A new chart displays a default number of bars, The number displayed, is somewhat related to the chosen units. Using the magnifying glass with vertical/horizontal arrows return back to this default.
Zooming in and out basically uses the centre of the chart as reference point. However if the current candle is, or enters the display window, the reference point becomes the current candle , which always displays to the right.
This is why zooming appears logical in the middle of charts data, but zoom out too far ( which your going to do with a mouse wheel), and the reference point changes to the current candle reference and you end up in a different place.
Zooming, approximately doubles or halves the number of displayed candle of loaded historical data.
In ‘current candle reference’, the increase or decrease of candles appear to the left of prior displayed candles.
With ‘centre window reference’ the increase/decrease candles are split and added to the left and the right of the prior displayed candles.
There are other variations and options but above is basics as I see them.
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