SIGFPE when moving mouse over newly created chart
lazarus / 55-TAChart

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CM630 · 2012-09-14 10:23

Probably I should send this to the bugzilla?
Here is a problem, that occurs in later versions of Lazarus (it does
not exists in Build 38237 with FPC 2,6,1 but exists in version 38648,
fpc. 2,6,1 (Windows XP)).
So if you run the example and press the button on the right and you do
not move the mouse some curves will appear. But if after pressing the
button you start moving thje mouse over the left area of the form
(where the curves are shown), the app will crash.

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Ask · 2012-09-14 11:10

Thanks for your report -- TAChart does not (yet) have many users,
so every tester is very valuable.

To increase the effect of your contributions, please try to give your
messages more meaningful subjects -- for example,
I have edited the subject of this topic so that future users searching
for the
same or similar problem may be able to find it.

QuoteProbably I should send this to the bugzilla?In this specific case
it is unnecessary, since I have already fixed the bug.
However, if you have (or will have) some bugs or feature requests
which take a long time to fix/implement, then it is a good idea to add
them
to bugtracker so that they will not be forgotten.

Please test r38651.

Looking at your demo, I notice that you wrote HorizontalSync procedure
yourself
instead of using TChartExtentLink component -- why?

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CM630 · 2012-09-17 06:02

Quote from: Ask on September 14, 2012, 01:10:17 pmThanks for your
report -- TAChart does not (yet) have many users, so every tester is
very valuable.
It would make a nice OCX, though I personally will have no benefit
from that.

Quote from: Ask on September 14, 2012, 01:10:17 pm...please try to
give your messages more meaningful subjects...I tried to, but anyway I
thought that it crashed while populating the data in the charts, so I
would have mislead you, if I had done so.

Quote from: Ask on September 14, 2012, 01:10:17 pmPlease test r38651.
Now it does not crash, thank you!

Quote from: Ask on September 14, 2012, 01:10:17 pmLooking at your
demo, I notice that you wrote HorizontalSync procedure yourself
instead of using TChartExtentLink component -- why?
I had no idea, that it existed, thought when I googled it for
documentation I found out, that you have already recommended it to me.

Anyway, I could not find how to use dynamically. So I have:
Quotechartextentlink1.linkedcharts.addAdd takes no parameters. I
sought a property for chartextentlink1.linkedcharts.items[0] but I
found nothing suitable. What shall I do?

BTW, I found that Chart1.Logicalextent.coords is read only. Just to
let you know, if this is not done on purpose.

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Ask · 2012-09-17 08:23

Quotechartextentlink1.linkedcharts.addAs usual for the TCollection,
Add returns newly added item.
It was TCollectionItem, so required a cast.

For convenience, I overridden it in r38711 -- you can now write
Code: [Select]ChartExtentLink1.LinkedCharts.Add.Chart := MyChart;
QuoteBTW, I found that Chart1.LogicalExtent.coords is read only.It is
a feature not of TAChart, but of FPC compiler, see
http://wiki.freepascal.org/User_Changes_2.4.0#Treating_direct-
mapped_properties_as_regular_fields

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CM630 · 2012-09-21 08:17

IMHO, ChartExtentLink1.LinkedCharts.Add.Chart(mychart) or
ChartExtentLink1.LinkedCharts.AddChart(mychart) is better, it will be
similar to
Series.add (myseries);

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Ask · 2012-09-21 11:25

Ok, added ChartExtentLink1.AddChart in r38782