Fix inset legend backgroud when only one legend item - #588

c3.js

@@ -3723,7 +3723,7 @@
         function updatePositions(textElement, id, index) {
             var reset = index === 0, isLast = index === targetIds.length - 1,
                 box = $$.getTextRect(textElement.textContent, CLASS.legendItem),
-                itemWidth = box.width + tileWidth + (isLast && !$$.isLegendRight ? 0 : paddingRight),
+                itemWidth = box.width + tileWidth + (isLast && !($$.isLegendRight || $$.isLegendInset) ? 0 : paddingRight),
                 itemHeight = box.height + paddingTop,
                 itemLength = $$.isLegendRight || $$.isLegendInset ? itemHeight : itemWidth,
                 areaLength = $$.isLegendRight || $$.isLegendInset ? $$.getLegendHeight() : $$.getLegendWidth(),

spec/legend-spec.js

@@ -84,6 +84,26 @@ describe('c3 chart legend', function () {
             expect(box.height).toBe(48);
         });
 
+        it('should update args to have only one series', function () {
+            args = {
+                data: {
+                    columns: [
+                        ['data1', 30, 200, 100, 400, 150, 250],
+                    ]
+                },
+                legend: {
+                    position: 'inset'
+                }
+            };
+            expect(true).toBeTruthy();
+        });
+
+        it('should locate legend properly', function () {
+            var box = d3.select('.c3-legend-background').node().getBoundingClientRect();
+            expect(box.height).toBe(28);
+            expect(box.width).toBeGreaterThan(64);
+        });
+
     });
 
 });

src/legend.js

@@ -116,7 +116,7 @@ c3_chart_internal_fn.updateLegend = function (targetIds, options, transitions) {
     function updatePositions(textElement, id, index) {
         var reset = index === 0, isLast = index === targetIds.length - 1,
             box = $$.getTextRect(textElement.textContent, CLASS.legendItem),
-            itemWidth = box.width + tileWidth + (isLast && !$$.isLegendRight ? 0 : paddingRight),
+            itemWidth = box.width + tileWidth + (isLast && !($$.isLegendRight || $$.isLegendInset) ? 0 : paddingRight),
             itemHeight = box.height + paddingTop,
             itemLength = $$.isLegendRight || $$.isLegendInset ? itemHeight : itemWidth,
             areaLength = $$.isLegendRight || $$.isLegendInset ? $$.getLegendHeight() : $$.getLegendWidth(),