Tests failing after startAtZero was removed

[pmairoldi]

I just looked into why the tests are failing and it seems to have happened here when startAtZero was deprecated.

Setting the customAxisMin = 0.0 in the tests does kind of make it look like it should but there is still an offset. @danielgindi any ideas?

[danielgindi]

Yes it seems like there's some kind of residue. Weird since startAtZero was effectively setting customAxisMin to 0.0, just with a lot more code...
I'm looking into it

[danielgindi]

We can see the problem here:

@PhilJay I think that this originates here: https://github.com/PhilJay/MPAndroidChart/blob/master/MPChartLib/src/com/github/mikephil/charting/charts/BarLineChartBase.java#L358
Do you know if we still need this?
This used to always render "a little bit more" of the grid - except when startAtZero was enabled, which meant we want to trim the axis there.
Maybe we should introduce a new property for how much more we want to draw past the min/max? Or just a boolean?

[PhilJay]

Yes, we draw a "little bit more" in that case. But that case should only occur if the range is 0 and hence all values in the dataset are equal. If that is not the case, this should not be an issue.

[danielgindi]

@PhilJay Yes it seems that that's not the source of the issue... But it still happens, on the Android side also.

Try to replace the code in BarChartActivity with this:

        mChart = (BarChart) findViewById(R.id.chart1);

        // Sample data
        float[] values = new float[]{8, 104, 81, 93, 52, 44, 97, 101, 75, 28,
        76, 25, 20, 13, 52, 44, 57, 23, 45, 91,
        99, 14, 84, 48, 40, 71, 106, 41, 45, 61};

        ArrayList<BarEntry> entries = new ArrayList<>();
        ArrayList<String> xValues = new ArrayList<>();

        for (int i = 0; i < values.length; i++)
        {
            entries.add(new BarEntry(values[i], i));
            xValues.add(Integer.toString(i));
        }

        BarDataSet dataSet = new BarDataSet(entries, "Bar chart unit test data");

        mChart.setData(new BarData(xValues, dataSet));

[danielgindi]

Okay after further investigation - two things happened:

1. I was so tired that I didn't notice I've added the customAxisMin when testing after the setData, without calling notifyDataSetChanged or calcMinMax or anything like that.
2. Even when setting customAxisMin correctly - there's a slight difference in drawing the axis. Like the scale changed by a fraction. I'm still looking into the cause of this - as nothing should have actually changed.

[danielgindi]

So more info: axis ranges are multiplied by the spacing factor. But when there was startAtZero as a standalone property - the range was subtracted 0.0 instead of min.
It seems like the range does not take into account the customAxisMin (or max)

[danielgindi]

@PhilJay I've created a PR in MPAndroidChart