Revert "Fixed tooltip labelling on Bar Chart when min is defined (#3618)"

[etimberg]

Reverts #3620 per comments in #3618
@KoyoSE would this fix the issue you found?

[KoyoSE]

@etimberg Yes. I think this fix does not solve the fundamental problem.

[etimberg]

@KoyoSE what's the correct way to solve the underlying problem?

[KoyoSE]

@etimberg Good morning. Ah... just revents #3620. I think #3649 is correct way (better way). If it merge both, the corrected tooltip will shift again. :)

I think underlying problem is here. (already fixed by #3649.)
https://github.com/KoyoSE/Chart.js/blob/98670d2f5f93ff9f1612a39820730ffe69b68af2/src/scales/scale.category.js#L57-L60

@Jareechang I am sorry about your efforts.

[Jareechang]

hi @KoyoSE, your change is essentially the same as mine. Our code basically do the same thing.

I've written unit test to cover the issue. The only thing I can see why it won't work is because we're both apply same changes.

Either way, I do like how simple your code is. However, getLabelForIndex method is what the name suggest — getting the label. It shouldn't do anything else.

Hence, i've add adjustIndex method in core.element.js.

[KoyoSE]

Hello @Jareechang

However, getLabelForIndex method is what the name suggest — getting the label. It shouldn't do anything else.

I understand what you say.
...
( I think I'm something wrong. Now check again. Just moment.)

[KoyoSE]

List-1 is the first code.(code of before)

list-1

getLabelForIndex: function(index, datasetIndex) {
		var me = this;
		var data = me.chart.data;
		var isHorizontal = me.isHorizontal();

		if ((data.xLabels && isHorizontal) || (data.yLabels && !isHorizontal)) {
			return me.getRightValue(data.datasets[datasetIndex].data[index]);
		}

		return me.ticks[index];  
	},

ex)
labels = 1,2,3,4,5,6
min = 2
ticks = 2,3,4,5,6
Index is from 0.
Therefore, the label shifts. and wrong label returned .

List-2 is the code I changed. = current code

list-2

getLabelForIndex: function(index, datasetIndex) {
		var me = this;
		var data = me.chart.data;
		var isHorizontal = me.isHorizontal();

		if (data.yLabels && !isHorizontal) { // <<< for xLabels yLabels bug
			return me.getRightValue(data.datasets[datasetIndex].data[index]);
		}

		return me.ticks[index - me.minIndex];  // <<<
	},

ticks is from min then I added " - me.minIndex".

Actually, should we do like this(list-3)?

list-3

getLabelForIndex: function(index, datasetIndex) {
		var me = this;
		var data = me.chart.data;
		var isHorizontal = me.isHorizontal();
		var labels = me.getLabels();  // <<<

		if (data.yLabels && !isHorizontal) {
			return me.getRightValue(data.datasets[datasetIndex].data[index]);
		}

		return labels[index]; // <<< 
	},

I think it is a simple bug.
It is labels, not ticks.
Bugs should fix for this function.

list-2 & list-3 is the same result, but List-3 may be better.

By the way, #3620 error occurs in the horizontalBar , Radar-chart.
If merge #3620, we need to fix it and revert #3649.

current code is here :
https://github.com/chartjs/Chart.js/blob/master/src/scales/scale.category.js#L52-L61