Added "bar.space" parameter to set space between bars in bar charts

8 years ago · f3fd649900
5 changed files with 189 additions and 4 deletions
--- a/htdocs/index.html
+++ b/htdocs/index.html
@ -44,6 +44,9 @@
            </div>
            <div class="col-md-4">
              <h3>Bar Chart</h3>
+              <a href="./samples/chart_bar_space.html">
+                  Bar chart with spaces
+              </a>
              <a href="./samples/chart_bar.html">
                Bar chart with ordinary data
              </a>
--- a/htdocs/samples/chart_bar_space.html
+++ b/htdocs/samples/chart_bar_space.html
@ -0,0 +1,28 @@
+<html>
+  <head>
+    <link href="/css/c3.css" rel="stylesheet" type="text/css">
+  </head>
+  <body>
+    <div id="chart"></div>
+
+    <script src="http://d3js.org/d3.v3.min.js" charset="utf-8"></script>
+    <script src="/js/c3.js"></script>
+    <script>
+
+      var generate = function () { return c3.generate({
+        data: {
+          columns: [
+            ['data1', 30, 200, 100],
+            ['data2', 50, 20, 10],
+            ['data3', 150, 120, 110]
+          ],
+          type: 'bar'
+        },
+        bar: {
+          space: 0.25
+        }
+      }); }, chart = generate();
+
+    </script>
+  </body>
+</html>
--- a/spec/shape.bar-spec.js
+++ b/spec/shape.bar-spec.js
@ -178,4 +178,156 @@ describe('c3 chart shape bar', function () {

    });

