Add error when computing axis scales that just won't display because of an invalid...

diff --git a/dygraph-canvas.js b/dygraph-canvas.js
index b90695b..9b70f81 100644 (file)
--- a/dygraph-canvas.js
+++ b/dygraph-canvas.js
@@ -91,6 +91,10 @@ DygraphLayout.prototype._evaluateLimits = function() {
 
     axis.ylogrange = Dygraph.log10(axis.maxyval) - Dygraph.log10(axis.minyval);
     axis.ylogscale = (axis.ylogrange != 0 ? 1.0 / axis.ylogrange : 1.0);
+    if (axis.g.attr_("logscale") && isNaN(axis.ylogrange)) {
+      axis.g.error('axis ' + i + ' can\'t be displayed in log scale for range [' +
+          axis.minyval + ' - ' + axis.maxyval + ']');
+    }
   }
 };
 
@@ -105,7 +109,7 @@ DygraphLayout.prototype._evaluateLineCharts = function() {
 
     for (var j = 0; j < dataset.length; j++) {
       var item = dataset[j];
-      
+
       var yval;
       if (axis.logscale) {
         yval = 1.0 - ((Dygraph.log10(parseFloat(item[1])) - Dygraph.log10(axis.minyval)) * axis.ylogscale); // really should just be yscale.

diff --git a/tests/logscale.html b/tests/logscale.html
index 1d17bfa..be26ea1 100644 (file)
--- a/tests/logscale.html
+++ b/tests/logscale.html
@@ -51,12 +51,12 @@
       };
 
       var g0 = new Dygraph(document.getElementById("div_g0"),
-                      data0, { logscale : true });
-      var g1 = new Dygraph(document.getElementById("div_g1"),
-                      data1, { logscale : true });
+                      data0, { logscale : true, valueRange: [-1,100] });
+  //    var g1 = new Dygraph(document.getElementById("div_g1"),
+                      //data1, { logscale : true });
       function setLogScale(val) {
         g0.updateOptions({ logscale: val });
-        g1.updateOptions({ logscale: val });
+        // g1.updateOptions({ logscale: val });
         document.getElementById("linear").disabled = !val;
         document.getElementById("log").disabled = val;
       }