Steema Central

Posted: **Mon Feb 15, 2010 2:50 pm**

I have been tinkering with the TDBChart and have some questions I was unable to find in either the online help or on the board.

1) I have created a TDBChart at runtime, placed it on a panel which I have given some width and height values, and have set the chart's alignment to alClient. After I have populated the dataset with values and added series accordingly I would like to have the chart resize in both 3D mode as well as in 2D mode to fit both legend and chart in on screen. However after I display the chart the chart is zoomed in so far that I only see approx 20% of the chart. I have found out that by using TDBChart.View3DOptions.Zoomfactor I can alter the visible area but I was hoping this could be done automatically since all the charts that need to be displayed have different sets of series/data/ranges etc.

2) Why is the gradient of a chart ( TDBChart.Gradient ) overruled by a greyish colour when I like to set a gradient from yellow to white? When I set the gradient from yellow to red or any other color than white the gradient shows correctly but using white as a terminal color transforms the gradient into a greyish endpoint.

Code: Select all

    mDBChart.Gradient.Visible := True;
    mDBChart.Gradient.StartColor := lColor; // Some colour
    mDBChart.Gradient.EndColor := $FFFFFF; // White
    mDBChart.Gradient.Direction := gdDiagonalDown;

In 2D this will go from some color to grey and in 3D mode this gradient displays correctly.

Thanks in advance.

Posted: **Mon Feb 15, 2010 3:31 pm**

Hi Michael,

1. This is very strange. I wouldn't expect this to happen. Can you please attach a simple example project we can run "as-is" to reproduce the problem here?

2. It works fine for me here using this code:

Code: Select all

uses TeCanvas, TeeJPEG;

procedure TForm4.FormCreate(Sender: TObject);
begin
  Chart1.Gradient.Visible := True;
  Chart1.Gradient.StartColor := RGB(120, 34, 123); // Some colour
  Chart1.Gradient.EndColor := $FFFFFF; // White
  Chart1.Gradient.Direction:= gdDiagonalDown;

  Chart1.View3D:=false;
end;

That's what I get in 2D and 3D using our latest v8 sources:

: 2D chart; 2DGradient.jpg (19.26 KiB) Viewed 8532 times

: 3D chart; 3DGradient.jpg (20.01 KiB) Viewed 8548 times

Which Teechart version are you using? Can you post an image of what you get?

Thanks in advance.

Posted: **Mon Feb 15, 2010 3:55 pm**

I am using the version Build 8.06.60902 taken from the release.txt
I am currently trying to reproduce this in a version without the use of devexpress components but still with runtime created TDBCharts.
I will post my example as soon as possible/

Posted: **Tue Feb 16, 2010 8:19 am**

After making a standard application I found out that without a TeeOpenGL component attached to the Chart, the chart will paint just fine (will show entire chart and legend/lines/axes correctly). However when I add the TeeOpenGL to the chart this will somehow make the chart viewing area incorrect.
When I set the TeeOpenGL to inactive the chart is painted correctly and the background gradient is painted correctly as well. When I reactivate the TeeOpenGL the chart is painted incorrectly. Somehow the viewing area is incorrectly determined when using the component.
Do I need to install a specific version of OpenGL or other software to make this work?

Posted: **Tue Feb 16, 2010 9:45 am**

Hi Michael,

I'm not sure if some graphic cards with better OpenGL built-in capabilities would handle this. Anyway, I think this is a bug which I have added to the defect list (TV52014687) to be fixed for future releases.

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