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Bug 687

Summary:	TColorLineTool seems to blend its color with the series drawn
Product:	VCL TeeChart	Reporter:	yeray alonso <yeray>
Component:	Tools	Assignee:	Steema Issue Manager <issuemanager>
Status:	CONFIRMED ---
Severity:	enhancement	CC:	david
Priority:	---
Version:	140220
Target Milestone:	---
Hardware:	PC
OS:	Windows
URL:	http://www.teechart.net/support/viewtopic.php?f=1&t=14811
Chart Series:	---	Delphi / C++ Builder RAD IDE Version:
Attachments:	colorline blend

Description yeray alonso 2014-03-31 06:57:12 EDT

Created attachment 144 [details]
colorline blend

TColorLineTool seems to blend its color with the series drawn.
See the example below and the image attached

uses Series, TeeTools;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Chart1.View3D:=false;

  Chart1.Axes.Left.Grid.Visible:=false;
  Chart1.Axes.Bottom.Grid.Visible:=false;

  with Chart1.AddSeries(TBarSeries) do
  begin
    Color:=clRed;
    Pen.Width:=5;
    AddArray([10,20,10,20]);
  end;

  with Chart1.AddSeries(TLineSeries) do
  begin
    Color:=clBlue;
    Pen.Width:=5;
    AddArray([20,10,20,10]);
  end;

  with Chart1.Tools.Add(TColorLineTool) as TColorLineTool do
  begin
    Pen.Color:=clRed;
    Pen.Width:=5;
    Axis:=Chart1.Axes.Left;
    Value:=18;
  end;
end;

Comment 1 david berneda 2014-03-31 11:52:31 EDT

I think this is as designed. When the cursor tool FullRepaint is False, the only way to avoid repainting the whole chart is by using "xor" painting mode, which blends foreground and background colors.

Setting FullRepaint:=True will repaint the whole chart at every cursor drag movement, without doing the "xor" color blending.

Note: Firemonkey does not support "xor" painting, so every time all tools repaint the whole chart (FullRepaint is always True).

In VCL, GDI supports xor painting natively, but with GDI+ canvas we're using an internal GDI canvas to do it.  OpenGL does not support xor painting.

The FullRepaint reason is speed. If you have a one-million series chart and a cursor tool, moving the cursor will take a lot of time if the chart has to be fully repainted.