tachart/tutorials/mandelbrot

[kiyo]

I am using Windows version .
have compiled the following project:
C:/lazarus/components/tachart/tutorials/mandelbrot
however
Zoom with mouse left-drag does not work.
Please let me know the cause and solution.

[wp]

Thanks for reporting. It seems that something broke it between v2.2.6 and v3.0.0...

[EDIT]
Found it - it was caused by some optimization more than two years ago. Is fixed in Laz/main and /fixes (i.e. will be included in v.4.2). If you want to fix your current version open file tagraph.pas from folder components/tachart of your Lazarus installation. Find the implementation of TChart.SetLogicalExtent. Insert "FOldClipRect := ZeroRect" before the line "FLogicalExtent := AValue"

Code: Pascal  [Select][+][-]

1. procedure TChart.SetLogicalExtent(AValue: TDoubleRect);
2. var
3.   AllowChange: Boolean;
4.   w, h: Double;
5. begin
6.   [...]
7.   if FLogicalExtent = AValue then exit;
8.   w := Abs(AValue.a.X - AValue.b.X);
9.   h := Abs(AValue.a.Y - AValue.b.Y);
10.   with ExtentSizeLimit do
11.     if
12.       UseXMin and (w < XMin) or UseXMax and (w > XMax) or
13.       UseYMin and (h < YMin) or UseYMax and (h > YMax)
14.     then
15.       exit;
16.   FOldClipRect := ZeroRect;
17.   FLogicalExtent := AValue;
18.   FIsZoomed := true;
19.   StyleChanged(Self);
20. end;

Then do the same in TChart.ZoomFull:

Code: Pascal  [Select][+][-]

1. procedure TChart.ZoomFull(AImmediateRecalc: Boolean);
2. begin
3.   if AImmediateRecalc then
4.     FLogicalExtent := GetFullExtent;
5.   if not FIsZoomed then exit;
6.   FIsZoomed := false;
7.   FOldClipRect := ZeroRect;
8.   Invalidate;
9. end;  

[kiyo]

Thank you for your prompt response
I confirmed that the issue has been resolved in Lazarus 4.0.