x - x % g);
+          x = d.getHours();
+          d.setHours(x - x % g);
         } else {
           d.setHours(0);
           g /= 24;
@@ -375,9 +406,38 @@ Dygraph.getDateAxis = function(start_time, end_time, granularity, opts, dg) {
     }
     start_time = d.getTime();
 
+    // For spacings coarser than two-hourly, we want to ignore daylight
+    // savings transitions to get consistent ticks. For finer-grained ticks,
+    // it's essential to show the DST transition in all its messiness.
+    var start_offset_min = new Date(start_time).getTimezoneOffset();
+    var check_dst = (spacing >= Dygraph.SHORT_SPACINGS[Dygraph.TWO_HOURLY]);
+
     for (t = start_time; t <= end_time; t += spacing) {
+      d = new Date(t);
+
+      // This ensures that we stay on the same hourly "rhythm" across
+      // daylight savings transitions. Without this, the ticks could get off
+      // by an hour. See tests/daylight-savings.html or issue 147.
+      if (check_dst && d.getTimezoneOffset() != start_offset_min) {
+        var delta_min = d.getTimezoneOffset() - start_offset_min;
+        t += delta_min * 60 * 1000;
+        d = new Date(t);
+        start_offset_min = d.getTimezoneOffset();
+
+        // Check whether we've backed into the previous timezone again.
+        // This can happen during a "spring forward" transition. In this case,
+        // it's best to skip this tick altogether (we may be shooting for a
+        // non-existent time like the 2AM that's skipped) and go to the next
+        // one.
+        if (new Date(t + spacing).getTimezoneOffset() != start_offset_min) {
+          t += spacing;
+          d = new Date(t);
+          start_offset_min = d.getTimezoneOffset();
+        }
+      }
+
       ticks.push({ v:t,
-                   label: formatter(new Date(t), granularity, opts, dg)
+                   label: formatter(d, granularity, opts, dg)
                  });
     }
   } else {
@@ -387,20 +447,9 @@ Dygraph.getDateAxis = function(start_time, end_time, granularity, opts, dg) {
     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 ];
-    } 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;
+    if (granularity < Dygraph.NUM_GRANULARITIES) {
+      months = Dygraph.LONG_TICK_PLACEMENTS[granularity].months;
+      year_mod = Dygraph.LONG_TICK_PLACEMENTS[granularity].year_mod;
     } else {
       Dygraph.warn("Span of dates is too long");
     }
@@ -426,11 +475,13 @@ Dygraph.getDateAxis = function(start_time, end_time, granularity, opts, dg) {
 
 // These are set here so that this file can be included after dygraph.js
 // or independently.
-Dygraph.DEFAULT_ATTRS = Dygraph.DEFAULT_ATTRS || {};
-Dygraph.DEFAULT_ATTRS['axes'] = Dygraph.DEFAULT_ATTRS['axes'] || {};
-Dygraph.DEFAULT_ATTRS['axes']['x'] = Dygraph.DEFAULT_ATTRS['axes']['x'] || {};
-Dygraph.DEFAULT_ATTRS['axes']['y'] = Dygraph.DEFAULT_ATTRS['axes']['y'] || {};
-Dygraph.DEFAULT_ATTRS['axes']['y2'] = Dygraph.DEFAULT_ATTRS['axes']['y2'] || {};
-Dygraph.DEFAULT_ATTRS['axes']['x']['ticker'] = Dygraph.dateTicker;
-Dygraph.DEFAULT_ATTRS['axes']['y']['ticker'] = Dygraph.numericTicks;
-Dygraph.DEFAULT_ATTRS['axes']['y2']['ticker'] = Dygraph.numericTicks;
+if (Dygraph &&
+    Dygraph.DEFAULT_ATTRS &&
+    Dygraph.DEFAULT_ATTRS['axes'] &&
+    Dygraph.DEFAULT_ATTRS['axes']['x'] &&
+    Dygraph.DEFAULT_ATTRS['axes']['y'] &&
+    Dygraph.DEFAULT_ATTRS['axes']['y2']) {
+  Dygraph.DEFAULT_ATTRS['axes']['x']['ticker'] = Dygraph.dateTicker;
+  Dygraph.DEFAULT_ATTRS['axes']['y']['ticker'] = Dygraph.numericTicks;
+  Dygraph.DEFAULT_ATTRS['axes']['y2']['ticker'] = Dygraph.numericTicks;
+}