Zoom problem in v2011

[Jamie]

Hi

There seems to be a problem with the zoom function in v2011. I display a chart with around 1500 bars and allow the user to zoom in using the mouse, in the standard fashion but restricted to horizontal zoom only.

This is how it used to look in v8 (zoomed in to show 2 out of 30 days) :-

This is how the v8 zoom looked

Old Zoom.jpg (205.32 KiB) Viewed 10929 times

This is how it looks in v2011 (also showing approx 2 out of 30 days) :-

This is how it looks in v2011

New Zoom.jpg (286.87 KiB) Viewed 10912 times

Is there a way to change this behaviour?

Regards,
Jamie

[Yeray]

Hello Jamie,

You could try setting (being Series1 your TBarSeries):

Code: Select all

Series1.AutoBarSize:=true;

[Jamie]

Hi Yeray

Thanks, that seems to have improved the situation.

The effect is not exactly what I was after (either before zoom or during), as I wanted the bars to be drawn without gaps, but it is much better than setting the bar width to 100% (as I was before).

Regards,
Jamie

[Yeray]

Hello Jamie,

Another option you could try would be using THistogramSeries instead of TBarSeries. Have you tried it?

[Jamie]

Hi Yeray

Thanks, no I hadn't tried it. I have now.

It almost does the trick. With the LinesPen visible it looks better than the bar series for several of the charts drawn (and the zoom is fine). Unfortunately the number of points varies considerably in this application and with large numbers of points it either becomes obvious that the bars are of different widths (which appear to overlap) or the pen seems to hide the bar colour. These effects seem less obvious with the bar series.

I'll stick with the bars in this instance, but thank you for pointing out that the histogram is a viable alternative in some instances. I will almost certainly use it sometime in the future.

Regards,
Jamie

[Yeray]

Hello Jamie,

Taking another look to this, I've observed some problems with BarWidthPercent that seem to be introduced with the quite big modifications applied to the Bar series in the v2010.02.

1. The Bars may look superposed.
2. If you zoom, the bars become separated. If you have a lot of bars, AutoBarSize=true fixes the problem for moderated zooms.
3. If you set AutoBarSize=true, the problems above still happen with a few bars, and a new one appears: if you scroll the chart, the bars become thinner and separated.

These problems are less evident with a lot of bars, so in your case you may not be very affected for them, but I've added them to the defect list to be fixed in future releases (TV52015681).

[Toreba]

Hi,

Has this been fixed in TeeChart 2011.04.41118? I don't think it is mentioned in the release notes.

Toreba

[Yeray]

Hi,

I confirm it hasn't been fixed yet.

[Toreba]

Hi,

Do you have any news yet on plans to fix this? Users are complaining! TeeChart is a wonderful product, so bugs like this really catch the eye and disappoint!

Thanks

Toreba

[Yeray]

Hi Toreba,

This is bug priority is quite high in the list but the time until we can fix it also depends on other variables such as the complexity of the problem, the study of the possible collateral damages, the number of issues with even higher priority that claims our team attention,...

I recommend you to be aware at this forum, our RSS news feed, twitter and facebook accounts for new release announcements and what's implemented on them.