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lazutils: EllipsePolygon sincos

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This commit is contained in:
mattias 2023-07-11 17:46:16 +02:00
parent c423a794b5
commit 347b49bbf3
1 changed files with 10 additions and 7 deletions
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17
components/lazutils/graphmath.pp
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@ -796,7 +796,7 @@ function EllipsePolygon(const aRect: TRect): TPointArray;
var
n_points, i, n4, aLeft, aRight, aTop, aBottom: Integer;
Xc, Yc, a, b, MaxR, t: single;
AX, AY, BX, BY, CX, CY, Deviation: single;
SinT, CosT, AX, AY, BX, BY, CX, CY, Deviation: single;
begin
Xc:=single(aRect.Left+aRect.Right)/2;
Yc:=single(aRect.Top+aRect.Bottom)/2;
@ -811,10 +811,12 @@ begin
repeat
inc(n_points,4);
t := single(1) / single(n_points) * 2 * Pi;
AX := MaxR * cos(t);
AY := MaxR * sin(t);
BX := MaxR * cos(t/2);
BY := MaxR * sin(t/2);
SinCos(t,SinT,CosT);
AX := MaxR * CosT;
AY := MaxR * SinT;
SinCos(t/2,SinT,CosT);
BX := MaxR * CosT;
BY := MaxR * SinT;
CX := (AX + MaxR) /2;
CY := (AY + 0) /2;
Deviation := sqrt(sqr(BX-CX)+sqr(BY-CY));
@ -828,9 +830,10 @@ begin
for i := 0 to n4 do
begin
t := single(i) / single(n_points) * 2 * Pi;
aRight := Round(Xc + a * cos(t));
SinCos(t,SinT,CosT);
aRight := Round(Xc + a * CosT);
aLeft := Trunc(2*Xc - aRight);
aTop := Round(Yc + b * sin(t));
aTop := Round(Yc + b * SinT);
aBottom := Trunc(2*Yc - aTop);
Result[i].X := aRight;
Result[i].Y := aTop;