[Lazarus] TAChart marks on mouseoverpoint

[Alexander Klenin]

On Wed, Sep 23, 2009 at 20:58, Andrea Mauri <andrea.mauri.75 at gmail.com> wrote:
>
>> Do you have some concrete proposal to reduce overlapping?
> Looking at TeeChart from Steema (an old version, Delphi 6 ;) ) I noticed two
> things.
> 1. Marks are drawn over the points (the serie) and not below.
Currently, they are drawn below points with negative Y and above others.
This is intended to reduce clutter, and is absolutely required for
bar series -- but maybe it was not a good idea for line series, I am not sure.

> 2. There is "Clipped" property for Marks. If Clipped is true the marks
> behave as Marks on TAChart (they are visible only inside the Chart Axis).
> Otherwise if Clipped is False the marks are visible also outside the Chart
> Axis. See image below.
It seems you forgot to attach the image.
Anyway, implemented Marks.Clipped in r21840.

> 3. An option could be that the marks can be dragged...
This is not easy to do correctly and effectively, so patches are welcome ;-)

> Another option I like in Steema Chart is the possibility to have Panel
> properties (BevelInner, BevelOuter...) But it is not a so important thing,
> actually I put the TAChart on a panel to do that.
I think it is better this way -- the chart component is already overcrowded
with it's own properties, there is no need to add ones from Panel too

>> Do you mean to create something like
>> http://www.steema.com/products/teechart/screenshots/infopoint3dpolaradar.htm ?
>> If so, you are very welcome to contribute your code back to the TAChart
> Actually I just need to draw a Principal Component Analysis Loading Plot.
> That is not a polar chart, it is a simple scatter plot where as an option a
> unitary circle can be drawn and the rays from the center to the points can
> be drawn also.
I see. This is a borderline case, probably too exotic to be included
in the general component.
Still, if you have inclination to work on a patch, I would suggest to change
TLineSeries.ShowLines property from boolean to enumeration
(slNone, slFromPrevious, slFromOrigin).

> Anyway I would like to contribute to the development of TAChart. Now I am
> just using it and trying to understand it looking at the source. I am a
> final user and I am not sure I have the capabilities to contribute on a
> development basis.. we'll see. :)
Meaningful feedback is very useful too, so you have already
contributed in a small way.

-- 
Alexander S. Klenin