Some insights on using intraday charts

[MarioMuYao]

What are you trying to do

Thoughts on using the intraday chart in the latest version.
1、If there are very few data points and gridColumns is set, they get squashed together. Is it possible to space them out evenly and fix their positions within the chart?
2、When lockPriceScale is set to true, if the tick price falls outside the price scale range, the line will extend beyond the chart area and become invisible.
3、When lockPriceScale is set to true, The value on the price axis should change in accordance with the values ​​of the data points?
4、Does it support custom modification of the values ​​on the price and time axis?
5、Is support provided for additional vertical axis, such as a "change %" axis?

These are just some of my personal thoughts.

Finally,have a pleasant day.

How you are working around it today

No response

What it might look like

[CtrlAltDevelop]

Thanks for the detailed write-up — I went through each point against the code.
All five are addressed.

1. Few data points + gridColumns → points squashed together

Confirmed, and it followed from the layout model. Candle x positions came from a
fixed pointWidth (getX(i) = i * pointWidth + pointWidth/2) and the total data
length is itemCount * pointWidth, while the grid is drawn across the full plot
width. So a dozen intraday points occupied a narrow strip on the left while the
grid spanned everything.

There is now a fit-to-width mode:

chartStyle: ChartStyle(fitContent: true),

A series too short to fill the plot is spread across the whole of it, and the
candle and volume bars widen with it so they keep their proportions. The spacing
is worked out from the chart's own width, so nothing in your code has to know
how wide it ended up. It only ever widens: a series long enough to fill the
plot, or one zoomed in past it, is laid out on pointWidth as before, so the
flag can stay on while history pages in.

2. lockPriceScale: true + a tick price outside the locked range

A real bug, and fixed. drawHorizontalLines drew at getMainY(line.price) with
no clamp and no clip around the main pane, so an out-of-range price was painted
over the volume and indicator panes, or off the canvas entirely.

A line at a price the axis cannot reach is now left out of the plot, and its
label is pinned to the edge the price went past and marked with an arrow, so the
level is still findable rather than silently gone. The same clamp covers the
current-price line, the signal lines and the trading tags — those were clamped
to the window's high and low, which under a locked axis are not the axis's
extremes, so they escaped too. That is most likely the "tick price" you saw.

3. Should the price axis follow the data when lockPriceScale is true?

The lock exists precisely so the axis does not move while you scroll or while
live ticks arrive — that is what makes reading a level off it stable — so that
stays the default. Keeping the market on screen is now available alongside it:

lockPriceScale: true,
lockedScaleFollowsPrice: true,

The locked range grows just enough to keep the newest candle on the chart, and
never shrinks back or refits to the window, so the axis still sits still while
you scroll. Only the newest candle counts, and only while it is in view: growing
the axis to swallow the history a scroll moves over would undo the lock a little
at a time. KChartController.resetPriceScale() still refits and re-locks, and
is what a chart switching instruments should call.

4. Custom formatting of the price and time axis values

The time axis takes dateFormatter. The price axis had only fixedLength, so a
currency symbol, a thousands separator or a tick size had nowhere to go. Its
counterpart now exists:

priceFormatter: (price) => NumberFormat.currency(symbol: r'$').format(price),

It writes every price the chart itself says: the axis labels, the crosshair's
price label, the current-price tag, the high, low and signal tags, and the OHLC
legend. An axis that reads out a move rather than a price writes that move
itself and does not ask. Drawings keep their own title.

5. A second vertical axis, e.g. "change %"

Reading the axis as a percentage has its own scale, which the crosshair's price
label and the current-price tag follow too:

priceAxisScale: PriceAxisScale.percentage,

And for price and change % at the same time, there is now a second axis:

secondaryPriceAxisScale: PriceAxisScale.percentage,
chartStyle: ChartStyle(priceAxisWidth: 56, secondaryPriceAxisWidth: 56),

It sits in a gutter on the side verticalTextAlignment left free, and marks its
own round values — +2%, +4%, +6% — rather than labelling whatever percentages
the round prices work out at. The grid stays ruled by the price axis, and the
crosshair and the price tags keep following priceAxisScale. The two gutters
are clamped against each other, so between them they can never take more than
half the chart's width.

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The example app has a toggle for each of these, and the intraday demo uses
fitContent rather than working the spacing out by hand.

Really useful feedback — thank you. Have a good one.