Fix: minOpen is true will drop a piece

[susiwen8]

Brief Information

This pull request is in the type of:

• bug fixing
• new feature
• others

What does this PR do?

When minOpen is true, index shouldn't increase to 1

Fixed issues

Close #12121

Details

Before: What was the problem?

After: How is it fixed in this PR?

Usage

Are there any API changes?

• The API has been changed.

Related test cases or examples to use the new APIs

NA.

Others

Merging options

• Please squash the commits into a single one when merge.

Other information

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[pissang]

In this way, the splitNumber is not 6 instead of 5. I'm not sure it's correct by design. @100pah Please have a look at this.

[100pah]

Only remove ++ is not correct. Because after ++ removed, the first piece and the second piece has the same index.
That cause when click on the first piece, both the first piece and the second pieces are highlighted/downplayed.

[100pah]

Also consider
(1) @pissang mentioned: when the split number is 5, the final pieces should better be 5.
(2) The potential bug that the piece.index forget to change after reformIntervals(pieceList) called.

I think the code to resolve this issue could be:

    splitNumber: function () {
        var thisOption = this.option;
        var pieceList = this._pieceList;
        var precision = Math.min(thisOption.precision, 20);
        var dataExtent = this.getExtent();
        var splitNumber = thisOption.splitNumber;
        splitNumber = Math.max(parseInt(splitNumber, 10), 1);
        thisOption.splitNumber = splitNumber;
+       var closedIntervalCount = splitNumber - (+thisOption.minOpen) - (+thisOption.maxOpen);

-       var splitStep = (dataExtent[1] - dataExtent[0]) / splitNumber;
+       var splitStep = (dataExtent[1] - dataExtent[0]) / closedIntervalCount;
        // Precision auto-adaption
        while (+splitStep.toFixed(precision) !== splitStep && precision < 5) {
            precision++;
        }
        thisOption.precision = precision;
        splitStep = +splitStep.toFixed(precision);

-       var index = 0;

        if (thisOption.minOpen) {
            pieceList.push({
-               index++,
                interval: [-Infinity, dataExtent[0]],
                close: [0, 0]
            });
        }

        for (
-           var curr = dataExtent[0], len = index + splitNumber;
-           index < len;
-           curr += splitStep
+           var index = 0, curr = dataExtent[0];
+           index < closedIntervalCount;
+           curr += splitStep, index++
        ) {
            var max = index === splitNumber - 1 ? dataExtent[1] : (curr + splitStep);

            pieceList.push({
-               index: index++,
                interval: [curr, max],
                close: [1, 1]
            });
        }

        if (thisOption.maxOpen) {
            pieceList.push({
-               index: index++,
                interval: [dataExtent[1], Infinity],
                close: [0, 0]
            });
        }

        reformIntervals(pieceList);

-       zrUtil.each(pieceList, function (piece) {
+       zrUtil.each(pieceList, function (piece, index) {
+           piece.index = index;
            piece.text = this.formatValueText(piece.interval);
        }, this);
    },

[susiwen8]

@pissang @100pah I have reservation on split number, clearly user wants to add a piece if they specify minOpen or maxOpen

I expect a piece to be added to the pieces in the chart, meaning that it should have 6 pieces now. 5 for the range between min and max value and 1 for values lower min.

[100pah]

@susiwen8

I have reservation on split number, clearly user wants to add a piece if they specify minOpen or maxOpen

@pissang have mentioned me and think your suggestion is reasonable:
That is,
finalPieceCount = userSpecifiedSplitNumber + (minOpen ? 1 : 0) + (maxOption ? 1 : 0)

[echarts-bot]

Congratulations! Your PR has been merged. Thanks for your contribution! 👍