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Chart features


mengpps

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Hi, everyone;

We have to come back and evaluate NET chart controls again. We need to implement some chart features, and find problems in using the chart controls of some vendors.

Here they are:

1. Selection Drawing

We want to allow the user to draw a mark on the chart. In particular, when the user clicks a data point, a triangle mark is drawn  on the chart to label the clicked position. We do not want to use annotation in this case, instead we want to have a direct access to graphics API, so we can draw any graphics we like on the top of the chart at runtime.

2. Annotation

We evaluated Dundas chart, which provides a proprietary techniques called FastLine. which allows data intense chart be painted much faster. This is nice, but annotation does not work within the context of FastLine.

However, without FastLine, to draw a line chart consits of dozens of thousands of points is not only time consuming, but very very slow when a user click a point in the chart to see the point value. In Delph version, to draw a dozens of thousands of points in the chart, and add annotations on it is quite efficient, and point clicking is quite responsive.

 

3. Change X Axis value type from double to date time  at runtime.

In Dundas chart, it takes quite bit effort to achieve this. We need not only clear all series in the chart, but the chart areas as well, it seems a bit overacting. Since we have a work around solution, this is not our top concen now.

Can ChartFx  address those mentioned above? Thanks for your kindly input.

 

Meng

 

 

 

 

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> 1. Selection Drawing

You can achieve this by either changing the attributes of the point clicked (e.g. Changing Marker Shape, size or color), by using annotation objects (why not?) and you also have access to the graphics of the chart using the PrePaint and PostPaint events.

> 2. Annotation

If you get rid of the gradients and elaborated marker shapes, you will get a performance similar of that you obtained in Chart FX for Delphi.

 > 3. Change X Axis value type from double to date time  at runtime.

No problem. You can change the format at any time using the API.

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