Fix axis.y.min/max when smaller/bigger than targets' - #562

c3.js

@@ -1257,6 +1257,15 @@
             isZeroBased = ($$.hasType('bar', yTargets) && config.bar_zerobased) || ($$.hasType('area', yTargets) && config.area_zerobased),
             showHorizontalDataLabel = $$.hasDataLabel() && config.axis_rotated,
             showVerticalDataLabel = $$.hasDataLabel() && !config.axis_rotated;
+
+        if (yDomainMax < yDomainMin) {
+            if (isValue(yMin)) {
+                yDomainMax = yDomainMin + 10; // TODO: introduce axis.y.maxMin
+            } else {
+                yDomainMin = yDomainMax - 10; // TODO: introduce axis.y.minMax
+            }
+        }
+
         if (yTargets.length === 0) { // use current domain if target of axisId is none
             return axisId === 'y2' ? $$.y2.domain() : $$.y.domain();
         }

spec/domain-spec.js

@@ -0,0 +1,96 @@
+var describe = window.describe,
+    expect = window.expect,
+    it = window.it,
+    beforeEach = window.beforeEach;
+
+var initDom = window.initDom;
+
+describe('c3 chart axis', function () {
+    'use strict';
+
+    var chart, d3;
+
+    var args = {
+        data: {
+            columns: [
+                ['data1', 30, 200, 100, 400, 150, 250],
+                ['data2', 50, 20, 10, 40, 15, 25]
+            ]
+        },
+        axis: {
+            y: {},
+            y2: {}
+        }
+    };
+
+    beforeEach(function (done) {
+        if (typeof chart === 'undefined') {
+            initDom();
+        }
+        chart = window.c3.generate(args);
+        d3 = chart.internal.d3;
+        chart.internal.d3.select('.jasmine_html-reporter').style('display', 'none');
+
+        window.setTimeout(function () {
+            done();
+        }, 10);
+    });
+
+    describe('axis.y.min', function () {
+
+        it('should change axis.y.min to -100', function () {
+            args.axis.y.min = -100;
+            expect(true).toBeTruthy();
+        });
+
+        it('should be set properly when smaller than max of data', function () {
+            var domain = chart.internal.y.domain();
+            expect(domain[0]).toBe(-150);
+            expect(domain[1]).toBe(450);
+        });
+
+        it('should change axis.y.min to 500', function () {
+            args.axis.y.min = 500;
+            expect(true).toBeTruthy();
+        });
+
+        it('should be set properly when bigger than max of data', function () {
+            var domain = chart.internal.y.domain();
+            expect(domain[0]).toBe(499);
+            expect(domain[1]).toBe(511);
+        });
+
+        it('should change axis.y.min to undefined', function () {
+            args.axis.y.min = undefined;
+            expect(true).toBeTruthy();
+        });
+
+    });
+
+    describe('axis.y.max', function () {
+
+        it('should change axis.y.max to 1000', function () {
+            args.axis.y.max = 1000;
+            expect(true).toBeTruthy();
+        });
+
+        it('should be set properly when bigger than min of data', function () {
+            var domain = chart.internal.y.domain();
+            expect(domain[0]).toBe(-89);
+            expect(domain[1]).toBe(1099);
+        });
+
+        it('should change axis.y.max to 0', function () {
+            args.axis.y.max = 0;
+            expect(true).toBeTruthy();
+        });
+
+        it('should be set properly when smaller than min of data', function () {
+            var domain = chart.internal.y.domain();
+            expect(domain[0]).toBe(-11);
+            expect(domain[1]).toBe(1);
+        });
+
+    });
+
+});

src/domain.js

@@ -73,6 +73,15 @@ c3_chart_internal_fn.getYDomain = function (targets, axisId) {
         isZeroBased = ($$.hasType('bar', yTargets) && config.bar_zerobased) || ($$.hasType('area', yTargets) && config.area_zerobased),
         showHorizontalDataLabel = $$.hasDataLabel() && config.axis_rotated,
         showVerticalDataLabel = $$.hasDataLabel() && !config.axis_rotated;
+
+    if (yDomainMax < yDomainMin) {
+        if (isValue(yMin)) {
+            yDomainMax = yDomainMin + 10; // TODO: introduce axis.y.maxMin
+        } else {
+            yDomainMin = yDomainMax - 10; // TODO: introduce axis.y.minMax
+        }
+    }
+
     if (yTargets.length === 0) { // use current domain if target of axisId is none
         return axisId === 'y2' ? $$.y2.domain() : $$.y.domain();
     }