bar: implement attributes base, offset and width

Author: n-riesco

src/traces/bar/calc.js

@@ -40,14 +40,40 @@ module.exports = function calc(gd, trace) {
     var serieslen = Math.min(pos.length, size.length),
         cd = [];
 
+    // set position
     for(i = 0; i < serieslen; i++) {
 
         // add bars with non-numeric sizes to calcdata
         // so that ensure that traces with gaps are
         // plotted in the correct order
 
         if(isNumeric(pos[i])) {
-            cd.push({p: pos[i], s: size[i], b: 0});
+            cd.push({p: pos[i]});
+        }
+    }
+
+    // set base
+    var base = trace.base;
+
+    if(Array.isArray(base)) {
+        for(i = 0; i < Math.min(base.length, cd.length); i++) {
+            cd[i].b = base[i];
+        }
+        for(; i < cd.length; i++) {
+            cd[i].b = 0;
+        }
+    }
+    else {
+        var b = (base === undefined) ? 0 : base;
+        for(i = 0; i < cd.length; i++) {
+            cd[i].b = b;
+        }
+    }
+
+    // set size
+    for(i = 0; i < cd.length; i++) {
+        if(isNumeric(size[i])) {
+            cd[i].s = size[i] - cd[i].b;
         }
     }
 

src/traces/bar/plot.js

@@ -34,30 +34,39 @@ module.exports = function plot(gd, plotinfo, cdbar) {
         .attr('class', 'points')
         .each(function(d) {
             var t = d[0].t,
-                trace = d[0].trace;
+                trace = d[0].trace,
+                poffset = t.poffset,
+                poffsetIsArray = Array.isArray(poffset),
+                barwidth = t.barwidth,
+                barwidthIsArray = Array.isArray(barwidth);
 
             arraysToCalcdata(d);
 
             d3.select(this).selectAll('path')
                 .data(Lib.identity)
               .enter().append('path')
-                .each(function(di) {
+                .each(function(di, i) {
                     // now display the bar
                     // clipped xf/yf (2nd arg true): non-positive
                     // log values go off-screen by plotwidth
                     // so you see them continue if you drag the plot
+                    var p0 = di.p + ((poffsetIsArray) ? poffset[i] : poffset),
+                        p1 = p0 + ((barwidthIsArray) ? barwidth[i] : barwidth),
+                        s0 = di.b,
+                        s1 = s0 + di.s;
+
                     var x0, x1, y0, y1;
                     if(trace.orientation === 'h') {
-                        y0 = ya.c2p(t.poffset + di.p, true);
-                        y1 = ya.c2p(t.poffset + di.p + t.barwidth, true);
-                        x0 = xa.c2p(di.b, true);
-                        x1 = xa.c2p(di.s + di.b, true);
+                        y0 = ya.c2p(p0, true);
+                        y1 = ya.c2p(p1, true);
+                        x0 = xa.c2p(s0, true);
+                        x1 = xa.c2p(s1, true);
                     }
                     else {
-                        x0 = xa.c2p(t.poffset + di.p, true);
-                        x1 = xa.c2p(t.poffset + di.p + t.barwidth, true);
-                        y1 = ya.c2p(di.s + di.b, true);
-                        y0 = ya.c2p(di.b, true);
+                        x0 = xa.c2p(p0, true);
+                        x1 = xa.c2p(p1, true);
+                        y0 = ya.c2p(s0, true);
+                        y1 = ya.c2p(s1, true);
                     }
 
                     if(!isNumeric(x0) || !isNumeric(x1) ||