Show values on bar chart

This patch shows values on each bar by appending text nodes to bars. Values will appear if global variable showValues is true. For better control it should be made a config option.

Second change is about shouldShowTickText function. It returns always true, because when using axis❌categories, I wish all axis values to appear.

c3.js

@@ -4,6 +4,8 @@
     var c3 = window.c3 = {};
     var d3 = window.d3;
 
+    var showValues = true;	//added 23.2.2014 - fiery-
+    var mainBarTxt = null;	//
     /*
      * Generate chart according to config
      */
@@ -566,7 +568,7 @@
                 yMax = axisId === 'y2' ? __axis_y2_max : __axis_y_max,
                 yDomainMin = (yMin) ? yMin : getYDomainMin(yTargets),
                 yDomainMax = (yMax) ? yMax : getYDomainMax(yTargets),
-                padding = Math.abs(yDomainMax - yDomainMin) * 0.1,
+                padding = Math.abs(yDomainMax - yDomainMin) * 0.22, //0.1 -> 0.22 - 23.2.2014 - fiery-
                 padding_top = padding, padding_bottom = padding,
                 center = axisId === 'y2' ? __axis_y2_center : __axis_y_center;
             if (center) {
@@ -869,6 +871,7 @@
         function classBar(d, i) { return classShape(d, i) + " -bar -bar-" + i; }
         function classRegion(d, i) { return 'region region-' + i + ' ' + ('classes' in d ? [].concat(d.classes).join(' ') : ''); }
         function classEvent(d, i) { return "event-rect event-rect-" + i; }
+        function classTextBar(d, i) { return classShape(d, i) + " -bartxt -bartxt-" + i; }	//added 24.2.2014 - fiery-
 
         function opacityCircle(d) {
             return isValue(d.value) ? isScatterType(d) ? 0.5 : 1 : 0;
@@ -1381,6 +1384,37 @@
                 return path;
             };
         };
+        
+        //showValues on Bar - added 23.2.2014 - fiery-
+         var textVal = function (barIndices, isSub_, inIsXY) {
+            var barTargetsNum = barIndices.__max__ + 1,
+                isSub = arguments.length > 1 ? isSub_ : true,
+                barW = getBarW(xAxis, barTargetsNum, !!isSub),
+                x = getBarX(barW, barTargetsNum, barIndices, !!isSub),
+                y = getBarY(!!isSub),
+                barOffset = getBarOffset(barIndices, !!isSub),
+                yScale = isSub ? getSubYScale : getYScale;
+
+            return function (d, i) {
+                var y0 = yScale(d.id)(0),
+                    offset = barOffset(d, i) || y0; // offset is for stacked bar chart
+
+                // 4 points that make a bar
+                var points = [
+                    [x(d), offset],
+                    [x(d), y(d) - (y0 - offset)],
+                    [x(d) + barW, y(d) - (y0 - offset)],
+                    [x(d) + barW, offset]
+                ];
+
+                // switch points if axis is rotated, not applicable for sub chart
+                var indexX = __axis_rotated ? 1 : 0;
+                var indexY = __axis_rotated ? 0 : 1;
+		
+		        if(inIsXY == 'X') return d.value < 0 ? points[2][indexX] - 4 : points[2][indexX] + 4;
+		        return (points[0][indexY] + points[2][indexY])/2;
+            };
+        };
 
         // For brush region
         var lineOnSub = (function () {
@@ -2189,6 +2223,31 @@
             mainBar.exit().transition().duration(duration)
                 .style('opacity', 0)
                 .remove();
+            
+            //showValues on Bar - added 23.2.2014 - fiery-
+            if (showValues) {
+        		mainBarTxt = main.selectAll('.-bars').selectAll('.-bartxt')
+        			.data(barData);
+        		mainBarTxt.enter().append('text')
+        		    .attr('text-anchor', function(d,i) { return d.value < 0 ? 'end' : 'start' ; })
+        		    .attr('y', textVal(barIndices, false, 'Y'))
+        		    .attr('x', textVal(barIndices, false, 'X'))
+        		    .attr('dy', '.32em')
+        		    .style("stroke", 'none')
+        		    .style("opacity", 0)
+        		    .text(function(d,i) { return d3.format(',.2f')(d.value); })
+        		    .attr("class", classTextBar);		
+        		mainBarTxt
+        		    .style("opacity", initialOpacity)
+        		    .transition().duration(duration)
+        		    .attr('y', textVal(barIndices, false, 'Y'))
+        		    .attr('x', textVal(barIndices, false, 'X'))
+        		    .style("opacity", 1);    
+        		mainBarTxt.exit()
+        		    .transition().duration(duration)
+        		    .style('opacity', 0)
+        		    .remove();
+        	}
 
             // lines and cricles
             main.selectAll('.-line')
@@ -2988,7 +3047,7 @@
             return ticks;
         }
         function shouldShowTickText(ticks, i) {
-            return ticks.length < tickTextNum || i % Math.ceil(ticks.length / tickTextNum) === 0;
+            return true || ticks.length < tickTextNum || i % Math.ceil(ticks.length / tickTextNum) === 0;
         }
         function category(i) {
             return i < categories.length ? categories[i] : i;