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TAChart: Fix SIGFPE on very small charts.

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git-svn-id: trunk@19706 -
This commit is contained in:
ask 2009-04-30 09:03:17 +00:00
parent 469effabc4
commit c4221ad3ac
1 changed files with 38 additions and 34 deletions
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72
components/tachart/tagraph.pas
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@ -434,41 +434,45 @@ begin
end;
procedure TChart.CalculateTransformationCoeffs(const AMargin: TRect);
var
lo, hi: Integer;
type
TConvFunc = function (AX: Integer): Double of object;
procedure CalcOneCoord(
AInverted: boolean; AConv: TConvFunc; var AGraphMin, AGraphMax: Double;
AImageLo, AImageHi, AMarginLo, AMarginHi, ASign: Integer;
out AScale, AOffset: Double);
var
lo, hi: Integer;
begin
lo := AImageLo + AMarginLo;
hi := AImageHi + AMarginHi;
if (AGraphMax = AGraphMin) or (Sign(hi - lo) <> ASign) then begin
AScale := 1;
AOffset := 0;
exit;
end;
if AInverted then
Exchange(lo, hi);
AScale := (hi - lo) / (AGraphMax - AGraphMin);
AOffset := hi - AScale * AGraphMax;
AGraphMin := AConv(AImageLo);
AGraphMax := AConv(AImageHi);;
if AInverted then
Exchange(AGraphMin, AGraphMax);
end;
begin
if XGraphMax <> XGraphMin then begin
lo := FClipRect.Left + AMargin.Left;
hi := FClipRect.Right - AMargin.Right;
if BottomAxis.Inverted then
Exchange(lo, hi);
FScale.X := (hi - lo) / (XGraphMax - XGraphMin);
FOffset.X := hi - FScale.X * XGraphMax;
FCurrentExtent.a.X := XImageToGraph(FClipRect.Left);
FCurrentExtent.b.X := XImageToGraph(FClipRect.Right);
if BottomAxis.Inverted then
Exchange(FCurrentExtent.a.X, FCurrentExtent.b.X);
end
else begin
FScale.X := 1;
FOffset.X := 0;
end;
if YGraphMax <> YGraphMin then begin
lo := FClipRect.Bottom - AMargin.Bottom;
hi := FClipRect.Top + AMargin.Top;
if LeftAxis.Inverted then
Exchange(lo, hi);
FScale.Y := (hi - lo) / (YGraphMax - YGraphMin);
FOffset.Y := hi - FScale.Y * YGraphMax;
FCurrentExtent.a.Y := YImageToGraph(FClipRect.Bottom);
FCurrentExtent.b.Y := YImageToGraph(FClipRect.Top);
if LeftAxis.Inverted then
Exchange(FCurrentExtent.a.Y, FCurrentExtent.b.Y);
end
else begin
FScale.Y := 1;
FOffset.Y := 0;
end;
CalcOneCoord(
BottomAxis.Inverted, @XImageToGraph, FCurrentExtent.a.X, FCurrentExtent.b.X,
FClipRect.Left, FClipRect.Right, AMargin.Left, -AMargin.Right, 1,
FScale.X, FOffset.X);
CalcOneCoord(
LeftAxis.Inverted, @YImageToGraph, FCurrentExtent.a.Y, FCurrentExtent.b.Y,
FClipRect.Bottom, FClipRect.Top, -AMargin.Bottom, AMargin.Top, -1,
FScale.Y, FOffset.Y);
end;
procedure TChart.Clean(ACanvas: TCanvas; ARect: TRect);