+    describe('bar spacing', function() {
+
+        var createArgs = function(spacing) {
+            return {
+                size: {
+                  width: 500
+                },
+                data: {
+                    columns: [
+                        ['data1', 30, 200, 100],
+                        ['data2', 50, 20, 10],
+                        ['data3', 150, 120, 110],
+                        ['data4', 12, 24, 20 ]
+                    ],
+                    type: 'bar',
+                    groups: [
+                        [ 'data1', 'data4' ]
+                    ]
+                },
+                bar: {
+                    space: spacing
+                }
+            };
+        };
+
+        var getBBox = function(selector) {
+          return d3.select(selector).node().getBBox();
+        };
+
+        var getBarContainerWidth = function() {
+            return parseInt(getBBox('.c3-chart-bars').width);
+        };
+
+        var getBarContainerOffset = function() {
+            return parseInt(getBBox('.c3-chart-bars').x);
+        };
+
+        var getBarBBox = function(name, idx) {
+            return getBBox('.c3-target-' + name + ' .c3-bar-' + (idx || 0));
+        };
+
+        var getBarWidth = function(name, idx) {
+          return parseInt(getBarBBox(name, idx).width);
+        };
+
+        var getBarOffset = function(name1, name2, idx) {
+            var bbox1 = getBarBBox(name1, idx);
+            var bbox2 = getBarBBox(name2, idx);
+            return parseInt(bbox2.x - (bbox1.x + bbox1.width));
+        };
+
+        it('should set bar spacing to 0', function () {
+            args = createArgs(0);
+            expect(true).toBeTruthy();
+        });
+
+        it('should display the bars without any spacing', function () {
+            // all bars should have the same width
+            expect(getBarWidth('data1', 0)).toEqual(30);
+            expect(getBarWidth('data2', 0)).toEqual(30);
+            expect(getBarWidth('data3', 0)).toEqual(30);
+            expect(getBarWidth('data1', 1)).toEqual(30);
+            expect(getBarWidth('data2', 1)).toEqual(30);
+            expect(getBarWidth('data3', 1)).toEqual(30);
+            expect(getBarWidth('data1', 2)).toEqual(30);
+            expect(getBarWidth('data2', 2)).toEqual(30);
+            expect(getBarWidth('data3', 2)).toEqual(30);
+
+            // all offsets should be the same
+            expect(getBarOffset('data1', 'data2', 0)).toEqual(0);
+            expect(getBarOffset('data2', 'data3', 0)).toEqual(0);
+            expect(getBarOffset('data1', 'data2', 1)).toEqual(0);
+            expect(getBarOffset('data2', 'data3', 1)).toEqual(0);
+            expect(getBarOffset('data1', 'data2', 2)).toEqual(0);
+            expect(getBarOffset('data2', 'data3', 2)).toEqual(0);
+
+            // default width/offset of the container for this chart
+            expect(getBarContainerWidth()).toEqual(396);
+            expect(getBarContainerOffset()).toEqual(31);
+        });
+
+        it('should set bar spacing to 0.25', function () {
+            args = createArgs(0.25);
+            expect(true).toBeTruthy();
+        });
+
+        it('should display the bars with a spacing ratio of 0.25', function () {
+            // with bar_space of 0.25, the space between bars is
+            // expected to be 25% of the original bar's width
+            // which is ~7
+
+            // expect all bars to be the same width
+            expect(getBarWidth('data1', 0)).toEqual(22);
+            expect(getBarWidth('data2', 0)).toEqual(22);
+            expect(getBarWidth('data3', 0)).toEqual(22);
+            expect(getBarWidth('data1', 1)).toEqual(22);
+            expect(getBarWidth('data2', 1)).toEqual(22);
+            expect(getBarWidth('data3', 1)).toEqual(22);
+            expect(getBarWidth('data1', 2)).toEqual(22);
+            expect(getBarWidth('data2', 2)).toEqual(22);
+            expect(getBarWidth('data3', 2)).toEqual(22);
+
+            // all offsets should be the same
+            expect(getBarOffset('data1', 'data2', 0)).toEqual(7);
+            expect(getBarOffset('data2', 'data3', 0)).toEqual(7);
+            expect(getBarOffset('data1', 'data2', 1)).toEqual(7);
+            expect(getBarOffset('data2', 'data3', 1)).toEqual(7);
+            expect(getBarOffset('data1', 'data2', 2)).toEqual(7);
+            expect(getBarOffset('data2', 'data3', 2)).toEqual(7);
+
+            // expect the container to shrink a little because of
+            // the offsets from the first/last chart
+            // we add/subtract 1 because of approximation due to rounded values
+            expect(getBarContainerWidth()).toEqual(396 - 7 - 1);
+            expect(getBarContainerOffset()).toEqual(31 + (parseInt(7 / 2) + 1));
+        });
+
+        it('should set bar spacing to 0.5', function () {
+            args = createArgs(0.5);
+            expect(true).toBeTruthy();
+        });
+
+        it('should display the bars with a spacing ratio of 0.5', function () {
+            // with bar_space of 0.5, the space between bars is
+            // expected to be 50% of the original bar's width
+            // which is ~15
+
+            // expect all bars to be the same width
+            expect(getBarWidth('data1', 0)).toEqual(15);
+            expect(getBarWidth('data2', 0)).toEqual(15);
+            expect(getBarWidth('data3', 0)).toEqual(15);
+            expect(getBarWidth('data1', 1)).toEqual(15);
+            expect(getBarWidth('data2', 1)).toEqual(15);
+            expect(getBarWidth('data3', 1)).toEqual(15);
+            expect(getBarWidth('data1', 2)).toEqual(15);
+            expect(getBarWidth('data2', 2)).toEqual(15);
+            expect(getBarWidth('data3', 2)).toEqual(15);
+
+            // all offsets should be the same
+            expect(getBarOffset('data1', 'data2', 0)).toEqual(15);
+            expect(getBarOffset('data2', 'data3', 0)).toEqual(15);
+            expect(getBarOffset('data1', 'data2', 1)).toEqual(15);
+            expect(getBarOffset('data2', 'data3', 1)).toEqual(15);
+            expect(getBarOffset('data1', 'data2', 2)).toEqual(15);
+            expect(getBarOffset('data2', 'data3', 2)).toEqual(15);
+
+            // expect the container to shrink a little because of
+            // the offsets from the first/last chart
+            expect(getBarContainerWidth()).toEqual(396 - 15);
+            expect(getBarContainerOffset()).toEqual(31 + parseInt(15 / 2));
+        });
+    });
 });
--- a/src/config.js
+++ b/src/config.js
@ -167,6 +167,7 @@ c3_chart_internal_fn.getDefaultConfig = function () {
        bar_width_ratio: 0.6,
        bar_width_max: undefined,
        bar_zerobased: true,
+        bar_space: 0,
        // area
        area_zerobased: true,
        area_above: false,
--- a/src/shape.bar.js
+++ b/src/shape.bar.js
@ -94,6 +94,7 @@ c3_chart_internal_fn.generateGetBarPoints = function (barIndices, isSub) {
        barX = $$.getShapeX(barW, barTargetsNum, barIndices, !!isSub),
        barY = $$.getShapeY(!!isSub),
        barOffset = $$.getShapeOffset($$.isBarType, barIndices, !!isSub),
+        barSpaceOffset = barW * ($$.config.bar_space / 2),
        yScale = isSub ? $$.getSubYScale : $$.getYScale;
    return function (d, i) {
        var y0 = yScale.call($$, d.id)(0),
@ -105,10 +106,10 @@ c3_chart_internal_fn.generateGetBarPoints = function (barIndices, isSub) {
        }
        // 4 points that make a bar
        return [
-            [posX, offset],
-            [posX, posY - (y0 - offset)],
-            [posX + barW, posY - (y0 - offset)],
-            [posX + barW, offset]
+            [posX + barSpaceOffset, offset],
+            [posX + barSpaceOffset, posY - (y0 - offset)],
+            [posX + barW - barSpaceOffset, posY - (y0 - offset)],
+            [posX + barW - barSpaceOffset, offset]
        ];
    };
 };