number of ticks or tick frequency

[cssesuc]

Dear support,
I am trying to fix the maximal number of ticks of the y axis for the attached plot for instance.
Is there some simple approach I could use here to control the number of ticks?
thanks in advance for the feedback.

[Narcís]

Dear Nabil,

Yes, you can do that using axis Increment property. You'll find more info about that in tutorial 4.

[cssesuc]

Hi,
the issue I have here is that I would need to figure out some algorithm to compute the increment value.
Is there some other solution I could use here instead?
thanks

[Yeray]

Hello,

Is there some other solution I could use here instead?

TeeChart by default tries to calculate an increment to show the labels preventing the overlapping.
However, if you are using custom labels you should do this job. Some tips that may help you:

- Chart height. This is the height of the are where the series can be drawn:

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  tmpH:=Chart1.ChartRect.Bottom - Chart1.ChartRect.Top;

- Font height for the left axis labels:

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  Chart1.Canvas.Font.Assign(Chart1.Axes.Left.LabelsFont);
  tmpFontH:=Chart1.Canvas.TextHeight('Wj');

- To transform axis values to pixel screen coordinates:

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  tmpPos:=Chart1.Axes.Left.CalcPosValue(tmpValue);

- To transform pixel screen coortinates to axis values:

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  tmpValue:=Chart1.Axes.Left.CalcPosPoint(tmpPos);

[cssesuc]

hI?
many thanks for the prompt reply. Indeed I am not using custom labels. Could it be simply that in my case, since I am using log scale, the algorithm which computes the "optimal spacing " between two consecutive labels is not working.
thanks

[cssesuc]

Hi,
I might have replied too quickly here... What I understand from your email is the following
I need to compute:
1- the size in pixels for the Chart:
2- the number of items for the left axis
3- get the size in pixels of one of the items of the left axis,
I believe one could simply use:
TAxisItem(Chart1.LeftAxis.Items.First).Format.Height; or ???
4- compute the total size of all these items
5- if this size exceeds the size computed at step 1, then remove items from the left axis (or remove their label)
6- iterate until the computed size is smaller than the chart size
does this sound feasible with the 2013 release ?
And my second question: at which "event" do you advise me to implement this algorithm if you think it could work.
thanks

[Yeray]

Hi,

3- get the size in pixels of one of the items of the left axis,
I believe one could simply use:
TAxisItem(Chart1.LeftAxis.Items.First).Format.Height; or ???

This takes the first axis item. If it exists I don't see any problem with using it.

4- compute the total size of all these items
5- if this size exceeds the size computed at step 1, then remove items from the left axis (or remove their label)
6- iterate until the computed size is smaller than the chart size
does this sound feasible with the 2013 release ?

The idea was a bit different.
I was thinking on clearing all the labels and adding those you want calculating how many can fit given the chart height and the labels height.
Your approach is also valid. I would use OnGetAxisLabel event to hide those you don't want, setting an empty LabelText string in that event.

Take a look at the examples at "All features\Welcome !\Axes\Labels\Custom Labels" and at "All features\Welcome !\Chart styles\Financial\Candle (OHLC)\Axis Labels no Weekends" to see simple examples of how to use Custom Labels and OnGetAxisLabel event respectively.
These examples are in the New Features Demo shipped with the binary installation.

[cssesuc]

OK, many thanks for the hint. I will digest your inputs and get back to you.