fix: boxplot negative number compatibility (fix #779)

[CoderSeoul]

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Description

PROBLEM

While using the boxplot chart, I found If data contains negative numbers, the boxplot series goes out of the area

SOLUTION

‘this.rect.height’ must be larger than ‘value * ratio’ This is because if the value is negative, it is out of the 'this.rect' area. Therefore, we need to convert all input values into positive so that the values can find a suitable y-position.

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[stale[bot]]

This issue has been automatically marked as inactive because there hasn’t been much going on it lately. It is going to be closed after 7 days. Thanks!

[stale[bot]]

This issue will be closed due to inactivity. Thanks for your contribution!